Fix T45605 crash with editmode selection on solidify modifier.

Looks like derivedmesh draw code always assumed a mesh is available.
Make sure that if we use a bmesh, a flag is used to control that.

3 files changed, 24 insertions, 5 deletions

diff --git a/source/blender/blenkernel/BKE_DerivedMesh.h b/source/blender/blenkernel/BKE_DerivedMesh.h
index 32baa452b4b..6b331980df5 100644
--- a/source/blender/blenkernel/BKE_DerivedMesh.h
+++ b/source/blender/blenkernel/BKE_DerivedMesh.h
@@ -151,6 +151,7 @@ typedef enum DMDrawFlag {
 	DM_DRAW_USE_TEXPAINT_UV     = (1 << 3),
 	DM_DRAW_SKIP_HIDDEN         = (1 << 4),
 	DM_DRAW_SKIP_SELECT         = (1 << 5),
+	DM_DRAW_SELECT_USE_EDITMODE = (1 << 6)
 } DMDrawFlag;
 
 typedef enum DMForeachFlag {
diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index 6a766037c8b..b5ff4f6ee5f 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -654,9 +654,15 @@ static void cdDM_drawMappedFaces(
 	/* if we do selection, fill the selection buffer color */
 	if (G.f & G_BACKBUFSEL) {
 		if (!(flag & DM_DRAW_SKIP_SELECT)) {
-			Mesh *me = userData;
+			Mesh *me = NULL;
+			BMesh *bm = NULL;
 			unsigned int *fi_map;
 
+			if (flag & DM_DRAW_SELECT_USE_EDITMODE)
+				bm = userData;
+			else
+				me = userData;
+
 			findex_buffer = GPU_buffer_alloc(dm->drawObject->tot_loop_verts * sizeof(int), false);
 			fi_map = GPU_buffer_lock(findex_buffer, GPU_BINDING_ARRAY);
 
@@ -664,10 +670,22 @@ static void cdDM_drawMappedFaces(
 				for (i = 0; i < totpoly; i++, mpoly++) {
 					int selcol = 0xFFFFFFFF;
 					const int orig = (index_mp_to_orig) ? index_mp_to_orig[i] : i;
+					bool is_hidden;
 
-					if ((orig != ORIGINDEX_NONE) && (!useHide || !(me->mpoly[orig].flag & ME_HIDE))) {
-						WM_framebuffer_index_get(orig + 1, &selcol);
+					if (useHide) {
+						if (flag & DM_DRAW_SELECT_USE_EDITMODE) {
+							BMFace *efa = BM_face_at_index(bm, orig);
+							is_hidden = BM_elem_flag_test(efa, BM_ELEM_HIDDEN) != 0;
+						}
+						else {
+							is_hidden = (me->mpoly[orig].flag & ME_HIDE) != 0;
+						}
+
+						if ((orig != ORIGINDEX_NONE) && !is_hidden)
+							WM_framebuffer_index_get(orig + 1, &selcol);
 					}
+					else if (orig != ORIGINDEX_NONE)
+						WM_framebuffer_index_get(orig + 1, &selcol);
 
 					for (j = 0; j < mpoly->totloop; j++)
 						fi_map[start_element++] = selcol;
diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index fee68057646..f03b008762f 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -8445,7 +8445,7 @@ static void bbs_mesh_solid_EM(BMEditMesh *em, Scene *scene, View3D *v3d,
 	cpack(0);
 
 	if (use_faceselect) {
-		dm->drawMappedFaces(dm, bbs_mesh_solid__setSolidDrawOptions, NULL, NULL, em->bm, DM_DRAW_SKIP_HIDDEN);
+		dm->drawMappedFaces(dm, bbs_mesh_solid__setSolidDrawOptions, NULL, NULL, em->bm, DM_DRAW_SKIP_HIDDEN | DM_DRAW_SELECT_USE_EDITMODE);
 
 		if (check_ob_drawface_dot(scene, v3d, ob->dt)) {
 			glPointSize(UI_GetThemeValuef(TH_FACEDOT_SIZE));
@@ -8457,7 +8457,7 @@ static void bbs_mesh_solid_EM(BMEditMesh *em, Scene *scene, View3D *v3d,
 
 	}
 	else {
-		dm->drawMappedFaces(dm, bbs_mesh_mask__setSolidDrawOptions, NULL, NULL, em->bm, DM_DRAW_SKIP_SELECT | DM_DRAW_SKIP_HIDDEN);
+		dm->drawMappedFaces(dm, bbs_mesh_mask__setSolidDrawOptions, NULL, NULL, em->bm, DM_DRAW_SKIP_SELECT | DM_DRAW_SKIP_HIDDEN | DM_DRAW_SELECT_USE_EDITMODE);
 	}
 }