/**
 * @file texture.cpp
 * Handles all texture loading 
 *
 * Copyright (C) 2019  Belle-Isle, Andrew <drumsetmonkey@gmail.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "texture.hpp"

#include <unordered_map>
#include <iostream>

// Stores a list of all textures we've already loaded. This makes sure we don't
// waste our precious CPU cycles reloading a texture.
std::unordered_map<std::string, GLuint> textureCache;

Texture::Texture(std::string filename)
{
    // Search to see if this texture has already been loading
    auto cacheSearch = textureCache.find(filename);

    if (cacheSearch == textureCache.end()) {
    // If this texture hasn't been loading

        unsigned char* image = SOIL_load_image(filename.c_str(),
                                               &width, &height, 0,
                                               SOIL_LOAD_RGBA);

        glGenTextures(1, &tex);
        glBindTexture(GL_TEXTURE_2D, tex);
        glPixelStoref(GL_UNPACK_ALIGNMENT, 1);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0,
                     GL_RGBA, GL_UNSIGNED_BYTE, image);

        SOIL_free_image_data(image);

        // Add new texture to the texture cache
        textureCache.emplace(filename, tex);

    } else {
    // If this texture has been loaded, just return the loaded texture
        tex = cacheSearch->second;
    }
}