GL_ARB_blend_func_extended
http://www.opengl.org/registry/specs/ARB/blend_func_extended.txt
GL_ARB_blend_func_extended
GL_SRC1_COLOR 0x88F9
GL_ONE_MINUS_SRC1_COLOR 0x88FA
GL_ONE_MINUS_SRC1_ALPHA 0x88FB
GL_MAX_DUAL_SOURCE_DRAW_BUFFERS 0x88FC
void glBindFragDataLocationIndexed (GLuint program, GLuint colorNumber, GLuint index, const GLchar * name)
GLint glGetFragDataIndex (GLuint program, const GLchar * name)