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

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

#include "game/graphics/texture.hpp"

#include <unordered_map>

#include "scope_guard/scope_guard.hpp"

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcomma"
#define STB_IMAGE_IMPLEMENTATION
#include "stb/stb_image.h"
#pragma clang diagnostic pop

#include "game/util/hash.hpp"
#include "helper.hpp"

unsigned char * stbi_load(char const *, int *, int *, int *, int);
void stbi_image_free(void *);

using namespace graphics;

namespace {
  std::unordered_map<std::string, flyweight<texture>> g_textures;
}

static textures::format format(int comps) {
  switch (comps) {
  case 3:
    return textures::format::RGB;
  case 4:
    return textures::format::RGBA;
  default:
    throw;
  }
}

flyweight<texture> texture::create(std::string const & imagefile) {
  auto found = g_textures.find(imagefile);
  if (found != g_textures.end()) { return found->second; }

  int components = 0;
  math::vec2i size;
  unsigned char * data =
      stbi_load(imagefile.c_str(), &size.x(), &size.y(), &components, 0);
  scope(exit) { stbi_image_free(data); };
  auto id = textures::init(format(components), size, data);
  flyweight<texture> fly{id, {id, size}};
  return g_textures.emplace(imagefile, fly).first->second;
}

texture texture::create(char const * data, math::vec2i size) {
  return {textures::init(format(4), size, data), size};
}

texture::texture(unsigned int id, math::vec2i sz)
    : identity<texture>(id), size(sz) {}

texture const texture::WHITE = texture::create("\xFF\xFF\xFF\xFF", {{1, 1}});
texture const texture::DARK_YELLOW =
    texture::create("\x80\x80\x00\xFF", {{1, 1}});
texture const texture::LIGHT_BLUE =
    texture::create("\x80\x80\xFF\xFF", {{1, 1}});