bugfix [#23150] Creating Vertex with CTRL-LMB not snapping

- Added EM_project_snap_verts so other functions can re-use this, similar to old retopo_do_all().
- Changed how the normal for selected geometry is calculated, was accumulating half selected edge's into normals which was OK with even surrounding geometry but could skew too easily if the surroundings were not so even. Now use the 2D screen space selected edge vector to calculate the normals in relation to the target mouse position.
- Option to rotate initial selection, gives better results in some cases. (Ctrl+Shift+Click to disable)
http://wiki.blender.org/index.php/File:ClickExtrudeFix.png

4 files changed, 81 insertions, 16 deletions

diff --git a/source/blender/editors/include/ED_mesh.h b/source/blender/editors/include/ED_mesh.h
index c4477ee5a8e..313df32fd6f 100644
--- a/source/blender/editors/include/ED_mesh.h
+++ b/source/blender/editors/include/ED_mesh.h
@@ -159,6 +159,8 @@ void		EM_solidify(struct EditMesh *em, float dist);
 
 int			EM_deselect_nth(struct EditMesh *em, int nth);
 
+void EM_project_snap_verts(struct bContext *C, struct ARegion *ar, struct Object *obedit, struct EditMesh *em);
+
 /* editmesh_mods.c */
 extern unsigned int em_vertoffs, em_solidoffs, em_wireoffs;
 
diff --git a/source/blender/editors/mesh/editmesh_add.c b/source/blender/editors/mesh/editmesh_add.c
index 90c5314bf3d..5850dc706b0 100644
--- a/source/blender/editors/mesh/editmesh_add.c
+++ b/source/blender/editors/mesh/editmesh_add.c
@@ -110,17 +110,20 @@ static short icoface[20][3] = {
 static int dupli_extrude_cursor(bContext *C, wmOperator *op, wmEvent *event)
 {
 	ViewContext vc;
-	EditVert *eve, *v1;
+	EditVert *eve;
 	float min[3], max[3];
 	int done= 0;
+	int rot_src= RNA_boolean_get(op->ptr, "rotate_source");
 	
 	em_setup_viewcontext(C, &vc);
 	
+	invert_m4_m4(vc.obedit->imat, vc.obedit->obmat); 
+	
 	INIT_MINMAX(min, max);
 	
-	for(v1= vc.em->verts.first;v1; v1=v1->next) {
-		if(v1->f & SELECT) {
-			DO_MINMAX(v1->co, min, max);
+	for(eve= vc.em->verts.first; eve; eve= eve->next) {
+		if(eve->f & SELECT) {
+			DO_MINMAX(eve->co, min, max);
 			done= 1;
 		}
 	}
@@ -131,25 +134,56 @@ static int dupli_extrude_cursor(bContext *C, wmOperator *op, wmEvent *event)
 		float vec[3], cent[3], mat[3][3];
 		float nor[3]= {0.0, 0.0, 0.0};
 		
-		/* check for edges that are half selected, use for rotation */
+		/* 2D normal calc */
+		float mval_f[2]= {(float)event->mval[0], (float)event->mval[1]};
+
+#define SIDE_OF_LINE(pa,pb,pp)	((pa[0]-pp[0])*(pb[1]-pp[1]))-((pb[0]-pp[0])*(pa[1]-pp[1]))
+		
 		done= 0;
+
+		/* calculate the normal for selected edges */
 		for(eed= vc.em->edges.first; eed; eed= eed->next) {
-			if( (eed->v1->f & SELECT)+(eed->v2->f & SELECT) == SELECT ) {
-				if(eed->v1->f & SELECT) sub_v3_v3v3(vec, eed->v1->co, eed->v2->co);
-				else sub_v3_v3v3(vec, eed->v2->co, eed->v1->co);
-				add_v3_v3(nor, vec);
+			if(eed->f & SELECT) {
+				float co1[3], co2[3];
+				mul_v3_m4v3(co1, vc.obedit->obmat, eed->v1->co);
+				mul_v3_m4v3(co2, vc.obedit->obmat, eed->v2->co);
+				project_float_noclip(vc.ar, co1, co1);
+				project_float_noclip(vc.ar, co2, co2);
+				
+				/* 2D rotate by 90d while subtracting
+				 *  (x, y) = (y, -x)
+				 *
+				 * accumulate the screenspace normal in 2D,
+				 * with screenspace edge length weighting the result. */
+				if(SIDE_OF_LINE(co1, co2, mval_f) >= 0.0f) {
+					nor[0] +=  (co1[1] - co2[1]);
+					nor[1] += -(co1[0] - co2[0]);
+				}
+				else {
+					nor[0] +=  (co2[1] - co1[1]);
+					nor[1] += -(co2[0] - co1[0]);
+				}
 				done= 1;
 			}
 		}
+
+#undef SIDE_OF_LINE
+
 		if(done) {
 			float view_vec[3], cross[3];
 
+			/* convert the 2D nomal into 3D */
+			mul_mat3_m4_v3(vc.rv3d->viewinv, nor); /* worldspace */
+			mul_mat3_m4_v3(vc.obedit->imat, nor); /* local space */
+			
 			/* correct the normal to be aligned on the view plane */
 			copy_v3_v3(view_vec, vc.rv3d->viewinv[2]);
 			mul_mat3_m4_v3(vc.obedit->imat, view_vec);
 			cross_v3_v3v3(cross, nor, view_vec);
 			cross_v3_v3v3(nor, view_vec, cross);
 			normalize_v3(nor);
+			
+			/* correct for flipping */
 		}
 		
 		/* center */
@@ -159,10 +193,9 @@ static int dupli_extrude_cursor(bContext *C, wmOperator *op, wmEvent *event)
 		
 		mul_m4_v3(vc.obedit->obmat, min);	// view space
 		view3d_get_view_aligned_coordinate(&vc, min, event->mval);
-		invert_m4_m4(vc.obedit->imat, vc.obedit->obmat); 
 		mul_m4_v3(vc.obedit->imat, min); // back in object space
 		
-		sub_v3_v3v3(min, min, cent);
+		sub_v3_v3(min, cent);
 		
 		/* calculate rotation */
 		unit_m3(mat);
@@ -179,16 +212,22 @@ static int dupli_extrude_cursor(bContext *C, wmOperator *op, wmEvent *event)
 				cross_v3_v3v3(cross, nor, vec);
 				normalize_v3(cross);
 				dot= 0.5f*saacos(dot);
+				
+				/* halve the rotation if its applied twice */
+				if(rot_src) dot *= 0.5f;
+				
 				si= (float)sin(dot);
 				q1[0]= (float)cos(dot);
 				q1[1]= cross[0]*si;
 				q1[2]= cross[1]*si;
-				q1[3]= cross[2]*si;
-				
+				q1[3]= cross[2]*si;				
 				quat_to_mat3( mat,q1);
 			}
 		}
 		
+		if(rot_src)
+			rotateflag(vc.em, SELECT, cent, mat);
+		
 		extrudeflag(vc.obedit, vc.em, SELECT, nor, 0);
 		rotateflag(vc.em, SELECT, cent, mat);
 		translateflag(vc.em, SELECT, min);
@@ -213,8 +252,13 @@ static int dupli_extrude_cursor(bContext *C, wmOperator *op, wmEvent *event)
 		
 		eve->f= SELECT;
 	}
-	
-	//retopo_do_all();
+
+	if(	((vc.scene->toolsettings->snap_flag & (SCE_SNAP|SCE_SNAP_PROJECT))==(SCE_SNAP|SCE_SNAP_PROJECT)) &&
+		(vc.scene->toolsettings->snap_mode==SCE_SNAP_MODE_FACE)
+	) {
+		EM_project_snap_verts(C, vc.ar, vc.obedit, vc.em);
+	}
+
 	WM_event_add_notifier(C, NC_GEOM|ND_DATA, vc.obedit->data); 
 	DAG_id_flush_update(vc.obedit->data, OB_RECALC_DATA);
 	
@@ -234,6 +278,8 @@ void MESH_OT_dupli_extrude_cursor(wmOperatorType *ot)
 	
 	/* flags */
 	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
+
+	RNA_def_boolean(ot->srna, "rotate_source", 1, "Rotate Source", "Rotate initial selection giving better shape");
 }
 
 
diff --git a/source/blender/editors/mesh/editmesh_lib.c b/source/blender/editors/mesh/editmesh_lib.c
index d34cca0d358..209a7975357 100644
--- a/source/blender/editors/mesh/editmesh_lib.c
+++ b/source/blender/editors/mesh/editmesh_lib.c
@@ -58,6 +58,7 @@ editmesh_lib: generic (no UI, no menus) operations/evaluators for editmesh data
 #include "ED_mesh.h"
 #include "ED_screen.h"
 #include "ED_view3d.h"
+#include "ED_transform.h"
 
 #include "mesh_intern.h"
 
@@ -2765,3 +2766,18 @@ int EM_deselect_nth(EditMesh *em, int nth)
 	return 0;
 }
 
+void EM_project_snap_verts(bContext *C, ARegion *ar, Object *obedit, EditMesh *em)
+{
+	EditVert *eve;
+	for(eve= em->verts.first;eve; eve=eve->next) {
+		if(eve->f & SELECT) {
+			float mval[2], vec[3], no_dummy[3];
+			int dist_dummy;
+			mul_v3_m4v3(vec, obedit->obmat, eve->co);
+			project_float_noclip(ar, vec, mval);
+			if(snapObjectsContext(C, mval, &dist_dummy, vec, no_dummy, SNAP_NOT_OBEDIT)) {
+				mul_v3_m4v3(eve->co, obedit->imat, vec);
+			}
+		}
+	}
+}
diff --git a/source/blender/editors/mesh/mesh_ops.c b/source/blender/editors/mesh/mesh_ops.c
index 51a4c67b19b..2ff7095cfea 100644
--- a/source/blender/editors/mesh/mesh_ops.c
+++ b/source/blender/editors/mesh/mesh_ops.c
@@ -292,7 +292,8 @@ void ED_keymap_mesh(wmKeyConfig *keyconf)
 
 	/* use KM_CLICK because same key is used for tweaks */
 	WM_keymap_add_item(keymap, "MESH_OT_dupli_extrude_cursor", ACTIONMOUSE, KM_CLICK, KM_CTRL, 0);
-	
+	RNA_boolean_set(WM_keymap_add_item(keymap, "MESH_OT_dupli_extrude_cursor", ACTIONMOUSE, KM_CLICK, KM_SHIFT|KM_CTRL, 0)->ptr, "rotate_source", 0);
+
 	WM_keymap_add_item(keymap, "MESH_OT_delete", XKEY, KM_PRESS, 0, 0);
 	WM_keymap_add_item(keymap, "MESH_OT_delete", DELKEY, KM_PRESS, 0, 0);