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

3 files changed, 24 insertions, 1 deletions

diff --git a/source/blender/editors/space_node/drawnode.c b/source/blender/editors/space_node/drawnode.c
index effb8eb7de5..0cdb17cb2d4 100644
--- a/source/blender/editors/space_node/drawnode.c
+++ b/source/blender/editors/space_node/drawnode.c
@@ -784,6 +784,7 @@ static void node_shader_buts_tex_image(uiLayout *layout, bContext *C, PointerRNA
 	uiTemplateID(layout, C, ptr, "image", NULL, "IMAGE_OT_open", NULL);
 	uiItemR(layout, ptr, "color_space", 0, "", ICON_NONE);
 	uiItemR(layout, ptr, "projection", 0, "", ICON_NONE);
+	uiItemR(layout, ptr, "interpolation", 0, "", ICON_NONE);
 
 	if (RNA_enum_get(ptr, "projection") == SHD_PROJ_BOX) {
 		uiItemR(layout, ptr, "projection_blend", 0, "Blend", ICON_NONE);
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
diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index d893a8c21f9..ae7dcdac423 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -3428,6 +3428,17 @@ static void def_sh_tex_image(StructRNA *srna)
 		{0, NULL, 0, NULL, NULL}
 	};
 
+	static const EnumPropertyItem prop_interpolation_items[] = {
+		{SHD_INTER_LINEAR,  "Linear", 0, "Linear",
+						"Linear interpolation"},
+		{SHD_INTER_CLOSEST, "Closest", 0, "Closest",
+						"No interpolation (sample closest texel"},
+		{SHD_INTER_CUBIC, "Cubic", 0, "Cubic",
+						"Cubic interpolation (OSL only)"},
+		{SHD_INTER_SMART, "Smart", 0, "Smart",
+						"Bicubic when maxifying, else bilinear (OSL only)"},
+		{0, NULL, 0, NULL, NULL}
+	};
 
 	PropertyRNA *prop;
 
@@ -3451,6 +3462,11 @@ static void def_sh_tex_image(StructRNA *srna)
 	RNA_def_property_ui_text(prop, "Projection", "Method to project 2D image on object with a 3D texture vector");
 	RNA_def_property_update(prop, 0, "rna_Node_update");
 
+	prop = RNA_def_property(srna, "interpolation", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, prop_interpolation_items);
+	RNA_def_property_ui_text(prop, "Interpolation", "Texture interpolation");
+	RNA_def_property_update(prop, 0, "rna_Node_update");
+
 	prop = RNA_def_property(srna, "projection_blend", PROP_FLOAT, PROP_FACTOR);
 	RNA_def_property_ui_text(prop, "Projection Blend", "For box projection, amount of blend to use between sides");
 	RNA_def_property_update(prop, 0, "rna_Node_update");