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.

4 files changed, 53 insertions, 1 deletions

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,