GRAPHICS: Enhanced setAlpha method

1 files changed, 4 insertions, 2 deletions

diff --git a/graphics/transparent_surface.cpp b/graphics/transparent_surface.cpp
index a24f7198aa..eb8d3fe5ce 100644
--- a/graphics/transparent_surface.cpp
+++ b/graphics/transparent_surface.cpp
@@ -719,15 +719,17 @@ void TransparentSurface::applyColorKey(uint8 rKey, uint8 gKey, uint8 bKey, bool
 /**
  * Sets alpha channel for all pixels to specified value
  * @param alpha  value of the alpha channel to set
+ * @param skipTransparent  if set to true, then do not touch pixels with alpha=0
  */
-void TransparentSurface::setAlpha(uint8 alpha) {
+void TransparentSurface::setAlpha(uint8 alpha, bool skipTransparent) {
 	assert(format.bytesPerPixel == 4);
 	for (int i = 0; i < h; i++) {
 		for (int j = 0; j < w; j++) {
 			uint32 pix = ((uint32 *)pixels)[i * w + j];
 			uint8 r, g, b, a;
 			format.colorToARGB(pix, a, r, g, b);
-			a = alpha;
+			if (!skipTransparent || a)
+				a = alpha;
 			((uint32 *)pixels)[i * w + j] = format.ARGBToColor(a, r, g, b);
 		}
 	}