Bufix #18942

Composite "Map UV" node was using false UVs (0,0) from neighbouring 
pixels when those pixels were not rendered (or have no UV).

This commit checks for each neighbour sample it takes if the UV was
correctly set. Solves bad errors on edges of UV maps. With FSA even
totally smooth. :)

1 files changed, 37 insertions, 7 deletions

diff --git a/source/blender/nodes/intern/CMP_nodes/CMP_mapUV.c b/source/blender/nodes/intern/CMP_nodes/CMP_mapUV.c
index ae3e5875aae..0a46b02e886 100644
--- a/source/blender/nodes/intern/CMP_nodes/CMP_mapUV.c
+++ b/source/blender/nodes/intern/CMP_nodes/CMP_mapUV.c
@@ -65,18 +65,48 @@ static void do_mapuv(CompBuf *stackbuf, CompBuf *cbuf, CompBuf *uvbuf, float thr
 		for(x=0; x<sx; x++, out+=4, uv+=3, uvnext+=3, uvprev+=3) {
 			if(x>0 && x<sx-1 && y>0 && y<sy-1) {
 				if(uv[2]!=0.0f) {
+					float uv_l, uv_r;
 					
 					/* adaptive sampling, red (U) channel */
-					dx= 0.5f*(fabs(uv[0]-uv[-3]) + fabs(uv[0]-uv[3]));
 					
-					dx+= 0.25f*(fabs(uv[0]-uvprev[-3]) + fabs(uv[0]-uvnext[-3]));
-					dx+= 0.25f*(fabs(uv[0]-uvprev[+3]) + fabs(uv[0]-uvnext[+3]));
+					/* prevent alpha zero UVs to be used */
+					uv_l= uv[-1]!=0.0f? fabs(uv[0]-uv[-3]) : 0.0f;
+					uv_r= uv[ 5]!=0.0f? fabs(uv[0]-uv[ 3]) : 0.0f;
+					
+					//dx= 0.5f*(fabs(uv[0]-uv[-3]) + fabs(uv[0]-uv[3]));
+					dx= 0.5f*(uv_l + uv_r);
+					
+					uv_l= uvprev[-1]!=0.0f? fabs(uv[0]-uvprev[-3]) : 0.0f;
+					uv_r= uvnext[-1]!=0.0f? fabs(uv[0]-uvnext[-3]) : 0.0f;
+					
+					//dx+= 0.25f*(fabs(uv[0]-uvprev[-3]) + fabs(uv[0]-uvnext[-3]));
+					dx+= 0.25f*(uv_l + uv_r);
+						
+					uv_l= uvprev[ 5]!=0.0f? fabs(uv[0]-uvprev[+3]) : 0.0f;
+					uv_r= uvnext[ 5]!=0.0f? fabs(uv[0]-uvnext[+3]) : 0.0f;
+					
+					//dx+= 0.25f*(fabs(uv[0]-uvprev[+3]) + fabs(uv[0]-uvnext[+3]));
+					dx+= 0.25f*(uv_l + uv_r);
 					
 					/* adaptive sampling, green (V) channel */
-					dy= 0.5f*(fabs(uv[1]-uv[-row+1]) + fabs(uv[1]-uv[row+1]));
-							 
-					dy+= 0.25f*(fabs(uv[1]-uvprev[+1-3]) + fabs(uv[1]-uvnext[+1-3]));
-					dy+= 0.25f*(fabs(uv[1]-uvprev[+1+3]) + fabs(uv[1]-uvnext[+1+3]));
+					
+					uv_l= uv[-row+2]!=0.0f? fabs(uv[1]-uv[-row+1]) : 0.0f;
+					uv_r= uv[ row+2]!=0.0f? fabs(uv[1]-uv[ row+1]) : 0.0f;
+					
+					//dy= 0.5f*(fabs(uv[1]-uv[-row+1]) + fabs(uv[1]-uv[row+1]));
+					dy= 0.5f*(uv_l + uv_r);
+					
+					uv_l= uvprev[-1]!=0.0f? fabs(uv[1]-uvprev[+1-3]) : 0.0f;
+					uv_r= uvnext[-1]!=0.0f? fabs(uv[1]-uvnext[+1-3]) : 0.0f;
+					
+					//dy+= 0.25f*(fabs(uv[1]-uvprev[+1-3]) + fabs(uv[1]-uvnext[+1-3]));
+					dy+= 0.25f*(uv_l + uv_r);
+					
+					uv_l= uvprev[ 5]!=0.0f? fabs(uv[1]-uvprev[+1+3]) : 0.0f;
+					uv_r= uvnext[ 5]!=0.0f? fabs(uv[1]-uvnext[+1+3]) : 0.0f;
+					
+					//dy+= 0.25f*(fabs(uv[1]-uvprev[+1+3]) + fabs(uv[1]-uvnext[+1+3]));
+					dy+= 0.25f*(uv_l + uv_r);
 					
 					/* UV to alpha threshold */
 					alpha= 1.0f - threshold*(dx+dy);