Fix for bug #13363: ray (qmc) shadows had some light leaking issues,

due to jittering of the start position for antialiasing in a pixel.

Now it distributes the start position over the fixed osa sample
positions, instead of of random positions in space. The ugly bit is
that a custom ordering was defined for osa 8/11/16 to ensure that the
first 4 are distributed relatively fair for adaptive sampling to decide
if more samples need to be taken.

1 files changed, 6 insertions, 6 deletions

diff --git a/source/blender/render/intern/source/rendercore.c b/source/blender/render/intern/source/rendercore.c
index 05ff0d3c020..1eb42bca569 100644
--- a/source/blender/render/intern/source/rendercore.c
+++ b/source/blender/render/intern/source/rendercore.c
@@ -1465,7 +1465,7 @@ static void shade_sample_sss(ShadeSample *ssamp, Material *mat, ObjectInstanceRe
 {
 	ShadeInput *shi= ssamp->shi;
 	ShadeResult shr;
-	float texfac, orthoarea, nor[3], alpha;
+	float texfac, orthoarea, nor[3], alpha, sx, sy;
 
 	/* cache for shadow */
 	shi->samplenr= R.shadowsamplenr[shi->thread]++;
@@ -1476,8 +1476,8 @@ static void shade_sample_sss(ShadeSample *ssamp, Material *mat, ObjectInstanceRe
 		shade_input_set_triangle_i(shi, obi, vlr, 0, 1, 2);
 
 	/* center pixel */
-	x += 0.5f;
-	y += 0.5f;
+	sx = x + 0.5f;
+	sy = y + 0.5f;
 
 	/* we estimate the area here using shi->dxco and shi->dyco. we need to
 	   enabled shi->osatex these are filled. we compute two areas, one with
@@ -1486,13 +1486,13 @@ static void shade_sample_sss(ShadeSample *ssamp, Material *mat, ObjectInstanceRe
 	shi->osatex= 1;
 
 	VECCOPY(nor, shi->facenor);
-	calc_view_vector(shi->facenor, x, y);
+	calc_view_vector(shi->facenor, sx, sy);
 	Normalize(shi->facenor);
-	shade_input_set_viewco(shi, x, y, z);
+	shade_input_set_viewco(shi, x, y, sx, sy, z);
 	orthoarea= VecLength(shi->dxco)*VecLength(shi->dyco);
 
 	VECCOPY(shi->facenor, nor);
-	shade_input_set_viewco(shi, x, y, z);
+	shade_input_set_viewco(shi, x, y, sx, sy, z);
 	*area= VecLength(shi->dxco)*VecLength(shi->dyco);
 	*area= MIN2(*area, 2.0f*orthoarea);