Cycles: color space control for image/environment texture nodes. Ideally would

be automated but need to think about how to do this, not so simply in a node
system. But guideline for now is, for color textures set to sRGB, for things like
bump or roughness map, set to Linear.

intern/cycles/blender/blender_shader.cpp

@@ -282,15 +282,17 @@ static ShaderNode *add_node(BL::BlendData b_data, ShaderGraph *graph, BL::Node *
 			/* todo: handle generated/builtin images */
 			if(b_image)
 				image->filename = blender_absolute_path(b_data, b_image, b_image.filepath());
+			image->color_space = ImageTextureNode::color_space_enum[(int)b_image_node.color_space()];
 			node = image;
 			break;
 		}
 		case BL::ShaderNode::type_TEX_ENVIRONMENT: {
-			BL::ShaderNodeTexEnvironment b_environment_node(b_node);
+			BL::ShaderNodeTexEnvironment b_env_node(b_node);
-			BL::Image b_image(b_environment_node.image());
+			BL::Image b_image(b_env_node.image());
 			EnvironmentTextureNode *env = new EnvironmentTextureNode();
 			if(b_image)
 				env->filename = blender_absolute_path(b_data, b_image, b_image.filepath());
+			env->color_space = EnvironmentTextureNode::color_space_enum[(int)b_env_node.color_space()];
 			node = env;
 			break;
 		}

intern/cycles/kernel/osl/nodes/node_environment_texture.osl

@@ -21,8 +21,12 @@
 shader node_environment_texture(
 	vector Vector = P,
 	string filename = "",
+	string color_space = "sRGB",
 	output color Color = color(0.0, 0.0, 0.0))
 {
 	Color = (color)environment(filename, Vector);
+
+	if(color_space == "sRGB")
+		Color = color_srgb_to_scene_linear(Color);
 }
 

intern/cycles/kernel/osl/nodes/node_image_texture.osl

@@ -21,8 +21,12 @@
 shader node_image_texture(
 	point Vector = P,
 	string filename = "",
+	string color_space = "sRGB",
 	output color Color = color(0.0, 0.0, 0.0))
 {
 	Color = (color)texture(filename, Vector[0], 1.0-Vector[1], "wrap", "periodic");
+
+	if(color_space == "sRGB")
+		Color = color_srgb_to_scene_linear(Color);
 }
 

intern/cycles/kernel/svm/svm.h

@@ -190,9 +190,9 @@ __device void svm_eval_nodes(KernelGlobals *kg, ShaderData *sd, ShaderType type,
 		else if(node.x == NODE_TEX_NOISE_V)
 			svm_node_tex_noise_v(sd, stack, node.y, node.z);
 		else if(node.x == NODE_TEX_IMAGE)
-			svm_node_tex_image(kg, sd, stack, node.y, node.z, node.w);
+			svm_node_tex_image(kg, sd, stack, node);
 		else if(node.x == NODE_TEX_ENVIRONMENT)
-			svm_node_tex_environment(kg, sd, stack, node.y, node.z, node.w);
+			svm_node_tex_environment(kg, sd, stack, node);
 		else if(node.x == NODE_TEX_SKY)
 			svm_node_tex_sky(kg, sd, stack, node.y, node.z);
 		else if(node.x == NODE_TEX_BLEND)

intern/cycles/kernel/svm/svm_image.h

@@ -140,22 +140,40 @@ __device float4 svm_image_texture(KernelGlobals *kg, int id, float x, float y)
 	return r;
 }
 
-__device void svm_node_tex_image(KernelGlobals *kg, ShaderData *sd, float *stack, uint id, uint co_offset, uint out_offset)
+__device void svm_node_tex_image(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node)
 {
+	uint id = node.y;
+	uint co_offset, out_offset, srgb;
+
+	decode_node_uchar4(node.z, &co_offset, &out_offset, &srgb, NULL);
+
 	float3 co = stack_load_float3(stack, co_offset);
 	float4 f = svm_image_texture(kg, id, co.x, co.y);
+	float3 r = make_float3(f.x, f.y, f.z);
 
-	stack_store_float3(stack, out_offset, make_float3(f.x, f.y, f.z));
+	if(srgb)
+		r = color_srgb_to_scene_linear(r);
+
+	stack_store_float3(stack, out_offset, r);
 }
 
-__device void svm_node_tex_environment(KernelGlobals *kg, ShaderData *sd, float *stack, uint id, uint co_offset, uint out_offset)
+__device void svm_node_tex_environment(KernelGlobals *kg, ShaderData *sd, float *stack, uint4 node)
 {
+	uint id = node.y;
+	uint co_offset, out_offset, srgb;
+
+	decode_node_uchar4(node.z, &co_offset, &out_offset, &srgb, NULL);
+
 	float3 co = stack_load_float3(stack, co_offset);
 	float u = (atan2f(co.y, co.x) + M_PI_F)/(2*M_PI_F);
 	float v = atan2f(co.z, hypotf(co.x, co.y))/M_PI_F + 0.5f;
 	float4 f = svm_image_texture(kg, id, u, v);
+	float3 r = make_float3(f.x, f.y, f.z);
 
-	stack_store_float3(stack, out_offset, make_float3(f.x, f.y, f.z));
+	if(srgb)
+		r = color_srgb_to_scene_linear(r);
+
+	stack_store_float3(stack, out_offset, r);
 }
 
 CCL_NAMESPACE_END

intern/cycles/render/nodes.cpp

@@ -27,12 +27,25 @@ CCL_NAMESPACE_BEGIN
 
 /* Image Texture */
 
+static ShaderEnum color_space_init()
+{
+	ShaderEnum enm;
+
+	enm.insert("Linear", 0);
+	enm.insert("sRGB", 1);
+
+	return enm;
+}
+
+ShaderEnum ImageTextureNode::color_space_enum = color_space_init();
+
 ImageTextureNode::ImageTextureNode()
 : ShaderNode("image_texture")
 {
 	image_manager = NULL;
 	slot = -1;
 	filename = "";
+	color_space = ustring("sRGB");
 
 	add_input("Vector", SHADER_SOCKET_POINT, ShaderInput::TEXTURE_COORDINATE);
 	add_output("Color", SHADER_SOCKET_COLOR);
@@ -65,7 +78,12 @@ void ImageTextureNode::compile(SVMCompiler& compiler)
 
 	if(slot != -1) {
 		compiler.stack_assign(vector_in);
-		compiler.add_node(NODE_TEX_IMAGE, slot, vector_in->stack_offset, color_out->stack_offset);
+		compiler.add_node(NODE_TEX_IMAGE,
+			slot,
+			compiler.encode_uchar4(
+				vector_in->stack_offset,
+				color_out->stack_offset,
+				color_space_enum[color_space]));
 	}
 	else {
 		/* image not found */
@@ -77,17 +95,21 @@ void ImageTextureNode::compile(SVMCompiler& compiler)
 void ImageTextureNode::compile(OSLCompiler& compiler)
 {
 	compiler.parameter("filename", filename.c_str());
+	compiler.parameter("color_space", color_space.c_str());
 	compiler.add(this, "node_image_texture");
 }
 
 /* Environment Texture */
 
+ShaderEnum EnvironmentTextureNode::color_space_enum = color_space_init();
+
 EnvironmentTextureNode::EnvironmentTextureNode()
 : ShaderNode("environment_texture")
 {
 	image_manager = NULL;
 	slot = -1;
 	filename = "";
+	color_space = ustring("sRGB");
 
 	add_input("Vector", SHADER_SOCKET_VECTOR, ShaderInput::POSITION);
 	add_output("Color", SHADER_SOCKET_COLOR);
@@ -120,7 +142,12 @@ void EnvironmentTextureNode::compile(SVMCompiler& compiler)
 
 	if(slot != -1) {
 		compiler.stack_assign(vector_in);
-		compiler.add_node(NODE_TEX_ENVIRONMENT, slot, vector_in->stack_offset, color_out->stack_offset);
+		compiler.add_node(NODE_TEX_ENVIRONMENT,
+			slot,
+			compiler.encode_uchar4(
+				vector_in->stack_offset,
+				color_out->stack_offset,
+				color_space_enum[color_space]));
 	}
 	else {
 		/* image not found */
@@ -132,6 +159,7 @@ void EnvironmentTextureNode::compile(SVMCompiler& compiler)
 void EnvironmentTextureNode::compile(OSLCompiler& compiler)
 {
 	compiler.parameter("filename", filename.c_str());
+	compiler.parameter("color_space", color_space.c_str());
 	compiler.add(this, "node_environment_texture");
 }
 

intern/cycles/render/nodes.h

@@ -39,6 +39,9 @@ public:
 	ImageManager *image_manager;
 	int slot;
 	string filename;
+	ustring color_space;
+
+	static ShaderEnum color_space_enum;
 };
 
 class EnvironmentTextureNode : public ShaderNode {
@@ -50,6 +53,9 @@ public:
 	ImageManager *image_manager;
 	int slot;
 	string filename;
+	ustring color_space;
+
+	static ShaderEnum color_space_enum;
 };
 
 class SkyTextureNode : public ShaderNode {

source/blender/editors/space_node/drawnode.c

@@ -400,6 +400,7 @@ static void node_shader_buts_tex_image(uiLayout *layout, bContext *C, PointerRNA
 {
 	//uiItemR(layout, ptr, "image", 0, "", ICON_NONE);
 	uiTemplateID(layout, C, ptr, "image", NULL, "IMAGE_OT_open", NULL);
+	uiItemR(layout, ptr, "color_space", 0, "", ICON_NONE);
 }
 
 static void node_shader_buts_tex_sky(uiLayout *layout, bContext *UNUSED(C), PointerRNA *ptr)

source/blender/makesdna/DNA_node_types.h

@@ -355,11 +355,11 @@ typedef struct NodeTexSky {
 } NodeTexSky;
 
 typedef struct NodeTexImage {
-	int pad;
+	int color_space;
 } NodeTexImage;
 
 typedef struct NodeTexEnvironment {
-	int pad;
+	int color_space;
 } NodeTexEnvironment;
 
 typedef struct NodeTexBlend {
@@ -499,6 +499,10 @@ typedef struct TexNodeOutput {
 #define SHD_WOOD_BAND_NOISE	2
 #define SHD_WOOD_RING_NOISE	3
 
+/* image/environment texture */
+#define SHD_COLORSPACE_LINEAR	0
+#define SHD_COLORSPACE_SRGB		1
+
 /* blur node */
 #define CMP_NODE_BLUR_ASPECT_NONE		0
 #define CMP_NODE_BLUR_ASPECT_Y			1

source/blender/makesrna/intern/rna_nodetree.c

@@ -1044,20 +1044,11 @@ static void def_sh_tex_sky(StructRNA *srna)
 
 static void def_sh_tex_environment(StructRNA *srna)
 {
-	PropertyRNA *prop;
+	static const EnumPropertyItem prop_color_space_items[]= {
+		{SHD_COLORSPACE_SRGB, "SRGB", 0, "sRGB", "Image is in sRGB color space"},
+		{SHD_COLORSPACE_LINEAR, "LINEAR", 0, "Linear", "Image is in scene linear color space"},
+		{0, NULL, 0, NULL, NULL}};
 
-	prop = RNA_def_property(srna, "image", PROP_POINTER, PROP_NONE);
-	RNA_def_property_pointer_sdna(prop, NULL, "id");
-	RNA_def_property_struct_type(prop, "Image");
-	RNA_def_property_flag(prop, PROP_EDITABLE);
-	RNA_def_property_ui_text(prop, "Image", "");
-	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_update");
-
-	RNA_def_struct_sdna_from(srna, "NodeTexEnvironment", "storage");
-}
-
-static void def_sh_tex_image(StructRNA *srna)
-{
 	PropertyRNA *prop;
 
 	prop = RNA_def_property(srna, "image", PROP_POINTER, PROP_NONE);
@@ -1068,6 +1059,35 @@ static void def_sh_tex_image(StructRNA *srna)
 	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_update");
 
 	RNA_def_struct_sdna_from(srna, "NodeTexImage", "storage");
+
+	prop= RNA_def_property(srna, "color_space", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, prop_color_space_items);
+	RNA_def_property_ui_text(prop, "Color Space", "Image file color space");
+	RNA_def_property_update(prop, 0, "rna_Node_update");
+}
+
+static void def_sh_tex_image(StructRNA *srna)
+{
+	static const EnumPropertyItem prop_color_space_items[]= {
+		{SHD_COLORSPACE_LINEAR, "LINEAR", 0, "Linear", "Image is in scene linear color space"},
+		{SHD_COLORSPACE_SRGB, "SRGB", 0, "sRGB", "Image is in sRGB color space"},
+		{0, NULL, 0, NULL, NULL}};
+
+	PropertyRNA *prop;
+
+	prop = RNA_def_property(srna, "image", PROP_POINTER, PROP_NONE);
+	RNA_def_property_pointer_sdna(prop, NULL, "id");
+	RNA_def_property_struct_type(prop, "Image");
+	RNA_def_property_flag(prop, PROP_EDITABLE);
+	RNA_def_property_ui_text(prop, "Image", "");
+	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_update");
+
+	RNA_def_struct_sdna_from(srna, "NodeTexImage", "storage");
+
+	prop= RNA_def_property(srna, "color_space", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, prop_color_space_items);
+	RNA_def_property_ui_text(prop, "Color Space", "Image file color space");
+	RNA_def_property_update(prop, 0, "rna_Node_update");
 }
 
 static void def_sh_tex_blend(StructRNA *srna)

source/blender/nodes/intern/SHD_nodes/SHD_tex_environment.c

@@ -44,6 +44,7 @@ static bNodeSocketType sh_node_tex_environment_out[]= {
 static void node_shader_init_tex_environment(bNode *node)
 {
 	NodeTexEnvironment *tex = MEM_callocN(sizeof(NodeTexEnvironment), "NodeTexEnvironment");
+	tex->color_space = SHD_COLORSPACE_SRGB;
 
 	node->storage = tex;
 }

source/blender/nodes/intern/SHD_nodes/SHD_tex_image.c

@@ -44,6 +44,7 @@ static bNodeSocketType sh_node_tex_image_out[]= {
 static void node_shader_init_tex_image(bNode *node)
 {
 	NodeTexImage *tex = MEM_callocN(sizeof(NodeTexImage), "NodeTexImage");
+	tex->color_space = SHD_COLORSPACE_SRGB;
 
 	node->storage = tex;
 }