[Bf-blender-cvs] [845ba1a6fb] master: Cycles: Experiment with replacing Sharp Glossy with GGX when Filter Glossy is used

[Sergey Sharybin]

Commit: 845ba1a6fbd29de324b2d193fa6d166c0798baad
Author: Sergey Sharybin
Date:   Wed Dec 14 12:22:57 2016 +0100
Branches: master
https://developer.blender.org/rB845ba1a6fbd29de324b2d193fa6d166c0798baad

Cycles: Experiment with replacing Sharp Glossy with GGX when Filter Glossy is used

The idea is to make it simpler to remove noise from scenes when some prop uses
Sharp glossy closure and causes noise in certain cases. Previously Sharp Glossy
was not affected by Filter Glossy at all, which was quite confusing.

Here is a file which demonstrates the issue: {F417797}

After applying the patch all the noise from the scene is gone.

This change also solves fireflies reported in T50700.

Reviewers: brecht, lukasstockner97

Differential Revision: https://developer.blender.org/D2416

===================================================================

M	intern/cycles/render/nodes.cpp
M	intern/cycles/render/nodes.h

===================================================================

diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index 13b149eddf..3ac3be20bd 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -1931,21 +1931,36 @@ GlossyBsdfNode::GlossyBsdfNode()
 void GlossyBsdfNode::simplify_settings(Scene *scene)
 {
 	if(distribution_orig == NBUILTIN_CLOSURES) {
+		roughness_orig = roughness;
 		distribution_orig = distribution;
 	}
+	else {
+		/* By default we use original values, so we don't worry about restoring
+		 * defaults later one and can only do override when needed.
+		 */
+		roughness = roughness_orig;
+		distribution = distribution_orig;
+	}
 	Integrator *integrator = scene->integrator;
+	ShaderInput *roughness_input = input("Roughness");
 	if(integrator->filter_glossy == 0.0f) {
 		/* Fallback to Sharp closure for Roughness close to 0.
 		 * Note: Keep the epsilon in sync with kernel!
 		 */
-		ShaderInput *roughness_input = input("Roughness");
 		if(!roughness_input->link && roughness <= 1e-4f) {
 			distribution = CLOSURE_BSDF_REFLECTION_ID;
 		}
 	}
 	else {
-		/* Rollback to original distribution when filter glossy is used. */
-		distribution = distribution_orig;
+		/* If filter glossy is used we replace Sharp glossy with GGX so we can
+		 * benefit from closure blur to remove unwanted noise.
+		 */
+		if(roughness_input->link == NULL &&
+		   distribution == CLOSURE_BSDF_REFLECTION_ID)
+		{
+			distribution = CLOSURE_BSDF_MICROFACET_GGX_ID;
+			roughness = 0.0f;
+		}
 	}
 	closure = distribution;
 }
@@ -1953,7 +1968,8 @@ void GlossyBsdfNode::simplify_settings(Scene *scene)
 bool GlossyBsdfNode::has_integrator_dependency()
 {
 	ShaderInput *roughness_input = input("Roughness");
-	return !roughness_input->link && roughness <= 1e-4f;
+	return !roughness_input->link &&
+	       (distribution == CLOSURE_BSDF_REFLECTION_ID || roughness <= 1e-4f);
 }
 
 void GlossyBsdfNode::compile(SVMCompiler& compiler)
@@ -2008,21 +2024,36 @@ GlassBsdfNode::GlassBsdfNode()
 void GlassBsdfNode::simplify_settings(Scene *scene)
 {
 	if(distribution_orig == NBUILTIN_CLOSURES) {
+		roughness_orig = roughness;
 		distribution_orig = distribution;
 	}
+	else {
+		/* By default we use original values, so we don't worry about restoring
+		 * defaults later one and can only do override when needed.
+		 */
+		roughness = roughness_orig;
+		distribution = distribution_orig;
+	}
 	Integrator *integrator = scene->integrator;
+	ShaderInput *roughness_input = input("Roughness");
 	if(integrator->filter_glossy == 0.0f) {
 		/* Fallback to Sharp closure for Roughness close to 0.
 		 * Note: Keep the epsilon in sync with kernel!
 		 */
-		ShaderInput *roughness_input = input("Roughness");
 		if(!roughness_input->link && roughness <= 1e-4f) {
 			distribution = CLOSURE_BSDF_SHARP_GLASS_ID;
 		}
 	}
 	else {
-		/* Rollback to original distribution when filter glossy is used. */
-		distribution = distribution_orig;
+		/* If filter glossy is used we replace Sharp glossy with GGX so we can
+		 * benefit from closure blur to remove unwanted noise.
+		 */
+		if(roughness_input->link == NULL &&
+		   distribution == CLOSURE_BSDF_SHARP_GLASS_ID)
+		{
+			distribution = CLOSURE_BSDF_MICROFACET_GGX_GLASS_ID;
+			roughness = 0.0f;
+		}
 	}
 	closure = distribution;
 }
@@ -2030,7 +2061,8 @@ void GlassBsdfNode::simplify_settings(Scene *scene)
 bool GlassBsdfNode::has_integrator_dependency()
 {
 	ShaderInput *roughness_input = input("Roughness");
-	return !roughness_input->link && roughness <= 1e-4f;
+	return !roughness_input->link &&
+	       (distribution == CLOSURE_BSDF_SHARP_GLASS_ID || roughness <= 1e-4f);
 }
 
 void GlassBsdfNode::compile(SVMCompiler& compiler)
@@ -2085,21 +2117,36 @@ RefractionBsdfNode::RefractionBsdfNode()
 void RefractionBsdfNode::simplify_settings(Scene *scene)
 {
 	if(distribution_orig == NBUILTIN_CLOSURES) {
+		roughness_orig = roughness;
 		distribution_orig = distribution;
 	}
+	else {
+		/* By default we use original values, so we don't worry about restoring
+		 * defaults later one and can only do override when needed.
+		 */
+		roughness = roughness_orig;
+		distribution = distribution_orig;
+	}
 	Integrator *integrator = scene->integrator;
+	ShaderInput *roughness_input = input("Roughness");
 	if(integrator->filter_glossy == 0.0f) {
 		/* Fallback to Sharp closure for Roughness close to 0.
 		 * Note: Keep the epsilon in sync with kernel!
 		 */
-		ShaderInput *roughness_input = input("Roughness");
 		if(!roughness_input->link && roughness <= 1e-4f) {
 			distribution = CLOSURE_BSDF_REFRACTION_ID;
 		}
 	}
 	else {
-		/* Rollback to original distribution when filter glossy is used. */
-		distribution = distribution_orig;
+		/* If filter glossy is used we replace Sharp glossy with GGX so we can
+		 * benefit from closure blur to remove unwanted noise.
+		 */
+		if(roughness_input->link == NULL &&
+		   distribution == CLOSURE_BSDF_REFRACTION_ID)
+		{
+			distribution = CLOSURE_BSDF_MICROFACET_GGX_REFRACTION_ID;
+			roughness = 0.0f;
+		}
 	}
 	closure = distribution;
 }
@@ -2107,7 +2154,8 @@ void RefractionBsdfNode::simplify_settings(Scene *scene)
 bool RefractionBsdfNode::has_integrator_dependency()
 {
 	ShaderInput *roughness_input = input("Roughness");
-	return !roughness_input->link && roughness <= 1e-4f;
+	return !roughness_input->link &&
+	       (distribution == CLOSURE_BSDF_REFRACTION_ID || roughness <= 1e-4f);
 }
 
 void RefractionBsdfNode::compile(SVMCompiler& compiler)
diff --git a/intern/cycles/render/nodes.h b/intern/cycles/render/nodes.h
index eb0f7977dd..d159c80181 100644
--- a/intern/cycles/render/nodes.h
+++ b/intern/cycles/render/nodes.h
@@ -388,7 +388,7 @@ public:
 	bool has_integrator_dependency();
 	ClosureType get_closure_type() { return distribution; }
 
-	float roughness;
+	float roughness, roughness_orig;
 	ClosureType distribution, distribution_orig;
 };
 
@@ -400,7 +400,7 @@ public:
 	bool has_integrator_dependency();
 	ClosureType get_closure_type() { return distribution; }
 
-	float roughness, IOR;
+	float roughness, roughness_orig, IOR;
 	ClosureType distribution, distribution_orig;
 };
 
@@ -412,7 +412,7 @@ public:
 	bool has_integrator_dependency();
 	ClosureType get_closure_type() { return distribution; }
 
-	float roughness, IOR;
+	float roughness, roughness_orig, IOR;
 	ClosureType distribution, distribution_orig;
 };