Eevee: Volumetrics: Support Smoke simulation textures.

It should behave like cycles.

Even if not efficient at all, we still do the same create - draw - free process that was done in the old viewport to save vram (maybe not really the case now) and not care about simulation's GPU texture state sync.

5 files changed, 81 insertions, 6 deletions

diff --git a/source/blender/gpu/GPU_material.h b/source/blender/gpu/GPU_material.h
index 1508941f706..de274b87f9e 100644
--- a/source/blender/gpu/GPU_material.h
+++ b/source/blender/gpu/GPU_material.h
@@ -82,11 +82,12 @@ typedef enum GPUType {
 
 	/* Values not in GPU_DATATYPE_STR */
 	GPU_TEX2D = 1002,
-	GPU_SHADOW2D = 1003,
-	GPU_TEXCUBE = 1004,
+	GPU_TEX3D = 1003,
+	GPU_SHADOW2D = 1004,
+	GPU_TEXCUBE = 1005,
 
 	/* GLSL Struct types */
-	GPU_CLOSURE = 1005,
+	GPU_CLOSURE = 1006,
 
 	/* Opengl Attributes */
 	GPU_ATTRIB = 3001
@@ -108,7 +109,9 @@ typedef enum GPUBuiltin {
 	GPU_PARTICLE_ANG_VELOCITY = (1 << 12),
 	GPU_LOC_TO_VIEW_MATRIX =    (1 << 13),
 	GPU_INVERSE_LOC_TO_VIEW_MATRIX = (1 << 14),
-	GPU_OBJECT_INFO =           (1 << 15)
+	GPU_OBJECT_INFO =           (1 << 15),
+	GPU_VOLUME_DENSITY =        (1 << 16),
+	GPU_VOLUME_FLAME =          (1 << 17)
 } GPUBuiltin;
 
 typedef enum GPUOpenGLBuiltin {
diff --git a/source/blender/gpu/intern/gpu_codegen.c b/source/blender/gpu/intern/gpu_codegen.c
index b5a7d751f2a..bc91df895c8 100644
--- a/source/blender/gpu/intern/gpu_codegen.c
+++ b/source/blender/gpu/intern/gpu_codegen.c
@@ -190,6 +190,9 @@ static void gpu_parse_functions_string(GHash *hash, char *code)
 			if (!type && gpu_str_prefix(code, "sampler2D")) {
 				type = GPU_TEX2D;
 			}
+			if (!type && gpu_str_prefix(code, "sampler3D")) {
+				type = GPU_TEX3D;
+			}
 
 			if (!type && gpu_str_prefix(code, "Closure")) {
 				type = GPU_CLOSURE;
@@ -420,6 +423,10 @@ const char *GPU_builtin_name(GPUBuiltin builtin)
 		return "unfparticleangvel";
 	else if (builtin == GPU_OBJECT_INFO)
 		return "unfobjectinfo";
+	else if (builtin == GPU_VOLUME_DENSITY)
+		return "sampdensity";
+	else if (builtin == GPU_VOLUME_FLAME)
+		return "sampflame";
 	else
 		return "";
 }
@@ -537,7 +544,14 @@ static int codegen_process_uniforms_functions(GPUMaterial *material, DynStr *ds,
 					builtins |= input->builtin;
 					name = GPU_builtin_name(input->builtin);
 
-					if (gpu_str_prefix(name, "unf")) {
+					if (gpu_str_prefix(name, "samp")) {
+						if ((input->builtin == GPU_VOLUME_DENSITY) ||
+						    (input->builtin == GPU_VOLUME_FLAME))
+						{
+							BLI_dynstr_appendf(ds, "uniform sampler3D %s;\n", name);
+						}
+					}
+					else if (gpu_str_prefix(name, "unf")) {
 						BLI_dynstr_appendf(ds, "uniform %s %s;\n",
 							GPU_DATATYPE_STR[input->type], name);
 					}
diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index cc6afe983ca..9f1fdcfe551 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -1259,6 +1259,16 @@ void GPU_create_smoke(SmokeModifierData *smd, int highres)
 			else {
 				sds->tex = GPU_texture_create_3D_custom(sds->res[0], sds->res[1], sds->res[2], 1,
 				                                 GPU_R8, smoke_get_density(sds->fluid), NULL);
+
+				/* Swizzle the RGBA components to read the Red channel so
+				 * that the shader stay the same for colored and non color
+				 * density textures. */
+				GPU_texture_bind(sds->tex, 0);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_R, GL_RED);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_G, GL_RED);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_B, GL_RED);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_A, GL_RED);
+				GPU_texture_unbind(sds->tex);
 			}
 			sds->tex_flame = (smoke_has_fuel(sds->fluid)) ?
 			                  GPU_texture_create_3D_custom(sds->res[0], sds->res[1], sds->res[2], 1,
@@ -1277,6 +1287,16 @@ void GPU_create_smoke(SmokeModifierData *smd, int highres)
 			else {
 				sds->tex = GPU_texture_create_3D_custom(sds->res_wt[0], sds->res_wt[1], sds->res_wt[2], 1,
 				                                        GPU_R8, smoke_turbulence_get_density(sds->wt), NULL);
+
+				/* Swizzle the RGBA components to read the Red channel so
+				 * that the shader stay the same for colored and non color
+				 * density textures. */
+				GPU_texture_bind(sds->tex, 0);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_R, GL_RED);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_G, GL_RED);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_B, GL_RED);
+				glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_SWIZZLE_A, GL_RED);
+				GPU_texture_unbind(sds->tex);
 			}
 			sds->tex_flame = (smoke_turbulence_has_fuel(sds->wt)) ?
 			                  GPU_texture_create_3D_custom(sds->res_wt[0], sds->res_wt[1], sds->res_wt[2], 1,
diff --git a/source/blender/gpu/intern/gpu_material.c b/source/blender/gpu/intern/gpu_material.c
index 312cd7bc20a..cdd3f789cca 100644
--- a/source/blender/gpu/intern/gpu_material.c
+++ b/source/blender/gpu/intern/gpu_material.c
@@ -2401,6 +2401,7 @@ GPUShaderExport *GPU_shader_export(struct Scene *scene, struct Material *ma)
 						break;
 
 					case GPU_NONE:
+					case GPU_TEX3D:
 					case GPU_TEXCUBE:
 					case GPU_FLOAT:
 					case GPU_VEC2:
@@ -2439,6 +2440,7 @@ GPUShaderExport *GPU_shader_export(struct Scene *scene, struct Material *ma)
 					case GPU_NONE:
 					case GPU_CLOSURE:
 					case GPU_TEX2D:
+					case GPU_TEX3D:
 					case GPU_TEXCUBE:
 					case GPU_SHADOW2D:
 					case GPU_ATTRIB:
diff --git a/source/blender/gpu/shaders/gpu_shader_material.glsl b/source/blender/gpu/shaders/gpu_shader_material.glsl
index 0dd8e6643b2..afb5eca5263 100644
--- a/source/blender/gpu/shaders/gpu_shader_material.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_material.glsl
@@ -3093,11 +3093,47 @@ void node_gamma(vec4 col, float gamma, out vec4 outcol)
 
 /* geometry */
 
+void node_attribute_volume_density(sampler3D tex, out vec4 outcol, out vec3 outvec, out float outf)
+{
+#if defined(EEVEE_ENGINE) && defined(MESH_SHADER) && defined(VOLUMETRICS)
+	vec3 cos = volumeObjectLocalCoord;
+#else
+	vec3 cos = vec3(0.0);
+#endif
+	outvec = texture(tex, cos).aaa;
+	outcol = vec4(outvec, 1.0);
+	outf = dot(vec3(1.0 / 3.0), outvec);
+}
+
+void node_attribute_volume_color(sampler3D tex, out vec4 outcol, out vec3 outvec, out float outf)
+{
+#if defined(EEVEE_ENGINE) && defined(MESH_SHADER) && defined(VOLUMETRICS)
+	vec3 cos = volumeObjectLocalCoord;
+#else
+	vec3 cos = vec3(0.0);
+#endif
+	outvec = texture(tex, cos).rgb;
+	outcol = vec4(outvec, 1.0);
+	outf = dot(vec3(1.0 / 3.0), outvec);
+}
+
+void node_attribute_volume_flame(sampler3D tex, out vec4 outcol, out vec3 outvec, out float outf)
+{
+#if defined(EEVEE_ENGINE) && defined(MESH_SHADER) && defined(VOLUMETRICS)
+	vec3 cos = volumeObjectLocalCoord;
+#else
+	vec3 cos = vec3(0.0);
+#endif
+	outvec = texture(tex, cos).rrr;
+	outcol = vec4(outvec, 1.0);
+	outf = dot(vec3(1.0 / 3.0), outvec);
+}
+
 void node_attribute(vec3 attr, out vec4 outcol, out vec3 outvec, out float outf)
 {
 	outcol = vec4(attr, 1.0);
 	outvec = attr;
-	outf = (attr.x + attr.y + attr.z) / 3.0;
+	outf =  dot(vec3(1.0 / 3.0), attr);
 }
 
 void node_uvmap(vec3 attr_uv, out vec3 outvec)