== Constraints - Geometry Targets Improvements ==

This commit features fixes/improvements for problems I didn't manage to fix in time for the commit yesterday.

* Now for Meshes, the normals of the vertices in the VertexGroup are averaged and used to find the 'rotation' that needs to be applied. Unfortunately, this does not work with Lattices as they do not have normals.
* Depsgraph should now play nicely with geometry targets. Before, the constrained object's location wasn't being updated after the target's geometry was modified.

1 files changed, 41 insertions, 16 deletions

diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index 651b8a102e9..7f736a644f9 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -1116,6 +1116,8 @@ static void contarget_get_mesh_mat (Object *ob, char *substring, float mat[][4])
 {
 	DerivedMesh *dm = (DerivedMesh *)ob->derivedFinal;
 	float vec[3] = {0.0f, 0.0f, 0.0f}, tvec[3];
+	float normal[3] = {0.0f, 0.0f, 0.0f}, plane[3];
+	float imat[3][3], tmat[3][3];
 	int dgroup;
 	
 	/* initialize target matrix using target matrix */
@@ -1131,7 +1133,8 @@ static void contarget_get_mesh_mat (Object *ob, char *substring, float mat[][4])
 		int *index = (int *)dm->getVertDataArray(dm, CD_ORIGINDEX);
 		int numVerts = dm->getNumVerts(dm);
 		int i, j, count = 0;
-		float co[3];
+		float co[3], nor[3];
+		
 		
 		/* get the average of all verts with that are in the vertex-group */
 		for (i = 0; i < numVerts; i++, index++) {	
@@ -1139,7 +1142,9 @@ static void contarget_get_mesh_mat (Object *ob, char *substring, float mat[][4])
 				/* does this vertex belong to nominated vertex group? */
 				if (dvert[i].dw[j].def_nr == dgroup) {
 					dm->getVertCo(dm, i, co);
+					dm->getVertNo(dm, i, nor);
 					VecAddf(vec, vec, co);
+					VecAddf(normal, normal, nor);
 					count++;
 					break;
 				}
@@ -1147,12 +1152,38 @@ static void contarget_get_mesh_mat (Object *ob, char *substring, float mat[][4])
 			}
 		}
 		
-		/* calculate average, and apply as new location for matrix */
-		if (count > 0)
+		
+		/* calculate averages of normal and coordinates */
+		if (count > 0) {
 			VecMulf(vec, 1.0f / count);
-		VecMat4MulVecfl(tvec, ob->obmat, vec);
+			VecMulf(normal, 1.0f / count);
+		}
 		
-		/* copy new location to matrix */
+		
+		/* derive the rotation from the average normal: 
+		 *		- code taken from transform_manipulator.c, 
+		 *			calc_manipulator_stats, V3D_MANIP_NORMAL case
+		 */
+		/*	we need the transpose of the inverse for a normal... */
+		Mat3CpyMat4(imat, ob->obmat);
+		
+		Mat3Inv(tmat, imat);
+		Mat3Transp(tmat);
+		Mat3MulVecfl(tmat, normal);
+
+		Normalize(normal);
+		VECCOPY(plane, tmat[1]);
+		
+		VECCOPY(tmat[2], normal);
+		Crossf(tmat[0], normal, plane);
+		Crossf(tmat[1], tmat[2], tmat[0]);
+		
+		Mat4CpyMat3(mat, tmat);
+		Mat4Ortho(mat);
+		
+		
+		/* apply the average coordinate as the new location */
+		VecMat4MulVecfl(tvec, ob->obmat, vec);
 		VECCOPY(mat[3], tvec);
 	}
 }
@@ -1224,25 +1255,19 @@ static void constraint_target_to_mat4 (Object *ob, char *substring, float mat[][
 	}
 	/* 	Case VERTEXGROUP */
 	/* Current method just takes the average location of all the points in the
-	 * VertexGroup, and uses that as the location value of the target's matrix 
-	 * instead. 
+	 * VertexGroup, and uses that as the location value of the targets. Where 
+	 * possible, the orientation will also be calculated, by calculating an
+	 * 'average' vertex normal, and deriving the rotaation from that.
 	 *
-	 * TODO: figure out a way to find 3-points to define a rotation plane based
-	 *		on the normal of the triangle formed by those three points.
-	 * NOTE: editmode is not currently taken into consideration when doing this
+	 * NOTE: EditMode is not currently supported, and will most likely remain that
+	 *		way as constraints can only really affect things on object/bone level.
 	 */
 	else if (ob->type == OB_MESH) {
-		/* devise a matrix from the vertices in the vertexgroup */
 		contarget_get_mesh_mat(ob, substring, mat);
-		
-		/* make sure it's in the right space for evaluation */
 		constraint_mat_convertspace(ob, NULL, mat, from, to);
 	}
 	else if (ob->type == OB_LATTICE) {
-		/* devise a matrix from the vertices in the vertexgroup */
 		contarget_get_lattice_mat(ob, substring, mat);
-		
-		/* make sure it's in the right space for evaluation */
 		constraint_mat_convertspace(ob, NULL, mat, from, to);
 	}
 	/*	Case BONE */