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

5 files changed, 34 insertions, 20 deletions

diff --git a/intern/cycles/kernel/kernel.cpp b/intern/cycles/kernel/kernel.cpp
index 6cd14d3c51c..5d74feed9f4 100644
--- a/intern/cycles/kernel/kernel.cpp
+++ b/intern/cycles/kernel/kernel.cpp
@@ -37,7 +37,7 @@ void kernel_const_copy(KernelGlobals *kg, const char *name, void *host, size_t s
 		assert(0);
 }
 
-void kernel_tex_copy(KernelGlobals *kg, const char *name, device_ptr mem, size_t width, size_t height)
+void kernel_tex_copy(KernelGlobals *kg, const char *name, device_ptr mem, size_t width, size_t height, InterpolationType interpolation)
 {
 	if(0) {
 	}
@@ -63,6 +63,7 @@ void kernel_tex_copy(KernelGlobals *kg, const char *name, device_ptr mem, size_t
 			tex->data = (float4*)mem;
 			tex->width = width;
 			tex->height = height;
+			tex->interpolation = interpolation;
 		}
 	}
 	else if(strstr(name, "__tex_image")) {
@@ -78,6 +79,7 @@ void kernel_tex_copy(KernelGlobals *kg, const char *name, device_ptr mem, size_t
 			tex->data = (uchar4*)mem;
 			tex->width = width;
 			tex->height = height;
+			tex->interpolation = interpolation;
 		}
 	}
 	else
diff --git a/intern/cycles/kernel/kernel.h b/intern/cycles/kernel/kernel.h
index 039dc791b08..a4f13e78006 100644
--- a/intern/cycles/kernel/kernel.h
+++ b/intern/cycles/kernel/kernel.h
@@ -32,7 +32,7 @@ void *kernel_osl_memory(KernelGlobals *kg);
 bool kernel_osl_use(KernelGlobals *kg);
 
 void kernel_const_copy(KernelGlobals *kg, const char *name, void *host, size_t size);
-void kernel_tex_copy(KernelGlobals *kg, const char *name, device_ptr mem, size_t width, size_t height);
+void kernel_tex_copy(KernelGlobals *kg, const char *name, device_ptr mem, size_t width, size_t height, InterpolationType interpolation=INTERPOLATION_LINEAR);
 
 void kernel_cpu_path_trace(KernelGlobals *kg, float *buffer, unsigned int *rng_state,
 	int sample, int x, int y, int offset, int stride);
diff --git a/intern/cycles/kernel/kernel_compat_cpu.h b/intern/cycles/kernel/kernel_compat_cpu.h
index a9c66ec2d68..55f4484ba1f 100644
--- a/intern/cycles/kernel/kernel_compat_cpu.h
+++ b/intern/cycles/kernel/kernel_compat_cpu.h
@@ -117,14 +117,19 @@ template<typename T> struct texture_image  {
 			niy = wrap_clamp(iy+1, height);
 		}
 
-		float4 r = (1.0f - ty)*(1.0f - tx)*read(data[ix + iy*width]);
-		r += (1.0f - ty)*tx*read(data[nix + iy*width]);
-		r += ty*(1.0f - tx)*read(data[ix + niy*width]);
-		r += ty*tx*read(data[nix + niy*width]);
-
-		return r;
+		if(interpolation == INTERPOLATION_CLOSEST) {
+			return read(data[ix + iy*width]);
+		}
+		else {
+			float4 r = (1.0f - ty)*(1.0f - tx)*read(data[ix + iy*width]);
+			r += (1.0f - ty)*tx*read(data[nix + iy*width]);
+			r += ty*(1.0f - tx)*read(data[ix + niy*width]);
+			r += ty*tx*read(data[nix + niy*width]);
+			return r;
+		}
 	}
 
+	int interpolation;
 	T *data;
 	int width, height;
 };
@@ -146,7 +151,6 @@ typedef texture_image<uchar4> texture_image_uchar4;
 #define kernel_tex_fetch_m128i(tex, index) (kg->tex.fetch_m128i(index))
 #define kernel_tex_lookup(tex, t, offset, size) (kg->tex.lookup(t, offset, size))
 #define kernel_tex_image_interp(tex, x, y) ((tex < MAX_FLOAT_IMAGES) ? kg->texture_float_images[tex].interp(x, y) : kg->texture_byte_images[tex - MAX_FLOAT_IMAGES].interp(x, y))
-
 #define kernel_data (kg->__data)
 
 CCL_NAMESPACE_END
diff --git a/intern/cycles/kernel/shaders/node_image_texture.osl b/intern/cycles/kernel/shaders/node_image_texture.osl
index caa755636b9..7238a1e8862 100644
--- a/intern/cycles/kernel/shaders/node_image_texture.osl
+++ b/intern/cycles/kernel/shaders/node_image_texture.osl
@@ -17,9 +17,9 @@
 #include "stdosl.h"
 #include "node_color.h"
 
-color image_texture_lookup(string filename, string color_space, float u, float v, output float Alpha, int use_alpha, int is_float)
+color image_texture_lookup(string filename, string color_space, float u, float v, output float Alpha, int use_alpha, int is_float, string interpolation)
 {
-	color rgb = (color)texture(filename, u, 1.0 - v, "wrap", "periodic", "alpha", Alpha);
+	color rgb = (color)texture(filename, u, 1.0 - v, "wrap", "periodic", "interp", interpolation, "alpha", Alpha);
 
 	if (use_alpha) {
 		rgb = color_unpremultiply(rgb, Alpha);
@@ -42,6 +42,7 @@ shader node_image_texture(
 	string filename = "",
 	string color_space = "sRGB",
 	string projection = "Flat",
+	string interpolation = "smartcubic",
 	float projection_blend = 0.0,
 	int is_float = 1,
 	int use_alpha = 1,
@@ -54,7 +55,7 @@ shader node_image_texture(
 		p = transform(mapping, p);
 	
 	if (projection == "Flat") {
-		Color = image_texture_lookup(filename, color_space, p[0], p[1], Alpha, use_alpha, is_float);
+		Color = image_texture_lookup(filename, color_space, p[0], p[1], Alpha, use_alpha, is_float, interpolation);
 	}
 	else if (projection == "Box") {
 		/* object space normal */
@@ -119,15 +120,15 @@ shader node_image_texture(
 		float tmp_alpha;
 
 		if (weight[0] > 0.0) {
-			Color += weight[0] * image_texture_lookup(filename, color_space, p[1], p[2], tmp_alpha, use_alpha, is_float);
+			Color += weight[0] * image_texture_lookup(filename, color_space, p[1], p[2], tmp_alpha, use_alpha, is_float, interpolation);
 			Alpha += weight[0] * tmp_alpha;
 		}
 		if (weight[1] > 0.0) {
-			Color += weight[1] * image_texture_lookup(filename, color_space, p[0], p[2], tmp_alpha, use_alpha, is_float);
+			Color += weight[1] * image_texture_lookup(filename, color_space, p[0], p[2], tmp_alpha, use_alpha, is_float, interpolation);
 			Alpha += weight[1] * tmp_alpha;
 		}
 		if (weight[2] > 0.0) {
-			Color += weight[2] * image_texture_lookup(filename, color_space, p[1], p[0], tmp_alpha, use_alpha, is_float);
+			Color += weight[2] * image_texture_lookup(filename, color_space, p[1], p[0], tmp_alpha, use_alpha, is_float, interpolation);
 			Alpha += weight[2] * tmp_alpha;
 		}
 	}
diff --git a/intern/cycles/kernel/svm/svm_image.h b/intern/cycles/kernel/svm/svm_image.h
index bc76ea1e662..750af97150e 100644
--- a/intern/cycles/kernel/svm/svm_image.h
+++ b/intern/cycles/kernel/svm/svm_image.h
@@ -60,7 +60,8 @@ ccl_device float4 svm_image_texture(KernelGlobals *kg, int id, float x, float y,
 	uint width = info.x;
 	uint height = info.y;
 	uint offset = info.z;
-	uint periodic = info.w;
+	uint periodic = (info.w & 0x1);
+	uint interpolation = info.w >> 1;
 
 	int ix, iy, nix, niy;
 	float tx = svm_image_texture_frac(x*width, &ix);
@@ -81,10 +82,16 @@ ccl_device float4 svm_image_texture(KernelGlobals *kg, int id, float x, float y,
 		niy = svm_image_texture_wrap_clamp(iy+1, height);
 	}
 
-	float4 r = (1.0f - ty)*(1.0f - tx)*svm_image_texture_read(kg, offset + ix + iy*width);
-	r += (1.0f - ty)*tx*svm_image_texture_read(kg, offset + nix + iy*width);
-	r += ty*(1.0f - tx)*svm_image_texture_read(kg, offset + ix + niy*width);
-	r += ty*tx*svm_image_texture_read(kg, offset + nix + niy*width);
+	float4 r;
+	if (interpolation == INTERPOLATION_CLOSEST){
+		r = svm_image_texture_read(kg, offset + ix + iy*width);
+	}
+	else { /* We default to linear interpolation if it is not closest */
+		r = (1.0f - ty)*(1.0f - tx)*svm_image_texture_read(kg, offset + ix + iy*width);
+		r += (1.0f - ty)*tx*svm_image_texture_read(kg, offset + nix + iy*width);
+		r += ty*(1.0f - tx)*svm_image_texture_read(kg, offset + ix + niy*width);
+		r += ty*tx*svm_image_texture_read(kg, offset + nix + niy*width);
+	}
 
 	if(use_alpha && r.w != 1.0f && r.w != 0.0f) {
 		float invw = 1.0f/r.w;