Maths Node: Additional functions

When creating shaders and using maths functions it is expected that Blender should match functions in other DCC applications, game engines and shading languages such as GLSL and OSL.

This patch adds missing functions to the Blender maths node.

Ideally, it would be nice to have these functions available to vectors too but that is not part of this patch.

This patch adds the following functions trunc, snap, wrap, compare, pingpong, sign, radians, degrees, cosh, sinh, tanh, exp, smoothmin and inversesqrt.

Sign function is based on GLSL and OSL functions and returns zero when x == 0.

Differential Revision: https://developer.blender.org/D5957

1 files changed, 62 insertions, 0 deletions

diff --git a/intern/cycles/kernel/shaders/node_math.osl b/intern/cycles/kernel/shaders/node_math.osl
index 13e4c91ba10..1eccb56405b 100644
--- a/intern/cycles/kernel/shaders/node_math.osl
+++ b/intern/cycles/kernel/shaders/node_math.osl
@@ -26,6 +26,35 @@ float safe_modulo(float a, float b)
   return (b != 0.0) ? fmod(a, b) : 0.0;
 }
 
+float fract(float a)
+{
+  return a - floor(a);
+}
+
+/* Adapted from godotengine math_funcs.h. */
+float wrap(float value, float max, float min)
+{
+  float range = max - min;
+  return (range != 0.0) ? value - (range * floor((value - min) / range)) : min;
+}
+
+/* See: https://www.iquilezles.org/www/articles/smin/smin.htm. */
+float smoothmin(float a, float b, float c)
+{
+  if (c != 0.0) {
+    float h = max(c - abs(a - b), 0.0) / c;
+    return min(a, b) - h * h * h * c * (1.0 / 6.0);
+  }
+  else {
+    return min(a, b);
+  }
+}
+
+float pingpong(float a, float b)
+{
+  return (b != 0.0) ? abs(fract((a - b) / (b * 2.0)) * b * 2.0 - b) : 0.0;
+}
+
 float safe_sqrt(float a)
 {
   return (a > 0.0) ? sqrt(a) : 0.0;
@@ -40,6 +69,7 @@ float safe_log(float a, float b)
 shader node_math(string type = "add",
                  float Value1 = 0.5,
                  float Value2 = 0.5,
+                 float Value3 = 0.5,
                  output float Value = 0.0)
 {
   if (type == "add")
@@ -56,8 +86,14 @@ shader node_math(string type = "add",
     Value = safe_log(Value1, Value2);
   else if (type == "sqrt")
     Value = safe_sqrt(Value1);
+  else if (type == "inversesqrt")
+    Value = inversesqrt(Value1);
   else if (type == "absolute")
     Value = fabs(Value1);
+  else if (type == "radians")
+    Value = radians(Value1);
+  else if (type == "degrees")
+    Value = degrees(Value1);
   else if (type == "minimum")
     Value = min(Value1, Value2);
   else if (type == "maximum")
@@ -76,12 +112,26 @@ shader node_math(string type = "add",
     Value = Value1 - floor(Value1);
   else if (type == "modulo")
     Value = safe_modulo(Value1, Value2);
+  else if (type == "trunc")
+    Value = trunc(Value1);
+  else if (type == "snap")
+    Value = floor(safe_divide(Value1, Value2)) * Value2;
+  else if (type == "wrap")
+    Value = wrap(Value1, Value2, Value3);
+  else if (type == "pingpong")
+    Value = pingpong(Value1, Value2);
   else if (type == "sine")
     Value = sin(Value1);
   else if (type == "cosine")
     Value = cos(Value1);
   else if (type == "tangent")
     Value = tan(Value1);
+  else if (type == "sinh")
+    Value = sinh(Value1);
+  else if (type == "cosh")
+    Value = cosh(Value1);
+  else if (type == "tanh")
+    Value = tanh(Value1);
   else if (type == "arcsine")
     Value = asin(Value1);
   else if (type == "arccosine")
@@ -90,6 +140,18 @@ shader node_math(string type = "add",
     Value = atan(Value1);
   else if (type == "arctan2")
     Value = atan2(Value1, Value2);
+  else if (type == "sign")
+    Value = sign(Value1);
+  else if (type == "exponent")
+    Value = exp(Value1);
+  else if (type == "compare")
+    Value = ((Value1 == Value2) || (abs(Value1 - Value2) <= max(Value3, 1e-5))) ? 1.0 : 0.0;
+  else if (type == "multiply_add")
+    Value = Value1 * Value2 + Value3;
+  else if (type == "smoothmin")
+    Value = smoothmin(Value1, Value2, Value3);
+  else if (type == "smoothmax")
+    Value = -(smoothmin(-Value1, -Value2, Value3));
   else
     warning("%s", "Unknown math operator!");
 }