graphics-snippets
Changing the geometry with tessellation shaders
A simple OGL 4.0 GLSL shader program that shows that shows how to add details with tessellation shader to the geometry. The program is executed with a python script. To run the script, PyOpenGL and NumPy must be installed.
The basic mesh in this example is an icosahedron that consists of 20 triangles. The tessellation control shader defines how each triangle is divided into a set of many small parts. When tessellating a triangle, the generated data are barycentric coordinates based on the original triangle. The tessellation evaluation shader generates new geometry from the data obtained in this way. In this example, each triangle gets a peak in the middle, which rises outward from the center of the icosahedron. In this way a much more complex geometry is generated than the original icosahedron.
Vertex shader
tess.vert
#version 400
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;
}
Tessellation control shader
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;
}
}
Tessellation evaluation shader
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 );
}
Fragment shader
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;
}
Python script
from OpenGL.GL import *
from OpenGL.GLUT import *
from OpenGL.GLU import *
import numpy
from time import time
import math
import sys
def Cross( a, b ): return ( a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 )
def Dot( a, b ): return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]
def Normalize( v ):
len = math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] )
return (v[0] / len, v[1] / len, v[2] / len)
def IdentityMat44(): return numpy.matrix(numpy.identity(4), copy=False, dtype='float32')
class Camera:
def __init__(self):
self.pos = (0, -1.6, 0.5)
self.target = (0, 0, 0)
self.up = (0, 0, 1)
self.fov_y = 90
self.vp = (800, 600)
self.near = 0.5
self.far = 100.0
def Perspective(self):
fn, f_n = self.far + self.near, self.far - self.near
r, t = self.vp[0] / self.vp[1], 1.0 / math.tan( math.radians( self.fov_y ) / 2.0 )
return numpy.matrix( [ [t/r,0,0,0], [0,t,0,0], [0,0,-fn/f_n,-1], [0,0,-2*self.far*self.near/f_n,0] ] )
def LookAt(self):
mz = Normalize( (self.pos[0]-self.target[0], self.pos[1]-self.target[1], self.pos[2]-self.target[2]) ) # inverse line of sight
mx = Normalize( Cross( self.up, mz ) )
my = Normalize( Cross( mz, mx ) )
tx = Dot( mx, self.pos )
ty = Dot( my, self.pos )
tz = -Dot( mz, self.pos )
return numpy.matrix( [ [mx[0], my[0], mz[0], 0], [mx[1], my[1], mz[1], 0], [mx[2], my[2], mz[2], 0], [tx, ty, tz, 1] ] )
def Translate(matA, trans):
matB = numpy.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 = numpy.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, angRad, a0, a1):
matB = numpy.copy(matA)
sinAng, cosAng = math.sin(angRad), math.cos(angRad)
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, angRad): return RotateHlp(matA, angRad, 1, 2)
def RotateY(matA, angRad): return RotateHlp(matA, angRad, 2, 0)
def RotateZ(matA, angRad): return RotateHlp(matA, angRad, 0, 1)
def RotateView(matA, angRad): return RotateZ(RotateY(RotateX(matA, angRad[0]), angRad[1]), angRad[2])
def Multiply(matA, matB):
matC = numpy.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 = numpy.matrix(numpy.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 = numpy.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
# shader program object
class ShaderProgram:
def __init__( self, shaderList ):
shaderObjs = []
for sh_info in shaderList: shaderObjs.append( self.CompileShader(sh_info[0], sh_info[1] ) )
self.LinkProgram( shaderObjs )
strLengthData = numpy.zeros(1, dtype=int)
arraysizeData = numpy.zeros(1, dtype=int)
typeData = numpy.zeros(1, dtype='uint32')
nameData = numpy.chararray(glGetProgramiv( self.__prog, GL_ACTIVE_ATTRIBUTE_MAX_LENGTH ) + 1)
self.__attributeLocation = {}
for i_attr in range(0, glGetProgramiv( self.__prog, GL_ACTIVE_ATTRIBUTES )):
glGetActiveAttrib( self.__prog, i_attr, nameData.size-1, strLengthData, arraysizeData, typeData, nameData.data )
name = nameData.tostring()[:strLengthData[0]]
self.__attributeLocation[name] = glGetAttribLocation( self.__prog, name )
print( "attribute %-30s at loaction %d" % (name, self.__attributeLocation[name]) )
nameData = numpy.chararray(glGetProgramiv( self.__prog, GL_ACTIVE_UNIFORM_MAX_LENGTH ) + 1)
self.__unifomLocation = {}
for i_attr in range(0, glGetProgramiv( self.__prog, GL_ACTIVE_UNIFORMS )):
glGetActiveUniform( self.__prog, i_attr, nameData.size-1, strLengthData, arraysizeData, typeData, nameData.data )
name = nameData.tostring()[:strLengthData[0]]
self.__unifomLocation[name] = glGetUniformLocation( self.__prog, name )
print( "uniform %-30s at loaction %d" % (name, self.__unifomLocation[name]) )
# glGetFragDataLocation( self.__prog, name )
def Prog( self ):
return self.__prog
def Use(self):
glUseProgram( self.__prog )
def UniformLocation( self, name ):
return self.__unifomLocation[name]
def SetUniformI1( self, name, val ):
if name in self.__unifomLocation: glUniform1i( self.__unifomLocation[name], val )
def SetUniformF1( self, name, arr ):
if name in self.__unifomLocation: glUniform1fv( self.__unifomLocation[name], 1, numpy.array( arr, dtype="float" ) )
def SetUniformF2( self, name, arr ):
if name in self.__unifomLocation: glUniform2fv( self.__unifomLocation[name], 1, numpy.array( arr, dtype="float" ) )
def SetUniformF3( self, name, arr ):
if name in self.__unifomLocation: glUniform3fv( self.__unifomLocation[name], 1, numpy.array( arr, dtype="float" ) )
def SetUniformF4( self, name, arr ):
if name in self.__unifomLocation: glUniform4fv( self.__unifomLocation[name], 1, numpy.array( arr, dtype="float" ) )
def SetUniformM33( self, name, mat ):
if name in self.__unifomLocation: glUniformMatrix3fv( self.__unifomLocation[name], 1, GL_FALSE, mat )
def SetUniformM44( self, name, mat ):
if name in self.__unifomLocation: glUniformMatrix4fv( self.__unifomLocation[name], 1, GL_FALSE, mat )
# read shader program and compile shader
def CompileShader(self, sourceFileName, shaderStage):
with open( sourceFileName, 'r' ) as sourceFile:
sourceCode = sourceFile.read()
nameMap = { GL_COMPUTE_SHADER: 'compute', GL_VERTEX_SHADER: 'vertex', GL_TESS_CONTROL_SHADER: 'tessellation control', GL_TESS_EVALUATION_SHADER: 'tessellation evaluation', 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(self, shaderObjs):
self.__prog = glCreateProgram()
for shObj in shaderObjs: glAttachShader( self.__prog, shObj )
glLinkProgram( self.__prog )
result = glGetProgramiv( self.__prog, GL_LINK_STATUS )
if not ( result ):
print( 'link error:' )
print( glGetProgramInfoLog( self.__prog ) )
sys.exit()
# vertex array object
class VAObject:
def __init__( self, dataArrays, indices = [], type = GL_TRIANGLES, patch_vertices = 3 ):
self.__obj = glGenVertexArrays( 1 )
self.__noOfIndices = len( indices )
self.__indexArr = numpy.array( indices, dtype='uint' )
self.__type = type
self.__patch_vertices = patch_vertices
self.__vertexSize = []
self.__dataLength = []
self.__noOfBuffers = len( dataArrays )
self.__buffers = glGenBuffers( self.__noOfBuffers )
glBindVertexArray( self.__obj )
for i_buffer in range( 0, self.__noOfBuffers ):
vertexSize, dataArr = dataArrays[i_buffer]
self.__vertexSize.append( vertexSize )
self.__dataLength.append( len( dataArr ) )
glBindBuffer( GL_ARRAY_BUFFER, self.__buffers if self.__noOfBuffers == 1 else self.__buffers[i_buffer] )
glBufferData( GL_ARRAY_BUFFER, numpy.array( dataArr, dtype='float32' ), GL_STATIC_DRAW )
glEnableVertexAttribArray( i_buffer )
glVertexAttribPointer( i_buffer, self.__vertexSize[i_buffer], GL_FLOAT, GL_FALSE, 0, None )
self.__iBuffer = glGenBuffers( 1 )
glBindBuffer( GL_ARRAY_BUFFER, 0 )
if self.__noOfIndices > 0:
glBindBuffer( GL_ELEMENT_ARRAY_BUFFER, self.__iBuffer )
glBufferData( GL_ELEMENT_ARRAY_BUFFER, self.__indexArr, GL_STATIC_DRAW )
glBindVertexArray( 0 )
def DrawArray(self):
glBindVertexArray( self.__obj )
if self.__type == GL_PATCHES:
glPatchParameteri( GL_PATCH_VERTICES, self.__patch_vertices )
glDrawArrays( GL_PATCHES, 0, self.__dataLength[0] )
glBindVertexArray( 0 )
def Draw(self):
if self.__noOfIndices == 0:
self.DrawArray()
return
glBindVertexArray( self.__obj )
#for i_buffer in range( 0, self.__noOfBuffers ):
# glBindBuffer( GL_ARRAY_BUFFER, self.__buffers if self.__noOfBuffers == 1 else self.__buffers[i_buffer] )
# glEnableVertexAttribArray( i_buffer )
# glVertexAttribPointer( i_buffer, self.__vertexSize[i_buffer], GL_FLOAT, GL_FALSE, 0, None )
#glDrawElements( self.__type, self.__noOfIndices, GL_UNSIGNED_INT, self.__indexArr )
if self.__type == GL_PATCHES:
glPatchParameteri( GL_PATCH_VERTICES, self.__patch_vertices )
glDrawElements( self.__type, self.__noOfIndices, GL_UNSIGNED_INT, None )
glBindVertexArray( 0 )
# glut window
class Window:
def __init__( self, cx, cy ):
self.__vpsize = ( cx, cy )
glutSetOption( GLUT_MULTISAMPLE, 8 )
glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE | GLUT_ALPHA | GLUT_DEPTH | GLUT_MULTISAMPLE )
glutInitWindowPosition( 0, 0 )
glutInitWindowSize( self.__vpsize[0], self.__vpsize[1] )
self.__id = glutCreateWindow( b'OGL window' )
glutDisplayFunc( self.OnDraw )
glutIdleFunc( self.OnDraw )
def Run( self ):
self.__startTime = time()
glutMainLoop()
# draw event
def OnDraw(self):
self.__vpsize = ( glutGet( GLUT_WINDOW_WIDTH ), glutGet( GLUT_WINDOW_HEIGHT ) )
currentTime = time()
# set up camera
camera = Camera()
camera.vp = self.__vpsize
# set up projection matrix
prjMat = camera.Perspective()
# set up view matrix
viewMat = camera.LookAt()
# 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
modelMat = IdentityMat44()
modelMat = RotateX( modelMat, self.CalcAng( currentTime, 13.0 ) )
modelMat = RotateY( modelMat, self.CalcAng( currentTime, 17.0 ) )
# set up attributes and shader program
glEnable( GL_DEPTH_TEST )
glClearColor( 1, 1, 1, 0 )
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT )
progTess.Use()
progTess.SetUniformM44( b"u_projectionMat44", prjMat )
lightSourceBuffer.BindToTarget()
# draw icosahedron
icoMaterialBuffer.BindToTarget()
modelViewMat = Multiply(viewMat, modelMat)
progTess.SetUniformM44( b"u_modelViewMat44", modelViewMat )
progTess.SetUniformM33( b"u_normalMat33", ToMat33(modelViewMat) )
icoVAO.Draw()
glutSwapBuffers()
def Fract( self, val ): return val - math.trunc(val)
def CalcAng( self, currentTime, intervall ): return self.Fract( (currentTime - self.__startTime) / intervall ) * 2.0 * math.pi
# 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 = numpy.zeros(1, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, intData)
self.count = intData[0]
self.indices = numpy.zeros(self.count, dtype=int)
glGetActiveUniformBlockiv(self.shaderProg, self.index, GL_UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES, self.indices)
self.offsets = numpy.zeros(self.count, dtype=int)
glGetActiveUniformsiv(self.shaderProg, self.count, self.indices, GL_UNIFORM_OFFSET, self.offsets)
strLengthData = numpy.zeros(1, dtype=int)
arraysizeData = numpy.zeros(1, dtype=int)
typeData = numpy.zeros(1, dtype='uint32')
nameData = numpy.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 = numpy.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 = numpy.array(dataArr, dtype='float32')
glBufferSubData(GL_UNIFORM_BUFFER, self.offsets[self.namemap[name]], len(dataArr)*4, dataArray)
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
wnd = Window( 800, 600 )
# 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 )
icoVAO = VAObject( [ (3, icoPosData), (3, icoNVData)], [], GL_PATCHES, 3 )
# load, compile and link shader
progTess = ShaderProgram(
[ ('ogl/tessellation/tess.vert', GL_VERTEX_SHADER),
('ogl/tessellation/tess.tesc', GL_TESS_CONTROL_SHADER),
('ogl/tessellation/tess.tese', GL_TESS_EVALUATION_SHADER),
('ogl/tessellation/tess.frag', GL_FRAGMENT_SHADER ) ] )
# linke uniform blocks
ubMaterial = UniformBlock(progTess.Prog(), "UB_material")
ubLightSource = UniformBlock(progTess.Prog(), "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
wnd.Run()
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