Add support for multiple interpolation modes on cycles image textures

All textures are sampled bi-linear currently with the exception of OSL there texture sampling is fixed and set to smart bi-cubic.

This patch adds user control to this setting.

Added:
- bits to DNA / RNA in the form of an enum for supporting multiple interpolations types
- changes to the image texture node drawing code ( add enum)
- to ImageManager (this needs to know to allocate second texture when interpolation type is different)
- to node compiler (pass on interpolation type)
- to device tex_alloc this also needs to get the concept of multiple interpolation types
- implementation for doing non interpolated lookup for cuda and cpu
- implementation where we pass this along to osl ( this makes OSL also do linear untill I add smartcubic to the interface / DNA/ RNA)

Reviewers: brecht, dingto

Reviewed By: brecht

CC: dingto, venomgfx

Differential Revision: https://developer.blender.org/D317

1 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/makesdna/DNA_node_types.h b/source/blender/makesdna/DNA_node_types.h
index cd9595d8185..1ad713e64e0 100644
--- a/source/blender/makesdna/DNA_node_types.h
+++ b/source/blender/makesdna/DNA_node_types.h
@@ -724,7 +724,7 @@ typedef struct NodeTexImage {
 	int color_space;
 	int projection;
 	float projection_blend;
-	int pad;
+	int interpolation;
 } NodeTexImage;
 
 typedef struct NodeTexChecker {
@@ -951,6 +951,12 @@ typedef struct NodeShaderNormalMap {
 #define SHD_PROJ_FLAT				0
 #define SHD_PROJ_BOX				1
 
+/* image texture interpolation */
+#define SHD_INTER_LINEAR		0
+#define SHD_INTER_CLOSEST		1
+#define SHD_INTER_CUBIC			2
+#define SHD_INTER_SMART			3
+
 /* tangent */
 #define SHD_TANGENT_RADIAL			0
 #define SHD_TANGENT_UVMAP			1