Shader Nodes: Add Interpolation modes to Map Range node

Modes: Linear interpolation (default), stepped linear, smoothstep and smootherstep.

This also includes an additional option for the **Clamp node** to switch between **Min Max** (default) and **Range** mode.

This was needed to allow clamping when **To Max** is less than **To Min**.

Reviewed By: JacquesLucke, brecht

Differential Revision: https://developer.blender.org/D5827

2 files changed, 37 insertions, 4 deletions

diff --git a/intern/cycles/kernel/shaders/node_clamp.osl b/intern/cycles/kernel/shaders/node_clamp.osl
index 87dc1ccdb12..d689ba7f809 100644
--- a/intern/cycles/kernel/shaders/node_clamp.osl
+++ b/intern/cycles/kernel/shaders/node_clamp.osl
@@ -16,7 +16,11 @@
 
 #include "stdosl.h"
 
-shader node_clamp(float Value = 1.0, float Min = 0.0, float Max = 1.0, output float Result = 0.0)
+shader node_clamp(string type = "minmax",
+                  float Value = 1.0,
+                  float Min = 0.0,
+                  float Max = 1.0,
+                  output float Result = 0.0)
 {
-  Result = clamp(Value, Min, Max);
+  Result = (type == "range" && (Min > Max)) ? clamp(Value, Max, Min) : clamp(Value, Min, Max);
 }
diff --git a/intern/cycles/kernel/shaders/node_map_range.osl b/intern/cycles/kernel/shaders/node_map_range.osl
index 8a28edf5f35..242ec4271ed 100644
--- a/intern/cycles/kernel/shaders/node_map_range.osl
+++ b/intern/cycles/kernel/shaders/node_map_range.osl
@@ -16,14 +16,43 @@
 
 #include "stdosl.h"
 
-shader node_map_range(float Value = 1.0,
+float safe_divide(float a, float b)
+{
+  return (b != 0.0) ? a / b : 0.0;
+}
+
+float smootherstep(float edge0, float edge1, float x)
+{
+  float t = clamp(safe_divide((x - edge0), (edge1 - edge0)), 0.0, 1.0);
+  return t * t * t * (t * (t * 6.0 - 15.0) + 10.0);
+}
+
+shader node_map_range(string type = "linear",
+                      float Value = 1.0,
                       float FromMin = 0.0,
                       float FromMax = 1.0,
                       float ToMin = 0.0,
                       float ToMax = 1.0,
+                      float Steps = 4.0,
                       output float Result = 0.0)
 {
   if (FromMax != FromMin) {
-    Result = ToMin + ((Value - FromMin) / (FromMax - FromMin)) * (ToMax - ToMin);
+    float Factor = Value;
+    if (type == "stepped") {
+      Factor = (Value - FromMin) / (FromMax - FromMin);
+      Factor = (Steps > 0) ? floor(Factor * (Steps + 1.0)) / Steps : 0.0;
+    }
+    else if (type == "smoothstep") {
+      Factor = (FromMin > FromMax) ? 1.0 - smoothstep(FromMax, FromMin, Value) :
+                                     smoothstep(FromMin, FromMax, Value);
+    }
+    else if (type == "smootherstep") {
+      Factor = (FromMin > FromMax) ? 1.0 - smootherstep(FromMax, FromMin, Value) :
+                                     smootherstep(FromMin, FromMax, Value);
+    }
+    else {
+      Factor = (Value - FromMin) / (FromMax - FromMin);
+    }
+    Result = ToMin + Factor * (ToMax - ToMin);
   }
 }