Eevee: Add support for new Hair geometry system.

This now can shade actual poly strips that mimics cylinders.
This makes hair coverage exact compared to the line method and result in
smoother fading hair.

This does make the sampling a bit more exact but needs more samples to
converge properly.

1 files changed, 110 insertions, 65 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_materials.c b/source/blender/draw/engines/eevee/eevee_materials.c
index 32bd6f23d84..85c312d311c 100644
--- a/source/blender/draw/engines/eevee/eevee_materials.c
+++ b/source/blender/draw/engines/eevee/eevee_materials.c
@@ -49,10 +49,13 @@
 /* *********** STATIC *********** */
 static struct {
 	char *frag_shader_lib;
+	char *vert_shader_str;
 	char *volume_shader_lib;
 
 	struct GPUShader *default_prepass_sh;
 	struct GPUShader *default_prepass_clip_sh;
+	struct GPUShader *default_hair_prepass_sh;
+	struct GPUShader *default_hair_prepass_clip_sh;
 	struct GPUShader *default_lit[VAR_MAT_MAX];
 	struct GPUShader *default_background;
 	struct GPUShader *default_studiolight_background;
@@ -83,6 +86,7 @@ extern char datatoc_bsdf_common_lib_glsl[];
 extern char datatoc_bsdf_direct_lib_glsl[];
 extern char datatoc_bsdf_sampling_lib_glsl[];
 extern char datatoc_common_uniforms_lib_glsl[];
+extern char datatoc_common_hair_lib_glsl[];
 extern char datatoc_common_view_lib_glsl[];
 extern char datatoc_irradiance_lib_glsl[];
 extern char datatoc_octahedron_lib_glsl[];
@@ -100,6 +104,8 @@ extern char datatoc_volumetric_geom_glsl[];
 extern char datatoc_volumetric_frag_glsl[];
 extern char datatoc_volumetric_lib_glsl[];
 
+extern char datatoc_gpu_shader_uniform_color_frag_glsl[];
+
 extern Material defmaterial;
 extern GlobalsUboStorage ts;
 
@@ -421,7 +427,7 @@ static void create_default_shader(int options)
 
 	char *defines = eevee_get_defines(options);
 
-	e_data.default_lit[options] = DRW_shader_create(datatoc_lit_surface_vert_glsl, NULL, frag_str, defines);
+	e_data.default_lit[options] = DRW_shader_create(e_data.vert_shader_str, NULL, frag_str, defines);
 
 	MEM_freeN(defines);
 	MEM_freeN(frag_str);
@@ -533,8 +539,6 @@ static void EEVEE_update_viewvecs(float invproj[4][4], float winmat[4][4], float
 void EEVEE_materials_init(EEVEE_ViewLayerData *sldata, EEVEE_StorageList *stl, EEVEE_FramebufferList *fbl)
 {
 	if (!e_data.frag_shader_lib) {
-		char *frag_str = NULL;
-
 		/* Shaders */
 		e_data.frag_shader_lib = BLI_string_joinN(
 		        datatoc_common_view_lib_glsl,
@@ -575,9 +579,10 @@ void EEVEE_materials_init(EEVEE_ViewLayerData *sldata, EEVEE_StorageList *stl, E
 		        datatoc_volumetric_lib_glsl,
 		        datatoc_volumetric_frag_glsl);
 
-		frag_str = BLI_string_joinN(
-		        e_data.frag_shader_lib,
-		        datatoc_default_frag_glsl);
+		e_data.vert_shader_str = BLI_string_joinN(
+		        datatoc_common_view_lib_glsl,
+		        datatoc_common_hair_lib_glsl,
+		        datatoc_lit_surface_vert_glsl);
 
 		e_data.default_background = DRW_shader_create(
 		        datatoc_background_vert_glsl, NULL, datatoc_default_world_frag_glsl,
@@ -595,7 +600,21 @@ void EEVEE_materials_init(EEVEE_ViewLayerData *sldata, EEVEE_StorageList *stl, E
 		        datatoc_prepass_vert_glsl, NULL, datatoc_prepass_frag_glsl,
 		        "#define CLIP_PLANES\n");
 
-		MEM_freeN(frag_str);
+		char *vert_str = BLI_string_joinN(
+		        datatoc_common_view_lib_glsl,
+		        datatoc_common_hair_lib_glsl,
+		        datatoc_prepass_vert_glsl);
+
+		e_data.default_hair_prepass_sh = DRW_shader_create(
+		        vert_str, NULL, datatoc_prepass_frag_glsl,
+		        "#define HAIR_SHADER\n");
+
+		e_data.default_hair_prepass_clip_sh = DRW_shader_create(
+		        vert_str, NULL, datatoc_prepass_frag_glsl,
+		        "#define HAIR_SHADER\n"
+		        "#define CLIP_PLANES\n");
+
+		MEM_freeN(vert_str);
 
 		e_data.update_noise_sh = DRW_shader_create_fullscreen(
 		        datatoc_update_noise_frag_glsl, NULL);
@@ -712,7 +731,7 @@ struct GPUMaterial *EEVEE_material_mesh_get(
 
 	mat = DRW_shader_create_from_material(
 	        scene, ma, engine, options,
-	        datatoc_lit_surface_vert_glsl, NULL, e_data.frag_shader_lib,
+	        e_data.vert_shader_str, NULL, e_data.frag_shader_lib,
 	        defines);
 
 	MEM_freeN(defines);
@@ -772,7 +791,7 @@ struct GPUMaterial *EEVEE_material_mesh_depth_get(
 
 	mat = DRW_shader_create_from_material(
 	        scene, ma, engine, options,
-	        (is_shadow) ? datatoc_shadow_vert_glsl : datatoc_lit_surface_vert_glsl,
+	        (is_shadow) ? datatoc_shadow_vert_glsl : e_data.vert_shader_str,
 	        NULL,
 	        frag_str,
 	        defines);
@@ -800,7 +819,7 @@ struct GPUMaterial *EEVEE_material_hair_get(
 
 	mat = DRW_shader_create_from_material(
 	        scene, ma, engine, options,
-	        datatoc_lit_surface_vert_glsl, NULL, e_data.frag_shader_lib,
+	        e_data.vert_shader_str, NULL, e_data.frag_shader_lib,
 	        defines);
 
 	MEM_freeN(defines);
@@ -842,12 +861,15 @@ static struct DRWShadingGroup *EEVEE_default_shading_group_create(
  **/
 static struct DRWShadingGroup *EEVEE_default_shading_group_get(
         EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata,
+        Object *ob, ParticleSystem *psys, ModifierData *md,
         bool is_hair, bool is_flat_normal, bool use_ssr, int shadow_method)
 {
 	static int ssr_id;
 	ssr_id = (use_ssr) ? 1 : -1;
 	int options = VAR_MAT_MESH;
 
+	BLI_assert(!is_hair || (ob && psys && md));
+
 	if (is_hair) options |= VAR_MAT_HAIR;
 	if (is_flat_normal) options |= VAR_MAT_FLAT;
 
@@ -861,13 +883,25 @@ static struct DRWShadingGroup *EEVEE_default_shading_group_get(
 		DRWState state = DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_EQUAL | DRW_STATE_CLIP_PLANES | DRW_STATE_WIRE;
 		vedata->psl->default_pass[options] = DRW_pass_create("Default Lit Pass", state);
 
-		DRWShadingGroup *shgrp = DRW_shgroup_create(e_data.default_lit[options], vedata->psl->default_pass[options]);
 		/* XXX / WATCH: This creates non persistent binds for the ubos and textures.
-		 * But it's currently OK because the following shgroups does not add any bind. */
-		add_standard_uniforms(shgrp, sldata, vedata, &ssr_id, NULL, false, false);
+		 * But it's currently OK because the following shgroups does not add any bind.
+		 * EDIT: THIS IS NOT THE CASE FOR HAIRS !!! DUMMY!!! */
+		if (!is_hair) {
+			DRWShadingGroup *shgrp = DRW_shgroup_create(e_data.default_lit[options], vedata->psl->default_pass[options]);
+			add_standard_uniforms(shgrp, sldata, vedata, &ssr_id, NULL, false, false);
+		}
 	}
 
-	return DRW_shgroup_create(e_data.default_lit[options], vedata->psl->default_pass[options]);
+	if (is_hair) {
+		DRWShadingGroup *shgrp = DRW_shgroup_hair_create(ob, psys, md,
+		                                                 vedata->psl->default_pass[options], vedata->psl->hair_tf_pass,
+		                                                 e_data.default_lit[options]);
+		add_standard_uniforms(shgrp, sldata, vedata, NULL, NULL, false, false);
+		return shgrp;
+	}
+	else {
+		return DRW_shgroup_create(e_data.default_lit[options], vedata->psl->default_pass[options]);
+	}
 }
 
 /**
@@ -984,7 +1018,7 @@ void EEVEE_materials_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata)
 	}
 
 	{
-		DRWState state = DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_EQUAL | DRW_STATE_CLIP_PLANES | DRW_STATE_WIRE;
+		DRWState state = DRW_STATE_WRITE_COLOR | DRW_STATE_DEPTH_LESS_EQUAL | DRW_STATE_CLIP_PLANES | DRW_STATE_WIRE;
 		psl->material_pass = DRW_pass_create("Material Shader Pass", state);
 	}
 
@@ -1039,6 +1073,9 @@ void EEVEE_materials_cache_init(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata)
 		DRW_shgroup_call_add(grp, DRW_cache_fullscreen_quad_get(), NULL);
 	}
 
+	{
+		psl->hair_tf_pass = DRW_pass_create("Update Hair Pass", DRW_STATE_TRANS_FEEDBACK);
+	}
 }
 
 #define ADD_SHGROUP_CALL(shgrp, ob, geom, oedata) do { \
@@ -1216,7 +1253,9 @@ static void material_opaque(
 	/* Fallback to default shader */
 	if (*shgrp == NULL) {
 		bool use_ssr = ((effects->enabled_effects & EFFECT_SSR) != 0);
-		*shgrp = EEVEE_default_shading_group_get(sldata, vedata, false, use_flat_nor, use_ssr, linfo->shadow_method);
+		*shgrp = EEVEE_default_shading_group_get(sldata, vedata,
+		                                         NULL, NULL, NULL,
+		                                         false, use_flat_nor, use_ssr, linfo->shadow_method);
 		DRW_shgroup_uniform_vec3(*shgrp, "basecol", color_p, 1);
 		DRW_shgroup_uniform_float(*shgrp, "metallic", metal_p, 1);
 		DRW_shgroup_uniform_float(*shgrp, "specular", spec_p, 1);
@@ -1557,7 +1596,7 @@ void EEVEE_materials_cache_populate(EEVEE_Data *vedata, EEVEE_ViewLayerData *sld
 				if (draw_as != PART_DRAW_PATH) {
 					continue;
 				}
-				struct Gwn_Batch *hair_geom = DRW_cache_particles_get_hair(ob, psys, md);
+
 				DRWShadingGroup *shgrp = NULL;
 				Material *ma = give_current_material(ob, part->omat);
 
@@ -1570,56 +1609,60 @@ void EEVEE_materials_cache_populate(EEVEE_Data *vedata, EEVEE_ViewLayerData *sld
 				float *spec_p = &ma->spec;
 				float *rough_p = &ma->gloss_mir;
 
-				DRW_shgroup_call_add(stl->g_data->depth_shgrp, hair_geom, NULL);
-				DRW_shgroup_call_add(stl->g_data->depth_shgrp_clip, hair_geom, NULL);
-
-				shgrp = BLI_ghash_lookup(material_hash, (const void *)ma);
-
-				if (shgrp) {
-					DRW_shgroup_call_add(shgrp, hair_geom, NULL);
-				}
-				else {
-					if (ma->use_nodes && ma->nodetree) {
-						static float half = 0.5f;
-						static float error_col[3] = {1.0f, 0.0f, 1.0f};
-						static float compile_col[3] = {0.5f, 0.5f, 0.5f};
-						struct GPUMaterial *gpumat = EEVEE_material_hair_get(scene, ma, sldata->lamps->shadow_method);
-
-						switch (GPU_material_status(gpumat)) {
-							case GPU_MAT_SUCCESS:
-							{
-								shgrp = DRW_shgroup_material_create(gpumat, psl->material_pass);
-								add_standard_uniforms(shgrp, sldata, vedata, NULL, NULL, false, false);
-								break;
-							}
-							case GPU_MAT_QUEUED:
-							{
-								sldata->probes->all_materials_updated = false;
-								color_p = compile_col;
-								metal_p = spec_p = rough_p = ½
-								break;
-							}
-							case GPU_MAT_FAILED:
-							default:
-								color_p = error_col;
-								metal_p = spec_p = rough_p = ½
-								break;
+				shgrp = DRW_shgroup_hair_create(
+				        ob, psys, md,
+				        psl->depth_pass, psl->hair_tf_pass,
+				        e_data.default_hair_prepass_sh);
+
+				shgrp = DRW_shgroup_hair_create(
+				        ob, psys, md,
+				        psl->depth_pass_clip, psl->hair_tf_pass,
+				        e_data.default_hair_prepass_clip_sh);
+				DRW_shgroup_uniform_block(shgrp, "clip_block", sldata->clip_ubo);
+
+				shgrp = NULL;
+				if (ma->use_nodes && ma->nodetree) {
+					static float half = 0.5f;
+					static float error_col[3] = {1.0f, 0.0f, 1.0f};
+					static float compile_col[3] = {0.5f, 0.5f, 0.5f};
+					struct GPUMaterial *gpumat = EEVEE_material_hair_get(scene, ma, sldata->lamps->shadow_method);
+
+					switch (GPU_material_status(gpumat)) {
+						case GPU_MAT_SUCCESS:
+						{
+							shgrp = DRW_shgroup_material_hair_create(
+							        ob, psys, md,
+							        psl->material_pass, psl->hair_tf_pass,
+							        gpumat);
+							add_standard_uniforms(shgrp, sldata, vedata, NULL, NULL, false, false);
+							break;
 						}
+						case GPU_MAT_QUEUED:
+						{
+							sldata->probes->all_materials_updated = false;
+							color_p = compile_col;
+							metal_p = spec_p = rough_p = ½
+							break;
+						}
+						case GPU_MAT_FAILED:
+						default:
+							color_p = error_col;
+							metal_p = spec_p = rough_p = ½
+							break;
 					}
+				}
 
-					/* Fallback to default shader */
-					if (shgrp == NULL) {
-						bool use_ssr = ((stl->effects->enabled_effects & EFFECT_SSR) != 0);
-						shgrp = EEVEE_default_shading_group_get(sldata, vedata, true, false, use_ssr,
-						                                        sldata->lamps->shadow_method);
-						DRW_shgroup_uniform_vec3(shgrp, "basecol", color_p, 1);
-						DRW_shgroup_uniform_float(shgrp, "metallic", metal_p, 1);
-						DRW_shgroup_uniform_float(shgrp, "specular", spec_p, 1);
-						DRW_shgroup_uniform_float(shgrp, "roughness", rough_p, 1);
-					}
-
-					DRW_shgroup_call_add(shgrp, hair_geom, NULL);
-					BLI_ghash_insert(material_hash, ma, shgrp);
+				/* Fallback to default shader */
+				if (shgrp == NULL) {
+					bool use_ssr = ((stl->effects->enabled_effects & EFFECT_SSR) != 0);
+					shgrp = EEVEE_default_shading_group_get(sldata, vedata,
+					                                        ob, psys, md,
+					                                        true, false, use_ssr,
+					                                        sldata->lamps->shadow_method);
+					DRW_shgroup_uniform_vec3(shgrp, "basecol", color_p, 1);
+					DRW_shgroup_uniform_float(shgrp, "metallic", metal_p, 1);
+					DRW_shgroup_uniform_float(shgrp, "specular", spec_p, 1);
+					DRW_shgroup_uniform_float(shgrp, "roughness", rough_p, 1);
 				}
 			}
 		}
@@ -1679,8 +1722,10 @@ void EEVEE_materials_free(void)
 		DRW_SHADER_FREE_SAFE(e_data.default_lit[i]);
 	}
 	MEM_SAFE_FREE(e_data.frag_shader_lib);
-	MEM_SAFE_FREE(e_data.frag_shader_lib);
+	MEM_SAFE_FREE(e_data.vert_shader_str);
 	MEM_SAFE_FREE(e_data.volume_shader_lib);
+	DRW_SHADER_FREE_SAFE(e_data.default_hair_prepass_sh);
+	DRW_SHADER_FREE_SAFE(e_data.default_hair_prepass_clip_sh);
 	DRW_SHADER_FREE_SAFE(e_data.default_prepass_sh);
 	DRW_SHADER_FREE_SAFE(e_data.default_prepass_clip_sh);
 	DRW_SHADER_FREE_SAFE(e_data.default_background);