Added another 2 checks for if an image has the premul flag set, 1 in the image

compositor node, another in render_realtime_texture.  Note that multilayer images 
in the image compositor node do not respect the premul flag (though I did write 
commented out code for it).

As far as I can tell, the premul option never worked for multilayer images in the
image node, so I'm a little nervous about making it work properly there.

ton, any comments?

1 files changed, 34 insertions, 1 deletions

diff --git a/source/blender/nodes/intern/CMP_nodes/CMP_image.c b/source/blender/nodes/intern/CMP_nodes/CMP_image.c
index 0984aa4bfe1..659629457f8 100644
--- a/source/blender/nodes/intern/CMP_nodes/CMP_image.c
+++ b/source/blender/nodes/intern/CMP_nodes/CMP_image.c
@@ -79,6 +79,21 @@ static CompBuf *node_composit_get_image(RenderData *rd, Image *ima, ImageUser *i
 		stackbuf->rect= ibuf->rect_float;
 	}
 	
+	/*code to respect the premul flag of images; I'm
+	  not sure if this is a good idea for multilayer images,
+	  since it never worked before for them.
+	if (type==CB_RGBA && ima->flag & IMA_DO_PREMUL) {
+		//premul the image
+		int i;
+		float *pixel = stackbuf->rect;
+		
+		for (i=0; i<stackbuf->x*stackbuf->y; i++, pixel += 4) {
+			pixel[0] *= pixel[3];
+			pixel[1] *= pixel[3];
+			pixel[2] *= pixel[3];
+		}
+	}
+	*/
 	return stackbuf;
 };
 
@@ -186,7 +201,25 @@ static void node_composit_exec_image(void *data, bNode *node, bNodeStack **in, b
 		}
 		else {
 			stackbuf= node_composit_get_image(rd, ima, iuser);
-
+			
+			/*respect image premul option*/
+			if (stackbuf->type==CB_RGBA && ima->flag & IMA_DO_PREMUL) {
+			
+				/*first duplicate stackbuf->rect, since it's just a pointer
+				  to the source imbuf, and we don't want to change that.*/
+				stackbuf->rect = MEM_dupallocN(stackbuf->rect);
+				
+				/*premul the image*/
+				int i;
+				float *pixel = stackbuf->rect;
+				
+				for (i=0; i<stackbuf->x*stackbuf->y; i++, pixel += 4) {
+					pixel[0] *= pixel[3];
+					pixel[1] *= pixel[3];
+					pixel[2] *= pixel[3];
+				}
+			}
+			
 			/* put image on stack */	
 			out[0]->data= stackbuf;