New voxel texture mode "Hair", for displaying the internal hair volume

structure as a texture.

This is mostly a debugging feature that may be removed again later.

release/scripts/startup/bl_ui/properties_texture.py

@@ -771,6 +771,8 @@ class TEXTURE_PT_voxeldata(TextureButtonsPanel, Panel):
         elif vd.file_format == 'SMOKE':
             layout.prop(vd, "domain_object")
             layout.prop(vd, "smoke_data_type")
+        elif vd.file_format == 'HAIR':
+            layout.prop(vd, "domain_object")
         elif vd.file_format == 'IMAGE_SEQUENCE':
             layout.template_ID(tex, "image", open="image.open")
             layout.template_image(tex, "image", tex.image_user, compact=True)

source/blender/blenkernel/BKE_cloth.h

@@ -42,6 +42,7 @@ struct MFace;
 struct DerivedMesh;
 struct ClothModifierData;
 struct CollisionTree;
+struct VoxelData;
 
 #define DO_INLINE MALWAYS_INLINE
 
@@ -196,6 +197,8 @@ int implicit_free (struct ClothModifierData *clmd );
 int implicit_solver (struct Object *ob, float frame, struct ClothModifierData *clmd, struct ListBase *effectors );
 void implicit_set_positions (struct ClothModifierData *clmd );
 
+bool implicit_hair_volume_get_texture_data(struct Object *UNUSED(ob), struct ClothModifierData *clmd, struct ListBase *UNUSED(effectors), struct VoxelData *vd);
+
 /////////////////////////////////////////////////
 // cloth.c
 ////////////////////////////////////////////////

source/blender/blenkernel/intern/implicit.c

@@ -36,6 +36,7 @@
 #include "DNA_object_types.h"
 #include "DNA_object_force.h"
 #include "DNA_meshdata_types.h"
+#include "DNA_texture_types.h"
 
 #include "BLI_math.h"
 #include "BLI_linklist.h"
@@ -1293,34 +1294,33 @@ static void hair_velocity_collision(const HairGridVert *collgrid, const float gm
 	}
 }
 
-static void hair_volume_forces(ClothModifierData *clmd, lfVector *lF, lfVector *lX, lfVector *lV, unsigned int numverts)
+static void hair_volume_get_boundbox(lfVector *lX, unsigned int numverts, float gmin[3], float gmax[3])
 {
-	int size = hair_grid_size(hair_grid_res);
-	HairGridVert *hairgrid;
-	HairGridVert *collgrid;
-	ListBase *colliders;
-	ColliderCache *col = NULL;
-	float gmin[3], gmax[3], density;
-	/* 2.0f is an experimental value that seems to give good results */
-	float smoothfac = 2.0f * clmd->sim_parms->velocity_smooth;
-	float collfac = 2.0f * clmd->sim_parms->collider_friction;
-	unsigned int	v = 0;
-	int	            i = 0;
+	int i;
 	
 	INIT_MINMAX(gmin, gmax);
 	for (i = 0; i < numverts; i++)
 		DO_MINMAX(lX[i], gmin, gmax);
+}
+
+static HairGridVert *hair_volume_create_hair_grid(ClothModifierData *clmd, lfVector *lX, lfVector *lV, unsigned int numverts)
+{
+	int size = hair_grid_size(hair_grid_res);
+	HairGridVert *hairgrid;
+	float gmin[3], gmax[3], density;
+	/* 2.0f is an experimental value that seems to give good results */
+	float smoothfac = 2.0f * clmd->sim_parms->velocity_smooth;
+	unsigned int	v = 0;
+	int	            i = 0;
+
+	hair_volume_get_boundbox(lX, numverts, gmin, gmax);
 
 	hairgrid = MEM_mallocN(sizeof(HairGridVert) * size, "hair voxel data");
-	collgrid = MEM_mallocN(sizeof(HairGridVert) * size, "hair collider voxel data");
 
 	/* initialize grid */
 	for (i = 0; i < size; ++i) {
 		zero_v3(hairgrid[i].velocity);
 		hairgrid[i].density = 0.0f;
-		
-		zero_v3(collgrid[i].velocity);
-		collgrid[i].density = 0.0f;
 	}
 
 	/* gather velocities & density */
@@ -1335,6 +1335,42 @@ static void hair_volume_forces(ClothModifierData *clmd, lfVector *lF, lfVector *
 		}
 	}
 
+	/* divide velocity with density */
+	for (i = 0; i < size; i++) {
+		density = hairgrid[i].density;
+		if (density > 0.0f) {
+			hairgrid[i].velocity[0] /= density;
+			hairgrid[i].velocity[1] /= density;
+			hairgrid[i].velocity[2] /= density;
+		}
+	}
+	
+	return hairgrid;
+}
+
+
+static HairGridVert *hair_volume_create_collision_grid(ClothModifierData *clmd, lfVector *lX, unsigned int numverts)
+{
+	int size = hair_grid_size(hair_grid_res);
+	HairGridVert *collgrid;
+	ListBase *colliders;
+	ColliderCache *col = NULL;
+	float gmin[3], gmax[3], density;
+	/* 2.0f is an experimental value that seems to give good results */
+	float collfac = 2.0f * clmd->sim_parms->collider_friction;
+	unsigned int	v = 0;
+	int	            i = 0;
+
+	hair_volume_get_boundbox(lX, numverts, gmin, gmax);
+
+	collgrid = MEM_mallocN(sizeof(HairGridVert) * size, "hair collider voxel data");
+
+	/* initialize grid */
+	for (i = 0; i < size; ++i) {
+		zero_v3(collgrid[i].velocity);
+		collgrid[i].density = 0.0f;
+	}
+
 	/* gather colliders */
 	colliders = get_collider_cache(clmd->scene, NULL, NULL);
 	if (colliders && collfac > 0.0f) {
@@ -1359,13 +1395,6 @@ static void hair_volume_forces(ClothModifierData *clmd, lfVector *lF, lfVector *
 
 	/* divide velocity with density */
 	for (i = 0; i < size; i++) {
-		density = hairgrid[i].density;
-		if (density > 0.0f) {
-			hairgrid[i].velocity[0] /= density;
-			hairgrid[i].velocity[1] /= density;
-			hairgrid[i].velocity[2] /= density;
-		}
-		
 		density = collgrid[i].density;
 		if (density > 0.0f) {
 			collgrid[i].velocity[0] /= density;
@@ -1374,6 +1403,21 @@ static void hair_volume_forces(ClothModifierData *clmd, lfVector *lF, lfVector *
 		}
 	}
 	
+	return collgrid;
+}
+
+static void hair_volume_forces(ClothModifierData *clmd, lfVector *lF, lfVector *lX, lfVector *lV, unsigned int numverts)
+{
+	HairGridVert *hairgrid, *collgrid;
+	float gmin[3], gmax[3];
+	/* 2.0f is an experimental value that seems to give good results */
+	float smoothfac = 2.0f * clmd->sim_parms->velocity_smooth;
+	float collfac = 2.0f * clmd->sim_parms->collider_friction;
+
+	hair_volume_get_boundbox(lX, numverts, gmin, gmax);
+	hairgrid = hair_volume_create_hair_grid(clmd, lX, lV, numverts);
+	collgrid = hair_volume_create_collision_grid(clmd, lX, numverts);
+
 	hair_velocity_smoothing(hairgrid, gmin, gmax, smoothfac, lF, lX, lV, numverts);
 	hair_velocity_collision(collgrid, gmin, gmax, collfac, lF, lX, lV, numverts);
 
@@ -1381,6 +1425,47 @@ static void hair_volume_forces(ClothModifierData *clmd, lfVector *lF, lfVector *
 	MEM_freeN(collgrid);
 }
 
+bool implicit_hair_volume_get_texture_data(Object *UNUSED(ob), ClothModifierData *clmd, ListBase *UNUSED(effectors), VoxelData *vd)
+{
+	lfVector *lX, *lV;
+	HairGridVert *hairgrid/*, *collgrid*/;
+	int numverts;
+	int totres, i;
+
+	if (!clmd->clothObject || !clmd->clothObject->implicit)
+		return false;
+
+	lX = clmd->clothObject->implicit->X;
+	lV = clmd->clothObject->implicit->V;
+	numverts = clmd->clothObject->numverts;
+
+	hairgrid = hair_volume_create_hair_grid(clmd, lX, lV, numverts);
+//	collgrid = hair_volume_create_collision_grid(clmd, lX, numverts);
+
+	vd->resol[0] = hair_grid_res;
+	vd->resol[1] = hair_grid_res;
+	vd->resol[2] = hair_grid_res;
+	
+	totres = hair_grid_size(hair_grid_res);
+	
+	vd->data_type = TEX_VD_INTENSITY;
+	if (totres > 0) {
+		vd->dataset = (float *)MEM_mapallocN(sizeof(float) * (totres), "hair volume texture data");
+		for (i = 0; i < totres; ++i) {
+			vd->dataset[i] = hairgrid[i].density;
+		}
+	}
+	else
+		vd->dataset = NULL;
+	
+	MEM_freeN(hairgrid);
+//	MEM_freeN(collgrid);
+	
+	return true;
+}
+
+/* ================================ */
+
 static void cloth_calc_force(ClothModifierData *clmd, float UNUSED(frame), lfVector *lF, lfVector *lX, lfVector *lV, fmatrix3x3 *dFdV, fmatrix3x3 *dFdX, ListBase *effectors, float time, fmatrix3x3 *M)
 {
 	/* Collect forces and derivatives:  F, dFdX, dFdV */
@@ -1798,4 +1883,3 @@ void implicit_set_positions(ClothModifierData *clmd)
 	if (G.debug_value > 0)
 		printf("implicit_set_positions\n");
 }
-

source/blender/makesdna/DNA_texture_types.h

@@ -617,6 +617,7 @@ enum {
 #define TEX_VD_RAW_16BIT		2
 #define TEX_VD_IMAGE_SEQUENCE	3
 #define TEX_VD_SMOKE			4
+#define TEX_VD_HAIR				5
 /* for voxels which use VoxelData->source_path */
 #define TEX_VD_IS_SOURCE_PATH(_format) (ELEM(_format, TEX_VD_BLENDERVOXEL, TEX_VD_RAW_8BIT, TEX_VD_RAW_16BIT))
 

source/blender/makesrna/intern/rna_texture.c

@@ -1851,6 +1851,7 @@ static void rna_def_texture_voxeldata(BlenderRNA *brna)
 		{TEX_VD_IMAGE_SEQUENCE, "IMAGE_SEQUENCE", 0, "Image Sequence",
 		                        "Generate voxels from a sequence of image slices"},
 		{TEX_VD_SMOKE, "SMOKE", 0, "Smoke", "Render voxels from a Blender smoke simulation"},
+		{TEX_VD_HAIR, "HAIR", 0, "Hair", "Render voxels from a Blender hair simulation"},
 		{0, NULL, 0, NULL, NULL}
 	};
 	

source/blender/render/intern/source/voxeldata.c

@@ -51,6 +51,7 @@
 #include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
 
+#include "BKE_cloth.h"
 #include "BKE_global.h"
 #include "BKE_image.h"
 #include "BKE_main.h"
@@ -61,6 +62,7 @@
 #include "DNA_texture_types.h"
 #include "DNA_object_force.h"
 #include "DNA_object_types.h"
+#include "DNA_particle_types.h"
 #include "DNA_modifier_types.h"
 #include "DNA_smoke_types.h"
 
@@ -364,6 +366,27 @@ static void init_frame_smoke(VoxelData *vd, int cfra)
 #endif
 }
 
+static void init_frame_hair(VoxelData *vd, int UNUSED(cfra))
+{
+	Object *ob;
+	ModifierData *md;
+	bool found = false;
+	
+	vd->dataset = NULL;
+	if (vd->object == NULL) return;
+	ob = vd->object;
+	
+	if ((md = (ModifierData *)modifiers_findByType(ob, eModifierType_ParticleSystem))) {
+		ParticleSystemModifierData *pmd = (ParticleSystemModifierData *)md;
+		
+		if (pmd->psys && pmd->psys->clmd) {
+			found |= implicit_hair_volume_get_texture_data(ob, pmd->psys->clmd, NULL, vd);
+		}
+	}
+	
+	vd->ok = found;
+}
+
 void cache_voxeldata(Tex *tex, int scene_frame)
 {	
 	VoxelData *vd = tex->vd;
@@ -397,6 +420,9 @@ void cache_voxeldata(Tex *tex, int scene_frame)
 		case TEX_VD_SMOKE:
 			init_frame_smoke(vd, scene_frame);
 			return;
+		case TEX_VD_HAIR:
+			init_frame_hair(vd, scene_frame);
+			return;
 		case TEX_VD_BLENDERVOXEL:
 			BLI_path_abs(path, G.main->name);
 			if (!BLI_exists(path)) return;