+void DrawTransparentBitmap(uint32 * screen, uint32 x, uint32 y, const void * bitmap)
+{
+ uint32 pitch = sdlemuGetOverlayWidthInPixels();
+ uint32 address = x + (y * pitch);
+ uint32 count = 0;
+
+ for(uint32 yy=0; yy<((Bitmap *)bitmap)->height; yy++)
+ {
+ for(uint32 xx=0; xx<((Bitmap *)bitmap)->width; xx++)
+ {
+ uint32 color = ((uint32 *)((Bitmap *)bitmap)->pixelData)[count];
+ uint32 blendedColor = color;
+ uint32 existingColor = *(screen + address + xx + (yy * pitch));
+
+ if (existingColor >> 24 != 0x00) // Pixel needs blending
+ {
+ uint8 trans = color >> 24;
+ uint8 invTrans = trans ^ 0xFF;
+
+ uint8 eRed = existingColor & 0xFF,
+ eGreen = (existingColor >> 8) & 0xFF,
+ eBlue = (existingColor >> 16) & 0xFF,
+
+ nRed = color & 0xFF,
+ nGreen = (color >> 8) & 0xFF,
+ nBlue = (color >> 16) & 0xFF;
+
+ uint32 bRed = (eRed * invTrans + nRed * trans) / 255;
+ uint32 bGreen = (eGreen * invTrans + nGreen * trans) / 255;
+ uint32 bBlue = (eBlue * invTrans + nBlue * trans) / 255;
+
+ blendedColor = 0xFF000000 | bRed | (bGreen << 8) | (bBlue << 16);
+ }
+
+ *(screen + address + xx + (yy * pitch)) = blendedColor;
+ count++;
+ }
+ }
+}