private static void PaintAt(int x, int y, System.Drawing.Color paint, ProcessorState state)
{
int idx = Util.toID(x, y, width, height, kColorStride);
state.overlay_bitmap_bits_[idx] = paint.B;
state.overlay_bitmap_bits_[idx + 1] = paint.G;
state.overlay_bitmap_bits_[idx + 2] = paint.R;
}