Fix T53348: Cycles difference between gradient texture on CPU and GPU.

2017-11-23 16:10:38 +01:00
parent e704d8a616
commit e50ed90e4d
2 changed files with 8 additions and 2 deletions
--- a/intern/cycles/kernel/svm/svm_gradient.h
+++ b/intern/cycles/kernel/svm/svm_gradient.h
@@ -46,7 +46,10 @@ ccl_device float svm_gradient(float3 p, NodeGradientType type)
 		return atan2f(y, x) / M_2PI_F + 0.5f;
 	}
 	else {
-		float r = fmaxf(1.0f - sqrtf(x*x + y*y + z*z), 0.0f);
+		/* Bias a little bit for the case where p is a unit length vector,
+		 * to get exactly zero instead of a small random value depending
+		 * on float precision. */
+		float r = fmaxf(0.999999f - sqrtf(x*x + y*y + z*z), 0.0f);

 		if(type == NODE_BLEND_QUADRATIC_SPHERE)
 			return r*r;