Problems with coordinate_mode = 1 (math coords)

[raivis-berzins]

When using math coordinates and drawing an image with ever-increasing x and y coordinates, the image itself is flipped vertically and still moves from top-left to bottom-right, instead of the expected behavior of being upright and moving from bottom-left to top-right.

Code:

int main(int argc, char* args[])
{
    GPU_Target *target = GPU_Init(1024, 576, GPU_DEFAULT_INIT_FLAGS);
    if (!target)
    {
        GPU_LogError("no target");
        return 0;
    }

    GPU_SetCoordinateMode(1);
    GPU_Image *img =  GPU_LoadImage("data/test.png");
    
    float pos_x = 0.0f;
    float pos_y = 0.0f;

    float x_virt, y_virt;
    GPU_GetVirtualCoords(target, &x_virt, &y_virt, 5.0f, 5.0f);

    GPU_LogInfo("x, y: %f, %f\n", x_virt, y_virt);
    // output:
    // x, y: 5.000000, 571.000000
    // (as expected)

    bool quit = false;
    while (!quit)
    {
        SDL_Event e;
        while (SDL_PollEvent(&e))
        {
            if (e.type == SDL_QUIT)
            {
                quit = true;
            }
        }
        
        GPU_ClearRGBA(target, 220, 100, 200, 255);

        GPU_Blit(img, NULL, target, pos_x, pos_y);
        pos_x += 0.25f;
        pos_y += 0.25f;
        GPU_Flip(target);
    }
    return 0;
}

Behavior:
https://user-images.githubusercontent.com/67956318/103039776-59367580-457a-11eb-8ca0-169f7daef62d.mp4

If GPU_SetCoordinateMode(1); is omitted, everything works as expected: the image is normal, and the GPU_LogInfo prints x, y: 5.000000, 5.000000