[Bf-blender-cvs] [6c98748c701] hair_guides_grooming: Snap groom curves to the scalp surface in the curve cache.

[Lukas Tönne]

Commit: 6c98748c701b4cbc7064243bbaa5ed4080e46729
Author: Lukas Tönne
Date:   Sun Jun 3 17:11:05 2018 +0100
Branches: hair_guides_grooming
https://developer.blender.org/rB6c98748c701b4cbc7064243bbaa5ed4080e46729

Snap groom curves to the scalp surface in the curve cache.

This also makes sure that guide curve (which are generated using the
curve cache) run inside the actual bundle volume. Otherwise they might
get an offset that aligns the root, but makes them diverge in non-root
sections.

===================================================================

M	source/blender/blenkernel/BKE_groom.h
M	source/blender/blenkernel/intern/groom.c

===================================================================

diff --git a/source/blender/blenkernel/BKE_groom.h b/source/blender/blenkernel/BKE_groom.h
index e140c7709f0..a23a8f540bb 100644
--- a/source/blender/blenkernel/BKE_groom.h
+++ b/source/blender/blenkernel/BKE_groom.h
@@ -59,7 +59,7 @@ struct BoundBox *BKE_groom_boundbox_get(struct Object *ob);
 
 /* === Curve cache === */
 
-void BKE_groom_curve_cache_update(struct Groom *groom);
+void BKE_groom_curve_cache_update(struct Groom *groom, const struct Mesh *scalp);
 void BKE_groom_curve_cache_clear(struct Groom *groom);
 
 
diff --git a/source/blender/blenkernel/intern/groom.c b/source/blender/blenkernel/intern/groom.c
index 90bea0aa99f..bc77942bea9 100644
--- a/source/blender/blenkernel/intern/groom.c
+++ b/source/blender/blenkernel/intern/groom.c
@@ -886,8 +886,30 @@ static void groom_eval_center_curve_section(
 	}
 }
 
+static void groom_eval_shape_vertex(const GroomBundle *bundle, const Mesh *scalp, int vertex_idx, int section_idx, float r_co[3])
+{
+	if (section_idx == 0 && bundle->scalp_region != NULL)
+	{
+		/* For bound regions use location on the scalp */
+		const MeshSample *bound_loc = &bundle->scalp_region[vertex_idx];
+		float nor[3], tang[3];
+		BKE_mesh_sample_eval(scalp, bound_loc, r_co, nor, tang);
+	}
+	else
+	{
+		const GroomSection *section = &bundle->sections[section_idx];
+		const GroomSectionVertex *vertex = &bundle->verts[vertex_idx + section_idx * bundle->numshapeverts];
+		
+		float tmp[3] = {0.0f, 0.0f, 0.0f};
+		copy_v2_v2(tmp, vertex->co);
+		mul_v3_m3v3(r_co, section->mat, tmp);
+		add_v3_v3(r_co, section->center);
+	}
+}
+
 static void groom_eval_shape_curves(
         GroomBundle *bundle,
+        const Mesh *scalp,
         int curve_res)
 {
 	BLI_assert(bundle->totsections >= 2);
@@ -898,42 +920,25 @@ static void groom_eval_shape_curves(
 		GroomCurveCache *cache = bundle->curvecache + i * bundle->curvesize;
 		for (int j = 0; j < bundle->totsections-1; ++j, cache += curve_res)
 		{
-			const GroomSection *section = &bundle->sections[j];
 			const float *co0 = NULL, *co1 = NULL, *co2 =NULL, *co3 = NULL;
 			
 			float vec0[3], vec1[3], vec2[3], vec3[3];
 			if (j > 0)
 			{
-				const GroomSectionVertex *v0 = &bundle->verts[(j-1) * bundle->numshapeverts + i];
-				float tmp[3] = {0.0f, 0.0f, 0.0f};
-				copy_v2_v2(tmp, v0->co);
-				mul_v3_m3v3(vec0, section[-1].mat, tmp);
-				add_v3_v3(vec0, section[-1].center);
+				groom_eval_shape_vertex(bundle, scalp, i, j-1, vec0);
 				co0 = vec0;
 			}
 			{
-				const GroomSectionVertex *v1 = &bundle->verts[(j) * bundle->numshapeverts + i];
-				float tmp[3] = {0.0f, 0.0f, 0.0f};
-				copy_v2_v2(tmp, v1->co);
-				mul_v3_m3v3(vec1, section[0].mat, tmp);
-				add_v3_v3(vec1, section[0].center);
+				groom_eval_shape_vertex(bundle, scalp, i, j, vec1);
 				co1 = vec1;
 			}
 			{
-				const GroomSectionVertex *v2 = &bundle->verts[(j+1) * bundle->numshapeverts + i];
-				float tmp[3] = {0.0f, 0.0f, 0.0f};
-				copy_v2_v2(tmp, v2->co);
-				mul_v3_m3v3(vec2, section[+1].mat, tmp);
-				add_v3_v3(vec2, section[+1].center);
+				groom_eval_shape_vertex(bundle, scalp, i, j+1, vec2);
 				co2 = vec2;
 			}
 			if (j < bundle->totsections - 2)
 			{
-				const GroomSectionVertex *v3 = &bundle->verts[(j+2) * bundle->numshapeverts + i];
-				float tmp[3] = {0.0f, 0.0f, 0.0f};
-				copy_v2_v2(tmp, v3->co);
-				mul_v3_m3v3(vec3, section[+2].mat, tmp);
-				add_v3_v3(vec3, section[+2].center);
+				groom_eval_shape_vertex(bundle, scalp, i, j+2, vec3);
 				co3 = vec3;
 			}
 			
@@ -991,7 +996,7 @@ static void groom_eval_section_mats(GroomBundle *bundle, int curve_res)
 	copy_m3_m3(section->mat, mat);
 }
 
-void BKE_groom_curve_cache_update(Groom *groom)
+void BKE_groom_curve_cache_update(Groom *groom, const Mesh *scalp)
 {
 	ListBase *bundles = (groom->editgroom ? &groom->editgroom->bundles : &groom->bundles);
 	
@@ -1033,7 +1038,7 @@ void BKE_groom_curve_cache_update(Groom *groom)
 		groom_eval_section_mats(bundle, curve_res);
 		
 		/* Calculate shape curves */
-		groom_eval_shape_curves(bundle, curve_res);
+		groom_eval_shape_curves(bundle, scalp, curve_res);
 	}
 }
 
@@ -1067,7 +1072,7 @@ void BKE_groom_eval_geometry(const struct Depsgraph *depsgraph, Groom *groom)
 	BKE_groom_apply_constraints(groom, scalp_eval);
 	
 	/* calculate curves for interpolating shapes */
-	BKE_groom_curve_cache_update(groom);
+	BKE_groom_curve_cache_update(groom, scalp_eval);
 	
 	/* generate actual guide curves for hair */
 	BKE_groom_hair_update_guide_curves(groom);