Current File : //usr/share/doc/python3-freetype/examples/shader.py
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# -----------------------------------------------------------------------------
# Copyright (C) 2009-2010 Nicolas P. Rougier
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
# -----------------------------------------------------------------------------
#
# Copyright Tristam Macdonald 2008.
#
# Distributed under the Boost Software License, Version 1.0
# (see http://www.boost.org/LICENSE_1_0.txt)
#
''' Base shader class.
Example:
--------
shader = Shader()
shader.bind()
glActiveTexture(GL_TEXTURE1)
glBindTexture(lut.target, lut.id)
shader.uniformi('lut', 1)
glActiveTexture(GL_TEXTURE0)
glBindTexture(texture.target, texture.id)
shader.uniformi('texture', 0)
shader.uniformf('pixel', 1.0/texture.width, 1.0/texture.height)
texture.blit(x,y,w,h)
shader.unbind()
'''
import os
import OpenGL.GL as gl
import ctypes
class Shader:
''' Base shader class. '''
def __init__(self, vert = None, frag = None, name=''):
''' vert, frag and geom take arrays of source strings
the arrays will be concatenated into one string by OpenGL.'''
self.uniforms = {}
self.name = name
# create the program handle
self.handle = gl.glCreateProgram()
# we are not linked yet
self.linked = False
# create the vertex shader
self._build_shader(vert, gl.GL_VERTEX_SHADER)
# create the fragment shader
self._build_shader(frag, gl.GL_FRAGMENT_SHADER)
# the geometry shader will be the same, once pyglet supports the
# extension self.createShader(frag, GL_GEOMETRY_SHADER_EXT) attempt to
# link the program
self._link()
def _build_shader(self, strings, stype):
''' Actual building of the shader '''
count = len(strings)
# if we have no source code, ignore this shader
if count < 1:
return
# create the shader handle
shader = gl.glCreateShader(stype)
# Upload shader code
gl.glShaderSource(shader, strings)
# compile the shader
gl.glCompileShader(shader)
# retrieve the compile status
status = gl.glGetShaderiv(shader, gl.GL_COMPILE_STATUS)
# if compilation failed, print the log
if not status:
# display the log
print (gl.glGetShaderInfoLog(shader))
else:
# all is well, so attach the shader to the program
gl.glAttachShader(self.handle, shader)
def _link(self):
''' Link the program '''
gl.glLinkProgram(self.handle)
# retrieve the link status
temp = ctypes.c_int(0)
gl.glGetProgramiv(self.handle, gl.GL_LINK_STATUS, ctypes.byref(temp))
# if linking failed, print the log
if not temp:
# retrieve the log length
gl.glGetProgramiv(self.handle,
gl.GL_INFO_LOG_LENGTH, ctypes.byref(temp))
# create a buffer for the log
#buffer = ctypes.create_string_buffer(temp.value)
# retrieve the log text
log = gl.glGetProgramInfoLog(self.handle) #, temp, None, buffer)
# print the log to the console
print (log)
else:
# all is well, so we are linked
self.linked = True
def bind(self):
''' Bind the program, i.e. use it. '''
gl.glUseProgram(self.handle)
def unbind(self):
''' Unbind whatever program is currently bound - not necessarily this
program, so this should probably be a class method instead. '''
gl.glUseProgram(0)
def uniformf(self, name, *vals):
''' Uploads float uniform(s), program must be currently bound. '''
loc = self.uniforms.get(name,
gl.glGetUniformLocation(self.handle,name))
self.uniforms[name] = loc
# Check there are 1-4 values
if len(vals) in range(1, 5):
# Select the correct function
{ 1 : gl.glUniform1f,
2 : gl.glUniform2f,
3 : gl.glUniform3f,
4 : gl.glUniform4f
# Retrieve uniform location, and set it
}[len(vals)](loc, *vals)
def uniformi(self, name, *vals):
''' Upload integer uniform(s), program must be currently bound. '''
loc = self.uniforms.get(name,
gl.glGetUniformLocation(self.handle,name))
self.uniforms[name] = loc
# Checks there are 1-4 values
if len(vals) in range(1, 5):
# Selects the correct function
{ 1 : gl.glUniform1i,
2 : gl.glUniform2i,
3 : gl.glUniform3i,
4 : gl.glUniform4i
# Retrieves uniform location, and set it
}[len(vals)](loc, *vals)
def uniform_matrixf(self, name, mat):
''' Upload uniform matrix, program must be currently bound. '''
loc = self.uniforms.get(name,
gl.glGetUniformLocation(self.handle,name))
self.uniforms[name] = loc
# Upload the 4x4 floating point matrix
gl.glUniformMatrix4fv(loc, 1, False, (ctypes.c_float * 16)(*mat))
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