GLint glGetSubroutineUniformLocation(GLuint program, GLenum shadertype, const GLchar *name);
If name is not the name of a subroutine uniform in the shader stage, -1 is returned, but no error is generated. If name is the name of a subroutine uniform in the shader stage, a value between zero and the value of GL_ACTIVE_SUBROUTINE_LOCATIONS minus one will be returned. Subroutine locations are assigned using consecutive integers in the range from zero to the value of GL_ACTIVE_SUBROUTINE_LOCATIONS minus one for the shader stage. For active subroutine uniforms declared as arrays, the declared array elements are assigned consecutive locations.
GL_INVALID_VALUE is generated if program is not the name of an existing program object.
|Function / Feature Name||2.0||2.1||3.0||3.1||3.2||3.3||4.0||4.1||4.2||4.3||4.4||4.5|