gimp r27269 - in trunk: . app/gegl

[martinn svn gnome org]

Author: martinn
Date: Mon Oct 13 19:27:43 2008
New Revision: 27269
URL: http://svn.gnome.org/viewvc/gimp?rev=27269&view=rev

Log:
* app/gegl/gimpoperationadditionmode.c
(gimp_operation_addition_mode_process): Update with a new version
that is the best known so far (maybe it's even correct?).


Modified:
   trunk/ChangeLog
   trunk/app/gegl/gimpoperationadditionmode.c

Modified: trunk/app/gegl/gimpoperationadditionmode.c
==============================================================================
--- trunk/app/gegl/gimpoperationadditionmode.c	(original)
+++ trunk/app/gegl/gimpoperationadditionmode.c	Mon Oct 13 19:27:43 2008
@@ -72,11 +72,21 @@
   while (samples--)
     {
 #if 1
+      // Best so far (maybe even correct?)
+      dest[RED_PIX]   = src[RED_PIX]   + aux[RED_PIX]   * aux[ALPHA_PIX];
+      dest[GREEN_PIX] = src[GREEN_PIX] + aux[GREEN_PIX] * aux[ALPHA_PIX];
+      dest[BLUE_PIX]  = src[BLUE_PIX]  + aux[BLUE_PIX]  * aux[ALPHA_PIX];
+      dest[ALPHA_PIX] = src[ALPHA_PIX];
+#else
+      // Wrong, doesn't take layer opacity of Addition-mode layer into
+      // account
       dest[RED_PIX]   = src[RED_PIX]   + aux[RED_PIX];
       dest[GREEN_PIX] = src[GREEN_PIX] + aux[GREEN_PIX];
       dest[BLUE_PIX]  = src[BLUE_PIX]  + aux[BLUE_PIX];
       dest[ALPHA_PIX] = src[ALPHA_PIX];
-#else
+
+      // Wrong, toggling visibility of completely transparent
+      // Addition-mode layer changes projection
       dest[RED_PIX]   = src[RED_PIX]   * src[ALPHA_PIX] + aux[RED_PIX]   * aux[ALPHA_PIX];
       dest[GREEN_PIX] = src[GREEN_PIX] * src[ALPHA_PIX] + aux[GREEN_PIX] * aux[ALPHA_PIX];
       dest[BLUE_PIX]  = src[BLUE_PIX]  * src[ALPHA_PIX] + aux[BLUE_PIX]  * aux[ALPHA_PIX];