#3598

Uninitialized 'alpha' flag in Image texture could cause render errors.
Didn't show in OSX though... (stupid system here inits stack to zero).
But, Ken Hughes found this, so all credits are for him!

source/blender/render/intern/source/imagetexture.c

@@ -496,6 +496,8 @@ static void boxsample(ImBuf *ibuf, float minx, float miny, float maxx, float max
 	rf->ymin= miny*(ibuf->y);
 	rf->ymax= maxy*(ibuf->y);
 
+	texr.talpha= texres->talpha;	/* is read by boxsample_clip */
+	
 	if(imapextend) {
 		CLAMP(rf->xmin, 0.0f, ibuf->x-1);
 		CLAMP(rf->xmax, 0.0f, ibuf->x-1);