void
UniformGroup::apply_subroutines(ProgramPtr prog, GLenum shadertype,
const std::unordered_map<std::string, std::string>& subroutines)
{
assert_gl("apply_subroutines:enter");
GLint num_uniform_locations;
glGetProgramStageiv(prog->get_id(), shadertype, GL_ACTIVE_SUBROUTINE_UNIFORM_LOCATIONS, &num_uniform_locations);
std::vector<GLuint> subroutine_mappings;
for(int i = 0; i < num_uniform_locations; ++i)
{
char name[256];
GLsizei length;
glGetActiveSubroutineUniformName(prog->get_id(), shadertype, i, sizeof(name), &length, name);
const auto& it = subroutines.find(name);
if (it == subroutines.end())
{
log_error("unmapped subroutine: %s", name);
}
else
{
GLuint loc = glGetSubroutineIndex(prog->get_id(), shadertype, it->second.c_str());
if (loc == GL_INVALID_INDEX)
{
log_error("unknown subroutine: %s", it->second);
}
else
{
subroutine_mappings.emplace_back(loc);
}
}
}
glUniformSubroutinesuiv(shadertype, subroutine_mappings.size(), subroutine_mappings.data());
assert_gl("apply_subroutines:exit");
}
