[#27615] Box select of mesh object disabled or translated due to curve object

ED_view3d_init_mats_rv3d was calling glMultMatrixf() which was mostly harmless but could also lead to confusing bugs (2 reported previously).
Looked into this and every call to ED_view3d_init_mats_rv3d except for object drawing, doesn't need this so made a second version of ED_view3d_init_mats_rv3d - ED_view3d_init_mats_rv3d_gl which does the matrix multiplication, remove confusing checks in selection code.

source/blender/editors/include/ED_view3d.h

@@ -265,6 +265,7 @@ struct ARegion *ED_view3d_context_region_unlock(struct bContext *C);
 int ED_operator_rv3d_unlock_poll(struct bContext *C);
 
 void ED_view3d_init_mats_rv3d(struct Object *ob, struct RegionView3D *rv3d);
+void ED_view3d_init_mats_rv3d_gl(struct Object *ob, struct RegionView3D *rv3d);
 
 int ED_view3d_scene_layer_set(int lay, const int *values, int *active);
 

source/blender/editors/space_view3d/drawobject.c

@@ -5812,7 +5812,7 @@ void draw_object(Scene *scene, ARegion *ar, View3D *v3d, Base *base, int flag)
 
 	/* multiply view with object matrix.
 	 * local viewmat and persmat, to calculate projections */
-	ED_view3d_init_mats_rv3d(ob, rv3d);
+	ED_view3d_init_mats_rv3d_gl(ob, rv3d);
 
 	/* which wire color */
 	if((flag & DRAW_CONSTCOLOR) == 0) {

source/blender/editors/space_view3d/space_view3d.c

@@ -208,13 +208,18 @@ void ED_view3d_init_mats_rv3d(struct Object *ob, struct RegionView3D *rv3d)
 	mul_m4_m4m4(rv3d->viewmatob, ob->obmat, rv3d->viewmat);
 	mul_m4_m4m4(rv3d->persmatob, ob->obmat, rv3d->persmat);
 
+	/* initializes object space clipping, speeds up clip tests */
+	ED_view3d_local_clipping(rv3d, ob->obmat);
+}
+
+void ED_view3d_init_mats_rv3d_gl(struct Object *ob, struct RegionView3D *rv3d)
+{
+	ED_view3d_init_mats_rv3d(ob, rv3d);
+
 	/* we have to multiply instead of loading viewmatob to make
 	   it work with duplis using displists, otherwise it will
 	   override the dupli-matrix */
 	glMultMatrixf(ob->obmat);
-
-	/* initializes object space clipping, speeds up clip tests */
-	ED_view3d_local_clipping(rv3d, ob->obmat);
 }
 
 /* ******************** default callbacks for view3d space ***************** */

source/blender/editors/space_view3d/view3d_select.c

@@ -485,11 +485,8 @@ static void do_lasso_select_mesh(ViewContext *vc, int mcords[][2], short moves,
 	if (extend == 0 && select)
 		EM_deselect_all(vc->em);
 
-	/* workaround: init mats first, EM_mask_init_backbuf_border can change
+	 /* for non zbuf projections, dont change the GL state */
-	   view matrix to pixel space, breaking edge select with backbuf. fixes bug [#20936] */
+	ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d);
-
-	/* [#21018] breaks zbuf select. run below. only if bbsel fails */
-	/* ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d) */
 
 	glLoadMatrixf(vc->rv3d->viewmat);
 	bbsel= EM_mask_init_backbuf_border(vc, mcords, moves, rect.xmin, rect.ymin, rect.xmax, rect.ymax);
@@ -497,15 +494,13 @@ static void do_lasso_select_mesh(ViewContext *vc, int mcords[][2], short moves,
 	if(ts->selectmode & SCE_SELECT_VERTEX) {
 		if (bbsel) {
 			EM_backbuf_checkAndSelectVerts(vc->em, select);
-		} else {
+		}
-			ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d); /* for foreach's screen/vert projection */
+		else {
 			mesh_foreachScreenVert(vc, do_lasso_select_mesh__doSelectVert, &data, 1);
 		}
 	}
 	if(ts->selectmode & SCE_SELECT_EDGE) {
 		/* Does both bbsel and non-bbsel versions (need screen cos for both) */
-		ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d); /* for foreach's screen/vert projection */
-
 		data.pass = 0;
 		mesh_foreachScreenEdge(vc, do_lasso_select_mesh__doSelectEdge, &data, 0);
 
@@ -518,8 +513,8 @@ static void do_lasso_select_mesh(ViewContext *vc, int mcords[][2], short moves,
 	if(ts->selectmode & SCE_SELECT_FACE) {
 		if (bbsel) {
 			EM_backbuf_checkAndSelectFaces(vc->em, select);
-		} else {
+		}
-			ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d); /* for foreach's screen/vert projection */
+		else {
 			mesh_foreachScreenFace(vc, do_lasso_select_mesh__doSelectFace, &data);
 		}
 	}
@@ -1491,12 +1486,8 @@ static int do_mesh_box_select(ViewContext *vc, rcti *rect, int select, int exten
 	if (extend == 0 && select)
 		EM_deselect_all(vc->em);
 
-	/* workaround: init mats first, EM_mask_init_backbuf_border can change
+	/* for non zbuf projections, dont change the GL state */
-	   view matrix to pixel space, breaking edge select with backbuf. fixes bug #20936 */
+	ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d);
-	/*ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d);*/ /* for foreach's screen/vert projection */
-
-	/* [#21018] breaks zbuf select. run below. only if bbsel fails */
-	/* ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d) */
 
 	glLoadMatrixf(vc->rv3d->viewmat);
 	bbsel= EM_init_backbuf_border(vc, rect->xmin, rect->ymin, rect->xmax, rect->ymax);
@@ -1505,7 +1496,6 @@ static int do_mesh_box_select(ViewContext *vc, rcti *rect, int select, int exten
 		if (bbsel) {
 			EM_backbuf_checkAndSelectVerts(vc->em, select);
 		} else {
-			ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d);
 			mesh_foreachScreenVert(vc, do_mesh_box_select__doSelectVert, &data, 1);
 		}
 	}
@@ -1525,7 +1515,6 @@ static int do_mesh_box_select(ViewContext *vc, rcti *rect, int select, int exten
 		if(bbsel) {
 			EM_backbuf_checkAndSelectFaces(vc->em, select);
 		} else {
-			ED_view3d_init_mats_rv3d(vc->obedit, vc->rv3d);
 			mesh_foreachScreenFace(vc, do_mesh_box_select__doSelectFace, &data);
 		}
 	}