glsl учебник
Начало работы с glsl
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замечания
В этом разделе представлен обзор того, что такое glsl, и почему разработчик может захотеть его использовать.
Следует также упомянуть о любых крупных предметах в glsl и ссылаться на связанные темы. Поскольку документация для glsl нова, вам может потребоваться создать начальные версии этих связанных тем.
Версии
Язык затенения OpenGL
| Версия GLSL | Версия OpenGL | Препроцессор шейдеров | Дата выхода |
|---|---|---|---|
| 1,10 | 2,0 | #version 110 | 2004-09-07 |
| 1,20 | 2,1 | #version 120 | 2006-07-02 |
| 1,30 | 3.0 | #version 130 | 2008-08-11 |
| 1,40 | 3,1 | #version 140 | 2009-03-24 |
| 1,50 | 3,2 | #version 150 | 2009-08-03 |
| 3.30 | 3,3 | #version 330 | 2010-02-12 |
| 4,00 | 4,0 | #version 400 | 2010-03-11 |
| 4,10 | 4,1 | #version 410 | 2010-07-26 |
| 4,20 | 4,2 | #version 420 | 2011-08-08 |
| 4,30 | 4,3 | #version 430 | 2012-08-06 |
| 4,40 | 4,4 | #version 440 | 2013-07-22 |
| 4,50 | 4.5 | #version 450 | 2014-08-11 |
Язык затенения OpenGL ES
| Версия GLSL ES | Версия OpenGL ES | Препроцессор шейдеров | Дата выхода |
|---|---|---|---|
| 1.00 ES | 2,0 | #version 100 | 2007-03-05 |
| 3,00 ES | 3.0 | #version 300 es | 2012-08-06 |
| 3.10 ES | 3,1 | #version 310 es | 2014-03-17 |
| 3.20 ES | 3,2 | #version 320 es | 2015-08-10 |
Установка или настройка
Подробные инструкции по установке или установке glsl.
Первая шейдерная программа OGL 4.0 GLSL
Простая программа шейдеров OGL 4.0 GLSL с атрибутом вершин и атрибутом цвета. Программа выполняется с помощью phyton-скрипта. Чтобы запустить скрипт, необходимо установить PyOpenGL.
Шейдерная программа состоит по крайней мере из вершинного шейдера и фрагментарного шейдера (за исключением компьютерных шейдеров). 1-й этап шейдера - это вершинный шейдер, а последний этап шейдера - это фрагмент-шейдер (между ними возможны дополнительные этапы, которые далее не описаны).
Вершинный шейдер
first.vet
Вершинный шейдер обрабатывает вершины и связанные с ними атрибуты, заданные командой рисования. Вершинный шейдер обрабатывает вершины из входного потока и может манипулировать им любым желаемым способом. Вершинный шейдер получает одну единственную вершину из входного потока и генерирует одну единственную вершину в выходной поток вершин.
В нашем примере мы рисуем один треугольник, поэтому вершинный шейдер выполняется 3 раза, один раз для каждой угловой точки треугольника. В этом случае вход в вершинный шейдер является вершинной позицией in vec3 inPos и атрибутом цвета in vec3 inCol . Атрибуты цвета передаются на следующую стадию шейдера ( out vec3 vertCol ).
#version 400
layout (location = 0) in vec3 inPos;
layout (location = 1) in vec3 inCol;
out vec3 vertCol;
void main()
{
vertCol = inCol;
gl_Position = vec4( inPos, 1.0 );
}
Фрагментный шейдер
first.frag
В этом примере шейдер фрагмента следует сразу после вершинного шейдера. Позиции и атрибуты вершины интерполируются в каждом лице для каждого фрагмента. Шейдер фрагмента выполняется один раз для каждого фрагмента на всем треугольнике и получает атрибут цвета из шейдера frgment. Поскольку треугольник рисуется, атрибут цвета интерполируется в соответствии с барицентрическими координатами фрагмента на основе рисованного треугольника.
#version 400
in vec3 vertCol;
out vec4 fragColor;
void main()
{
fragColor = vec4( vertCol, 1.0 );
}
Скрипт Phyton
Сценарий python - это просто компилировать, связывать и выполнять программу шейдеров и рисовать геометрию. Его можно было бы тривиально переписать на C или что-нибудь еще. Это не та часть этой документации, которой нужно уделять наибольшее внимание.
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
from sys import *
from array import array
# draw event
def OnDraw():
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glUseProgram( shaderProgram )
glBindVertexArray( vaObj )
glDrawArrays( GL_TRIANGLES, 0, 3 )
glutSwapBuffers()
# read vertex shader program
with open( 'first.vert', 'r' ) as vertFile:
vertCode = vertFile.read()
print( '\nvertex shader code:' )
print( vertCode )
# read fragment shader program
with open( 'first.frag', 'r' ) as fragFile:
fragCode = fragFile.read()
print( '\nfragment shader code:' )
print( fragCode )
# initialize glut
glutInit()
# create window
wndW = 800
wndH = 600
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
glutInitWindowPosition(0, 0)
glutInitWindowSize(wndW, wndH)
wndID = glutCreateWindow(b'OGL window')
glutDisplayFunc(OnDraw)
glutIdleFunc(OnDraw)
# define triangle data
posData = [ -0.636, -0.45, 0.0, 0.636, -0.45, 0.0, 0.0, 0.9, 0.0 ]
colData = [ 1.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0 ]
posAr = array( "f", posData )
colAr = array( "f", colData )
# create buffers
posBuffer = glGenBuffers(1)
glBindBuffer( GL_ARRAY_BUFFER, posBuffer )
glBufferData( GL_ARRAY_BUFFER, posAr.tostring(), GL_STATIC_DRAW )
colBuffer = glGenBuffers(1)
glBindBuffer( GL_ARRAY_BUFFER, colBuffer )
glBufferData( GL_ARRAY_BUFFER, colAr.tostring(), GL_STATIC_DRAW )
# create vertex array opject
vaObj = glGenVertexArrays( 1 )
glBindVertexArray( vaObj )
glEnableVertexAttribArray( 0 )
glEnableVertexAttribArray( 1 )
glBindBuffer( GL_ARRAY_BUFFER, posBuffer )
glVertexAttribPointer( 0, 3, GL_FLOAT, GL_FALSE, 0, None )
glBindBuffer( GL_ARRAY_BUFFER, colBuffer )
glVertexAttribPointer( 1, 3, GL_FLOAT, GL_FALSE, 0, None )
# compile vertex shader
vertShader = glCreateShader( GL_VERTEX_SHADER )
glShaderSource( vertShader, vertCode )
glCompileShader( vertShader )
result = glGetShaderiv( vertShader, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( vertShader ) )
sys.exit()
# compile fragment shader
fragShader = glCreateShader( GL_FRAGMENT_SHADER )
glShaderSource( fragShader, fragCode )
glCompileShader( fragShader )
result = glGetShaderiv( fragShader, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( fragShader ) )
sys.exit()
# link shader program
shaderProgram = glCreateProgram()
glAttachShader( shaderProgram, vertShader )
glAttachShader( shaderProgram, fragShader )
glLinkProgram( shaderProgram )
result = glGetProgramiv( shaderProgram, GL_LINK_STATUS )
if not (result):
print( 'link error:' )
print( glGetProgramInfoLog( shaderProgram ) )
sys.exit()
# start main loop
glutMainLoop()
Использование матрицы Model, View и Projection в OGL 4.0 GLSL
Простая программа шейдеров OGL 4.0 GLSL, которая показывает использование матрицы модели, представления и проекции. Программа выполняется с помощью phyton-скрипта. Для запуска скрипта необходимо установить PyOpenGL и NumPy.
Матрица проецирования: матрица проекции описывает отображение камеры-обскуры из трехмерных точек в мире на двумерные точки окна просмотра. В этом примере мы используем проекционную матрицу с полем обзора 90 градусов.
Матрица просмотра: матрица вида определяет положение глаза и направление просмотра на сцене. В этом примере мы движемся вокруг сцены, сохраняя направление просмотра в центр сцены.
Модельная матрица: матрица модели определяет местоположение и относительный размер объекта в сцене. В этом примере модельные матрицы перемещают объекты вверх и вниз.
Вершинный шейдер
mvp.vet
#version 400
layout (location = 0) in vec3 inPos;
layout (location = 1) in vec3 inCol;
out vec3 vertCol;
uniform mat4 projectionMat44;
uniform mat4 viewMat44;
uniform mat4 modelMat44;
void main()
{
vertCol = inCol;
vec4 modolPos = modelMat44 * vec4( inPos, 1.0 );
vec4 viewPos = viewMat44 * modolPos;
gl_Position = projectionMat44 * viewPos;
}
Фрагментный шейдер
mvp.frag
#version 400
in vec3 vertCol;
out vec4 fragColor;
void main()
{
fragColor = vec4( vertCol, 1.0 );
}
Скрипт Phyton
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy as np
from time import time
import math
import sys
# draw event
def OnDraw():
currentTime = time()
# set up projection matrix
prjMat = perspective( 90.0, wndW/wndH, 0.5, 100.0)
# set up view matrix
viewMat = Translate( np.matrix(np.identity(4), copy=False, dtype='float32'), np.array( [0.0, 0.0, -8.0] ) )
viewMat = RotateView( viewMat, [10.0, CalcAng( currentTime, 10.0 ), 0.0] )
# set up tetrahedron model matrix
tetModelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
tetModelMat = RotateX( tetModelMat, -90.0 )
tetModelMat = Scale( tetModelMat, np.repeat( 2.0, 3 ) )
tetModelMat = Translate( tetModelMat, np.array( [-2.0, 0.0, CalcMove(currentTime, 6.0, [-1.0, 1.0])] ) )
# set up icosahedron model matrix
icoModelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
icoModelMat = RotateX( icoModelMat, -90.0 )
icoModelMat = Scale( icoModelMat, np.repeat( 2.0, 3 ) )
icoModelMat = Translate( icoModelMat, np.array( [2.0, 0.0, CalcMove(currentTime, 6.0, [1.0, -1.0])] ) )
# set up attributes and shader program
glEnable( GL_DEPTH_TEST )
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glUseProgram( shaderProgram )
glUniformMatrix4fv( projectionMatLocation, 1, GL_FALSE, prjMat )
glUniformMatrix4fv( viewMatLocation, 1, GL_FALSE, viewMat )
# draw tetrahedron
glUniformMatrix4fv( modelMatLocation, 1, GL_FALSE, tetModelMat )
glBindVertexArray( tetVAObj )
glDrawElements(GL_TRIANGLES, len(tetIndices), GL_UNSIGNED_INT, tetIndices)
# draw tetrahedron
glUniformMatrix4fv( modelMatLocation, 1, GL_FALSE, icoModelMat )
glBindVertexArray( icoVAObj )
glDrawArrays( GL_TRIANGLES, 0, len(icoPosData) )
glutSwapBuffers()
def Fract(val): return val - math.trunc(val)
def CalcAng(currentTime, intervall): return Fract( (currentTime - startTime) / intervall ) * 360.0
def CalcMove(currentTime, intervall, range):
pos = Fract( (currentTime - startTime) / intervall ) * 2.0
pos = pos if pos < 1.0 else (2.0-pos)
return range[0] + (range[1] - range[0]) * pos
# read shader program and compile shader
def CompileShader( sourceFileName, shaderStage ):
with open( sourceFileName, 'r' ) as sourceFile:
sourceCode = sourceFile.read()
nameMap = { GL_VERTEX_SHADER: 'vertex', GL_FRAGMENT_SHADER: 'fragment' }
print( '\n%s shader code:' % nameMap.get(shaderStage, '') )
print( sourceCode )
shaderObj = glCreateShader( shaderStage )
glShaderSource( shaderObj, sourceCode )
glCompileShader( shaderObj )
result = glGetShaderiv( shaderObj, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( shaderObj ) )
sys.exit()
return shaderObj
# linke shader objects to shader program
def LinkProgram( shaderObjs ):
shaderProgram = glCreateProgram()
for shObj in shaderObjs:
glAttachShader( shaderProgram, shObj )
glLinkProgram( shaderProgram )
result = glGetProgramiv( shaderProgram, GL_LINK_STATUS )
if not (result):
print( 'link error:' )
print( glGetProgramInfoLog( shaderProgram ) )
sys.exit()
return shaderProgram
# create vertex array opject
def CreateVAO( dataArrays ):
noOfBuffers = len(dataArrays)
buffers = glGenBuffers(noOfBuffers)
newVAObj = glGenVertexArrays( 1 )
glBindVertexArray( newVAObj )
for inx in range(0, noOfBuffers):
vertexSize, dataArr = dataArrays[inx]
arr = np.array( dataArr, dtype='float32' )
glBindBuffer( GL_ARRAY_BUFFER, buffers[inx] )
glBufferData( GL_ARRAY_BUFFER, arr, GL_STATIC_DRAW )
glEnableVertexAttribArray( inx )
glVertexAttribPointer( inx, vertexSize, GL_FLOAT, GL_FALSE, 0, None )
return newVAObj
def Translate(matA, trans):
matB = np.copy(matA)
for i in range(0, 4): matB[3,i] = matA[0,i] * trans[0] + matA[1,i] * trans[1] + matA[2,i] * trans[2] + matA[3,i]
return matB
def Scale(matA, s):
matB = np.copy(matA)
for i0 in range(0, 3):
for i1 in range(0, 4): matB[i0,i1] = matA[i0,i1] * s[i0]
return matB
def RotateHlp(matA, angDeg, a0, a1):
matB = np.copy(matA)
ang = math.radians(angDeg)
sinAng, cosAng = math.sin(ang), math.cos(ang)
for i in range(0, 4):
matB[a0,i] = matA[a0,i] * cosAng + matA[a1,i] * sinAng
matB[a1,i] = matA[a0,i] * -sinAng + matA[a1,i] * cosAng
return matB
def RotateX(matA, angDeg): return RotateHlp(matA, angDeg, 1, 2)
def RotateY(matA, angDeg): return RotateHlp(matA, angDeg, 2, 0)
def RotateZ(matA, angDeg): return RotateHlp(matA, angDeg, 0, 1)
def RotateView(matA, angDeg): return RotateZ(RotateY(RotateX(matA, angDeg[0]), angDeg[1]), angDeg[2])
def perspective(fov, aspectRatio, near, far):
fn, f_n = far + near, far - near
r, t = aspectRatio, 1.0 / math.tan( math.radians(fov) / 2.0 )
return np.matrix( [ [t/r,0,0,0], [0,t,0,0], [0,0,-fn/f_n,-2.0*far*near/f_n], [0,0,-1,0] ] )
# initialize glut
glutInit()
# create window
wndW, wndH = 800, 600
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
glutInitWindowPosition(0, 0)
glutInitWindowSize(wndW, wndH)
wndID = glutCreateWindow(b'OGL window')
glutDisplayFunc(OnDraw)
glutIdleFunc(OnDraw)
# define tetrahedron vertex array opject
sin120 = 0.8660254
tetPposData = [ 0.0, 0.0, 1.0, 0.0, -sin120, -0.5, sin120 * sin120, 0.5 * sin120, -0.5, -sin120 * sin120, 0.5 * sin120, -0.5 ]
tetColData = [ 1.0, 0.0, 0.0, 1.0, 1.0, 0.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, ]
tetIndices = [ 0, 1, 2, 0, 2, 3, 0, 3, 1, 1, 3, 2 ]
tetVAObj = CreateVAO( [ (3, tetPposData), (3, tetColData) ] )
tetInxArr = np.array( tetIndices, dtype='uint' )
# define icosahedron vertex array opject
icoPts = [
[ 0.000, 0.000, 1.000], [ 0.894, 0.000, 0.447], [ 0.276, 0.851, 0.447], [-0.724, 0.526, 0.447],
[-0.724, -0.526, 0.447], [ 0.276, -0.851, 0.447], [ 0.724, 0.526, -0.447], [-0.276, 0.851, -0.447],
[-0.894, 0.000, -0.447], [-0.276, -0.851, -0.447], [ 0.724, -0.526, -0.447], [ 0.000, 0.000, -1.000] ]
icoCol = [ [1.0, 0.0, 0.0], [0.0, 0.0, 1.0], [1.0, 1.0, 0.0], [0.0, 1.0, 0.0], [1.0, 0.5, 0.0], [1.0, 0.0, 1.0] ]
icoIndices = [
2, 0, 1, 3, 0, 2, 4, 0, 3, 5, 0, 4, 1, 0, 5, 11, 7, 6, 11, 8, 7, 11, 9, 8, 11, 10, 9, 11, 6, 10,
1, 6, 2, 2, 7, 3, 3, 8, 4, 4, 9, 5, 5, 10, 1, 2, 6, 7, 3, 7, 8, 4, 8, 9, 5, 9, 10, 1, 10, 6 ]
icoPosData = []
for inx in icoIndices:
for inx_s in range(0, 3):
icoPosData.append( icoPts[inx][inx_s] )
icoColData = []
for inx in range(0, len(icoPosData) // 9):
inx_col = inx % len(icoCol)
for inx_p in range(0, 3):
for inx_s in range(0, 3):
icoColData.append( icoCol[inx_col][inx_s] )
icoVAObj = CreateVAO( [ (3, icoPosData), (3, icoColData) ] )
# load, compile and link shader
shaderProgram = LinkProgram( [
CompileShader( 'mvp.vert', GL_VERTEX_SHADER ),
CompileShader( 'mvp.frag', GL_FRAGMENT_SHADER )
] )
projectionMatLocation = glGetUniformLocation(shaderProgram, "projectionMat44")
viewMatLocation = glGetUniformLocation(shaderProgram, "viewMat44")
modelMatLocation = glGetUniformLocation(shaderProgram, "modelMat44")
# start main loop
startTime = time()
glutMainLoop()
Поместите текстуру на модель и используйте текстурную матрицу в OGL 4.0 GLSL
Простая программа OGL 4.0 GLSL shader, которая показывает, как сопоставить 2D-текстуру на сетке. Программа выполняется с помощью phyton-скрипта. Для запуска скрипта необходимо установить PyOpenGL и NumPy.
Матрица текстуры определяет, как текстура отображается на сетке. Управляя текстурной матрицей, текстуру можно смещать, масштабировать и поворачивать.
Вершинный шейдер
tex.vert
#version 400
layout (location = 0) in vec3 inPos;
layout (location = 1) in vec2 inTex;
out vec2 vertTex;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
uniform mat4 u_textureMat44;
void main()
{
vertTex = ( u_textureMat44 * vec4( inTex, 0.0, 1.0 ) ).st;
vec4 modolPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 viewPos = u_viewMat44 * modolPos;
gl_Position = u_projectionMat44 * viewPos;
}
Фрагментный шейдер
tex.frag
#version 400
in vec2 vertTex;
out vec4 fragColor;
uniform sampler2D u_texture;
void main()
{
vec4 texCol = texture( u_texture, vertTex.st );
fragColor = vec4( texCol.rgb, 1.0 );
}
Скрипт Phyton
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy as np
from time import time
import math
import sys
# draw event
def OnDraw():
currentTime = time()
# set up projection matrix
prjMat = perspective( 90.0, wndW/wndH, 0.5, 100.0)
# set up view matrix
viewMat = Translate( np.matrix(np.identity(4), copy=False, dtype='float32'), np.array( [0.0, 0.0, -15.0] ) )
viewMat = RotateView( viewMat, [30.0, CalcAng( currentTime, 60.0 ), 0.0] )
# set up tetrahedron model matrix
cubeModelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
cubeModelMat = RotateX( cubeModelMat, -90.0 )
cubeModelMat = Scale( cubeModelMat, np.repeat( 5.0, 3 ) )
# set up texture matrix
texMat = np.matrix(np.identity(4), copy=False, dtype='float32')
deltaT = Fract( (currentTime - startTime) / 28.0 ) * 28.0
if deltaT < 7.0 or deltaT >= 21.0:
texMat = Scale( texMat, np.repeat( CalcMove(currentTime, 7.0, [1.0, 2.0]), 3 ) )
if deltaT >= 7.0 and deltaT < 14.0 or deltaT >= 21.0:
transAng = math.radians( CalcAng(currentTime, 7.0) )
texMat = Translate( texMat, np.array( [math.sin(transAng)*0.5, math.cos(transAng)*0.5-0.5, 0.0] ) )
if deltaT >= 14.0:
texMat = RotateZ( texMat, CalcAng(currentTime, 7.0) )
# set up attributes and shader program
glEnable( GL_DEPTH_TEST )
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glUseProgram( shaderProgram )
glUniformMatrix4fv( projectionMatLocation, 1, GL_FALSE, prjMat )
glUniformMatrix4fv( viewMatLocation, 1, GL_FALSE, viewMat )
glUniformMatrix4fv( textureMatLocation, 1, GL_FALSE, texMat )
glUniform1i( textureLocation, 0 )
# draw cube
glUniformMatrix4fv( modelMatLocation, 1, GL_FALSE, cubeModelMat )
glBindVertexArray( cubeVAObj )
glDrawElements(GL_TRIANGLES, len(cubeIndices), GL_UNSIGNED_INT, cubeIndices)
glutSwapBuffers()
def Fract(val): return val - math.trunc(val)
def CalcAng(currentTime, intervall): return Fract( (currentTime - startTime) / intervall ) * 360.0
def CalcMove(currentTime, intervall, range):
pos = Fract( (currentTime - startTime) / intervall ) * 2.0
pos = pos if pos < 1.0 else (2.0-pos)
return range[0] + (range[1] - range[0]) * pos
# read shader program and compile shader
def CompileShader( sourceFileName, shaderStage ):
with open( sourceFileName, 'r' ) as sourceFile:
sourceCode = sourceFile.read()
nameMap = { GL_VERTEX_SHADER: 'vertex', GL_FRAGMENT_SHADER: 'fragment' }
print( '\n%s shader code:' % nameMap.get(shaderStage, '') )
print( sourceCode )
shaderObj = glCreateShader( shaderStage )
glShaderSource( shaderObj, sourceCode )
glCompileShader( shaderObj )
result = glGetShaderiv( shaderObj, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( shaderObj ) )
sys.exit()
return shaderObj
# linke shader objects to shader program
def LinkProgram( shaderObjs ):
shaderProgram = glCreateProgram()
for shObj in shaderObjs:
glAttachShader( shaderProgram, shObj )
glLinkProgram( shaderProgram )
result = glGetProgramiv( shaderProgram, GL_LINK_STATUS )
if not (result):
print( 'link error:' )
print( glGetProgramInfoLog( shaderProgram ) )
sys.exit()
return shaderProgram
# create vertex array object
def CreateVAO( dataArrays ):
noOfBuffers = len(dataArrays)
buffers = glGenBuffers(noOfBuffers)
newVAObj = glGenVertexArrays( 1 )
glBindVertexArray( newVAObj )
for inx in range(0, noOfBuffers):
vertexSize, dataArr = dataArrays[inx]
arr = np.array( dataArr, dtype='float32' )
glBindBuffer( GL_ARRAY_BUFFER, buffers[inx] )
glBufferData( GL_ARRAY_BUFFER, arr, GL_STATIC_DRAW )
glEnableVertexAttribArray( inx )
glVertexAttribPointer( inx, vertexSize, GL_FLOAT, GL_FALSE, 0, None )
return newVAObj
def Translate(matA, trans):
matB = np.copy(matA)
for i in range(0, 4): matB[3,i] = matA[0,i] * trans[0] + matA[1,i] * trans[1] + matA[2,i] * trans[2] + matA[3,i]
return matB
def Scale(matA, s):
matB = np.copy(matA)
for i0 in range(0, 3):
for i1 in range(0, 4): matB[i0,i1] = matA[i0,i1] * s[i0]
return matB
def RotateHlp(matA, angDeg, a0, a1):
matB = np.copy(matA)
ang = math.radians(angDeg)
sinAng, cosAng = math.sin(ang), math.cos(ang)
for i in range(0, 4):
matB[a0,i] = matA[a0,i] * cosAng + matA[a1,i] * sinAng
matB[a1,i] = matA[a0,i] * -sinAng + matA[a1,i] * cosAng
return matB
def RotateX(matA, angDeg): return RotateHlp(matA, angDeg, 1, 2)
def RotateY(matA, angDeg): return RotateHlp(matA, angDeg, 2, 0)
def RotateZ(matA, angDeg): return RotateHlp(matA, angDeg, 0, 1)
def RotateView(matA, angDeg): return RotateZ(RotateY(RotateX(matA, angDeg[0]), angDeg[1]), angDeg[2])
def perspective(fov, aspectRatio, near, far):
fn, f_n = far + near, far - near
r, t = aspectRatio, 1.0 / math.tan( math.radians(fov) / 2.0 )
return np.matrix( [ [t/r,0,0,0], [0,t,0,0], [0,0,-fn/f_n,-2.0*far*near/f_n], [0,0,-1,0] ] )
# initialize glut
glutInit()
# create window
wndW, wndH = 800, 600
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
glutInitWindowPosition(0, 0)
glutInitWindowSize(wndW, wndH)
wndID = glutCreateWindow(b'OGL window')
glutDisplayFunc(OnDraw)
glutIdleFunc(OnDraw)
# define cube vertex array opject
icoPts = [
[-1.0, -1.0, 1.0], [ 1.0, -1.0, 1.0], [ 1.0, 1.0, 1.0], [-1.0, 1.0, 1.0],
[-1.0, -1.0, -1.0], [ 1.0, -1.0, -1.0], [ 1.0, 1.0, -1.0], [-1.0, 1.0, -1.0] ]
cubePosData = []
for inx in [ 0, 1, 2, 3, 1, 5, 6, 2, 5, 4, 7, 6, 4, 0, 3, 7, 3, 2, 6, 7, 1, 0, 4, 5 ]:
for inx_s in range(0, 3): cubePosData.append( icoPts[inx][inx_s] )
cubeTexData = []
for inx in range(0, 6):
for texCoord in [-0.5, -0.5, 0.5, -0.5, 0.5, 0.5, -0.5, 0.5]: cubeTexData.append( texCoord )
icoCol = [ [1.0, 0.0, 0.0], [1.0, 0.5, 0.0], [1.0, 0.0, 1.0], [1.0, 1.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0] ]
cubeIndices = []
for inx in range(0, 6):
for inx_s in [0, 1, 2, 0, 2, 3]: cubeIndices.append( inx * 4 + inx_s )
cubeVAObj = CreateVAO( [ (3, cubePosData), (2, cubeTexData) ] )
cubeInxArr = np.array( cubeIndices, dtype='uint' )
# load, compile and link shader
shaderProgram = LinkProgram( [
CompileShader( 'python/ogl4tex/tex.vert', GL_VERTEX_SHADER ),
CompileShader( 'python/ogl4tex/tex.frag', GL_FRAGMENT_SHADER )
] )
projectionMatLocation = glGetUniformLocation(shaderProgram, "u_projectionMat44")
viewMatLocation = glGetUniformLocation(shaderProgram, "u_viewMat44")
modelMatLocation = glGetUniformLocation(shaderProgram, "u_modelMat44")
textureMatLocation = glGetUniformLocation(shaderProgram, "u_textureMat44")
textureLocation = glGetUniformLocation(shaderProgram, "u_texture")
# create texture
texCX, texCY = 128, 128
texPlan = np.zeros( texCX * texCY * 4, dtype=np.uint8 )
for inx_x in range(0, texCX):
for inx_y in range(0, texCY):
val_x = math.sin( math.pi * 6.0 * inx_x / texCX )
val_y = math.sin( math.pi * 6.0 * inx_y / texCY )
inx_tex = inx_y * texCX * 4 + inx_x * 4
texPlan[inx_tex + 0] = int( 128 + 127 * val_x )
texPlan[inx_tex + 1] = 63
texPlan[inx_tex + 2] = int( 128 + 127 * val_y )
texPlan[inx_tex + 3] = 255
glActiveTexture( GL_TEXTURE0 )
texObj = glGenTextures( 1 )
glBindTexture( GL_TEXTURE_2D, texObj )
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texCX, texCY, 0, GL_RGBA, GL_UNSIGNED_BYTE, texPlan)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
# start main loop
startTime = time()
glutMainLoop()
Использование блока интерфейса и единого блока: модель света Cook-Torrance в OGL 4.0 GLSL
Простая программа шейдеров шейдеров OGL 4.0 GLSL, которая показывает использование блока интерфейса и единый блок для реализации модели света с микрофоном Cook-Torrance. Программа выполняется с помощью phyton-скрипта. Для запуска скрипта необходимо установить PyOpenGL и NumPy.
Интерфейсный блок представляет собой группу входных, выходных, равномерных или буферных переменных GLSL. Равномерное Blockis является блоком интерфейса с хранением спецификатором uniform .
Вершинный шейдер
ibub.vert
#version 400
layout (location = 0) in vec3 inPos;
layout (location = 1) in vec3 inNV;
layout (location = 2) in vec3 inCol;
out TVertexData
{
vec3 pos;
vec3 nv;
vec3 col;
} outData;
uniform mat4 u_projectionMat44;
uniform mat4 u_modelViewMat44;
uniform mat3 u_normalMat33;
void main()
{
vec4 viewPos = u_modelViewMat44 * vec4( inPos, 1.0 );
outData.pos = viewPos.xyz / viewPos.w;
outData.nv = u_normalMat33 * normalize( inNV );
outData.col = inCol;
gl_Position = u_projectionMat44 * viewPos;
}
Фрагментный шейдер
ibub.frag
#version 400
in TVertexData
{
vec3 pos;
vec3 nv;
vec3 col;
} inData;
out vec4 fragColor;
uniform UB_material
{
float u_roughness;
float u_fresnel0;
vec4 u_specularTint;
};
struct TLightSource
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec4 dir;
};
uniform UB_lightSource
{
TLightSource u_lightSource;
};
vec3 CookTorrance( vec3 esPt, vec3 esPtNV, vec3 col, vec4 specularTint, float roughness, float fresnel0 )
{
vec3 esVLight = normalize( -u_lightSource.dir.xyz );
vec3 esVEye = normalize( -esPt );
vec3 halfVector = normalize( esVEye + esVLight );
vec3 reflVector = normalize( reflect( -esVLight, esPtNV ) );
float VdotR = dot( esVEye, reflVector );
float HdotL = dot( halfVector, esVLight );
float NdotL = dot( esPtNV, esVLight );
float NdotV = dot( esPtNV, esVEye );
float NdotH = dot( esPtNV, halfVector );
float NdotH2 = NdotH * NdotH;
float NdotL_clamped = max( NdotL, 0.0 );
float NdotV_clamped = max( NdotV, 0.0 );
float m2 = roughness * roughness;
// Lambertian diffuse
float k_diffuse = NdotL_clamped;
// Cook-Torrance fresnel
float theta = HdotL;
float n = (1.0 + sqrt(fresnel0)) / (1.0 - sqrt(fresnel0));
float g = sqrt( n*n + theta * theta + 1.0 );
float gc = g + theta;
float g_c = g - theta;
float q = (gc * theta - 1.0) / (g_c * theta + 1.0);
float fresnel = 0.5 * (g_c * g_c) / (gc * gc) * (1.0 + q * q);
// Gaussian distribution
float psi = acos( VdotR );
float distribution = max( 0.0, HdotL * exp( - psi * psi / m2 ) );
// Torrance-Sparrow geometric term
float geometric_att = min( 1.0, min( 2.0 * NdotH * NdotV_clamped / HdotL, 2.0 * NdotH * NdotL_clamped / HdotL ) );
// Microfacet bidirectional reflectance distribution function
float brdf_spec = fresnel * distribution * geometric_att / ( 4.0 * NdotL_clamped * NdotV_clamped );
float k_specular = brdf_spec;
vec3 lightColor = col.rgb * u_lightSource.ambient.rgb
+ max( 0.0, k_diffuse ) * col.rgb * u_lightSource.diffuse.rgb +
+ max( 0.0, k_specular ) * mix( col.rgb, specularTint.rgb, specularTint.a ) * u_lightSource.specular.rgb;
return lightColor;
}
void main()
{
vec3 lightCol = CookTorrance( inData.pos, inData.nv, inData.col, u_specularTint, u_roughness, u_fresnel0 );
fragColor = vec4( lightCol, 1.0 );
}
Скрипт Phyton
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy as np
from time import time
import math
import sys
sin120 = 0.8660254
rotateCamera = False
# draw event
def OnDraw():
dist = 3.0
currentTime = time()
comeraRotAng = CalcAng( currentTime, 10.0 )
# set up projection matrix
prjMat = Perspective(90.0, wndW/wndH, 0.5, 100.0)
# set up view matrix
viewMat = Translate( np.matrix(np.identity(4), copy=False, dtype='float32'), np.array( [0.0, 0.0, -12.0] ) )
viewMat = RotateView( viewMat, [30.0, comeraRotAng if rotateCamera else 0.0, 0.0] )
# set up light source
lightSourceBuffer.BindDataFloat(b'u_lightSource.dir', TransformVec4([-3.0, -2.0, -1.0, 0.0], viewMat) )
# set up tetrahedron model matrix
tetModelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
if not rotateCamera: tetModelMat = RotateY( tetModelMat, comeraRotAng )
tetModelMat = RotateX( tetModelMat, -90.0 )
tetModelMat = Scale( tetModelMat, np.repeat( 2.4, 3 ) )
tetModelMat = Translate( tetModelMat, np.array( [0.0, dist, 0.0] ) )
tetModelMat = RotateY( tetModelMat, CalcAng( currentTime, 20.0 ) )
tetModelMat = RotateX( tetModelMat, CalcAng( currentTime, 9.0 ) )
# set up icosahedron model matrix
icoModelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
if not rotateCamera: icoModelMat = RotateY( icoModelMat, comeraRotAng )
icoModelMat = RotateX( icoModelMat, -90.0 )
icoModelMat = Scale( icoModelMat, np.repeat( 2.0, 3 ) )
icoModelMat = Translate( icoModelMat, np.array( [dist * -sin120, dist * -0.5, 0.0] ) )
icoModelMat = RotateY( icoModelMat, CalcAng( currentTime, 20.0 ) )
icoModelMat = RotateX( icoModelMat, CalcAng( currentTime, 11.0 ) )
# set up cube model matrix
cubeModelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
if not rotateCamera: cubeModelMat = RotateY( cubeModelMat, comeraRotAng )
cubeModelMat = RotateX( cubeModelMat, -90.0 )
cubeModelMat = Scale( cubeModelMat, np.repeat( 1.6, 3 ) )
cubeModelMat = Translate( cubeModelMat, np.array( [dist * sin120, dist * -0.5, 0.0] ) )
cubeModelMat = RotateY( cubeModelMat, CalcAng( currentTime, 20.0 ) )
cubeModelMat = RotateX( cubeModelMat, CalcAng( currentTime, 13.0 ) )
# set up attributes and shader program
glEnable( GL_DEPTH_TEST )
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glUseProgram( shaderProgram )
glUniformMatrix4fv( projectionMatLocation, 1, GL_FALSE, prjMat )
lightSourceBuffer.BindToTarget()
# draw tetrahedron
tetMaterialBuffer.BindToTarget()
modelViewMat = Multiply(viewMat, tetModelMat)
glUniformMatrix4fv( modelViewMatLocation, 1, GL_FALSE, modelViewMat )
glUniformMatrix3fv( normalMatLocation, 1, GL_FALSE, ToMat33(modelViewMat) )
glBindVertexArray( tetVAObj )
glDrawArrays( GL_TRIANGLES, 0, len(tetPosData) )
# draw icosahedron
icoMaterialBuffer.BindToTarget()
modelViewMat = Multiply(viewMat, icoModelMat)
glUniformMatrix4fv( modelViewMatLocation, 1, GL_FALSE, modelViewMat )
glUniformMatrix3fv( normalMatLocation, 1, GL_FALSE, ToMat33(modelViewMat) )
glBindVertexArray( icoVAObj )
glDrawArrays( GL_TRIANGLES, 0, len(icoPosData) )
# draw cube
cubeMaterialBuffer.BindToTarget()
modelViewMat = Multiply(viewMat, cubeModelMat)
glUniformMatrix4fv( modelViewMatLocation, 1, GL_FALSE, modelViewMat )
glUniformMatrix3fv( normalMatLocation, 1, GL_FALSE, ToMat33(modelViewMat) )
glBindVertexArray( cubeVAObj )
glDrawElements(GL_TRIANGLES, len(cubeIndices), GL_UNSIGNED_INT, cubeIndices)
glutSwapBuffers()
def Fract(val): return val - math.trunc(val)
def CalcAng(currentTime, intervall): return Fract( (currentTime - startTime) / intervall ) * 360.0
def CalcMove(currentTime, intervall, range):
pos = Fract( (currentTime - startTime) / intervall ) * 2.0
pos = pos if pos < 1.0 else (2.0-pos)
return range[0] + (range[1] - range[0]) * pos
# read shader program and compile shader
def CompileShader( sourceFileName, shaderStage ):
with open( sourceFileName, 'r' ) as sourceFile:
sourceCode = sourceFile.read()
nameMap = { GL_VERTEX_SHADER: 'vertex', GL_FRAGMENT_SHADER: 'fragment' }
print( '\n%s shader code:' % nameMap.get(shaderStage, '') )
print( sourceCode )
shaderObj = glCreateShader( shaderStage )
glShaderSource( shaderObj, sourceCode )
glCompileShader( shaderObj )
result = glGetShaderiv( shaderObj, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( shaderObj ) )
sys.exit()
return shaderObj
# linke shader objects to shader program
def LinkProgram( shaderObjs ):
shaderProgram = glCreateProgram()
for shObj in shaderObjs:
glAttachShader( shaderProgram, shObj )
glLinkProgram( shaderProgram )
result = glGetProgramiv( shaderProgram, GL_LINK_STATUS )
if not (result):
print( 'link error:' )
print( glGetProgramInfoLog( shaderProgram ) )
sys.exit()
return shaderProgram
# create vertex array object
def CreateVAO( dataArrays ):
noOfBuffers = len(dataArrays)
buffers = glGenBuffers(noOfBuffers)
newVAObj = glGenVertexArrays( 1 )
glBindVertexArray( newVAObj )
for inx in range(0, noOfBuffers):
vertexSize, dataArr = dataArrays[inx]
arr = np.array( dataArr, dtype='float32' )
glBindBuffer( GL_ARRAY_BUFFER, buffers[inx] )
glBufferData( GL_ARRAY_BUFFER, arr, GL_STATIC_DRAW )
glEnableVertexAttribArray( inx )
glVertexAttribPointer( inx, vertexSize, GL_FLOAT, GL_FALSE, 0, None )
return newVAObj
# representation of a uniform block
class UniformBlock:
def __init__(self, shaderProg, name):
self.shaderProg = shaderProg
self.name = name
def Link(self, bindingPoint):
self.bindingPoint = bindingPoint
self.noOfUniforms = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORMS)
self.maxUniformNameLen = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORM_MAX_LENGTH)
self.index = glGetUniformBlockIndex(self.shaderProg, self.name)
intData = np.zeros(1, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, intData)
self.count = intData[0]
self.indices = np.zeros(self.count, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, self.indices)
self.offsets = np.zeros(self.count, dtype=int)
glGetActiveUniformsiv(self.shaderProg, self.count, self.indices, GL_UNIFORM_OFFSET, self.offsets)
self.size = 0
strLengthData = np.zeros(1, dtype=int)
arraysizeData = np.zeros(1, dtype=int)
typeData = np.zeros(1, dtype='uint32')
nameData = np.chararray(self.maxUniformNameLen+1)
self.namemap = {}
self.dataSize = 0
for inx in range(0, len(self.indices)):
glGetActiveUniform( self.shaderProg, self.indices[inx], self.maxUniformNameLen, strLengthData, arraysizeData, typeData, nameData.data )
name = nameData.tostring()[:strLengthData[0]]
self.namemap[name] = inx
self.dataSize = max(self.dataSize, self.offsets[inx] + arraysizeData * 16)
glUniformBlockBinding(self.shaderProg, self.index, self.bindingPoint)
print('\nuniform block %s size:%4d' % (self.name, self.dataSize))
for uName in self.namemap:
print( ' %-40s index:%2d offset:%4d' % (uName, self.indices[self.namemap[uName]], self.offsets [self.namemap[uName]]) )
# representation of a uniform block buffer
class UniformBlockBuffer:
def __init__(self, ub):
self.namemap = ub.namemap
self.offsets = ub.offsets
self.bindingPoint = ub.bindingPoint
self.object = glGenBuffers(1)
self.dataSize = ub.dataSize
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.zeros(self.dataSize//4, dtype='float32')
glBufferData(GL_UNIFORM_BUFFER, self.dataSize, dataArray, GL_DYNAMIC_DRAW)
def BindToTarget(self):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
glBindBufferBase(GL_UNIFORM_BUFFER, self.bindingPoint, self.object)
def BindDataFloat(self, name, dataArr):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.array(dataArr, dtype='float32')
glBufferSubData(GL_UNIFORM_BUFFER, self.offsets[self.namemap[name]], len(dataArr)*4, dataArray)
def Translate(matA, trans):
matB = np.copy(matA)
for i in range(0, 4): matB[3,i] = matA[0,i] * trans[0] + matA[1,i] * trans[1] + matA[2,i] * trans[2] + matA[3,i]
return matB
def Scale(matA, s):
matB = np.copy(matA)
for i0 in range(0, 3):
for i1 in range(0, 4): matB[i0,i1] = matA[i0,i1] * s[i0]
return matB
def RotateHlp(matA, angDeg, a0, a1):
matB = np.copy(matA)
ang = math.radians(angDeg)
sinAng, cosAng = math.sin(ang), math.cos(ang)
for i in range(0, 4):
matB[a0,i] = matA[a0,i] * cosAng + matA[a1,i] * sinAng
matB[a1,i] = matA[a0,i] * -sinAng + matA[a1,i] * cosAng
return matB
def RotateX(matA, angDeg): return RotateHlp(matA, angDeg, 1, 2)
def RotateY(matA, angDeg): return RotateHlp(matA, angDeg, 2, 0)
def RotateZ(matA, angDeg): return RotateHlp(matA, angDeg, 0, 1)
def RotateView(matA, angDeg): return RotateZ(RotateY(RotateX(matA, angDeg[0]), angDeg[1]), angDeg[2])
def Multiply(matA, matB):
matC = np.copy(matA)
for i0 in range(0, 4):
for i1 in range(0, 4):
matC[i0,i1] = matB[i0,0] * matA[0,i1] + matB[i0,1] * matA[1,i1] + matB[i0,2] * matA[2,i1] + matB[i0,3] * matA [3,i1]
return matC
def ToMat33(mat44):
mat33 = np.matrix(np.identity(3), copy=False, dtype='float32')
for i0 in range(0, 3):
for i1 in range(0, 3): mat33[i0, i1] = mat44[i0, i1]
return mat33
def TransformVec4(vecA,mat44):
vecB = np.zeros(4, dtype='float32')
for i0 in range(0, 4):
vecB[i0] = vecA[0] * mat44[0,i0] + vecA[1] * mat44[1,i0] + vecA[2] * mat44[2,i0] + vecA[3] * mat44[3,i0]
return vecB
def Perspective(fov, aspectRatio, near, far):
fn, f_n = far + near, far - near
r, t = aspectRatio, 1.0 / math.tan( math.radians(fov) / 2.0 )
return np.matrix( [ [t/r,0,0,0], [0,t,0,0], [0,0,-fn/f_n,-2.0*far*near/f_n], [0,0,-1,0] ] )
def AddToBuffer( buffer, data, count=1 ):
for inx_c in range(0, count):
for inx_s in range(0, len(data)): buffer.append( data[inx_s] )
# initialize glut
glutInit()
# create window
wndW, wndH = 800, 600
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
glutInitWindowPosition(0, 0)
glutInitWindowSize(wndW, wndH)
wndID = glutCreateWindow(b'OGL window')
glutDisplayFunc(OnDraw)
glutIdleFunc(OnDraw)
# define tetrahedron vertex array opject
tetPts = [ (0.0, 0.0, 1.0), (0.0, -sin120, -0.5), (sin120 * sin120, 0.5 * sin120, -0.5), (-sin120 * sin120, 0.5 * sin120, -0.5) ]
tetCol = [ [1.0, 0.0, 0.0], [1.0, 1.0, 0.0], [0.0, 0.0, 1.0], [0.0, 1.0, 0.0], ]
tetInxdices = [ 0, 1, 2, 0, 2, 3, 0, 3, 1, 1, 3, 2 ]
tetPosData = []
for inx in tetInxdices: AddToBuffer( tetPosData, tetPts[inx] )
tetNVData = []
for inx_nv in range(0, len(tetInxdices) // 3):
nv = [0.0, 0.0, 0.0]
for inx_p in range(0, 3):
for inx_s in range(0, 3): nv[inx_s] += tetPts[ tetInxdices[inx_nv*3 + inx_p] ][inx_s]
AddToBuffer( tetNVData, nv, 3 )
tetColData = []
for inx_col in range(0, len(tetInxdices) // 3): AddToBuffer( tetColData, tetCol[inx_col % len(tetCol)], 3 )
tetVAObj = CreateVAO( [ (3, tetPosData), (3, tetNVData), (3, tetColData) ] )
# define icosahedron vertex array opject
icoPts = [
( 0.000, 0.000, 1.000), ( 0.894, 0.000, 0.447), ( 0.276, 0.851, 0.447), (-0.724, 0.526, 0.447),
(-0.724, -0.526, 0.447), ( 0.276, -0.851, 0.447), ( 0.724, 0.526, -0.447), (-0.276, 0.851, -0.447),
(-0.894, 0.000, -0.447), (-0.276, -0.851, -0.447), ( 0.724, -0.526, -0.447), ( 0.000, 0.000, -1.000) ]
icoCol = [ [1.0, 0.0, 0.0], [0.0, 0.0, 1.0], [1.0, 1.0, 0.0], [0.0, 1.0, 0.0], [1.0, 0.5, 0.0], [1.0, 0.0, 1.0] ]
icoIndices = [
2, 0, 1, 3, 0, 2, 4, 0, 3, 5, 0, 4, 1, 0, 5, 11, 7, 6, 11, 8, 7, 11, 9, 8, 11, 10, 9, 11, 6, 10,
1, 6, 2, 2, 7, 3, 3, 8, 4, 4, 9, 5, 5, 10, 1, 2, 6, 7, 3, 7, 8, 4, 8, 9, 5, 9, 10, 1, 10, 6 ]
icoPosData = []
for inx in icoIndices: AddToBuffer( icoPosData, icoPts[inx] )
icoNVData = []
for inx in icoIndices: AddToBuffer( icoNVData, icoPts[inx] )
#for inx_nv in range(0, len(icoIndices) // 3):
# nv = [0.0, 0.0, 0.0]
# for inx_p in range(0, 3):
# for inx_s in range(0, 3): nv[inx_s] += icoPts[ icoIndices[inx_nv*3 + inx_p] ][inx_s]
# AddToBuffer( icoNVData, nv, 3 )
icoColData = []
for inx_col in range(0, len(icoIndices) // 3): AddToBuffer( icoColData, icoCol[inx_col % len(icoCol)], 3 )
icoVAObj = CreateVAO( [ (3, icoPosData), (3, icoNVData), (3, icoColData) ] )
# define cube vertex array opject
cubePts = [
(-1.0, -1.0, 1.0), ( 1.0, -1.0, 1.0), ( 1.0, 1.0, 1.0), (-1.0, 1.0, 1.0),
(-1.0, -1.0, -1.0), ( 1.0, -1.0, -1.0), ( 1.0, 1.0, -1.0), (-1.0, 1.0, -1.0) ]
cubeCol = [ [1.0, 0.0, 0.0], [1.0, 0.5, 0.0], [1.0, 0.0, 1.0], [1.0, 1.0, 0.0], [0.0, 1.0, 0.0], [0.0, 0.0, 1.0] ]
cubeHlpInx = [ 0, 1, 2, 3, 1, 5, 6, 2, 5, 4, 7, 6, 4, 0, 3, 7, 3, 2, 6, 7, 1, 0, 4, 5 ]
cubePosData = []
for inx in cubeHlpInx: AddToBuffer( cubePosData, cubePts[inx] )
cubeNVData = []
for inx_nv in range(0, len(cubeHlpInx) // 4):
nv = [0.0, 0.0, 0.0]
for inx_p in range(0, 4):
for inx_s in range(0, 3): nv[inx_s] += cubePts[ cubeHlpInx[inx_nv*4 + inx_p] ][inx_s]
AddToBuffer( cubeNVData, nv, 4 )
cubeColData = []
for inx_col in range(0, 6):
AddToBuffer( cubeColData, cubeCol[inx_col % len(cubeCol)], 4 )
cubeIndices = []
for inx in range(0, 6):
for inx_s in [0, 1, 2, 0, 2, 3]: cubeIndices.append( inx * 4 + inx_s )
cubeVAObj = CreateVAO( [ (3, cubePosData), (3, cubeNVData), (3, cubeColData) ] )
# load, compile and link shader
shaderProgram = LinkProgram( [
CompileShader( 'ibub.vert', GL_VERTEX_SHADER ),
CompileShader( 'ibub.frag', GL_FRAGMENT_SHADER )
] )
# get unifor locations
projectionMatLocation = glGetUniformLocation(shaderProgram, "u_projectionMat44")
modelViewMatLocation = glGetUniformLocation(shaderProgram, "u_modelViewMat44")
normalMatLocation = glGetUniformLocation(shaderProgram, "u_normalMat33")
# linke uniform blocks
ubMaterial = UniformBlock(shaderProgram, "UB_material")
ubLightSource = UniformBlock(shaderProgram, "UB_lightSource")
ubMaterial.Link(1)
ubLightSource.Link(2)
# create uniform block buffers
lightSourceBuffer = UniformBlockBuffer(ubLightSource)
lightSourceBuffer.BindDataFloat(b'u_lightSource.ambient', [0.1, 0.1, 0.1, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.diffuse', [0.4, 0.4, 0.4, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.specular', [1.0, 1.0, 1.0, 1.0])
tetMaterialBuffer = UniformBlockBuffer(ubMaterial)
tetMaterialBuffer.BindDataFloat(b'u_roughness', [0.3])
tetMaterialBuffer.BindDataFloat(b'u_fresnel0', [0.5])
tetMaterialBuffer.BindDataFloat(b'u_specularTint',[1.0, 1.0, 1.0, 0.7])
icoMaterialBuffer = UniformBlockBuffer(ubMaterial)
icoMaterialBuffer.BindDataFloat(b'u_roughness', [0.1])
icoMaterialBuffer.BindDataFloat(b'u_fresnel0', [0.2])
icoMaterialBuffer.BindDataFloat(b'u_specularTint',[1.0, 1.0, 1.0, 0.7])
cubeMaterialBuffer = UniformBlockBuffer(ubMaterial)
cubeMaterialBuffer.BindDataFloat(b'u_roughness', [0.5])
cubeMaterialBuffer.BindDataFloat(b'u_fresnel0', [0.3])
cubeMaterialBuffer.BindDataFloat(b'u_specularTint',[1.0, 1.0, 1.0, 0.7])
# start main loop
startTime = time()
glutMainLoop()
Создание геометрии с использованием геометрического шейдера в OGL 4.0 GLSL
Простая программа шейдеров OGL 4.0 GLSL, которая показывает использование геометрических шейдеров. Программа выполняется с помощью phyton-скрипта. Для запуска скрипта необходимо установить PyOpenGL и NumPy.
В этом примере вся геометрия (цилиндр) генерируется в геометрическом шейдере.
Вершинный шейдер
geo.vert
#version 400
layout (location = 0) in vec3 inPos;
layout (location = 1) in vec3 inNormal;
layout (location = 2) in vec3 inTangent;
out TVertexData
{
mat3 orientationMat;
} outData;
void main()
{
vec3 normal = normalize( inNormal );
vec3 tangent = normalize( inTangent );
vec3 binormal = cross( tangent, normal );
outData.orientationMat = mat3( normal, cross( binormal, normal ), binormal );
gl_Position = vec4( inPos, 1.0 );
}
Геометрический шейдер
geo.geo
#version 400
layout( invocations = 3 ) in;
layout( points ) in;
layout( triangle_strip, max_vertices = 160 ) out;
in TVertexData
{
mat3 orientationMat;
} inData[];
out TGeometryData
{
vec3 pos;
vec3 nv;
vec3 col;
} outData;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
void NewVertex( in vec3 pt, in mat4 transMat )
{
vec4 viewPos = transMat * vec4( pt, 1.0 );
outData.pos = viewPos.xyz / viewPos.w;
gl_Position = u_projectionMat44 * viewPos;
EmitVertex();
}
const int circumferenceTile = 36;
void main()
{
vec4 origin = gl_in[0].gl_Position;
origin /= origin.w;
mat4 orintationMat = mat4( vec4( inData[0].orientationMat[0], 0.0 ),
vec4( inData[0].orientationMat[1], 0.0 ),
vec4( inData[0].orientationMat[2], 0.0 ),
origin );
mat4 modelViewMat = u_viewMat44 * u_modelMat44 * orintationMat;
mat3 normalMat = mat3( modelViewMat );
outData.col = vec3( 0.5, 0.7, 0.6 );
if ( gl_InvocationID == 0 ) // top of the cylinder
{
outData.nv = normalMat * vec3(0.0, 0.0, 1.0);
vec2 prevPt = vec2( 0.0, 1.0 );
for ( int inx = 1; inx <= circumferenceTile; inx += 2 )
{
float ang1 = 2.0 * 3.14159 * float(inx) / float(circumferenceTile);
float ang2 = 2.0 * 3.14159 * float(inx+1) / float(circumferenceTile);
vec2 actPt1 = vec2( sin(ang1), cos(ang1) );
vec2 actPt2 = vec2( sin(ang2), cos(ang2) );
NewVertex( vec3(prevPt.xy, 1.0), modelViewMat );
NewVertex( vec3(actPt1.xy, 1.0), modelViewMat );
NewVertex( vec3(0.0, 0.0, 1.0), modelViewMat );
NewVertex( vec3(actPt2.xy, 1.0), modelViewMat );
EndPrimitive();
prevPt = actPt2;
}
}
if ( gl_InvocationID == 1 ) // bottom of the cylinder
{
outData.nv = normalMat * vec3(0.0, 0.0, -1.0);
vec2 prevPt = vec2( 0.0, 1.0 );
for ( int inx = circumferenceTile-1; inx >= 0; inx -= 2 )
{
float ang1 = 2.0 * 3.14159 * float(inx) / float(circumferenceTile);
float ang2 = 2.0 * 3.14159 * float(inx-1) / float(circumferenceTile);
vec2 actPt1 = vec2( sin(ang1), cos(ang1) );
vec2 actPt2 = vec2( sin(ang2), cos(ang2) );
NewVertex( vec3(prevPt.xy, -1.0), modelViewMat );
NewVertex( vec3(actPt1.xy, -1.0), modelViewMat );
NewVertex( vec3(0.0, 0.0, -1.0), modelViewMat );
NewVertex( vec3(actPt2.xy, -1.0), modelViewMat );
EndPrimitive();
prevPt = actPt2;
}
}
if ( gl_InvocationID == 2 ) // hull of the cylinder
{
vec2 prevPt = vec2( 0.0, 1.0 );
for ( int inx = 1; inx <= circumferenceTile; ++ inx )
{
float ang = 2.0 * 3.14159 * float(inx) / float(circumferenceTile);
vec2 actPt = vec2( sin(ang), cos(ang) );
outData.nv = normalMat * vec3(prevPt, 0.0);
NewVertex( vec3(prevPt.xy, -1.0), modelViewMat );
outData.nv = normalMat * vec3(actPt, 0.0);
NewVertex( vec3(actPt.xy, -1.0), modelViewMat );
outData.nv = normalMat * vec3(prevPt, 0.0);
NewVertex( vec3(prevPt.xy, 1.0), modelViewMat );
outData.nv = normalMat * vec3(actPt, 0.0);
NewVertex( vec3(actPt.xy, 1.0), modelViewMat );
prevPt = actPt;
}
EndPrimitive();
}
}
Фрагментный шейдер
geo.frag
#version 400
in TGeometryData
{
vec3 pos;
vec3 nv;
vec3 col;
} inData;
out vec4 fragColor;
uniform UB_material
{
float u_roughness;
float u_fresnel0;
vec4 u_specularTint;
};
struct TLightSource
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec4 dir;
};
uniform UB_lightSource
{
TLightSource u_lightSource;
};
float Fresnel_Schlick( float theta )
{
float m = clamp( 1.0 - theta, 0.0, 1.0 );
float m2 = m * m;
return m2 * m2 * m; // pow( m, 5.0 )
}
vec3 LightModel( vec3 esPt, vec3 esPtNV, vec3 col, vec4 specularTint, float roughness, float fresnel0 )
{
vec3 esVLight = normalize( -u_lightSource.dir.xyz );
vec3 esVEye = normalize( -esPt );
vec3 halfVector = normalize( esVEye + esVLight );
float HdotL = dot( halfVector, esVLight );
float NdotL = dot( esPtNV, esVLight );
float NdotV = dot( esPtNV, esVEye );
float NdotH = dot( esPtNV, halfVector );
float NdotH2 = NdotH * NdotH;
float NdotL_clamped = max( NdotL, 0.0 );
float NdotV_clamped = max( NdotV, 0.0 );
float m2 = roughness * roughness;
// Lambertian diffuse
float k_diffuse = NdotL_clamped;
// Schlick approximation
float fresnel = fresnel0 + ( 1.0 - fresnel0 ) * Fresnel_Schlick( HdotL );
// Beckmann distribution
float distribution = max( 0.0, exp( ( NdotH2 - 1.0 ) / ( m2 * NdotH2 ) ) / ( 3.14159265 * m2 * NdotH2 * NdotH2 ) );
// Torrance-Sparrow geometric term
float geometric_att = min( 1.0, min( 2.0 * NdotH * NdotV_clamped / HdotL, 2.0 * NdotH * NdotL_clamped / HdotL ) );
// Microfacet bidirectional reflectance distribution function
float k_specular = fresnel * distribution * geometric_att / ( 4.0 * NdotL_clamped * NdotV_clamped );
vec3 lightColor = col.rgb * u_lightSource.ambient.rgb +
max( 0.0, k_diffuse ) * col.rgb * u_lightSource.diffuse.rgb +
max( 0.0, k_specular ) * mix( col.rgb, specularTint.rgb, specularTint.a ) * u_lightSource.specular.rgb;
return lightColor;
}
void main()
{
vec3 lightCol = LightModel( inData.pos, inData.nv, inData.col, u_specularTint, u_roughness, u_fresnel0 );
fragColor = vec4( clamp( lightCol, 0.0, 1.0 ), 1.0 );
}
Скрипт Phyton
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy as np
from time import time
import math
import sys
sin120 = 0.8660254
rotateCamera = False
# draw event
def OnDraw():
dist = 3.0
currentTime = time()
comeraRotAng = CalcAng( currentTime, 10.0 )
# set up projection matrix
prjMat = Perspective(90.0, wndW/wndH, 0.5, 100.0)
# set up view matrix
viewMat = np.matrix(np.identity(4), copy=False, dtype='float32')
viewMat = Translate( viewMat, np.array( [0.0, 0.0, -12.0] ) )
viewMat = RotateView( viewMat, [30.0, comeraRotAng if rotateCamera else 0.0, 0.0] )
# set up light source
lightSourceBuffer.BindDataFloat(b'u_lightSource.dir', TransformVec4([-0.1, 1.0, -5.0, 0.0], viewMat) )
# set up the model matrix
modelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
if not rotateCamera: modelMat = RotateY( modelMat, comeraRotAng )
modelMat = Scale( modelMat, np.repeat( 4, 3 ) )
#modelMat = Translate( modelMat, np.array( [0.0, 0.0, 1.0] ) )
#modelMat = RotateY( modelMat, CalcAng( currentTime, 20.0 ) )
modelMat = RotateX( modelMat, CalcAng( currentTime, 9.0 ) )
# set up attributes and shader program
glEnable( GL_DEPTH_TEST )
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glUseProgram( shaderProgram )
glUniformMatrix4fv( projectionMatLocation, 1, GL_FALSE, prjMat )
glUniformMatrix4fv( viewMatLocation, 1, GL_FALSE, viewMat )
lightSourceBuffer.BindToTarget()
# draw point
materialBuffer.BindToTarget()
glUniformMatrix4fv( modelMatLocation, 1, GL_FALSE, modelMat )
glBindVertexArray( pointVAObj )
glDrawArrays( GL_POINTS, 0, 1 )
glutSwapBuffers()
def Fract(val): return val - math.trunc(val)
def CalcAng(currentTime, intervall): return Fract( (currentTime - startTime) / intervall ) * 360.0
def CalcMove(currentTime, intervall, range):
pos = Fract( (currentTime - startTime) / intervall ) * 2.0
pos = pos if pos < 1.0 else (2.0-pos)
return range[0] + (range[1] - range[0]) * pos
# read shader program and compile shader
def CompileShader( sourceFileName, shaderStage ):
with open( sourceFileName, 'r' ) as sourceFile:
sourceCode = sourceFile.read()
nameMap = { GL_VERTEX_SHADER: 'vertex', GL_GEOMETRY_SHADER: 'geometry', GL_FRAGMENT_SHADER: 'fragment' }
print( '\n%s shader code:' % nameMap.get(shaderStage, '') )
print( sourceCode )
shaderObj = glCreateShader( shaderStage )
glShaderSource( shaderObj, sourceCode )
glCompileShader( shaderObj )
result = glGetShaderiv( shaderObj, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( shaderObj ) )
sys.exit()
return shaderObj
# linke shader objects to shader program
def LinkProgram( shaderObjs ):
shaderProgram = glCreateProgram()
for shObj in shaderObjs:
glAttachShader( shaderProgram, shObj )
glLinkProgram( shaderProgram )
result = glGetProgramiv( shaderProgram, GL_LINK_STATUS )
if not (result):
print( 'link error:' )
print( glGetProgramInfoLog( shaderProgram ) )
sys.exit()
return shaderProgram
# create vertex array object
def CreateVAO( dataArrays ):
noOfBuffers = len(dataArrays)
buffers = glGenBuffers(noOfBuffers)
newVAObj = glGenVertexArrays( 1 )
glBindVertexArray( newVAObj )
for inx in range(0, noOfBuffers):
vertexSize, dataArr = dataArrays[inx]
arr = np.array( dataArr, dtype='float32' )
glBindBuffer( GL_ARRAY_BUFFER, buffers[inx] )
glBufferData( GL_ARRAY_BUFFER, arr, GL_STATIC_DRAW )
glEnableVertexAttribArray( inx )
glVertexAttribPointer( inx, vertexSize, GL_FLOAT, GL_FALSE, 0, None )
return newVAObj
# representation of a uniform block
class UniformBlock:
def __init__(self, shaderProg, name):
self.shaderProg = shaderProg
self.name = name
def Link(self, bindingPoint):
self.bindingPoint = bindingPoint
self.noOfUniforms = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORMS)
self.maxUniformNameLen = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORM_MAX_LENGTH)
self.index = glGetUniformBlockIndex(self.shaderProg, self.name)
intData = np.zeros(1, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, intData)
self.count = intData[0]
self.indices = np.zeros(self.count, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, self.indices)
self.offsets = np.zeros(self.count, dtype=int)
glGetActiveUniformsiv(self.shaderProg, self.count, self.indices, GL_UNIFORM_OFFSET, self.offsets)
strLengthData = np.zeros(1, dtype=int)
arraysizeData = np.zeros(1, dtype=int)
typeData = np.zeros(1, dtype='uint32')
nameData = np.chararray(self.maxUniformNameLen+1)
self.namemap = {}
self.dataSize = 0
for inx in range(0, len(self.indices)):
glGetActiveUniform( self.shaderProg, self.indices[inx], self.maxUniformNameLen, strLengthData, arraysizeData, typeData, nameData.data )
name = nameData.tostring()[:strLengthData[0]]
self.namemap[name] = inx
self.dataSize = max(self.dataSize, self.offsets[inx] + arraysizeData * 16)
glUniformBlockBinding(self.shaderProg, self.index, self.bindingPoint)
print('\nuniform block %s size:%4d' % (self.name, self.dataSize))
for uName in self.namemap:
print( ' %-40s index:%2d offset:%4d' % (uName, self.indices[self.namemap[uName]], self.offsets [self.namemap[uName]]) )
# representation of a uniform block buffer
class UniformBlockBuffer:
def __init__(self, ub):
self.namemap = ub.namemap
self.offsets = ub.offsets
self.bindingPoint = ub.bindingPoint
self.object = glGenBuffers(1)
self.dataSize = ub.dataSize
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.zeros(self.dataSize//4, dtype='float32')
glBufferData(GL_UNIFORM_BUFFER, self.dataSize, dataArray, GL_DYNAMIC_DRAW)
def BindToTarget(self):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
glBindBufferBase(GL_UNIFORM_BUFFER, self.bindingPoint, self.object)
def BindDataFloat(self, name, dataArr):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.array(dataArr, dtype='float32')
glBufferSubData(GL_UNIFORM_BUFFER, self.offsets[self.namemap[name]], len(dataArr)*4, dataArray)
def Translate(matA, trans):
matB = np.copy(matA)
for i in range(0, 4): matB[3,i] = matA[0,i] * trans[0] + matA[1,i] * trans[1] + matA[2,i] * trans[2] + matA[3,i]
return matB
def Scale(matA, s):
matB = np.copy(matA)
for i0 in range(0, 3):
for i1 in range(0, 4): matB[i0,i1] = matA[i0,i1] * s[i0]
return matB
def RotateHlp(matA, angDeg, a0, a1):
matB = np.copy(matA)
ang = math.radians(angDeg)
sinAng, cosAng = math.sin(ang), math.cos(ang)
for i in range(0, 4):
matB[a0,i] = matA[a0,i] * cosAng + matA[a1,i] * sinAng
matB[a1,i] = matA[a0,i] * -sinAng + matA[a1,i] * cosAng
return matB
def RotateX(matA, angDeg): return RotateHlp(matA, angDeg, 1, 2)
def RotateY(matA, angDeg): return RotateHlp(matA, angDeg, 2, 0)
def RotateZ(matA, angDeg): return RotateHlp(matA, angDeg, 0, 1)
def RotateView(matA, angDeg): return RotateZ(RotateY(RotateX(matA, angDeg[0]), angDeg[1]), angDeg[2])
def Multiply(matA, matB):
matC = np.copy(matA)
for i0 in range(0, 4):
for i1 in range(0, 4):
matC[i0,i1] = matB[i0,0] * matA[0,i1] + matB[i0,1] * matA[1,i1] + matB[i0,2] * matA[2,i1] + matB[i0,3] * matA [3,i1]
return matC
def ToMat33(mat44):
mat33 = np.matrix(np.identity(3), copy=False, dtype='float32')
for i0 in range(0, 3):
for i1 in range(0, 3): mat33[i0, i1] = mat44[i0, i1]
return mat33
def TransformVec4(vecA,mat44):
vecB = np.zeros(4, dtype='float32')
for i0 in range(0, 4):
vecB[i0] = vecA[0] * mat44[0,i0] + vecA[1] * mat44[1,i0] + vecA[2] * mat44[2,i0] + vecA[3] * mat44[3,i0]
return vecB
def Perspective(fov, aspectRatio, near, far):
fn, f_n = far + near, far - near
r, t = aspectRatio, 1.0 / math.tan( math.radians(fov) / 2.0 )
return np.matrix( [ [t/r,0,0,0], [0,t,0,0], [0,0,-fn/f_n,-2.0*far*near/f_n], [0,0,-1,0] ] )
def AddToBuffer( buffer, data, count=1 ):
for inx_c in range(0, count):
for inx_s in range(0, len(data)): buffer.append( data[inx_s] )
# initialize glut
glutInit()
# create window
wndW, wndH = 800, 600
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
glutInitWindowPosition(0, 0)
glutInitWindowSize(wndW, wndH)
wndID = glutCreateWindow(b'OGL window')
glutDisplayFunc(OnDraw)
glutIdleFunc(OnDraw)
# define location vertex array opject
pointVAObj = CreateVAO( [ (3, [0.0, 0.0, 0.0] ), (3, [0.0, 0.0, -1.0]), (3, [1.0, 0.0, 0.0]) ] )
# load, compile and link shader
shaderProgram = LinkProgram( [
CompileShader( 'geo.vert', GL_VERTEX_SHADER ),
CompileShader( 'geo.geo', GL_GEOMETRY_SHADER ),
CompileShader( 'geo.frag', GL_FRAGMENT_SHADER )
] )
# get unifor locations
projectionMatLocation = glGetUniformLocation(shaderProgram, "u_projectionMat44")
viewMatLocation = glGetUniformLocation(shaderProgram, "u_viewMat44")
modelMatLocation = glGetUniformLocation(shaderProgram, "u_modelMat44")
# linke uniform blocks
ubMaterial = UniformBlock(shaderProgram, "UB_material")
ubLightSource = UniformBlock(shaderProgram, "UB_lightSource")
ubMaterial.Link(1)
ubLightSource.Link(2)
# create uniform block buffers
lightSourceBuffer = UniformBlockBuffer(ubLightSource)
lightSourceBuffer.BindDataFloat(b'u_lightSource.ambient', [0.2, 0.2, 0.2, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.diffuse', [0.2, 0.2, 0.2, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.specular', [1.0, 1.0, 1.0, 1.0])
materialBuffer = UniformBlockBuffer(ubMaterial)
materialBuffer.BindDataFloat(b'u_roughness', [0.5])
materialBuffer.BindDataFloat(b'u_fresnel0', [0.2])
materialBuffer.BindDataFloat(b'u_specularTint',[1.0, 0.5, 0.5, 0.8])
# start main loop
startTime = time()
glutMainLoop()
Переключение геометрии и представления поверхности с помощью подпрограмм в OGL 4.0 GLSL
Простая программа шейдеров шейдеров OGL 4.0 GLSL, которая показывает использование шейдерных подпрограмм. Программа выполняется с помощью phyton-скрипта. Для запуска скрипта необходимо установить PyOpenGL и NumPy.
Подпрограммы переключаются между различными геометриями, генерируемыми в геометрическом шейдере, и изменяют представление поверхности.
Вершинный шейдер
subr.vert
#version 400
layout (location = 0) in vec3 inPos;
layout (location = 1) in vec3 inNormal;
layout (location = 2) in vec3 inTangent;
out TVertexData
{
mat3 orientationMat;
} outData;
void main()
{
vec3 normal = normalize( inNormal );
vec3 tangent = normalize( inTangent );
vec3 binormal = cross( tangent, normal );
outData.orientationMat = mat3( normal, cross( binormal, normal ), binormal );
gl_Position = vec4( inPos, 1.0 );
}
Геометрический шейдер
subr.geo
#version 400
layout( points ) in;
layout( triangle_strip, max_vertices = 512 ) out;
in TVertexData
{
mat3 orientationMat;
} inData[];
out TGeometryData
{
vec3 pos;
vec3 nv;
vec2 tex;
} outData;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
uniform mat4 u_textureMat44;
void SetTextureCoord( in vec2 tecCoord )
{
vec4 tex = u_textureMat44 * vec4( tecCoord, 0.0, 1.0 );
outData.tex = tex.xy;
}
void NewVertex( in vec3 pt, in mat4 transMat )
{
vec4 viewPos = transMat * vec4( pt, 1.0 );
outData.pos = viewPos.xyz / viewPos.w;
gl_Position = u_projectionMat44 * viewPos;
EmitVertex();
}
void NewVertexAndTex( in vec3 pt, in mat4 transMat )
{
SetTextureCoord( pt.xy * 0.5 + 0.5 );
NewVertex( pt, transMat );
}
void NewVertexNvTex( in vec3 pt, in mat4 transMat, in vec3 nv, in vec2 tex )
{
outData.nv = nv;
SetTextureCoord( tex );
vec4 viewPos = transMat * vec4( pt, 1.0 );
outData.pos = viewPos.xyz / viewPos.w;
gl_Position = u_projectionMat44 * viewPos;
EmitVertex();
}
subroutine void TShape( in mat4 );
subroutine uniform TShape su_shape;
void main()
{
vec4 origin = gl_in[0].gl_Position;
origin /= origin.w;
mat4 orintationMat = mat4( vec4( inData[0].orientationMat[0], 0.0 ),
vec4( inData[0].orientationMat[1], 0.0 ),
vec4( inData[0].orientationMat[2], 0.0 ),
origin );
mat4 modelMat = u_modelMat44 * orintationMat;
su_shape( modelMat );
}
subroutine(TShape) void DrawSphere( in mat4 modelMat )
{
const int circumferenceTile = 18;
const int layersTile = 11;
mat4 modelViewMat = u_viewMat44 * modelMat;
mat3 normalMat = mat3( modelViewMat );
float preStepLay = 0.0;
vec2 prePtLay = vec2( 0.0, -1.0 );
for ( int inxLay = 1; inxLay <= layersTile; ++ inxLay )
{
float stepLay = float(inxLay) / float(layersTile);
float angLay = 3.14159 * stepLay;
vec2 ptLay = vec2( sin(angLay), -cos(angLay) );
float preStepCir = 0.0;
vec2 prePtCir = vec2( 0.0, 1.0 );
for ( int inxCir = 0; inxCir <= circumferenceTile; ++ inxCir )
{
float stepCir = float(inxCir) / float(circumferenceTile);
float angCir = 2.0 * 3.14159 * stepCir;
vec2 ptCir = vec2( sin(angCir), cos(angCir) );
if ( inxLay == 1 )
{
if ( inxCir >= 0 )
{
vec3 pt1 = vec3( ptLay.x * prePtCir.x, ptLay.x * prePtCir.y, ptLay.y );
vec3 pt2 = vec3( 0.0, 0.0, -1.0 );
vec3 pt3 = vec3( ptLay.x * ptCir.x, ptLay.x * ptCir.y, ptLay.y );
NewVertexNvTex( pt1, modelViewMat, normalMat * pt1, vec2( preStepCir * 2.0, stepLay ) );
NewVertexNvTex( pt2, modelViewMat, normalMat * pt2, vec2( preStepCir + stepCir, preStepLay ) );
NewVertexNvTex( pt3, modelViewMat, normalMat * pt3, vec2( stepCir * 2.0, stepLay ) );
EndPrimitive();
}
}
else if ( inxLay == layersTile )
{
if ( inxCir > 0 )
{
vec3 pt1 = vec3( prePtLay.x * prePtCir.x, prePtLay.x * prePtCir.y, prePtLay.y );
vec3 pt2 = vec3( prePtLay.x * ptCir.x, prePtLay.x * ptCir.y, prePtLay.y );
vec3 pt3 = vec3( 0.0, 0.0, 1.0 );
NewVertexNvTex( pt1, modelViewMat, normalMat * pt1, vec2( preStepCir * 2.0, preStepLay ) );
NewVertexNvTex( pt2, modelViewMat, normalMat * pt2, vec2( stepCir * 2.0, preStepLay ) );
NewVertexNvTex( pt3, modelViewMat, normalMat * pt3, vec2( preStepCir + stepCir, stepLay ) );
EndPrimitive();
}
}
else
{
vec3 pt1 = vec3( prePtLay.x * ptCir.x, prePtLay.x * ptCir.y, prePtLay.y );
vec3 pt2 = vec3( ptLay.x * ptCir.x, ptLay.x * ptCir.y, ptLay.y );
NewVertexNvTex( pt1, modelViewMat, normalMat * pt1, vec2( stepCir * 2.0, preStepLay ) );
NewVertexNvTex( pt2, modelViewMat, normalMat * pt2, vec2( stepCir * 2.0, stepLay ) );
}
preStepCir = stepCir;
prePtCir = ptCir;
}
if ( inxLay > 1 && inxLay < layersTile )
EndPrimitive();
preStepLay = stepLay;
prePtLay = ptLay;
}
}
subroutine(TShape) void DrawTorus( in mat4 modelMat )
{
const int circumferenceTile = 12;
const int layersTile = 18;
const float torusRad = 0.8;
const float ringRad = 0.4;
mat4 modelViewMat = u_viewMat44 * modelMat;
mat3 normalMat = mat3( modelViewMat );
float preStepLay = 0.0;
mat4 prePosMat;
for ( int inxLay = 0; inxLay <= layersTile; ++ inxLay )
{
float stepLay = float(inxLay) / float(layersTile);
float angLay = 2.0 * 3.14159 * stepLay;
mat4 posMat = mat4(
vec4( cos(angLay), sin(angLay), 0.0, 0.0 ),
vec4( sin(angLay), cos(angLay), 0.0, 0.0 ),
vec4( 0.0, 0.0, 1.0, 0.0 ),
vec4( cos(angLay) * torusRad, sin(angLay) * torusRad, 0.0, 1.0 ) );
for ( int inxCir = 0; inxLay > 0 && inxCir <= circumferenceTile; ++ inxCir )
{
float stepCir = float(inxCir) / float(circumferenceTile);
float angCir = 2.0 * 3.14159 * stepCir;
vec2 ptCir = vec2( sin(angCir), cos(angCir) );
vec4 tempPt = vec4( ptCir.x * ringRad, 0.0, ptCir.y * ringRad, 1.0 );
vec4 pt1 = prePosMat * tempPt;
vec4 pt2 = posMat * tempPt;
NewVertexNvTex( pt1.xyz, modelViewMat, normalMat * normalize(pt1.xyz - prePosMat[3].xyz), vec2(stepCir, preStepLay*2.0) );
NewVertexNvTex( pt2.xyz, modelViewMat, normalMat * normalize(pt2.xyz - posMat[3].xyz), vec2(stepCir, stepLay*2.0) );
}
EndPrimitive();
preStepLay = stepLay;
prePosMat = posMat;
}
}
Фрагментный шейдер
subr.frag
#version 400
in TGeometryData
{
vec3 pos;
vec3 nv;
vec2 tex;
} inData;
out vec4 fragColor;
uniform sampler2D u_texture;
uniform UB_material
{
float u_roughness;
float u_fresnel0;
vec4 u_color;
vec4 u_specularTint;
};
struct TLightSource
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec4 dir;
};
uniform UB_lightSource
{
TLightSource u_lightSource;
};
subroutine vec4 TSurface( void );
subroutine uniform TSurface su_surface;
float Fresnel_Schlick( in float theta );
vec3 LightModel( in vec3 esPt, in vec3 esPtNV, in vec3 col, in vec4 specularTint, in float roughness, in float fresnel0 );
void main()
{
vec4 fragCol = su_surface();
vec3 lightCol = LightModel( inData.pos, inData.nv, fragCol.rgb, u_specularTint, u_roughness, u_fresnel0 );
fragColor = vec4( clamp( lightCol, 0.0, 1.0 ), fragCol.a );
}
subroutine(TSurface) vec4 SurfaceColor( void )
{
return u_color;
}
subroutine(TSurface) vec4 SurfaceTexture( void )
{
return texture( u_texture, inData.tex.st );
}
float Fresnel_Schlick( in float theta )
{
float m = clamp( 1.0 - theta, 0.0, 1.0 );
float m2 = m * m;
return m2 * m2 * m; // pow( m, 5.0 )
}
vec3 LightModel( in vec3 esPt, in vec3 esPtNV, in vec3 col, in vec4 specularTint, in float roughness, in float fresnel0 )
{
vec3 esVLight = normalize( -u_lightSource.dir.xyz );
vec3 esVEye = normalize( -esPt );
vec3 halfVector = normalize( esVEye + esVLight );
float HdotL = dot( halfVector, esVLight );
float NdotL = dot( esPtNV, esVLight );
float NdotV = dot( esPtNV, esVEye );
float NdotH = dot( esPtNV, halfVector );
float NdotH2 = NdotH * NdotH;
float NdotL_clamped = max( NdotL, 0.0 );
float NdotV_clamped = max( NdotV, 0.0 );
float m2 = roughness * roughness;
// Lambertian diffuse
float k_diffuse = NdotL_clamped;
// Schlick approximation
float fresnel = fresnel0 + ( 1.0 - fresnel0 ) * Fresnel_Schlick( HdotL );
// Beckmann distribution
float distribution = max( 0.0, exp( ( NdotH2 - 1.0 ) / ( m2 * NdotH2 ) ) / ( 3.14159265 * m2 * NdotH2 * NdotH2 ) );
// Torrance-Sparrow geometric term
float geometric_att = min( 1.0, min( 2.0 * NdotH * NdotV_clamped / HdotL, 2.0 * NdotH * NdotL_clamped / HdotL ) );
// Microfacet bidirectional reflectance distribution function
float k_specular = fresnel * distribution * geometric_att / ( 4.0 * NdotL_clamped * NdotV_clamped );
vec3 lightColor = col.rgb * u_lightSource.ambient.rgb +
max( 0.0, k_diffuse ) * col.rgb * u_lightSource.diffuse.rgb +
max( 0.0, k_specular ) * mix( col.rgb, specularTint.rgb, specularTint.a ) * u_lightSource.specular.rgb;
return lightColor;
}
Скрипт Phyton
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy as np
from time import time
import math
import sys
sin120 = 0.8660254
rotateCamera = False
# draw event
def OnDraw():
dist = 3.0
currentTime = time()
comeraRotAng = CalcAng( currentTime, 10.0 )
# set up projection matrix
prjMat = Perspective(90.0, wndW/wndH, 0.5, 100.0)
# set up view matrix
viewMat = np.matrix(np.identity(4), copy=False, dtype='float32')
viewMat = Translate( viewMat, np.array( [0.0, 0.0, -14.0] ) )
viewMat = RotateView( viewMat, [30.0, comeraRotAng if rotateCamera else 0.0, 0.0] )
# set up light source
lightSourceBuffer.BindDataFloat(b'u_lightSource.dir', TransformVec4([-1.0, -1.0, -5.0, 0.0], viewMat) )
# set up model matrices
modelMat = []
for inx in range(0, 2):
modelMat.append( np.matrix(np.identity(4), copy=False, dtype='float32') )
if not rotateCamera: modelMat[inx] = RotateY( modelMat[inx], comeraRotAng )
modelMat[0] = Scale( modelMat[0], np.repeat( 3, 3 ) )
modelMat[0] = Translate( modelMat[0], np.array( [0.0, 0.0, -2.0] ) )
modelMat[0] = RotateY( modelMat[0], CalcAng( currentTime, 23.0 ) )
modelMat[0] = RotateX( modelMat[0], CalcAng( currentTime, 13.0 ) )
modelMat[1] = Scale( modelMat[1], np.repeat( 3, 3 ) )
modelMat[1] = Translate( modelMat[1], np.array( [0.0, 0.0, 2.0] ) )
modelMat[1] = RotateY( modelMat[1], CalcAng( currentTime, 17.0 ) )
modelMat[1] = RotateX( modelMat[1], CalcAng( currentTime, 9.0 ) )
# set up texture matrix
texMat = np.matrix(np.identity(4), copy=False, dtype='float32')
# set up attributes and shader program
glEnable( GL_DEPTH_TEST )
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glUseProgram( shaderProgram )
glUniformMatrix4fv( projectionMatLocation, 1, GL_FALSE, prjMat )
glUniformMatrix4fv( viewMatLocation, 1, GL_FALSE, viewMat )
glUniformMatrix4fv( textureMatLocation, 1, GL_FALSE, texMat )
glUniform1i( textureLocation, 0 )
lightSourceBuffer.BindToTarget()
# draw points
glBindVertexArray( pointVAObj )
for inx in range(0, 2):
# set up geometry shader subroutine
shape = 1 if inx==0 else 0 # 0: sphere, 1: torus
glUniformSubroutinesuiv(GL_GEOMETRY_SHADER, 1, np.array( [shape], dtype='uint' ))
# set up fragment shader subroutine
surfaceKind = inx # 0: color, 1: texture
glUniformSubroutinesuiv(GL_FRAGMENT_SHADER, 1, np.array( [surfaceKind], dtype='uint' ))
materialBuffer[inx].BindToTarget()
glUniformMatrix4fv( modelMatLocation, 1, GL_FALSE, modelMat[inx] )
glDrawArrays( GL_POINTS, 0, 1 )
glutSwapBuffers()
def Fract(val): return val - math.trunc(val)
def CalcAng(currentTime, intervall): return Fract( (currentTime - startTime) / intervall ) * 360.0
def CalcMove(currentTime, intervall, range):
pos = Fract( (currentTime - startTime) / intervall ) * 2.0
pos = pos if pos < 1.0 else (2.0-pos)
return range[0] + (range[1] - range[0]) * pos
# read shader program and compile shader
def CompileShader( sourceFileName, shaderStage ):
with open( sourceFileName, 'r' ) as sourceFile:
sourceCode = sourceFile.read()
nameMap = { GL_VERTEX_SHADER: 'vertex', GL_GEOMETRY_SHADER: 'geometry', GL_FRAGMENT_SHADER: 'fragment' }
print( '\n%s shader code:' % nameMap.get(shaderStage, '') )
print( sourceCode )
shaderObj = glCreateShader( shaderStage )
glShaderSource( shaderObj, sourceCode )
glCompileShader( shaderObj )
result = glGetShaderiv( shaderObj, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( shaderObj ) )
sys.exit()
return shaderObj
# linke shader objects to shader program
def LinkProgram( shaderObjs ):
shaderProgram = glCreateProgram()
for shObj in shaderObjs:
glAttachShader( shaderProgram, shObj )
glLinkProgram( shaderProgram )
result = glGetProgramiv( shaderProgram, GL_LINK_STATUS )
if not (result):
print( 'link error:' )
print( glGetProgramInfoLog( shaderProgram ) )
sys.exit()
return shaderProgram
# create vertex array object
def CreateVAO( dataArrays ):
noOfBuffers = len(dataArrays)
buffers = glGenBuffers(noOfBuffers)
newVAObj = glGenVertexArrays( 1 )
glBindVertexArray( newVAObj )
for inx in range(0, noOfBuffers):
vertexSize, dataArr = dataArrays[inx]
arr = np.array( dataArr, dtype='float32' )
glBindBuffer( GL_ARRAY_BUFFER, buffers[inx] )
glBufferData( GL_ARRAY_BUFFER, arr, GL_STATIC_DRAW )
glEnableVertexAttribArray( inx )
glVertexAttribPointer( inx, vertexSize, GL_FLOAT, GL_FALSE, 0, None )
return newVAObj
# representation of a uniform block
class UniformBlock:
def __init__(self, shaderProg, name):
self.shaderProg = shaderProg
self.name = name
def Link(self, bindingPoint):
self.bindingPoint = bindingPoint
self.noOfUniforms = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORMS)
self.maxUniformNameLen = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORM_MAX_LENGTH)
self.index = glGetUniformBlockIndex(self.shaderProg, self.name)
intData = np.zeros(1, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, intData)
self.count = intData[0]
self.indices = np.zeros(self.count, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, self.indices)
self.offsets = np.zeros(self.count, dtype=int)
glGetActiveUniformsiv(self.shaderProg, self.count, self.indices, GL_UNIFORM_OFFSET, self.offsets)
strLengthData = np.zeros(1, dtype=int)
arraysizeData = np.zeros(1, dtype=int)
typeData = np.zeros(1, dtype='uint32')
nameData = np.chararray(self.maxUniformNameLen+1)
self.namemap = {}
self.dataSize = 0
for inx in range(0, len(self.indices)):
glGetActiveUniform( self.shaderProg, self.indices[inx], self.maxUniformNameLen, strLengthData, arraysizeData, typeData, nameData.data )
name = nameData.tostring()[:strLengthData[0]]
self.namemap[name] = inx
self.dataSize = max(self.dataSize, self.offsets[inx] + arraysizeData * 16)
glUniformBlockBinding(self.shaderProg, self.index, self.bindingPoint)
print('\nuniform block %s size:%4d' % (self.name, self.dataSize))
for uName in self.namemap:
print( ' %-40s index:%2d offset:%4d' % (uName, self.indices[self.namemap[uName]], self.offsets[self.namemap [uName]]) )
# representation of a uniform block buffer
class UniformBlockBuffer:
def __init__(self, ub):
self.namemap = ub.namemap
self.offsets = ub.offsets
self.bindingPoint = ub.bindingPoint
self.object = glGenBuffers(1)
self.dataSize = ub.dataSize
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.zeros(self.dataSize//4, dtype='float32')
glBufferData(GL_UNIFORM_BUFFER, self.dataSize, dataArray, GL_DYNAMIC_DRAW)
def BindToTarget(self):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
glBindBufferBase(GL_UNIFORM_BUFFER, self.bindingPoint, self.object)
def BindDataFloat(self, name, dataArr):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.array(dataArr, dtype='float32')
glBufferSubData(GL_UNIFORM_BUFFER, self.offsets[self.namemap[name]], len(dataArr)*4, dataArray)
def Translate(matA, trans):
matB = np.copy(matA)
for i in range(0, 4): matB[3,i] = matA[0,i] * trans[0] + matA[1,i] * trans[1] + matA[2,i] * trans[2] + matA[3,i]
return matB
def Scale(matA, s):
matB = np.copy(matA)
for i0 in range(0, 3):
for i1 in range(0, 4): matB[i0,i1] = matA[i0,i1] * s[i0]
return matB
def RotateHlp(matA, angDeg, a0, a1):
matB = np.copy(matA)
ang = math.radians(angDeg)
sinAng, cosAng = math.sin(ang), math.cos(ang)
for i in range(0, 4):
matB[a0,i] = matA[a0,i] * cosAng + matA[a1,i] * sinAng
matB[a1,i] = matA[a0,i] * -sinAng + matA[a1,i] * cosAng
return matB
def RotateX(matA, angDeg): return RotateHlp(matA, angDeg, 1, 2)
def RotateY(matA, angDeg): return RotateHlp(matA, angDeg, 2, 0)
def RotateZ(matA, angDeg): return RotateHlp(matA, angDeg, 0, 1)
def RotateView(matA, angDeg): return RotateZ(RotateY(RotateX(matA, angDeg[0]), angDeg[1]), angDeg[2])
def Multiply(matA, matB):
matC = np.copy(matA)
for i0 in range(0, 4):
for i1 in range(0, 4):
matC[i0,i1] = matB[i0,0] * matA[0,i1] + matB[i0,1] * matA[1,i1] + matB[i0,2] * matA[2,i1] + matB[i0,3] * matA[3,i1]
return matC
def ToMat33(mat44):
mat33 = np.matrix(np.identity(3), copy=False, dtype='float32')
for i0 in range(0, 3):
for i1 in range(0, 3): mat33[i0, i1] = mat44[i0, i1]
return mat33
def TransformVec4(vecA,mat44):
vecB = np.zeros(4, dtype='float32')
for i0 in range(0, 4):
vecB[i0] = vecA[0] * mat44[0,i0] + vecA[1] * mat44[1,i0] + vecA[2] * mat44[2,i0] + vecA[3] * mat44[3,i0]
return vecB
def Perspective(fov, aspectRatio, near, far):
fn, f_n = far + near, far - near
r, t = aspectRatio, 1.0 / math.tan( math.radians(fov) / 2.0 )
return np.matrix( [ [t/r,0,0,0], [0,t,0,0], [0,0,-fn/f_n,-2.0*far*near/f_n], [0,0,-1,0] ] )
def AddToBuffer( buffer, data, count=1 ):
for inx_c in range(0, count):
for inx_s in range(0, len(data)): buffer.append( data[inx_s] )
# initialize glut
glutInit()
# create window
wndW, wndH = 800, 600
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
glutInitWindowPosition(0, 0)
glutInitWindowSize(wndW, wndH)
wndID = glutCreateWindow(b'OGL window')
glutDisplayFunc(OnDraw)
glutIdleFunc(OnDraw)
# define location vertex array opject
pointVAObj = CreateVAO( [ (3, [0.0, 0.0, 0.0] ), (3, [0.0, 0.0, 1.0]), (3, [1.0, 0.0, 0.0]) ] )
# create texture
texCX, texCY = 128, 128
texPlan = np.zeros( texCX * texCY * 4, dtype=np.uint8 )
for inx_x in range(0, texCX):
for inx_y in range(0, texCY):
val_x = math.sin( math.pi * 6.0 * inx_x / texCX )
val_y = math.sin( math.pi * 6.0 * inx_y / texCY )
inx_tex = inx_y * texCX * 4 + inx_x * 4
texPlan[inx_tex + 0] = int( 128 + 127 * val_x )
texPlan[inx_tex + 1] = 63
texPlan[inx_tex + 2] = int( 128 + 127 * val_y )
texPlan[inx_tex + 3] = 255
glActiveTexture( GL_TEXTURE0 )
texObj = glGenTextures( 1 )
glBindTexture( GL_TEXTURE_2D, texObj )
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texCX, texCY, 0, GL_RGBA, GL_UNSIGNED_BYTE, texPlan)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
# load, compile and link shader
shaderProgram = LinkProgram( [
CompileShader( 'python/ogl4subr/subr.vert', GL_VERTEX_SHADER ),
CompileShader( 'python/ogl4subr/subr.geo', GL_GEOMETRY_SHADER ),
CompileShader( 'python/ogl4subr/subr.frag', GL_FRAGMENT_SHADER )
] )
# get unifor locations
projectionMatLocation = glGetUniformLocation(shaderProgram, "u_projectionMat44")
viewMatLocation = glGetUniformLocation(shaderProgram, "u_viewMat44")
modelMatLocation = glGetUniformLocation(shaderProgram, "u_modelMat44")
textureMatLocation = glGetUniformLocation(shaderProgram, "u_textureMat44")
textureLocation = glGetUniformLocation(shaderProgram, "u_texture")
# linke uniform blocks
ubMaterial = UniformBlock(shaderProgram, "UB_material")
ubLightSource = UniformBlock(shaderProgram, "UB_lightSource")
ubMaterial.Link(1)
ubLightSource.Link(2)
# create uniform block buffers
lightSourceBuffer = UniformBlockBuffer(ubLightSource)
lightSourceBuffer.BindDataFloat(b'u_lightSource.ambient', [0.2, 0.2, 0.2, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.diffuse', [0.2, 0.2, 0.2, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.specular', [1.0, 1.0, 1.0, 1.0])
materialBuffer = [ UniformBlockBuffer(ubMaterial), UniformBlockBuffer(ubMaterial) ]
materialBuffer[0].BindDataFloat(b'u_roughness', [0.45])
materialBuffer[0].BindDataFloat(b'u_fresnel0', [0.45])
materialBuffer[0].BindDataFloat(b'u_color', [0.5, 0.7, 0.6, 1.0])
materialBuffer[0].BindDataFloat(b'u_specularTint',[1.0, 0.5, 0.5, 0.8])
materialBuffer[1].BindDataFloat(b'u_roughness', [0.4])
materialBuffer[1].BindDataFloat(b'u_fresnel0', [0.4])
materialBuffer[1].BindDataFloat(b'u_color', [0.7, 0.5, 0.6, 1.0])
materialBuffer[1].BindDataFloat(b'u_specularTint',[0.5, 1.0, 0.5, 0.8])
# start main loop
startTime = time()
glutMainLoop()
Изменение геометрии с помощью тесселяционных шейдеров в OGL 4.0 GLSL
Простая программа шейдеров шейдеров OGL 4.0 GLSL, которая показывает, как добавить детали с помощью тесселяционного шейдера в геометрию. Программа выполняется с помощью скрипта python. Для запуска скрипта необходимо установить PyOpenGL и NumPy.
Основной сеткой в этом примере является икосаэдр, состоящий из 20 треугольников. Шейдер управления тесселяцией определяет, как каждый треугольник делится на множество мелких деталей. При тесселяции треугольника сгенерированные данные являются барицентрическими координатами на основе исходного треугольника. Шейдер оценки тесселяции генерирует новую геометрию из данных, полученных таким образом. В этом примере каждый треугольник получает пик посередине, который поднимается наружу от центра икосадера. Таким образом создается гораздо более сложная геометрия, чем исходный икосаэдр.
Вершинный шейдер
tess.vert
layout (location = 0) in vec3 inPos;
layout (location = 1) in vec3 inNV;
out TVertexData
{
vec3 pos;
vec3 nv;
} outData;
uniform mat4 u_projectionMat44;
uniform mat4 u_modelViewMat44;
uniform mat3 u_normalMat33;
void main()
{
vec4 viewPos = u_modelViewMat44 * vec4( inPos, 1.0 );
outData.pos = viewPos.xyz / viewPos.w;
outData.nv = u_normalMat33 * normalize( inNV );
gl_Position = u_projectionMat44 * viewPos;
}
Шейдер управления тесселяцией
tess.tctrl
#version 400
layout( vertices=3 ) out;
in TVertexData
{
vec3 pos;
vec3 nv;
} inData[];
out TVertexData
{
vec3 pos;
vec3 nv;
} outData[];
void main()
{
outData[gl_InvocationID].pos = inData[gl_InvocationID].pos;
outData[gl_InvocationID].nv = inData[gl_InvocationID].nv;
if ( gl_InvocationID == 0 )
{
gl_TessLevelOuter[0] = 10.0;
gl_TessLevelOuter[1] = 10.0;
gl_TessLevelOuter[2] = 10.0;
gl_TessLevelInner[0] = 10.0;
}
}
Шейдер оценки оценки тесселяции
tess.teval
#version 400
layout(triangles, equal_spacing, ccw) in;
in TVertexData
{
vec3 pos;
vec3 nv;
} inData[];
out TTessData
{
vec3 pos;
vec3 nv;
float height;
} outData;
uniform mat4 u_projectionMat44;
void main()
{
float sideLen[3] = float[3]
(
length( inData[1].pos - inData[0].pos ),
length( inData[2].pos - inData[1].pos ),
length( inData[0].pos - inData[2].pos )
);
float s = ( sideLen[0] + sideLen[1] + sideLen[2] ) / 2.0;
float rad = sqrt( (s - sideLen[0]) * (s - sideLen[1]) * (s - sideLen[2]) / s );
vec3 cpt = ( inData[0].pos + inData[1].pos + inData[2].pos ) / 3.0;
vec3 pos = inData[0].pos * gl_TessCoord.x + inData[1].pos * gl_TessCoord.y + inData[2].pos * gl_TessCoord.z;
vec3 nv = normalize( inData[0].nv * gl_TessCoord.x + inData[1].nv * gl_TessCoord.y + inData[2].nv * gl_TessCoord.z );
float cptDist = length( cpt - pos );
float sizeRelation = 1.0 - min( rad, cptDist ) / rad;
float height = pow( sizeRelation, 2.0 );
outData.pos = pos + nv * height * rad;
outData.nv = mix( nv, normalize( pos - cpt ), height );
outData.height = height;
gl_Position = u_projectionMat44 * vec4( outData.pos, 1.0 );
}
Фрагментный шейдер
tess.frag
#version 400
in TTessData
{
vec3 pos;
vec3 nv;
float height;
} inData;
out vec4 fragColor;
uniform sampler2D u_texture;
uniform UB_material
{
float u_roughness;
float u_fresnel0;
vec4 u_color;
vec4 u_specularTint;
};
struct TLightSource
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
vec4 dir;
};
uniform UB_lightSource
{
TLightSource u_lightSource;
};
float Fresnel_Schlick( in float theta );
vec3 LightModel( in vec3 esPt, in vec3 esPtNV, in vec3 col, in vec4 specularTint, in float roughness, in float fresnel0 );
void main()
{
vec3 col = mix( u_color.rgb, vec3( 1.0, 1.0, 1.0 ), inData.height );
vec3 lightCol = LightModel( inData.pos, inData.nv, col, u_specularTint, u_roughness, u_fresnel0 );
fragColor = vec4( clamp( lightCol, 0.0, 1.0 ), 1.0 );
}
float Fresnel_Schlick( in float theta )
{
float m = clamp( 1.0 - theta, 0.0, 1.0 );
float m2 = m * m;
return m2 * m2 * m; // pow( m, 5.0 )
}
vec3 LightModel( in vec3 esPt, in vec3 esPtNV, in vec3 col, in vec4 specularTint, in float roughness, in float fresnel0 )
{
vec3 esVLight = normalize( -u_lightSource.dir.xyz );
vec3 esVEye = normalize( -esPt );
vec3 halfVector = normalize( esVEye + esVLight );
float HdotL = dot( halfVector, esVLight );
float NdotL = dot( esPtNV, esVLight );
float NdotV = dot( esPtNV, esVEye );
float NdotH = dot( esPtNV, halfVector );
float NdotH2 = NdotH * NdotH;
float NdotL_clamped = max( NdotL, 0.0 );
float NdotV_clamped = max( NdotV, 0.0 );
float m2 = roughness * roughness;
// Lambertian diffuse
float k_diffuse = NdotL_clamped;
// Schlick approximation
float fresnel = fresnel0 + ( 1.0 - fresnel0 ) * Fresnel_Schlick( HdotL );
// Beckmann distribution
float distribution = max( 0.0, exp( ( NdotH2 - 1.0 ) / ( m2 * NdotH2 ) ) / ( 3.14159265 * m2 * NdotH2 * NdotH2 ) );
// Torrance-Sparrow geometric term
float geometric_att = min( 1.0, min( 2.0 * NdotH * NdotV_clamped / HdotL, 2.0 * NdotH * NdotL_clamped / HdotL ) );
// Microfacet bidirectional reflectance distribution function
float k_specular = fresnel * distribution * geometric_att / ( 4.0 * NdotL_clamped * NdotV_clamped );
vec3 lightColor = col.rgb * u_lightSource.ambient.rgb +
max( 0.0, k_diffuse ) * col.rgb * u_lightSource.diffuse.rgb +
max( 0.0, k_specular ) * mix( col.rgb, specularTint.rgb, specularTint.a ) * u_lightSource.specular.rgb;
return lightColor;
}
Скрипт Python
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy as np
from time import time
import math
import sys
sin120 = 0.8660254
rotateCamera = False
# draw event
def OnDraw():
dist = 3.0
currentTime = time()
comeraRotAng = CalcAng( currentTime, 10.0 )
# set up projection matrix
prjMat = Perspective(90.0, wndW/wndH, 0.5, 100.0)
# set up view matrix
viewMat = np.matrix(np.identity(4), copy=False, dtype='float32')
viewMat = Translate( viewMat, np.array( [0.0, 0.0, -12.0] ) )
viewMat = RotateView( viewMat, [30.0, comeraRotAng if rotateCamera else 0.0, 0.0] )
# set up light source
lightSourceBuffer.BindDataFloat(b'u_lightSource.dir', TransformVec4([-1.0, -1.0, -5.0, 0.0], viewMat) )
# set up icosahedron model matrix
icoModelMat = np.matrix(np.identity(4), copy=False, dtype='float32')
if not rotateCamera: icoModelMat = RotateY( icoModelMat, comeraRotAng )
icoModelMat = Scale( icoModelMat, np.repeat( 5, 3 ) )
icoModelMat = RotateY( icoModelMat, CalcAng( currentTime, 17.0 ) )
icoModelMat = RotateX( icoModelMat, CalcAng( currentTime, 13.0 ) )
# set up attributes and shader program
glEnable( GL_DEPTH_TEST )
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
glUseProgram( shaderProgram )
glUniformMatrix4fv( projectionMatLocation, 1, GL_FALSE, prjMat )
lightSourceBuffer.BindToTarget()
# draw icosahedron
icoMaterialBuffer.BindToTarget()
modelViewMat = Multiply(viewMat, icoModelMat)
glUniformMatrix4fv( modelViewMatLocation, 1, GL_FALSE, modelViewMat )
glUniformMatrix3fv( normalMatLocation, 1, GL_FALSE, ToMat33(modelViewMat) )
glBindVertexArray( icoVAObj )
glPatchParameteri( GL_PATCH_VERTICES, 3 )
glDrawArrays( GL_PATCHES, 0, len(icoPosData) )
glutSwapBuffers()
def Fract(val): return val - math.trunc(val)
def CalcAng(currentTime, intervall): return Fract( (currentTime - startTime) / intervall ) * 360.0
def CalcMove(currentTime, intervall, range):
pos = Fract( (currentTime - startTime) / intervall ) * 2.0
pos = pos if pos < 1.0 else (2.0-pos)
return range[0] + (range[1] - range[0]) * pos
# read shader program and compile shader
def CompileShader( sourceFileName, shaderStage ):
with open( sourceFileName, 'r' ) as sourceFile:
sourceCode = sourceFile.read()
nameMap = { GL_VERTEX_SHADER: 'vertex', GL_GEOMETRY_SHADER: 'geometry', GL_FRAGMENT_SHADER: 'fragment' }
print( '\n%s shader code:' % nameMap.get(shaderStage, '') )
print( sourceCode )
shaderObj = glCreateShader( shaderStage )
glShaderSource( shaderObj, sourceCode )
glCompileShader( shaderObj )
result = glGetShaderiv( shaderObj, GL_COMPILE_STATUS )
if not (result):
print( glGetShaderInfoLog( shaderObj ) )
sys.exit()
return shaderObj
# link shader objects to shader program
def LinkProgram( shaderObjs ):
shaderProgram = glCreateProgram()
for shObj in shaderObjs:
glAttachShader( shaderProgram, shObj )
glLinkProgram( shaderProgram )
result = glGetProgramiv( shaderProgram, GL_LINK_STATUS )
if not (result):
print( 'link error:' )
print( glGetProgramInfoLog( shaderProgram ) )
sys.exit()
return shaderProgram
# create vertex array object
def CreateVAO( dataArrays ):
noOfBuffers = len(dataArrays)
buffers = glGenBuffers(noOfBuffers)
newVAObj = glGenVertexArrays( 1 )
glBindVertexArray( newVAObj )
for inx in range(0, noOfBuffers):
vertexSize, dataArr = dataArrays[inx]
arr = np.array( dataArr, dtype='float32' )
glBindBuffer( GL_ARRAY_BUFFER, buffers[inx] )
glBufferData( GL_ARRAY_BUFFER, arr, GL_STATIC_DRAW )
glEnableVertexAttribArray( inx )
glVertexAttribPointer( inx, vertexSize, GL_FLOAT, GL_FALSE, 0, None )
return newVAObj
# representation of a uniform block
class UniformBlock:
def __init__(self, shaderProg, name):
self.shaderProg = shaderProg
self.name = name
def Link(self, bindingPoint):
self.bindingPoint = bindingPoint
self.noOfUniforms = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORMS)
self.maxUniformNameLen = glGetProgramiv(self.shaderProg, GL_ACTIVE_UNIFORM_MAX_LENGTH)
self.index = glGetUniformBlockIndex(self.shaderProg, self.name)
intData = np.zeros(1, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, intData)
self.count = intData[0]
self.indices = np.zeros(self.count, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, self.indices)
self.offsets = np.zeros(self.count, dtype=int)
glGetActiveUniformsiv(self.shaderProg, self.count, self.indices, GL_UNIFORM_OFFSET, self.offsets)
strLengthData = np.zeros(1, dtype=int)
arraysizeData = np.zeros(1, dtype=int)
typeData = np.zeros(1, dtype='uint32')
nameData = np.chararray(self.maxUniformNameLen+1)
self.namemap = {}
self.dataSize = 0
for inx in range(0, len(self.indices)):
glGetActiveUniform( self.shaderProg, self.indices[inx], self.maxUniformNameLen, strLengthData, arraysizeData, typeData, nameData.data )
name = nameData.tostring()[:strLengthData[0]]
self.namemap[name] = inx
self.dataSize = max(self.dataSize, self.offsets[inx] + arraysizeData * 16)
glUniformBlockBinding(self.shaderProg, self.index, self.bindingPoint)
print('\nuniform block %s size:%4d' % (self.name, self.dataSize))
for uName in self.namemap:
print( ' %-40s index:%2d offset:%4d' % (uName, self.indices[self.namemap[uName]], self.offsets[self.namemap [uName]]) )
# representation of a uniform block buffer
class UniformBlockBuffer:
def __init__(self, ub):
self.namemap = ub.namemap
self.offsets = ub.offsets
self.bindingPoint = ub.bindingPoint
self.object = glGenBuffers(1)
self.dataSize = ub.dataSize
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.zeros(self.dataSize//4, dtype='float32')
glBufferData(GL_UNIFORM_BUFFER, self.dataSize, dataArray, GL_DYNAMIC_DRAW)
def BindToTarget(self):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
glBindBufferBase(GL_UNIFORM_BUFFER, self.bindingPoint, self.object)
def BindDataFloat(self, name, dataArr):
glBindBuffer(GL_UNIFORM_BUFFER, self.object)
dataArray = np.array(dataArr, dtype='float32')
glBufferSubData(GL_UNIFORM_BUFFER, self.offsets[self.namemap[name]], len(dataArr)*4, dataArray)
def Translate(matA, trans):
matB = np.copy(matA)
for i in range(0, 4): matB[3,i] = matA[0,i] * trans[0] + matA[1,i] * trans[1] + matA[2,i] * trans[2] + matA[3,i]
return matB
def Scale(matA, s):
matB = np.copy(matA)
for i0 in range(0, 3):
for i1 in range(0, 4): matB[i0,i1] = matA[i0,i1] * s[i0]
return matB
def RotateHlp(matA, angDeg, a0, a1):
matB = np.copy(matA)
ang = math.radians(angDeg)
sinAng, cosAng = math.sin(ang), math.cos(ang)
for i in range(0, 4):
matB[a0,i] = matA[a0,i] * cosAng + matA[a1,i] * sinAng
matB[a1,i] = matA[a0,i] * -sinAng + matA[a1,i] * cosAng
return matB
def RotateX(matA, angDeg): return RotateHlp(matA, angDeg, 1, 2)
def RotateY(matA, angDeg): return RotateHlp(matA, angDeg, 2, 0)
def RotateZ(matA, angDeg): return RotateHlp(matA, angDeg, 0, 1)
def RotateView(matA, angDeg): return RotateZ(RotateY(RotateX(matA, angDeg[0]), angDeg[1]), angDeg[2])
def Multiply(matA, matB):
matC = np.copy(matA)
for i0 in range(0, 4):
for i1 in range(0, 4):
matC[i0,i1] = matB[i0,0] * matA[0,i1] + matB[i0,1] * matA[1,i1] + matB[i0,2] * matA[2,i1] + matB[i0,3] * matA[3,i1]
return matC
def ToMat33(mat44):
mat33 = np.matrix(np.identity(3), copy=False, dtype='float32')
for i0 in range(0, 3):
for i1 in range(0, 3): mat33[i0, i1] = mat44[i0, i1]
return mat33
def TransformVec4(vecA,mat44):
vecB = np.zeros(4, dtype='float32')
for i0 in range(0, 4):
vecB[i0] = vecA[0] * mat44[0,i0] + vecA[1] * mat44[1,i0] + vecA[2] * mat44[2,i0] + vecA[3] * mat44[3,i0]
return vecB
def Perspective(fov, aspectRatio, near, far):
fn, f_n = far + near, far - near
r, t = aspectRatio, 1.0 / math.tan( math.radians(fov) / 2.0 )
return np.matrix( [ [t/r,0,0,0], [0,t,0,0], [0,0,-fn/f_n,-2.0*far*near/f_n], [0,0,-1,0] ] )
def AddToBuffer( buffer, data, count=1 ):
for inx_c in range(0, count):
for inx_s in range(0, len(data)): buffer.append( data[inx_s] )
# initialize glut
glutInit()
# create window
wndW, wndH = 800, 600
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH)
glutInitWindowPosition(0, 0)
glutInitWindowSize(wndW, wndH)
wndID = glutCreateWindow(b'OGL window')
glutDisplayFunc(OnDraw)
glutIdleFunc(OnDraw)
# define icosahedron vertex array opject
icoPts = [
( 0.000, 0.000, 1.000), ( 0.894, 0.000, 0.447), ( 0.276, 0.851, 0.447), (-0.724, 0.526, 0.447),
(-0.724, -0.526, 0.447), ( 0.276, -0.851, 0.447), ( 0.724, 0.526, -0.447), (-0.276, 0.851, -0.447),
(-0.894, 0.000, -0.447), (-0.276, -0.851, -0.447), ( 0.724, -0.526, -0.447), ( 0.000, 0.000, -1.000) ]
icoCol = [ [1.0, 0.0, 0.0], [0.0, 0.0, 1.0], [1.0, 1.0, 0.0], [0.0, 1.0, 0.0], [1.0, 0.5, 0.0], [1.0, 0.0, 1.0] ]
icoIndices = [
2, 0, 1, 3, 0, 2, 4, 0, 3, 5, 0, 4, 1, 0, 5, 11, 7, 6, 11, 8, 7, 11, 9, 8, 11, 10, 9, 11, 6, 10,
1, 6, 2, 2, 7, 3, 3, 8, 4, 4, 9, 5, 5, 10, 1, 2, 6, 7, 3, 7, 8, 4, 8, 9, 5, 9, 10, 1, 10, 6 ]
icoPosData = []
for inx in icoIndices: AddToBuffer( icoPosData, icoPts[inx] )
icoNVData = []
for inx_nv in range(0, len(icoIndices) // 3):
nv = [0.0, 0.0, 0.0]
for inx_p in range(0, 3):
for inx_s in range(0, 3): nv[inx_s] += icoPts[ icoIndices[inx_nv*3 + inx_p] ][inx_s]
AddToBuffer( icoNVData, nv, 3 )
icoVAObj = CreateVAO( [ (3, icoPosData), (3, icoNVData) ] )
# load, compile and link shader
shaderProgram = LinkProgram( [
CompileShader( 'tess.vert', GL_VERTEX_SHADER ),
CompileShader( 'tess.tctrl', GL_TESS_CONTROL_SHADER ),
CompileShader( 'tess.teval', GL_TESS_EVALUATION_SHADER ),
CompileShader( 'tess.frag', GL_FRAGMENT_SHADER )
] )
# get unifor locations
projectionMatLocation = glGetUniformLocation(shaderProgram, "u_projectionMat44")
modelViewMatLocation = glGetUniformLocation(shaderProgram, "u_modelViewMat44")
normalMatLocation = glGetUniformLocation(shaderProgram, "u_normalMat33")
# linke uniform blocks
ubMaterial = UniformBlock(shaderProgram, "UB_material")
ubLightSource = UniformBlock(shaderProgram, "UB_lightSource")
ubMaterial.Link(1)
ubLightSource.Link(2)
# create uniform block buffers
lightSourceBuffer = UniformBlockBuffer(ubLightSource)
lightSourceBuffer.BindDataFloat(b'u_lightSource.ambient', [0.2, 0.2, 0.2, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.diffuse', [0.2, 0.2, 0.2, 1.0])
lightSourceBuffer.BindDataFloat(b'u_lightSource.specular', [1.0, 1.0, 1.0, 1.0])
icoMaterialBuffer = UniformBlockBuffer(ubMaterial)
icoMaterialBuffer.BindDataFloat(b'u_roughness', [0.45])
icoMaterialBuffer.BindDataFloat(b'u_fresnel0', [0.4])
icoMaterialBuffer.BindDataFloat(b'u_color', [0.6, 0.5, 0.8, 1.0])
icoMaterialBuffer.BindDataFloat(b'u_specularTint',[1.0, 0.5, 0.5, 0.8])
# start main loop
startTime = time()
glutMainLoop()
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