static void
RenderLayers(render_entry Entry);

static bool32
CheckQueue(uint16 Index)
{
    bool32 Result = 0;
    uint32 Q = SDL_AtomicGet(&QueuedEntries);
    uint32 C = SDL_AtomicGet(&CurrentEntry);
    if (Q > C)
    {
        if (SDL_AtomicCAS(&CurrentEntry, C, C + 1)) {
            // printf("C: %i START: F%i Thread %i, region X%i Y%i\n", C, Entry->FrameNumber, Index, Entry->RenderRegion.Min.x, Entry->RenderRegion.Min.y);
            RenderLayers(Entries[C]);
            // printf("END: F%i Thread %i, region X%i Y%i\n", Entry->FrameNumber, Index, Entry->RenderRegion.Min.x, Entry->RenderRegion.Min.y);
            SDL_AtomicAdd(&CompletedEntries, 1);
            Result = 1;
        }
    }
    return Result;
}

static int
TestThread(void *ptr)
{
    uint16 Index = *(uint16 *)ptr;
    for(;;)
    {
        if (!CheckQueue(Index))
        {
            SDL_SemWait(Semaphore);
        }
    }
}

static bool32
Threading_IsActive()
{
    uint32 C = SDL_AtomicGet(&CompletedEntries);
    Assert(C < 17);
    return (C == 16) ? false : true;
}

static void
Threading_BitmapOp(void *Data, void *OutputBuffer, rectangle InitialRenderRegion)
{
    uint16 TileWidth = (InitialRenderRegion.Max.x - InitialRenderRegion.Min.x) / 4;
    uint16 TileHeight = (InitialRenderRegion.Max.y - InitialRenderRegion.Min.y) / 4;

    SDL_AtomicSet(&QueuedEntries, 0);
    SDL_AtomicSet(&CurrentEntry, 0);
    SDL_AtomicSet(&CompletedEntries, 0);

    for (int y = 0; y < 4; y++) {
        for (int x = 0; x < 4; x++) {
            // if (x == y) {
                rectangle RenderRegion = { TileWidth*x, TileHeight*y, TileWidth + TileWidth*x, TileHeight + TileHeight*y };

                RenderRegion.Min.x -= RenderRegion.Min.x % 8;
                RenderRegion.Min.y -= RenderRegion.Min.y % 8;
                RenderRegion.Max.x -= RenderRegion.Max.x % 8;
                RenderRegion.Max.y -= RenderRegion.Max.y % 8;

                if (RenderRegion.Max.x > InitialRenderRegion.Max.x)
                    RenderRegion.Max.x = InitialRenderRegion.Max.x;
                if (RenderRegion.Max.y > InitialRenderRegion.Max.y)
                    RenderRegion.Max.y = InitialRenderRegion.Max.y;

                if (x == 3)
                    RenderRegion.Max.x = InitialRenderRegion.Max.x;
                if (y == 3)
                    RenderRegion.Max.y = InitialRenderRegion.Max.y;

                render_entry Entry = { Data, OutputBuffer, RenderRegion };

                uint32 Q = SDL_AtomicGet(&QueuedEntries);
                *(Entries + Q) = Entry;
                SDL_AtomicAdd(&QueuedEntries, 1);
                SDL_SemPost(Semaphore);
            }
        // }
    }
}