Cycles: Replace NaNs in the feature passes with zero

As soon as any feature pass sample is NaN, every pixel which contains that sample in its filter window will be black in the filtered result.
Ideally no NaNs should be generated in the first place, but there are quite a few cases where they are generated in Cycles and now become visible.
So, as a temporary fix, NaNs are now replaced with zero when storing the passes. Ideally these NaNs should be fixed for good, of course.

1 files changed, 17 insertions, 3 deletions

diff --git a/intern/cycles/kernel/kernel_passes.h b/intern/cycles/kernel/kernel_passes.h
index 252c45b37d8..39642a61cb0 100644
--- a/intern/cycles/kernel/kernel_passes.h
+++ b/intern/cycles/kernel/kernel_passes.h
@@ -16,6 +16,20 @@
 
 CCL_NAMESPACE_BEGIN
 
+ccl_device_inline float3 ensure_finite3(float3 a)
+{
+	if(!isfinite(a.x)) a.x = 0.0f;
+	if(!isfinite(a.y)) a.y = 0.0f;
+	if(!isfinite(a.z)) a.z = 0.0f;
+	return a;
+}
+
+ccl_device_inline float ensure_finite(float a)
+{
+	if(!isfinite(a)) return 0.0f;
+	return a;
+}
+
 ccl_device_inline void kernel_write_pass_float(ccl_global float *buffer, int sample, float value)
 {
 	ccl_global float *buf = buffer;
@@ -177,9 +191,9 @@ ccl_device_inline bool kernel_write_denoising_passes(KernelGlobals *kg, ccl_glob
 				/* This bounce is almost specular, so don't write the data yet. */
 				return false;
 			}
-			kernel_write_pass_float3_var(buffer, sample, normal/sum_weight);
-			kernel_write_pass_float3_var(buffer + 6, sample, albedo);
-			kernel_write_pass_float_var(buffer + 12, sample, state->path_length);
+			kernel_write_pass_float3_var(buffer, sample, ensure_finite3(normal/sum_weight));
+			kernel_write_pass_float3_var(buffer + 6, sample, ensure_finite3(albedo));
+			kernel_write_pass_float_var(buffer + 12, sample, ensure_finite(state->path_length));
 		}
 	}
 	else {