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

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

#include "game/graphics/material.hpp"

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

using namespace graphics;

namespace {
  using key_t = std::tuple<flyweight<shader_program>, std::string, std::string>;
  std::unordered_map<key_t, flyweight<material>> g_materials;
}

static math::vec2i ZERO{{0, 0}};

flyweight<texture> get_texture(std::string const & texture,
                               std::string const & uniform) {
  if (!texture.empty()) {
    try {
      return texture::create(texture);
    } catch (std::exception const & e) {
      // TODO: Logging
    }
  }
  if (uniform == "u_normalMap") {
    return texture::LIGHT_BLUE;
  } else if (uniform == "u_specularMap") {
    return texture::DARK_YELLOW;
  } else if (uniform == "u_diffuseMap") {
    return texture::WHITE;
  }
  throw;
}

flyweight<material> material::create(shader_program const & sp,
                                     std::string const & texture,
                                     std::string const & uniform) {
  key_t key = std::make_tuple(sp, texture, uniform);
  auto found = g_materials.find(key);
  if (found != g_materials.end()) { return found->second; }

  static unsigned int id{0};
  material mat{++id, sp};
  mat.uniforms.push_back({get_texture(texture, uniform),
                          shaders::uniform_location(sp.id, uniform)});
  flyweight<material> fly{id, mat};
  return g_materials.emplace(key, fly).first->second;
}

material::material(unsigned int id, shader_program const & sp)
    : identity<material>(id), shaders(sp) {}

math::vec2i material::size() const {
  return uniforms.empty() ? ZERO : uniforms.front().texture.actual().size;
}