#include <stdlib.h>
#include <SDL.h>
#include <SDL_image.h>
#include <iostream>
#include "TextureCache.h"

using namespace std;

GLuint TextureCache::load(const char *fname)
{
    string filename = fname;
    map<string,GLuint>::iterator it = m_cache.find(filename);
    if (it != m_cache.end())
    {
        return it->second;
    }

    GLuint texture;
    SDL_Surface * temp = IMG_Load(filename.c_str());
    if (!temp)
    {
        fprintf(stderr, "Failed to load image '%s'!\n", filename.c_str());
        return 0;
    }

    SDL_PixelFormat fmt;
    fmt.palette = NULL;
    fmt.BitsPerPixel = 32;
    fmt.BytesPerPixel = 4;
    fmt.Rmask = 0x000000FF;
    fmt.Gmask = 0x0000FF00;
    fmt.Bmask = 0x00FF0000;
    fmt.Amask = 0xFF000000;
    fmt.Rshift = 0;
    fmt.Gshift = 8;
    fmt.Bshift = 16;
    fmt.Ashift = 24;

    SDL_Surface * texsurf = SDL_ConvertSurface(temp, &fmt, SDL_SWSURFACE);
    SDL_FreeSurface(temp);
    if (!texsurf)
    {
        fprintf(stderr, "'%s' was not converted properly!\n", filename.c_str());
        return 0;
    }
    unsigned int * pixels = new unsigned int[texsurf->w * texsurf->h];
    int y;
    unsigned int dstOffset = texsurf->w * (texsurf->h - 1);
    unsigned int srcOffset = 0;
    for (y = 0; y < texsurf->h; y++)
    {
        memcpy(pixels + dstOffset,
            ((unsigned int *)texsurf->pixels) + srcOffset,
            texsurf->w << 2);
        dstOffset -= texsurf->w;
        srcOffset += texsurf->w;
    }
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texsurf->w, texsurf->h, 0,
        GL_RGBA, GL_UNSIGNED_BYTE, pixels);

    SDL_FreeSurface(texsurf);
    delete[] pixels;

    m_cache[filename] = texture;
    return texture;
}