Cycles: Support tube projection for images

This way Cycles finally becomes feature-full on image projections
compared to Blender Internal and Gooseberry Project Team could
finally finish the movie.

intern/cycles/kernel/shaders/node_image_texture.osl

@@ -17,13 +17,32 @@
 #include "stdosl.h"
 #include "node_color.h"
 
+point texco_remap_square(point co)
+{
+	return (co - point(0.5, 0.5, 0.5)) * 2.0;
+}
+
+point map_to_tube(vector dir)
+{
+	float u, v;
+	v = (dir[2] + 1.0) * 0.5;
+	float len = sqrt(dir[0]*dir[0] + dir[1]*dir[1]);
+	if (len > 0.0) {
+		u = (1.0 - (atan2(dir[0] / len, dir[1] / len) / M_PI)) * 0.5;
+	}
+	else {
+		v = u = 0.0; /* To avoid un-initialized variables. */
+	}
+	return point(u, v, 0.0);
+}
+
 point map_to_sphere(vector dir)
 {
 	float len = length(dir);
 	float v, u;
 	if(len > 0.0) {
 		if(dir[0] == 0.0 && dir[1] == 0.0) {
-			u = 0.0;  /* othwise domain error */
+			u = 0.0;  /* Othwise domain error. */
 		}
 		else {
 			u = (1.0 - atan2(dir[0], dir[1]) / M_PI) / 2.0;
@@ -31,7 +50,7 @@ point map_to_sphere(vector dir)
 		v = 1.0 - acos(dir[2] / len) / M_PI;
 	}
 	else {
-		v = u = 0.0; /* to avoid un-initialized variables */
+		v = u = 0.0;  /* To avoid un-initialized variables. */
 	}
 	return point(u, v, 0.0);
 }
@@ -156,7 +175,13 @@ shader node_image_texture(
 		}
 	}
 	else if (projection == "Sphere") {
-		point projected = map_to_sphere((p - vector(0.5, 0.5, 0.5)) * 2.0);
+		point projected = map_to_sphere(texco_remap_square(p));
+		Color = image_texture_lookup(filename, color_space,
+		                             projected[0], projected[1],
+		                             Alpha, use_alpha, is_float, interpolation);
+	}
+	else if (projection == "Tube") {
+		point projected = map_to_tube(texco_remap_square(p));
 		Color = image_texture_lookup(filename, color_space,
 		                             projected[0], projected[1],
 		                             Alpha, use_alpha, is_float, interpolation);

intern/cycles/kernel/svm/svm_image.h

@@ -354,6 +354,12 @@ ccl_device float4 svm_image_texture(KernelGlobals *kg, int id, float x, float y,
 
 #endif
 
+/* Remap coordnate from 0..1 box to -1..-1 */
+ccl_device_inline float3 texco_remap_square(float3 co)
+{
+	return (co - make_float3(0.5f, 0.5f, 0.5f)) * 2.0f;
+}
+
 ccl_device void svm_node_tex_image(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node)
 {
 	uint id = node.y;
@@ -364,9 +370,13 @@ ccl_device void svm_node_tex_image(KernelGlobals *kg, ShaderData *sd, float *sta
 	float3 co = stack_load_float3(stack, co_offset);
 	uint use_alpha = stack_valid(alpha_offset);
 	if(node.w == NODE_IMAGE_PROJ_SPHERE) {
-		co = (co - make_float3(0.5f, 0.5f, 0.5f)) * 2.0f;
+		co = texco_remap_square(co);
 		map_to_sphere(&co.x, &co.y, co.x, co.y, co.z);
 	}
+	else if(node.w == NODE_IMAGE_PROJ_TUBE) {
+		co = texco_remap_square(co);
+		map_to_tube(&co.x, &co.y, co.x, co.y, co.z);
+	}
 	float4 f = svm_image_texture(kg, id, co.x, co.y, srgb, use_alpha);
 
 	if(stack_valid(out_offset))

intern/cycles/kernel/svm/svm_types.h

@@ -338,6 +338,7 @@ typedef enum NodeImageProjection {
 	NODE_IMAGE_PROJ_FLAT   = 0,
 	NODE_IMAGE_PROJ_BOX    = 1,
 	NODE_IMAGE_PROJ_SPHERE = 2,
+	NODE_IMAGE_PROJ_TUBE   = 3,
 } NodeImageProjection;
 
 typedef enum ShaderType {

intern/cycles/render/nodes.cpp

@@ -177,6 +177,7 @@ static ShaderEnum image_projection_init()
 	enm.insert("Flat", NODE_IMAGE_PROJ_FLAT);
 	enm.insert("Box", NODE_IMAGE_PROJ_BOX);
 	enm.insert("Sphere", NODE_IMAGE_PROJ_SPHERE);
+	enm.insert("Tube", NODE_IMAGE_PROJ_TUBE);
 
 	return enm;
 }

intern/cycles/util/util_math.h

@@ -1450,6 +1450,20 @@ ccl_device bool ray_quad_intersect(
 }
 
 /* projections */
+ccl_device void map_to_tube(float *r_u, float *r_v,
+                            const float x, const float y, const float z)
+{
+	float len;
+	*r_v = (z + 1.0f) * 0.5f;
+	len = sqrtf(x * x + y * y);
+	if (len > 0.0f) {
+		*r_u = (1.0f - (atan2f(x / len, y / len) / (float)M_PI)) * 0.5f;
+	}
+	else {
+		*r_v = *r_u = 0.0f; /* To avoid un-initialized variables. */
+	}
+}
+
 ccl_device bool map_to_sphere(float *r_u, float *r_v,
                               const float x, const float y, const float z)
 {

source/blender/makesdna/DNA_node_types.h

@@ -963,6 +963,7 @@ typedef struct NodeSunBeams {
 #define SHD_PROJ_FLAT				0
 #define SHD_PROJ_BOX				1
 #define SHD_PROJ_SPHERE				2
+#define SHD_PROJ_TUBE				3
 
 /* image texture interpolation */
 #define SHD_INTERP_LINEAR		0

source/blender/makesrna/intern/rna_nodetree.c

@@ -3437,6 +3437,8 @@ static void def_sh_tex_image(StructRNA *srna)
 		                  "Image is projected using different components for each side of the object space bounding box"},
 		{SHD_PROJ_SPHERE, "SPHERE", 0, "Sphere",
 		                  "Image is projected spherically using the Z axis as central"},
+		{SHD_PROJ_TUBE,   "TUBE", 0, "Tube",
+		                  "Image is projected from the tube using the Z axis as central"},
 		{0, NULL, 0, NULL, NULL}
 	};