[#18837] if a sunlamp is set to a too high energy, speculars turn black

shr->spec values could be greater then 1.0, causing negative color when using (1.0-shr->spec[i]) as a blending factor.

When shr->spec[i] is 1.0 the mircol is ignored, so only mix the mircol when needed (like clamping the spec).

1 files changed, 9 insertions, 6 deletions

diff --git a/source/blender/render/intern/source/rayshade.c b/source/blender/render/intern/source/rayshade.c
index 75b9557f337..182e60365a6 100644
--- a/source/blender/render/intern/source/rayshade.c
+++ b/source/blender/render/intern/source/rayshade.c
@@ -1239,15 +1239,18 @@ void ray_trace(ShadeInput *shi, ShadeResult *shr)
 			}
 			
 			if(shi->combinedflag & SCE_PASS_REFLECT) {
+				/* values in shr->spec can be greater then 1.0.
+				 * in the case when it is 1.0 diff */
 				
-				f= fr*(1.0f-shr->spec[0]);	f1= 1.0f-i;
-				diff[0]= f*mircol[0] + f1*diff[0];
+				f1= 1.0f-i;
 				
-				f= fg*(1.0f-shr->spec[1]);	f1= 1.0f-i;
-				diff[1]= f*mircol[1] + f1*diff[1];
+				diff[0] *= f1;
+				diff[1] *= f1;
+				diff[2] *= f1;
 				
-				f= fb*(1.0f-shr->spec[2]);	f1= 1.0f-i;
-				diff[2]= f*mircol[2] + f1*diff[2];
+				if(shr->spec[0]<1.0f)	diff[0] += mircol[0] * (fr*(1.0f-shr->spec[0]));
+				if(shr->spec[1]<1.0f)	diff[1] += mircol[1] * (fg*(1.0f-shr->spec[1]));
+				if(shr->spec[2]<1.0f)	diff[2] += mircol[2] * (fb*(1.0f-shr->spec[2]));
 			}
 		}
 	}