Cycles: Expose volume voxel data interpolation to the interface

It is per-material setting which could be found under the Volume settings
in the material and world context buttons.

There could still be some code-wise improvements, like using variable-size
macro for interp3d instead of having interp3d_ex to which you can pass the
interpolation method.

1 files changed, 19 insertions, 0 deletions

diff --git a/intern/cycles/blender/addon/properties.py b/intern/cycles/blender/addon/properties.py
index 597ac1a9ce0..05a6f70d423 100644
--- a/intern/cycles/blender/addon/properties.py
+++ b/intern/cycles/blender/addon/properties.py
@@ -114,6 +114,11 @@ enum_volume_sampling = (
     ('MULTIPLE_IMPORTANCE', "Multiple Importance", "Combine distance and equi-angular sampling for volumes where neither method is ideal"),
     )
 
+enum_volume_interpolation = (
+    ('LINEAR', "Linear", "Good smoothness and speed"),
+    ('CUBIC', 'Cubic', 'Smoothed high quality interpolation, but slower')
+    )
+
 
 class CyclesRenderSettings(bpy.types.PropertyGroup):
     @classmethod
@@ -617,6 +622,13 @@ class CyclesMaterialSettings(bpy.types.PropertyGroup):
                 default='DISTANCE',
                 )
 
+        cls.volume_interpolation = EnumProperty(
+                name="Volume Interpolation",
+                description="Interpolation method to use for volumes",
+                items=enum_volume_interpolation,
+                default='LINEAR',
+                )
+
     @classmethod
     def unregister(cls):
         del bpy.types.Material.cycles
@@ -693,6 +705,13 @@ class CyclesWorldSettings(bpy.types.PropertyGroup):
                 default='EQUIANGULAR',
                 )
 
+        cls.volume_interpolation = EnumProperty(
+                name="Volume Interpolation",
+                description="Interpolation method to use for volumes",
+                items=enum_volume_interpolation,
+                default='LINEAR',
+                )
+
     @classmethod
     def unregister(cls):
         del bpy.types.World.cycles