Code refactor: reduce special node types, use generic constant folding.

8 files changed, 191 insertions, 259 deletions

diff --git a/intern/cycles/render/graph.cpp b/intern/cycles/render/graph.cpp
index 4a9b2f1103c..b23fd2a7a8b 100644
--- a/intern/cycles/render/graph.cpp
+++ b/intern/cycles/render/graph.cpp
@@ -290,18 +290,21 @@ void ShaderGraph::disconnect(ShaderInput *to)
 	from->links.erase(remove(from->links.begin(), from->links.end(), to), from->links.end());
 }
 
-void ShaderGraph::relink(vector<ShaderInput*> inputs, vector<ShaderInput*> outputs, ShaderOutput *output)
+void ShaderGraph::relink(ShaderNode *node, ShaderOutput *from, ShaderOutput *to)
 {
-	/* Remove nodes and re-link if output isn't NULL. */
-	foreach(ShaderInput *sock, inputs) {
+	/* Copy because disconnect modifies this list */
+	vector<ShaderInput*> outputs = from->links;
+
+	/* Bypass node by moving all links from "from" to "to" */
+	foreach(ShaderInput *sock, node->inputs) {
 		if(sock->link)
 			disconnect(sock);
 	}
 
 	foreach(ShaderInput *sock, outputs) {
 		disconnect(sock);
-		if(output)
-			connect(output, sock);
+		if(to)
+			connect(to, sock);
 	}
 }
 
@@ -411,39 +414,29 @@ void ShaderGraph::copy_nodes(ShaderNodeSet& nodes, ShaderNodeMap& nnodemap)
 /* Graph simplification */
 /* ******************** */
 
-/* Step 1: Remove unused nodes.
- * Remove nodes which are not needed in the graph, such as proxies,
- * mix nodes with a factor of 0 or 1, emission shaders without contribution...
+/* Step 1: Remove proxy nodes.
+ * These only exists temporarily when exporting groups, and we must remove them
+ * early so that node->attributes() and default links do not see them.
  */
-void ShaderGraph::remove_unneeded_nodes()
+void ShaderGraph::remove_proxy_nodes()
 {
 	vector<bool> removed(num_node_ids, false);
 	bool any_node_removed = false;
 
-	ShaderNode *geom = NULL;
-
-	/* find and unlink proxy nodes */
 	foreach(ShaderNode *node, nodes) {
 		if(node->special_type == SHADER_SPECIAL_TYPE_PROXY) {
-			ProxyNode *proxy = static_cast<ProxyNode*>(node);
+			ConvertNode *proxy = static_cast<ConvertNode*>(node);
 			ShaderInput *input = proxy->inputs[0];
 			ShaderOutput *output = proxy->outputs[0];
 
-			/* temp. copy of the output links list.
-			 * output->links is modified when we disconnect!
-			 */
-			vector<ShaderInput*> links(output->links);
-			ShaderOutput *from = input->link;
-
 			/* bypass the proxy node */
-			if(from) {
-				disconnect(input);
-				foreach(ShaderInput *to, links) {
-					disconnect(to);
-					connect(from, to);
-				}
+			if(input->link) {
+				relink(proxy, output, input->link);
 			}
 			else {
+				/* Copy because disconnect modifies this list */
+				vector<ShaderInput*> links(output->links);
+
 				foreach(ShaderInput *to, links) {
 					/* remove any autoconvert nodes too if they lead to
 					 * sockets with an automatically set default value */
@@ -465,132 +458,16 @@ void ShaderGraph::remove_unneeded_nodes()
 					}
 
 					disconnect(to);
-					
+
 					/* transfer the default input value to the target socket */
 					to->set(input->value);
 					to->set(input->value_string);
 				}
 			}
-			
+
 			removed[proxy->id] = true;
 			any_node_removed = true;
 		}
-		else if(node->special_type == SHADER_SPECIAL_TYPE_BACKGROUND) {
-			BackgroundNode *bg = static_cast<BackgroundNode*>(node);
-
-			if(bg->outputs[0]->links.size()) {
-				/* Black color or zero strength, remove node */
-				if((!bg->inputs[0]->link && bg->inputs[0]->value == make_float3(0.0f, 0.0f, 0.0f)) ||
-				   (!bg->inputs[1]->link && bg->inputs[1]->value.x == 0.0f))
-				{
-					vector<ShaderInput*> inputs = bg->outputs[0]->links;
-
-					relink(bg->inputs, inputs, NULL);
-					removed[bg->id] = true;
-					any_node_removed = true;
-				}
-			}
-		}
-		else if(node->special_type == SHADER_SPECIAL_TYPE_EMISSION) {
-			EmissionNode *em = static_cast<EmissionNode*>(node);
-
-			if(em->outputs[0]->links.size()) {
-				/* Black color or zero strength, remove node */
-				if((!em->inputs[0]->link && em->inputs[0]->value == make_float3(0.0f, 0.0f, 0.0f)) ||
-				   (!em->inputs[1]->link && em->inputs[1]->value.x == 0.0f))
-				{
-					vector<ShaderInput*> inputs = em->outputs[0]->links;
-
-					relink(em->inputs, inputs, NULL);
-					removed[em->id] = true;
-					any_node_removed = true;
-				}
-			}
-		}
-		else if(node->special_type == SHADER_SPECIAL_TYPE_BUMP) {
-			BumpNode *bump = static_cast<BumpNode*>(node);
-
-			if(bump->outputs[0]->links.size()) {
-				/* Height inputs is not connected. */
-				/* TODO(sergey): Ignore bump with zero strength. */
-				if(bump->inputs[0]->link == NULL) {
-					vector<ShaderInput*> inputs = bump->outputs[0]->links;
-					if(bump->inputs[4]->link == NULL) {
-						if(geom == NULL) {
-							geom = new GeometryNode();
-						}
-						relink(bump->inputs, inputs, geom->output("Normal"));
-					}
-					else {
-						relink(bump->inputs, inputs, bump->input("Normal")->link);
-					}
-					removed[bump->id] = true;
-					any_node_removed = true;
-				}
-			}
-		}
-		else if(node->special_type == SHADER_SPECIAL_TYPE_MIX_CLOSURE) {
-			MixClosureNode *mix = static_cast<MixClosureNode*>(node);
-
-			/* remove useless mix closures nodes */
-			if(mix->outputs[0]->links.size() && mix->inputs[1]->link == mix->inputs[2]->link) {
-				ShaderOutput *output = mix->inputs[1]->link;
-				vector<ShaderInput*> inputs = mix->outputs[0]->links;
-
-				relink(mix->inputs, inputs, output);
-				removed[mix->id] = true;
-				any_node_removed = true;
-			}
-		
-			/* remove unused mix closure input when factor is 0.0 or 1.0 */
-			/* check for closure links and make sure factor link is disconnected */
-			if(mix->outputs[0]->links.size() && mix->inputs[1]->link && mix->inputs[2]->link && !mix->inputs[0]->link) {
-				/* factor 0.0 */
-				if(mix->inputs[0]->value.x == 0.0f) {
-					ShaderOutput *output = mix->inputs[1]->link;
-					vector<ShaderInput*> inputs = mix->outputs[0]->links;
-
-					relink(mix->inputs, inputs, output);
-					removed[mix->id] = true;
-					any_node_removed = true;
-				}
-				/* factor 1.0 */
-				else if(mix->inputs[0]->value.x == 1.0f) {
-					ShaderOutput *output = mix->inputs[2]->link;
-					vector<ShaderInput*> inputs = mix->outputs[0]->links;
-
-					relink(mix->inputs, inputs, output);
-					removed[mix->id] = true;
-					any_node_removed = true;
-				}
-			}
-		}
-		else if(node->special_type == SHADER_SPECIAL_TYPE_MIX_RGB) {
-			MixNode *mix = static_cast<MixNode*>(node);
-
-			/* remove unused Mix RGB inputs when factor is 0.0 or 1.0 */
-			/* check for color links and make sure factor link is disconnected */
-			if(mix->outputs[0]->links.size() && mix->inputs[1]->link && mix->inputs[2]->link && !mix->inputs[0]->link) {
-				/* factor 0.0 */
-				if(mix->inputs[0]->value.x == 0.0f) {
-					ShaderOutput *output = mix->inputs[1]->link;
-					vector<ShaderInput*> inputs = mix->outputs[0]->links;
-
-					relink(mix->inputs, inputs, output);
-					removed[mix->id] = true;
-					any_node_removed = true;
-				}
-				/* factor 1.0 */
-				else if(mix->inputs[0]->value.x == 1.0f) {
-					ShaderOutput *output = mix->inputs[2]->link;
-					vector<ShaderInput*> inputs = mix->outputs[0]->links;
-
-					relink(mix->inputs, inputs, output);
-					removed[mix->id] = true;
-					any_node_removed = true;
-				}
-			}
-		}
 	}
 
 	/* remove nodes */
@@ -606,10 +483,6 @@ void ShaderGraph::remove_unneeded_nodes()
 
 		nodes = newnodes;
 	}
-
-	if(geom != NULL) {
-		add(geom);
-	}
 }
 
 /* Step 2: Constant folding.
@@ -634,6 +507,9 @@ void ShaderGraph::constant_fold()
 		traverse_queue.pop();
 		done.insert(node);
 		foreach(ShaderOutput *output, node->outputs) {
+			if (output->links.size() == 0) {
+				continue;
+			}
 			/* Schedule node which was depending on the value,
 			 * when possible. Do it before disconnect.
 			 */
@@ -652,7 +528,7 @@ void ShaderGraph::constant_fold()
 			}
 			/* Optimize current node. */
 			float3 optimized_value = make_float3(0.0f, 0.0f, 0.0f);
-			if(node->constant_fold(output, &optimized_value)) {
+			if(node->constant_fold(this, output, &optimized_value)) {
 				/* Apply optimized value to connected sockets. */
 				vector<ShaderInput*> links(output->links);
 				foreach(ShaderInput *input, links) {
@@ -737,8 +613,7 @@ void ShaderGraph::deduplicate_nodes()
 			}
 			/* TODO(sergey): Consider making it an utility function. */
 			for(int i = 0; i < node->outputs.size(); ++i) {
-				vector<ShaderInput*> inputs = node->outputs[i]->links;
-				relink(node->inputs, inputs, other_node->outputs[i]);
+				relink(node, node->outputs[i], other_node->outputs[i]);
 			}
 			break;
 		}
@@ -771,15 +646,9 @@ void ShaderGraph::break_cycles(ShaderNode *node, vector<bool>& visited, vector<b
 
 void ShaderGraph::clean(Scene *scene)
 {
-	/* Graph simplification:
-	 *  1: Remove unnecessary nodes
-	 *  2: Constant folding
-	 *  3: Simplification
-	 *  4: De-duplication
-	 */
+	/* Graph simplification */
 
-	/* 1: Remove proxy and unnecessary nodes. */
-	remove_unneeded_nodes();
+	/* 1: Remove proxy nodes was already done. */
 
 	/* 2: Constant folding. */
 	constant_fold();
@@ -892,7 +761,7 @@ void ShaderGraph::refine_bump_nodes()
 	 * to "center" input. */
 
 	foreach(ShaderNode *node, nodes) {
-		if(node->name == ustring("bump") && node->input("Height")->link) {
+		if(node->special_type == SHADER_SPECIAL_TYPE_BUMP && node->input("Height")->link) {
 			ShaderInput *bump_input = node->input("Height");
 			ShaderNodeSet nodes_bump;
 
diff --git a/intern/cycles/render/graph.h b/intern/cycles/render/graph.h
index 214199a1c52..2236f51957c 100644
--- a/intern/cycles/render/graph.h
+++ b/intern/cycles/render/graph.h
@@ -76,15 +76,11 @@ enum ShaderBump {
 enum ShaderNodeSpecialType {
 	SHADER_SPECIAL_TYPE_NONE,
 	SHADER_SPECIAL_TYPE_PROXY,
-	SHADER_SPECIAL_TYPE_MIX_CLOSURE,
-	SHADER_SPECIAL_TYPE_MIX_RGB, /* Only Mix subtype */
 	SHADER_SPECIAL_TYPE_AUTOCONVERT,
 	SHADER_SPECIAL_TYPE_GEOMETRY,
 	SHADER_SPECIAL_TYPE_SCRIPT,
-	SHADER_SPECIAL_TYPE_BACKGROUND,
 	SHADER_SPECIAL_TYPE_IMAGE_SLOT,
 	SHADER_SPECIAL_TYPE_CLOSURE,
-	SHADER_SPECIAL_TYPE_EMISSION,
 	SHADER_SPECIAL_TYPE_BUMP,
 };
 
@@ -197,7 +193,7 @@ public:
 
 	/* ** Node optimization ** */
 	/* Check whether the node can be replaced with single constant. */
-	virtual bool constant_fold(ShaderOutput * /*socket*/, float3 * /*optimized_value*/) { return false; }
+	virtual bool constant_fold(ShaderGraph * /*graph*/, ShaderOutput * /*socket*/, float3 * /*optimized_value*/) { return false; }
 
 	/* Simplify settings used by artists to the ones which are simpler to
 	 * evaluate in the kernel but keep the final result unchanged.
@@ -307,9 +303,9 @@ public:
 
 	void connect(ShaderOutput *from, ShaderInput *to);
 	void disconnect(ShaderInput *to);
-	void relink(vector<ShaderInput*> inputs, vector<ShaderInput*> outputs, ShaderOutput *output);
+	void relink(ShaderNode *node, ShaderOutput *from, ShaderOutput *to);
 
-	void remove_unneeded_nodes();
+	void remove_proxy_nodes();
 	void finalize(Scene *scene,
 	              bool do_bump = false,
 	              bool do_osl = false,
diff --git a/intern/cycles/render/mesh.cpp b/intern/cycles/render/mesh.cpp
index cc8519219ed..f8273107e1b 100644
--- a/intern/cycles/render/mesh.cpp
+++ b/intern/cycles/render/mesh.cpp
@@ -1210,7 +1210,7 @@ void MeshManager::device_update_displacement_images(Device *device,
 						                             progress);
 						return;
 					}
-					ImageSlotNode *image_node = static_cast<ImageSlotNode*>(node);
+					ImageSlotTextureNode *image_node = static_cast<ImageSlotTextureNode*>(node);
 					int slot = image_node->slot;
 					if(slot != -1) {
 						bump_images.insert(slot);
diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index 57fb1a78f5b..8e8b99ec5e7 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -1595,10 +1595,12 @@ ConvertNode::ConvertNode(ShaderSocketType from_, ShaderSocketType to_, bool auto
 	from = from_;
 	to = to_;
 
-	if(autoconvert)
-		special_type = SHADER_SPECIAL_TYPE_AUTOCONVERT;
-
-	assert(from != to);
+	if(autoconvert) {
+		if(from == to)
+			special_type = SHADER_SPECIAL_TYPE_PROXY;
+		else
+			special_type = SHADER_SPECIAL_TYPE_AUTOCONVERT;
+	}
 
 	if(from == SHADER_SOCKET_FLOAT)
 		add_input("Val", SHADER_SOCKET_FLOAT);
@@ -1614,6 +1616,8 @@ ConvertNode::ConvertNode(ShaderSocketType from_, ShaderSocketType to_, bool auto
 		add_input("Normal", SHADER_SOCKET_NORMAL);
 	else if(from == SHADER_SOCKET_STRING)
 		add_input("String", SHADER_SOCKET_STRING);
+	else if(from == SHADER_SOCKET_CLOSURE)
+		add_input("Closure", SHADER_SOCKET_CLOSURE);
 	else
 		assert(0);
 
@@ -1631,48 +1635,50 @@ ConvertNode::ConvertNode(ShaderSocketType from_, ShaderSocketType to_, bool auto
 		add_output("Normal", SHADER_SOCKET_NORMAL);
 	else if(to == SHADER_SOCKET_STRING)
 		add_output("String", SHADER_SOCKET_STRING);
+	else if(to == SHADER_SOCKET_CLOSURE)
+		add_output("Closure", SHADER_SOCKET_CLOSURE);
 	else
 		assert(0);
 }
 
-bool ConvertNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
+bool ConvertNode::constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value)
 {
 	ShaderInput *in = inputs[0];
 	float3 value = in->value;
 
 	/* TODO(DingTo): conversion from/to int is not supported yet, don't fold in that case */
 
-	if(socket == outputs[0] && in->link == NULL) {
+	if(in->link == NULL) {
 		if(from == SHADER_SOCKET_FLOAT) {
 			if(to == SHADER_SOCKET_INT)
-			/* float to int */
+				/* float to int */
 				return false;
 			else
-			/* float to float3 */
+				/* float to float3 */
 				*optimized_value = make_float3(value.x, value.x, value.x);
 		}
 		else if(from == SHADER_SOCKET_INT) {
 			if(to == SHADER_SOCKET_FLOAT)
-			/* int to float */
+				/* int to float */
 				return false;
 			else
-			/* int to vector/point/normal */
+				/* int to vector/point/normal */
 				return false;
 		}
 		else if(to == SHADER_SOCKET_FLOAT) {
 			if(from == SHADER_SOCKET_COLOR)
-			/* color to float */
+				/* color to float */
 				optimized_value->x = linear_rgb_to_gray(value);
 			else
-			/* vector/point/normal to float */
+				/* vector/point/normal to float */
 				optimized_value->x = average(value);
 		}
 		else if(to == SHADER_SOCKET_INT) {
 			if(from == SHADER_SOCKET_COLOR)
-			/* color to int */
+				/* color to int */
 				return false;
 			else
-			/* vector/point/normal to int */
+				/* vector/point/normal to int */
 				return false;
 		}
 		else {
@@ -1687,6 +1693,9 @@ bool ConvertNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
 
 void ConvertNode::compile(SVMCompiler& compiler)
 {
+	/* constant folding should eliminate proxy nodes */
+	assert(from != to);
+
 	ShaderInput *in = inputs[0];
 	ShaderOutput *out = outputs[0];
 
@@ -1753,6 +1762,9 @@ void ConvertNode::compile(SVMCompiler& compiler)
 
 void ConvertNode::compile(OSLCompiler& compiler)
 {
+	/* constant folding should eliminate proxy nodes */
+	assert(from != to);
+
 	if(from == SHADER_SOCKET_FLOAT)
 		compiler.add(this, "node_convert_from_float");
 	else if(from == SHADER_SOCKET_INT)
@@ -1769,26 +1781,6 @@ void ConvertNode::compile(OSLCompiler& compiler)
 		assert(0);
 }
 
-/* Proxy */
-
-ProxyNode::ProxyNode(ShaderSocketType type_)
-: ShaderNode("proxy")
-{
-	type = type_;
-	special_type = SHADER_SPECIAL_TYPE_PROXY;
-
-	add_input("Input", type);
-	add_output("Output", type);
-}
-
-void ProxyNode::compile(SVMCompiler& /*compiler*/)
-{
-}
-
-void ProxyNode::compile(OSLCompiler& /*compiler*/)
-{
-}
-
 /* BSDF Closure */
 
 BsdfNode::BsdfNode(bool scattering_)
@@ -2285,8 +2277,6 @@ bool SubsurfaceScatteringNode::has_bssrdf_bump()
 EmissionNode::EmissionNode()
 : ShaderNode("emission")
 {
-	special_type = SHADER_SPECIAL_TYPE_EMISSION;
-
 	add_input("Color", SHADER_SOCKET_COLOR, make_float3(0.8f, 0.8f, 0.8f));
 	add_input("Strength", SHADER_SOCKET_FLOAT, 10.0f);
 	add_input("SurfaceMixWeight", SHADER_SOCKET_FLOAT, 0.0f, ShaderInput::USE_SVM);
@@ -2315,13 +2305,20 @@ void EmissionNode::compile(OSLCompiler& compiler)
 	compiler.add(this, "node_emission");
 }
 
+bool EmissionNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput * /*socket*/, float3 * /*optimized_value*/)
+{
+	ShaderInput *color_in = input("Color");
+	ShaderInput *strength_in = input("Strength");
+
+	return ((!color_in->link && color_in->value == make_float3(0.0f, 0.0f, 0.0f)) ||
+	        (!strength_in->link && strength_in->value.x == 0.0f));
+}
+
 /* Background Closure */
 
 BackgroundNode::BackgroundNode()
 : ShaderNode("background")
 {
-	special_type = SHADER_SPECIAL_TYPE_BACKGROUND;
-
 	add_input("Color", SHADER_SOCKET_COLOR, make_float3(0.8f, 0.8f, 0.8f));
 	add_input("Strength", SHADER_SOCKET_FLOAT, 1.0f);
 	add_input("SurfaceMixWeight", SHADER_SOCKET_FLOAT, 0.0f, ShaderInput::USE_SVM);
@@ -2350,6 +2347,15 @@ void BackgroundNode::compile(OSLCompiler& compiler)
 	compiler.add(this, "node_background");
 }
 
+bool BackgroundNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput * /*socket*/, float3 * /*optimized_value*/)
+{
+	ShaderInput *color_in = input("Color");
+	ShaderInput *strength_in = input("Strength");
+
+	return ((!color_in->link && color_in->value == make_float3(0.0f, 0.0f, 0.0f)) ||
+	        (!strength_in->link && strength_in->value.x == 0.0f));
+}
+
 /* Holdout Closure */
 
 HoldoutNode::HoldoutNode()
@@ -3249,7 +3255,7 @@ ValueNode::ValueNode()
 	add_output("Value", SHADER_SOCKET_FLOAT);
 }
 
-bool ValueNode::constant_fold(ShaderOutput * /*socket*/,
+bool ValueNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput * /*socket*/,
                               float3 *optimized_value)
 {
 	*optimized_value = make_float3(value, value, value);
@@ -3280,7 +3286,7 @@ ColorNode::ColorNode()
 	add_output("Color", SHADER_SOCKET_COLOR);
 }
 
-bool ColorNode::constant_fold(ShaderOutput * /*socket*/,
+bool ColorNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput * /*socket*/,
                               float3 *optimized_value)
 {
 	*optimized_value = value;
@@ -3330,8 +3336,6 @@ void AddClosureNode::compile(OSLCompiler& compiler)
 MixClosureNode::MixClosureNode()
 : ShaderNode("mix_closure")
 {
-	special_type = SHADER_SPECIAL_TYPE_MIX_CLOSURE;
-	
 	add_input("Fac", SHADER_SOCKET_FLOAT, 0.5f);
 	add_input("Closure1", SHADER_SOCKET_CLOSURE);
 	add_input("Closure2", SHADER_SOCKET_CLOSURE);
@@ -3348,6 +3352,37 @@ void MixClosureNode::compile(OSLCompiler& compiler)
 	compiler.add(this, "node_mix_closure");
 }
 
+bool MixClosureNode::constant_fold(ShaderGraph *graph, ShaderOutput * /*socket*/, float3 * /*optimized_value*/)
+{
+	ShaderInput *fac_in = input("Fac");
+	ShaderInput *closure1_in = input("Closure1");
+	ShaderInput *closure2_in = input("Closure2");
+	ShaderOutput *closure_out = output("Closure");
+
+	/* remove useless mix closures nodes */
+	if(closure1_in->link == closure2_in->link) {
+		graph->relink(this, closure_out, closure1_in->link);
+		return true;
+	}
+
+	/* remove unused mix closure input when factor is 0.0 or 1.0 */
+	/* check for closure links and make sure factor link is disconnected */
+	if(closure1_in->link && closure2_in->link && !fac_in->link) {
+		/* factor 0.0 */
+		if(fac_in->value.x == 0.0f) {
+			graph->relink(this, closure_out, closure1_in->link);
+			return true;
+		}
+		/* factor 1.0 */
+		else if(fac_in->value.x == 1.0f) {
+			graph->relink(this, closure_out, closure2_in->link);
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /* Mix Closure */
 
 MixClosureWeightNode::MixClosureWeightNode()
@@ -3480,6 +3515,41 @@ void MixNode::compile(OSLCompiler& compiler)
 	compiler.add(this, "node_mix");
 }
 
+bool MixNode::constant_fold(ShaderGraph *graph, ShaderOutput * /*socket*/, float3 * /*optimized_value*/)
+{
+	if(type != ustring("Mix")) {
+		return false;
+	}
+
+	ShaderInput *fac_in = input("Fac");
+	ShaderInput *color1_in = input("Color1");
+	ShaderInput *color2_in = input("Color2");
+	ShaderOutput *color_out = output("Color");
+
+	/* remove useless mix colors nodes */
+	if(color1_in->link == color2_in->link) {
+		graph->relink(this, color_out, color1_in->link);
+		return true;
+	}
+
+	/* remove unused mix color input when factor is 0.0 or 1.0 */
+	/* check for color links and make sure factor link is disconnected */
+	if(color1_in->link && color2_in->link && !fac_in->link) {
+		/* factor 0.0 */
+		if(fac_in->value.x == 0.0f) {
+			graph->relink(this, color_out, color1_in->link);
+			return true;
+		}
+		/* factor 1.0 */
+		else if(fac_in->value.x == 1.0f) {
+			graph->relink(this, color_out, color2_in->link);
+			return true;
+		}
+	}
+
+	return false;
+}
+
 /* Combine RGB */
 CombineRGBNode::CombineRGBNode()
 : ShaderNode("combine_rgb")
@@ -3588,7 +3658,7 @@ GammaNode::GammaNode()
 	add_output("Color", SHADER_SOCKET_COLOR);
 }
 
-bool GammaNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
+bool GammaNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput *socket, float3 *optimized_value)
 {
 	ShaderInput *color_in = input("Color");
 	ShaderInput *gamma_in = input("Gamma");
@@ -3597,7 +3667,6 @@ bool GammaNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
 		if(color_in->link == NULL && gamma_in->link == NULL) {
 			*optimized_value = svm_math_gamma_color(color_in->value,
 			                                        gamma_in->value.x);
-
 			return true;
 		}
 	}
@@ -4058,14 +4127,13 @@ BlackbodyNode::BlackbodyNode()
 	add_output("Color", SHADER_SOCKET_COLOR);
 }
 
-bool BlackbodyNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
+bool BlackbodyNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput *socket, float3 *optimized_value)
 {
 	ShaderInput *temperature_in = input("Temperature");
 
 	if(socket == output("Color")) {
 		if(temperature_in->link == NULL) {
 			*optimized_value = svm_math_blackbody_color(temperature_in->value.x);
-
 			return true;
 		}
 	}
@@ -4165,7 +4233,7 @@ static ShaderEnum math_type_init()
 
 ShaderEnum MathNode::type_enum = math_type_init();
 
-bool MathNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
+bool MathNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput *socket, float3 *optimized_value)
 {
 	ShaderInput *value1_in = input("Value1");
 	ShaderInput *value2_in = input("Value2");
@@ -4242,7 +4310,7 @@ static ShaderEnum vector_math_type_init()
 
 ShaderEnum VectorMathNode::type_enum = vector_math_type_init();
 
-bool VectorMathNode::constant_fold(ShaderOutput *socket, float3 *optimized_value)
+bool VectorMathNode::constant_fold(ShaderGraph * /*graph*/, ShaderOutput *socket, float3 *optimized_value)
 {
 	ShaderInput *vector1_in = input("Vector1");
 	ShaderInput *vector2_in = input("Vector2");
@@ -4409,6 +4477,28 @@ void BumpNode::compile(OSLCompiler& compiler)
 	compiler.add(this, "node_bump");
 }
 
+bool BumpNode::constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value)
+{
+	ShaderInput *height_in = input("Height");
+	ShaderInput *normal_in = input("Normal");
+
+	if(height_in->link == NULL) {
+		if(normal_in->link == NULL) {
+			GeometryNode *geom = new GeometryNode();
+			graph->add(geom);
+			graph->relink(this, outputs[0], geom->output("Normal"));
+		}
+		else {
+			graph->relink(this, outputs[0], normal_in->link);
+		}
+		return true;
+	}
+
+	/* TODO(sergey): Ignore bump with zero strength. */
+
+	return false;
+}
+
 /* RGBCurvesNode */
 
 RGBCurvesNode::RGBCurvesNode()
diff --git a/intern/cycles/render/nodes.h b/intern/cycles/render/nodes.h
index a5495ff3671..9e93f30e75e 100644
--- a/intern/cycles/render/nodes.h
+++ b/intern/cycles/render/nodes.h
@@ -70,15 +70,6 @@ public:
 
 /* Nodes */
 
-/* Any node which uses image manager's slot should be a subclass of this one. */
-class ImageSlotNode : public ShaderNode {
-public:
-	ImageSlotNode(const char *name_) : ShaderNode(name_) {
-		special_type = SHADER_SPECIAL_TYPE_IMAGE_SLOT;
-	}
-	int slot;
-};
-
 class TextureNode : public ShaderNode {
 public:
 	TextureNode(const char *name_) : ShaderNode(name_) {}
@@ -90,15 +81,13 @@ public:
 	}
 };
 
-class ImageSlotTextureNode : public ImageSlotNode {
+/* Any node which uses image manager's slot should be a subclass of this one. */
+class ImageSlotTextureNode : public TextureNode {
 public:
-	ImageSlotTextureNode(const char *name_) : ImageSlotNode(name_) {}
-	TextureMapping tex_mapping;
-
-	virtual bool equals(const ShaderNode *other) {
-		return ShaderNode::equals(other) &&
-		       tex_mapping.equals(((const ImageSlotTextureNode*)other)->tex_mapping);
+	ImageSlotTextureNode(const char *name_) : TextureNode(name_) {
+		special_type = SHADER_SPECIAL_TYPE_IMAGE_SLOT;
 	}
+	int slot;
 };
 
 class ImageTextureNode : public ImageSlotTextureNode {
@@ -372,7 +361,7 @@ public:
 	ConvertNode(ShaderSocketType from, ShaderSocketType to, bool autoconvert = false);
 	SHADER_NODE_BASE_CLASS(ConvertNode)
 
-	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	ShaderSocketType from, to;
 
@@ -385,23 +374,6 @@ public:
 	}
 };
 
-class ProxyNode : public ShaderNode {
-public:
-	ProxyNode(ShaderSocketType type);
-	SHADER_NODE_BASE_CLASS(ProxyNode)
-
-	ShaderSocketType type;
-
-	virtual bool equals(const ShaderNode * /*other*/)
-	{
-		/* Proxy nodes are created for node groups and can't be duplicated
-		 * actually. So in order to make code a bit more robust in obscure cases
-		 * lets explicitly forbid de-duplication of proxy nodes for now.
-		 */
-		return false;
-	}
-};
-
 class BsdfNode : public ShaderNode {
 public:
 	BsdfNode(bool scattering = false);
@@ -505,6 +477,7 @@ public:
 class EmissionNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(EmissionNode)
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	bool has_surface_emission() { return true; }
 };
@@ -512,6 +485,7 @@ public:
 class BackgroundNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(BackgroundNode)
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 };
 
 class HoldoutNode : public ShaderNode {
@@ -650,7 +624,7 @@ class ValueNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(ValueNode)
 
-	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	float value;
 
@@ -665,7 +639,7 @@ class ColorNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(ColorNode)
 
-	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	float3 value;
 
@@ -684,6 +658,7 @@ public:
 class MixClosureNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(MixClosureNode)
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 };
 
 class MixClosureWeightNode : public ShaderNode {
@@ -701,6 +676,7 @@ public:
 class MixNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(MixNode)
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	virtual int get_group() { return NODE_GROUP_LEVEL_3; }
 
@@ -743,7 +719,7 @@ class GammaNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(GammaNode)
 
-	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	virtual int get_group() { return NODE_GROUP_LEVEL_1; }
 };
@@ -834,7 +810,7 @@ public:
 class BlackbodyNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(BlackbodyNode)
-	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	virtual int get_group() { return NODE_GROUP_LEVEL_3; }
 };
@@ -843,7 +819,7 @@ class MathNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(MathNode)
 	virtual int get_group() { return NODE_GROUP_LEVEL_1; }
-	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	bool use_clamp;
 
@@ -878,7 +854,7 @@ class VectorMathNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(VectorMathNode)
 	virtual int get_group() { return NODE_GROUP_LEVEL_1; }
-	bool constant_fold(ShaderOutput *socket, float3 *optimized_value);
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 
 	ustring type;
 	static ShaderEnum type_enum;
@@ -916,6 +892,7 @@ public:
 class BumpNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(BumpNode)
+	bool constant_fold(ShaderGraph *graph, ShaderOutput *socket, float3 *optimized_value);
 	bool has_spatial_varying() { return true; }
 	virtual int get_feature() {
 		return NODE_FEATURE_BUMP;
diff --git a/intern/cycles/render/osl.cpp b/intern/cycles/render/osl.cpp
index cb3cb8b9b1b..964ed8db3f7 100644
--- a/intern/cycles/render/osl.cpp
+++ b/intern/cycles/render/osl.cpp
@@ -483,11 +483,11 @@ bool OSLCompiler::node_skip_input(ShaderNode *node, ShaderInput *input)
 		if(strcmp(input->name, "Normal") == 0)
 			return true;
 	}
-	else if(node->name == ustring("bump")) {
+	else if(node->special_type == SHADER_SPECIAL_TYPE_BUMP) {
 		if(strcmp(input->name, "Height") == 0)
 			return true;
 	}
-	else if(current_type == SHADER_TYPE_DISPLACEMENT && input->link && input->link->parent->name == ustring("bump"))
+	else if(current_type == SHADER_TYPE_DISPLACEMENT && input->link && input->link->parent->special_type == SHADER_SPECIAL_TYPE_BUMP)
 		return true;
 
 	return false;
diff --git a/intern/cycles/render/shader.cpp b/intern/cycles/render/shader.cpp
index 09a6061abea..797f31ce92d 100644
--- a/intern/cycles/render/shader.cpp
+++ b/intern/cycles/render/shader.cpp
@@ -175,7 +175,7 @@ void Shader::set_graph(ShaderGraph *graph_)
 	 * are needed, since the node attribute callbacks check if their sockets
 	 * are connected but proxy nodes should not count */
 	if(graph_)
-		graph_->remove_unneeded_nodes();
+		graph_->remove_proxy_nodes();
 
 	/* assign graph */
 	delete graph;
diff --git a/intern/cycles/render/svm.cpp b/intern/cycles/render/svm.cpp
index 56fb57e9667..350ef921bc1 100644
--- a/intern/cycles/render/svm.cpp
+++ b/intern/cycles/render/svm.cpp
@@ -365,7 +365,7 @@ uint SVMCompiler::attribute(AttributeStandard std)
 bool SVMCompiler::node_skip_input(ShaderNode * /*node*/, ShaderInput *input)
 {
 	/* nasty exception .. */
-	if(current_type == SHADER_TYPE_DISPLACEMENT && input->link && input->link->parent->name == ustring("bump"))
+	if(current_type == SHADER_TYPE_DISPLACEMENT && input->link && input->link->parent->special_type == SHADER_SPECIAL_TYPE_BUMP)
 		return true;
 	
 	return false;