Mesh drawing optimization and fixes:

- Pass MFace, MTface and OrigIndex arrays via userData to compareDrawParams callback
  rather than looking up for this layers for each face
- This allowed to avoid massing DM to compare callback which seems like a bad-level pass
- Fixed crashes on some video cards when assigning different materials to different
  faces in edit mode. Both of intel and nvidia cards in my laptop were affected by
  this error

3 files changed, 33 insertions, 25 deletions

diff --git a/source/blender/blenkernel/intern/editderivedmesh.c b/source/blender/blenkernel/intern/editderivedmesh.c
index 8eccfd4d3f0..bb1d20f0187 100644
--- a/source/blender/blenkernel/intern/editderivedmesh.c
+++ b/source/blender/blenkernel/intern/editderivedmesh.c
@@ -273,7 +273,7 @@ static void emDM_drawMappedFaces(
 {
 	EditMeshDerivedMesh *emdm= (EditMeshDerivedMesh*) dm;
 	EditFace *efa;
-	int i, draw;
+	int i, draw, flush;
 	const int skip_normals= !glIsEnabled(GL_LIGHTING); /* could be passed as an arg */
 
 	/* GL_ZERO is used to detect if drawing has started or not */
@@ -352,7 +352,11 @@ static void emDM_drawMappedFaces(
 					}
 				}
 
-				if (draw==2) {
+				flush= (draw==2);
+				if (!skip_normals && !flush && efa->next)
+					flush|= efa->mat_nr != efa->next->mat_nr;
+
+				if (flush) {
 					glEnd();
 					poly_prev= GL_ZERO; /* force glBegin */
 
@@ -419,8 +423,11 @@ static void emDM_drawMappedFaces(
 					}
 				}
 
+				flush= (draw==2);
+				if (!skip_normals && !flush && efa->next)
+					flush|= efa->mat_nr != efa->next->mat_nr;
 
-				if (draw==2) {
+				if (flush) {
 					glEnd();
 					poly_prev= GL_ZERO; /* force glBegin */
 
diff --git a/source/blender/editors/space_view3d/drawmesh.c b/source/blender/editors/space_view3d/drawmesh.c
index e83591b73f5..6dd362b827f 100644
--- a/source/blender/editors/space_view3d/drawmesh.c
+++ b/source/blender/editors/space_view3d/drawmesh.c
@@ -513,7 +513,7 @@ static int draw_tface_mapped__set_draw(void *userData, int index)
 
 static int draw_em_tf_mapped__set_draw(void *userData, int index)
 {
-	struct {DerivedMesh *dm; EditMesh *em; short has_mcol; short has_mtface;} *data = userData;
+	struct {EditMesh *em; short has_mcol; short has_mtface; MFace *mf; MTFace *tf;} *data = userData;
 	EditMesh *em = data->em;
 	EditFace *efa= EM_get_face_for_index(index);
 	MTFace *tface;
@@ -631,14 +631,12 @@ static void draw_mesh_text(Scene *scene, Object *ob, int glsl)
 
 static int compareDrawOptions(void *userData, int cur_index, int next_index)
 {
-	DerivedMesh *dm= (DerivedMesh*) userData;
-	MFace *mf = DM_get_face_data_layer(dm, CD_MFACE);
-	MTFace *tf = DM_get_face_data_layer(dm, CD_MTFACE);
+	struct { MFace *mf; MTFace *tf; } *data = userData;
 
-	if(mf && mf[cur_index].mat_nr != mf[next_index].mat_nr)
+	if(data->mf && data->mf[cur_index].mat_nr != data->mf[next_index].mat_nr)
 		return 0;
 
-	if(tf && tf[cur_index].tpage != tf[next_index].tpage)
+	if(data->tf && data->tf[cur_index].tpage != data->tf[next_index].tpage)
 		return 0;
 
 	return 1;
@@ -646,14 +644,12 @@ static int compareDrawOptions(void *userData, int cur_index, int next_index)
 
 static int compareDrawOptionsEm(void *userData, int cur_index, int next_index)
 {
-	struct {DerivedMesh *dm; EditMesh *em; short has_mcol; short has_mtface;} *data= userData;
-	MFace *mf = DM_get_face_data_layer(data->dm, CD_MFACE);
-	MTFace *tf = DM_get_face_data_layer(data->dm, CD_MTFACE);
+	struct {EditMesh *em; short has_mcol; short has_mtface; MFace *mf; MTFace *tf;} *data= userData;
 
-	if(mf && mf[cur_index].mat_nr != mf[next_index].mat_nr)
+	if(data->mf && data->mf[cur_index].mat_nr != data->mf[next_index].mat_nr)
 		return 0;
 
-	if(tf && tf[cur_index].tpage != tf[next_index].tpage)
+	if(data->tf && data->tf[cur_index].tpage != data->tf[next_index].tpage)
 		return 0;
 
 	return 1;
@@ -673,12 +669,13 @@ void draw_mesh_textured_old(Scene *scene, View3D *v3d, RegionView3D *rv3d, Objec
 	glColor4f(1.0f,1.0f,1.0f,1.0f);
 
 	if(ob->mode & OB_MODE_EDIT) {
-		struct {DerivedMesh *dm; EditMesh *em; short has_mcol; short has_mtface;} data;
+		struct {EditMesh *em; short has_mcol; short has_mtface; MFace *mf; MTFace *tf;} data;
 
-		data.dm = dm;
 		data.em= me->edit_mesh;
 		data.has_mcol= CustomData_has_layer(&me->edit_mesh->fdata, CD_MCOL);
 		data.has_mtface= CustomData_has_layer(&me->edit_mesh->fdata, CD_MTFACE);
+		data.mf= DM_get_face_data_layer(dm, CD_MFACE);
+		data.tf= DM_get_face_data_layer(dm, CD_MTFACE);
 
 		dm->drawMappedFacesTex(dm, draw_em_tf_mapped__set_draw, compareDrawOptionsEm, &data);
 	}
@@ -696,10 +693,15 @@ void draw_mesh_textured_old(Scene *scene, View3D *v3d, RegionView3D *rv3d, Objec
 				dm->drawFacesTex(dm, draw_tface__set_draw_legacy, NULL, NULL);
 		}
 		else {
+			struct { MFace *mf; MTFace *tf; } userData;
+
 			if(!CustomData_has_layer(&dm->faceData,CD_TEXTURE_MCOL))
 				add_tface_color_layer(dm);
 
-			dm->drawFacesTex(dm, draw_tface__set_draw, compareDrawOptions, dm);
+			userData.mf = DM_get_face_data_layer(dm, CD_MFACE);
+			userData.tf = DM_get_face_data_layer(dm, CD_MTFACE);
+
+			dm->drawFacesTex(dm, draw_tface__set_draw, compareDrawOptions, &userData);
 		}
 	}
 
diff --git a/source/blender/editors/space_view3d/drawobject.c b/source/blender/editors/space_view3d/drawobject.c
index f6f2c35163f..b3eba8652b0 100644
--- a/source/blender/editors/space_view3d/drawobject.c
+++ b/source/blender/editors/space_view3d/drawobject.c
@@ -2349,7 +2349,7 @@ static void draw_dm_edges_sharp(DerivedMesh *dm)
 	 * return 2 for the active face so it renders with stipple enabled */
 static int draw_dm_faces_sel__setDrawOptions(void *userData, int index, int *UNUSED(drawSmooth_r))
 {
-	struct { DerivedMesh *dm; unsigned char *cols[3]; EditFace *efa_act; } * data = userData;
+	struct { unsigned char *cols[3]; EditFace *efa_act; int *orig_index; } * data = userData;
 	EditFace *efa = EM_get_face_for_index(index);
 	unsigned char *col;
 	
@@ -2369,17 +2369,16 @@ static int draw_dm_faces_sel__setDrawOptions(void *userData, int index, int *UNU
 
 static int draw_dm_faces_sel__compareDrawOptions(void *userData, int index, int next_index)
 {
-	struct { DerivedMesh *dm; unsigned char *cols[3]; EditFace *efa_act; } *data = userData;
-	int *orig_index= DM_get_face_data_layer(data->dm, CD_ORIGINDEX);
+	struct { unsigned char *cols[3]; EditFace *efa_act; int *orig_index; } *data = userData;
 	EditFace *efa;
 	EditFace *next_efa;
 	unsigned char *col, *next_col;
 
-	if(!orig_index)
+	if(!data->orig_index)
 		return 0;
 
-	efa= EM_get_face_for_index(orig_index[index]);
-	next_efa= EM_get_face_for_index(orig_index[next_index]);
+	efa= EM_get_face_for_index(data->orig_index[index]);
+	next_efa= EM_get_face_for_index(data->orig_index[next_index]);
 
 	if(efa == next_efa)
 		return 1;
@@ -2399,12 +2398,12 @@ static int draw_dm_faces_sel__compareDrawOptions(void *userData, int index, int
 /* also draws the active face */
 static void draw_dm_faces_sel(DerivedMesh *dm, unsigned char *baseCol, unsigned char *selCol, unsigned char *actCol, EditFace *efa_act) 
 {
-	struct { DerivedMesh *dm; unsigned char *cols[3]; EditFace *efa_act; } data;
-	data.dm= dm;
+	struct { unsigned char *cols[3]; EditFace *efa_act; int *orig_index; } data;
 	data.cols[0] = baseCol;
 	data.cols[1] = selCol;
 	data.cols[2] = actCol;
 	data.efa_act = efa_act;
+	data.orig_index = DM_get_face_data_layer(dm, CD_ORIGINDEX);
 
 	dm->drawMappedFaces(dm, draw_dm_faces_sel__setDrawOptions, GPU_enable_material, draw_dm_faces_sel__compareDrawOptions, &data, 0);
 }