cpp-game-engine/graphics/src/shader_program.cpp

//
//  shader_program.cpp
//  graphics
//
//  Created by Sam Jaffe on 7/5/16.
//

#include "game/graphics/shader_program.hpp"

#include <unordered_map>
#include <utility>

#include "game/graphics/shader.hpp"
#include "helper.hpp"

using namespace graphics;

namespace {
  using key_t = std::pair<std::string, std::string>;
  std::unordered_map<key_t, flyweight<shader_program>> g_shader_programs;
}

flyweight<shader_program> shader_program::create(std::string const & frag,
                                                 std::string const & vert) {
  auto key = std::make_pair(frag, vert);
  auto found = g_shader_programs.find(key);
  if (found != g_shader_programs.end()) { return found->second; }

  auto fragment_shader = shader::create(shaders::type::FRAGMENT, frag);
  auto vertex_shader = shader::create(shaders::type::VERTEX, vert);

  shader_program prog{shaders::init(fragment_shader, vertex_shader),
                      fragment_shader, vertex_shader};
  return g_shader_programs.emplace(key, std::move(prog)).first->second;
}

shader_program::shader_program(unsigned int id, flyweight<shader> frag,
                               flyweight<shader> vert)
    : identity<shader_program>(id), fragment_shader(frag), vertex_shader(vert) {
}

void shader_program::activate() const { shaders::activate(id); }