Cycles: add light falloff node, with quadratic/linear/constant falloff and a

smoothing factor to reduce high values near the light.
http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Nodes/More#Light_Falloff

Note that this was already possible to do manually with the Ray Length, but
this adds a convenient node for it. This commit also makes the mapping node
min/max option work, fixing #31348.

7 files changed, 133 insertions, 1 deletions

diff --git a/intern/cycles/blender/blender_shader.cpp b/intern/cycles/blender/blender_shader.cpp
index 52d97753db3..b33de789631 100644
--- a/intern/cycles/blender/blender_shader.cpp
+++ b/intern/cycles/blender/blender_shader.cpp
@@ -97,6 +97,13 @@ static void get_tex_mapping(TextureMapping *mapping, BL::ShaderNodeMapping b_map
 	mapping->translation = get_float3(b_mapping.translation());
 	mapping->rotation = get_float3(b_mapping.rotation());
 	mapping->scale = get_float3(b_mapping.scale());
+
+	mapping->use_minmax = b_mapping.use_min() || b_mapping.use_max();
+
+	if(b_mapping.use_min())
+		mapping->min = get_float3(b_mapping.min());
+	if(b_mapping.use_max())
+		mapping->max = get_float3(b_mapping.max());
 }
 
 static ShaderNode *add_node(BL::BlendData b_data, ShaderGraph *graph, BL::ShaderNode b_node)
@@ -323,6 +330,10 @@ static ShaderNode *add_node(BL::BlendData b_data, ShaderGraph *graph, BL::Shader
 			node = new LightPathNode();
 			break;
 		}
+		case BL::ShaderNode::type_LIGHT_FALLOFF: {
+			node = new LightFalloffNode();
+			break;
+		}
 		case BL::ShaderNode::type_TEX_IMAGE: {
 			BL::ShaderNodeTexImage b_image_node(b_node);
 			BL::Image b_image(b_image_node.image());
diff --git a/intern/cycles/kernel/svm/svm.h b/intern/cycles/kernel/svm/svm.h
index 50181c0cf2c..5f4d7bbd0c4 100644
--- a/intern/cycles/kernel/svm/svm.h
+++ b/intern/cycles/kernel/svm/svm.h
@@ -326,6 +326,9 @@ __device_noinline void svm_eval_nodes(KernelGlobals *kg, ShaderData *sd, ShaderT
 			case NODE_MAPPING:
 				svm_node_mapping(kg, sd, stack, node.y, node.z, &offset);
 				break;
+			case NODE_MIN_MAX:
+				svm_node_min_max(kg, sd, stack, node.y, node.z, &offset);
+				break;
 			case NODE_TEX_COORD:
 				svm_node_tex_coord(kg, sd, stack, node.y, node.z);
 				break;
@@ -344,6 +347,9 @@ __device_noinline void svm_eval_nodes(KernelGlobals *kg, ShaderData *sd, ShaderT
 			case NODE_RGB_CURVES:
 				svm_node_rgb_curves(kg, sd, stack, node, &offset);
 				break;
+			case NODE_LIGHT_FALLOFF:
+				svm_node_light_falloff(sd, stack, node);
+				break;
 			case NODE_END:
 			default:
 #ifndef __MULTI_CLOSURE__
diff --git a/intern/cycles/kernel/svm/svm_light_path.h b/intern/cycles/kernel/svm/svm_light_path.h
index ebbcb5be61f..b29dc9cbd45 100644
--- a/intern/cycles/kernel/svm/svm_light_path.h
+++ b/intern/cycles/kernel/svm/svm_light_path.h
@@ -39,5 +39,32 @@ __device void svm_node_light_path(ShaderData *sd, float *stack, uint type, uint
 	stack_store_float(stack, out_offset, info);
 }
 
+/* Light Falloff Node */
+
+__device void svm_node_light_falloff(ShaderData *sd, float *stack, uint4 node)
+{
+	uint strength_offset, out_offset, smooth_offset;
+
+	decode_node_uchar4(node.z, &strength_offset, &smooth_offset, &out_offset, NULL);
+
+	float strength = stack_load_float(stack, strength_offset);
+	uint type = node.y;
+
+	switch(type) {
+		case NODE_LIGHT_FALLOFF_QUADRATIC: break;
+		case NODE_LIGHT_FALLOFF_LINEAR: strength *= sd->ray_length; break;
+		case NODE_LIGHT_FALLOFF_CONSTANT: strength *= sd->ray_length*sd->ray_length; break;
+	}
+
+	float smooth = stack_load_float(stack, smooth_offset);
+
+	if(smooth > 0.0f) {
+		float squared = sd->ray_length*sd->ray_length;
+		strength *= squared/(smooth + squared);
+	}
+
+	stack_store_float(stack, out_offset, strength);
+}
+
 CCL_NAMESPACE_END
 
diff --git a/intern/cycles/kernel/svm/svm_mapping.h b/intern/cycles/kernel/svm/svm_mapping.h
index 6dc74aece08..96645ac97db 100644
--- a/intern/cycles/kernel/svm/svm_mapping.h
+++ b/intern/cycles/kernel/svm/svm_mapping.h
@@ -34,5 +34,16 @@ __device void svm_node_mapping(KernelGlobals *kg, ShaderData *sd, float *stack,
 	stack_store_float3(stack, out_offset, r);
 }
 
+__device void svm_node_min_max(KernelGlobals *kg, ShaderData *sd, float *stack, uint vec_offset, uint out_offset, int *offset)
+{
+	float3 v = stack_load_float3(stack, vec_offset);
+
+	float3 mn = float4_to_float3(read_node_float(kg, offset));
+	float3 mx = float4_to_float3(read_node_float(kg, offset));
+
+	float3 r = min(max(mn, v), mx);
+	stack_store_float3(stack, out_offset, r);
+}
+
 CCL_NAMESPACE_END
 
diff --git a/intern/cycles/kernel/svm/svm_types.h b/intern/cycles/kernel/svm/svm_types.h
index 8037c3964a9..867709f29e0 100644
--- a/intern/cycles/kernel/svm/svm_types.h
+++ b/intern/cycles/kernel/svm/svm_types.h
@@ -90,7 +90,9 @@ typedef enum NodeType {
 	NODE_TEX_CHECKER = 5700,
 	NODE_BRIGHTCONTRAST = 5800,
 	NODE_RGB_RAMP = 5900,
-	NODE_RGB_CURVES = 6000
+	NODE_RGB_CURVES = 6000,
+	NODE_MIN_MAX = 6100,
+	NODE_LIGHT_FALLOFF = 6200
 } NodeType;
 
 typedef enum NodeAttributeType {
@@ -119,6 +121,12 @@ typedef enum NodeLightPath {
 	NODE_LP_ray_length
 } NodeLightPath;
 
+typedef enum NodeLightFalloff {
+	NODE_LIGHT_FALLOFF_QUADRATIC,
+	NODE_LIGHT_FALLOFF_LINEAR,
+	NODE_LIGHT_FALLOFF_CONSTANT
+} NodeLightFalloff;
+
 typedef enum NodeTexCoord {
 	NODE_TEXCO_NORMAL,
 	NODE_TEXCO_OBJECT,
diff --git a/intern/cycles/render/nodes.cpp b/intern/cycles/render/nodes.cpp
index fd26c552f21..afc59098432 100644
--- a/intern/cycles/render/nodes.cpp
+++ b/intern/cycles/render/nodes.cpp
@@ -33,6 +33,11 @@ TextureMapping::TextureMapping()
 	rotation = make_float3(0.0f, 0.0f, 0.0f);
 	scale = make_float3(1.0f, 1.0f, 1.0f);
 
+	min = make_float3(-FLT_MAX, -FLT_MAX, -FLT_MAX);
+	max = make_float3(FLT_MAX, FLT_MAX, FLT_MAX);
+
+	use_minmax = false;
+
 	x_mapping = X;
 	y_mapping = Y;
 	z_mapping = Z;
@@ -69,6 +74,8 @@ bool TextureMapping::skip()
 	
 	if(x_mapping != X || y_mapping != Y || z_mapping != Z)
 		return false;
+	if(use_minmax)
+		return false;
 	
 	return true;
 }
@@ -85,6 +92,12 @@ void TextureMapping::compile(SVMCompiler& compiler, int offset_in, int offset_ou
 	compiler.add_node(tfm.y);
 	compiler.add_node(tfm.z);
 	compiler.add_node(tfm.w);
+
+	if(use_minmax) {
+		compiler.add_node(NODE_MIN_MAX, offset_out, offset_out);
+		compiler.add_node(float3_to_float4(min));
+		compiler.add_node(float3_to_float4(max));
+	}
 }
 
 /* Image Texture */
@@ -1686,6 +1699,54 @@ void LightPathNode::compile(OSLCompiler& compiler)
 	compiler.add(this, "node_light_path");
 }
 
+/* Light Path */
+
+LightFalloffNode::LightFalloffNode()
+: ShaderNode("light_path")
+{
+	add_input("Strength", SHADER_SOCKET_FLOAT, 100.0f);
+	add_input("Smooth", SHADER_SOCKET_FLOAT, 0.0f);
+	add_output("Quadratic", SHADER_SOCKET_FLOAT);
+	add_output("Linear", SHADER_SOCKET_FLOAT);
+	add_output("Constant", SHADER_SOCKET_FLOAT);
+}
+
+void LightFalloffNode::compile(SVMCompiler& compiler)
+{
+	ShaderInput *strength_in = input("Strength");
+	ShaderInput *smooth_in = input("Smooth");
+
+	compiler.stack_assign(strength_in);
+	compiler.stack_assign(smooth_in);
+
+	ShaderOutput *out = output("Quadratic");
+	if(!out->links.empty()) {
+		compiler.stack_assign(out);
+		compiler.add_node(NODE_LIGHT_FALLOFF, NODE_LIGHT_FALLOFF_QUADRATIC,
+			compiler.encode_uchar4(strength_in->stack_offset, smooth_in->stack_offset, out->stack_offset));
+	}
+
+	out = output("Linear");
+	if(!out->links.empty()) {
+		compiler.stack_assign(out);
+		compiler.add_node(NODE_LIGHT_FALLOFF, NODE_LIGHT_FALLOFF_LINEAR,
+			compiler.encode_uchar4(strength_in->stack_offset, smooth_in->stack_offset, out->stack_offset));
+		compiler.add_node(NODE_LIGHT_FALLOFF, NODE_LIGHT_FALLOFF_LINEAR, out->stack_offset);
+	}
+
+	out = output("Constant");
+	if(!out->links.empty()) {
+		compiler.stack_assign(out);
+		compiler.add_node(NODE_LIGHT_FALLOFF, NODE_LIGHT_FALLOFF_CONSTANT,
+			compiler.encode_uchar4(strength_in->stack_offset, smooth_in->stack_offset, out->stack_offset));
+	}
+}
+
+void LightFalloffNode::compile(OSLCompiler& compiler)
+{
+	compiler.add(this, "node_light_falloff");
+}
+
 /* Value */
 
 ValueNode::ValueNode()
diff --git a/intern/cycles/render/nodes.h b/intern/cycles/render/nodes.h
index 364209f8c5e..ff9e3647d01 100644
--- a/intern/cycles/render/nodes.h
+++ b/intern/cycles/render/nodes.h
@@ -41,6 +41,9 @@ public:
 	float3 rotation;
 	float3 scale;
 
+	float3 min, max;
+	bool use_minmax;
+
 	enum Mapping { NONE=0, X=1, Y=2, Z=3 };
 	Mapping x_mapping, y_mapping, z_mapping;
 
@@ -277,6 +280,11 @@ public:
 	SHADER_NODE_CLASS(LightPathNode)
 };
 
+class LightFalloffNode : public ShaderNode {
+public:
+	SHADER_NODE_CLASS(LightFalloffNode)
+};
+
 class ValueNode : public ShaderNode {
 public:
 	SHADER_NODE_CLASS(ValueNode)