Homebrew Textures block format

[Jim_e]

Sorry, I forgot to post the final code for this for anyone who can need it

void ReorderImageData(u8* src, u8* palette, u8* dst, int width, int height, void(copyFunc)(u8*, u8*, int, u8*, int))
{
    static int tile_order[] = {
         0,  1,  8,  9,  2,  3, 10, 11,
        16, 17, 24, 25, 18, 19, 26, 27,
         4,  5, 12, 13,  6,  7, 14, 15,
        20, 21, 28, 29, 22, 23, 30, 31,

        32, 33, 40, 41, 34, 35, 42, 43,
        48, 49, 56, 57, 50, 51, 58, 59,
        36, 37, 44, 45, 38, 39, 46, 47,
        52, 53, 60, 61, 54, 55, 62, 63
    };


    int idx = 0;
    int i, j;
    for(int y = 0; y < height; y += 8)
    {
        for(int x = 0; x < width; x += 8)
        {
            for(int k = 0; k < 64; ++ k)
            {
                i = (tile_order[k] % 8);
                j = (tile_order[k] - i) / 8;

                int src_idx = (height - (y + j) - 1) * width + (x + i);

                copyFunc(src, palette, src_idx, dst, idx);
      
                idx ++;
            }
        }
    }
}

where copyFunc is a pointer to a function similiar to these

void copyRGB(u8* src, u8* palette, int src_idx, u8* dst, int dst_idx)
{
    dst[dst_idx * 3 + 0] = src[src_idx * 3 + 2];
    dst[dst_idx * 3 + 1] = src[src_idx * 3 + 1];
    dst[dst_idx * 3 + 2] = src[src_idx * 3 + 0];
}

void copyRGBA(u8* src, u8* palette, int src_idx, u8* dst, int dst_idx)
{
    dst[dst_idx * 4 + 0] = src[src_idx * 4 + 3];
    dst[dst_idx * 4 + 1] = src[src_idx * 4 + 2];
    dst[dst_idx * 4 + 2] = src[src_idx * 4 + 1];
    dst[dst_idx * 4 + 3] = src[src_idx * 4 + 0];
}

If your interested in the in the textures internal format. I had to directly access textures for scale2x in gameyob. Steveice implemented an index remapping tool in CTRCommon which you can find here.

But in short this is one way to implement accessing the internal format.

inline u32 gpuTextureIndex(u32 x, u32 y, u32 w, u32 h) {
  return (((y >> 3) * (w >> 3) + (x >> 3)) << 6) + ((x & 1) | ((y & 1) << 1) | ((x & 2) << 1) | ((y & 2) << 2) | ((x & 4) << 2) | ((y & 4) << 3));
}