Bugfix for defocus node gamma correct. It applied gamma correct to

a premul image but that doesn't work correct. Now it depremuls and
premuls again around the gamma correction. Better solution might be
possible, but this gives compatible results.

3 files changed, 38 insertions, 1 deletions

diff --git a/source/blender/nodes/intern/CMP_nodes/CMP_defocus.c b/source/blender/nodes/intern/CMP_nodes/CMP_defocus.c
index 866bf406d1e..f8be69d8092 100644
--- a/source/blender/nodes/intern/CMP_nodes/CMP_defocus.c
+++ b/source/blender/nodes/intern/CMP_nodes/CMP_defocus.c
@@ -798,16 +798,22 @@ static void node_composit_exec_defocus(void *data, bNode *node, bNodeStack **in,
 	// ok, process
 	old = img;
 	if (nqd->gamco) {
-		// gamma correct, blender func is simplified, fixed value & RGBA only, should make user param
+		// gamma correct, blender func is simplified, fixed value & RGBA only,
+		// should make user param. also depremul and premul afterwards, gamma
+		// correction can't work with premul alpha
 		old = dupalloc_compbuf(img);
+		premul_compbuf(old, 1);
 		gamma_correct_compbuf(old, 0);
+		premul_compbuf(old, 0);
 	}
 	
 	new = alloc_compbuf(old->x, old->y, old->type, 1);
 	defocus_blur(node, new, old, zbuf_use, in[1]->vec[0]*nqd->scale);
 	
 	if (nqd->gamco) {
+		premul_compbuf(new, 1);
 		gamma_correct_compbuf(new, 1);
+		premul_compbuf(new, 0);
 		free_compbuf(old);
 	}
 	if(node->exec & NODE_BREAK) {
diff --git a/source/blender/nodes/intern/CMP_util.c b/source/blender/nodes/intern/CMP_util.c
index eee33e33ff5..21e0f034a15 100644
--- a/source/blender/nodes/intern/CMP_util.c
+++ b/source/blender/nodes/intern/CMP_util.c
@@ -575,6 +575,36 @@ void gamma_correct_compbuf(CompBuf *img, int inversed)
    }
 }
 
+void premul_compbuf(CompBuf *img, int inversed)
+{
+   float *drect;
+   int x;
+
+   if(img->type!=CB_RGBA) return;
+
+   drect= img->rect;
+   if(inversed) {
+      for(x=img->x*img->y; x>0; x--, drect+=4) {
+		 if(fabs(drect[3]) < 1e-5f) {
+			 drect[0]= 0.0f;
+			 drect[1]= 0.0f;
+			 drect[2]= 0.0f;
+		 }
+		 else {
+			 drect[0] /= drect[3];
+			 drect[1] /= drect[3];
+			 drect[2] /= drect[3];
+		 }
+      }
+   }
+   else {
+      for(x=img->x*img->y; x>0; x--, drect+=4) {
+		 drect[0] *= drect[3];
+		 drect[1] *= drect[3];
+		 drect[2] *= drect[3];
+      }
+   }
+}
 
 
 
diff --git a/source/blender/nodes/intern/CMP_util.h b/source/blender/nodes/intern/CMP_util.h
index 7cb10b75f3a..6fa5251710a 100644
--- a/source/blender/nodes/intern/CMP_util.h
+++ b/source/blender/nodes/intern/CMP_util.h
@@ -176,6 +176,7 @@ void do_hsva_to_rgba(bNode *node, float *out, float *in);
 void do_ycca_to_rgba(bNode *node, float *out, float *in);
 
 void gamma_correct_compbuf(CompBuf *img, int inversed);
+void premul_compbuf(CompBuf *img, int inversed);
 void convolve(CompBuf* dst, CompBuf* in1, CompBuf* in2);
 
 extern void node_ID_title_cb(void *node_v, void *unused_v);