Fix T45555 crash with subsurf edge drawing.

Loose edge count was double. It didn't fail on own
tests because they had a small number of loose edges,
but for bigger meshes it hit garbage indices at draw time
and crashed.

Also cleaned up the code to make it less verbose and easier to
understand how indices are counted.

Hope it's the last edge-related fix (fingers crossed)

1 files changed, 27 insertions, 27 deletions

diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index 05061f18b21..7e5d00af9e2 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -1814,7 +1814,7 @@ static void ccgDM_drawEdges(DerivedMesh *dm, bool drawLooseEdges, bool drawAllEd
 		}
 		else {
 			GPU_buffer_draw_elements(gdo->edges, GL_LINES, 0, gdo->tot_edge_drawn * 2);
-			GPU_buffer_draw_elements(gdo->edges, GL_LINES, gdo->loose_edge_offset * 2, dm->drawObject->tot_loose_edge_drawn * 2);
+			GPU_buffer_draw_elements(gdo->edges, GL_LINES, gdo->loose_edge_offset * 2, gdo->tot_loose_edge_drawn * 2);
 		}
 	}
 
@@ -2271,7 +2271,8 @@ static void ccgDM_buffer_copy_edge(
 {
 	CCGDerivedMesh *ccgdm = (CCGDerivedMesh *) dm;
 	CCGSubSurf *ss = ccgdm->ss;
-	int i, j, edgeSize = ccgSubSurf_getEdgeSize(ss);
+	/* getEdgeSuze returns num of verts, edges is one less */
+	int i, j, edgeSize = ccgSubSurf_getEdgeSize(ss) - 1;
 	int totedge = ccgSubSurf_getNumEdges(ss);
 	int grid_face_side = ccgSubSurf_getGridSize(ss) - 1;
 	int totface = ccgSubSurf_getNumFaces(ss);
@@ -2300,10 +2301,9 @@ static void ccgDM_buffer_copy_edge(
 	}
 
 	inorm = 0;
-	inormhidden = tot * grid_face_side;
-	/* multiply by two for loose edges, the indices are copied in a different way */
-	iloose = (tot + tot_hidden) * grid_face_side * 2;
-	iloosehidden = (tot + tot_hidden + tot_loose) * grid_face_side * 2;
+	inormhidden = tot * edgeSize;
+	iloose = (tot + tot_hidden) * edgeSize;
+	iloosehidden = (tot + tot_hidden + tot_loose) * edgeSize;
 	iloosevert = dm->drawObject->tot_loop_verts;
 
 	/* part one, handle all normal edges */
@@ -2338,7 +2338,7 @@ static void ccgDM_buffer_copy_edge(
 
 		if (ccgdm->edgeFlags && !(ccgdm->edgeFlags[j] & ME_EDGEDRAW)) {
 			if (!ccgSubSurf_getEdgeNumFaces(e)) {
-				for (i = 0; i < edgeSize - 1; i++) {
+				for (i = 0; i < edgeSize; i++) {
 					varray[iloosehidden * 2] = iloosevert;
 					varray[iloosehidden * 2 + 1] = iloosevert + 1;
 					iloosehidden++;
@@ -2351,17 +2351,17 @@ static void ccgDM_buffer_copy_edge(
 				index_start = ccgdm->faceMap[fhandle].startFace;
 
 				for (i = 0; i < grid_face_side; i++) {
-					varray[inormhidden * 4] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 1;
-					varray[inormhidden * 4 + 1] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 2;
-					varray[inormhidden * 4 + 2] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 2;
-					varray[inormhidden * 4 + 3] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 3;
-					inormhidden++;
+					varray[inormhidden * 2] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 1;
+					varray[inormhidden * 2 + 1] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 2;
+					varray[inormhidden * 2 + 2] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 2;
+					varray[inormhidden * 2 + 3] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 3;
+					inormhidden += 2;
 				}
 			}
 		}
 		else {
 			if (!ccgSubSurf_getEdgeNumFaces(e)) {
-				for (i = 0; i < edgeSize - 1; i++) {
+				for (i = 0; i < edgeSize; i++) {
 					varray[iloose * 2] = iloosevert;
 					varray[iloose * 2 + 1] = iloosevert + 1;
 					iloose++;
@@ -2374,11 +2374,11 @@ static void ccgDM_buffer_copy_edge(
 				index_start = ccgdm->faceMap[fhandle].startFace;
 
 				for (i = 0; i < grid_face_side; i++) {
-					varray[inorm * 4] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 1;
-					varray[inorm * 4 + 1] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 2;
-					varray[inorm * 4 + 2] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 2;
-					varray[inorm * 4 + 3] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 3;
-					inorm++;
+					varray[inorm * 2] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 1;
+					varray[inorm * 2 + 1] = (index_start + S * grid_tot_face + i * grid_face_side + grid_face_side - 1) * 4 + 2;
+					varray[inorm * 2 + 2] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 2;
+					varray[inorm * 2 + 3] = (index_start + ((S + 1) % totvert) * grid_tot_face + grid_face_side * (grid_face_side - 1) + i) * 4 + 3;
+					inorm += 2;
 				}
 			}
 		}
@@ -2415,11 +2415,11 @@ static void ccgDM_buffer_copy_edge(
 		}
 	}
 
-	dm->drawObject->tot_loose_edge_drawn = tot_loose * (edgeSize - 1) * 2;
-	dm->drawObject->loose_edge_offset = (tot + tot_hidden) * grid_face_side * 2;
-	dm->drawObject->tot_edge_drawn = tot * grid_face_side * 2;
+	dm->drawObject->tot_loose_edge_drawn = tot_loose * edgeSize;
+	dm->drawObject->loose_edge_offset = (tot + tot_hidden) * edgeSize;
+	dm->drawObject->tot_edge_drawn = tot * edgeSize;
 
-	dm->drawObject->interior_offset = totedge * grid_face_side * 2;
+	dm->drawObject->interior_offset = totedge * edgeSize;
 	dm->drawObject->totinterior = tot_interior;
 }
 
@@ -2472,13 +2472,13 @@ static GPUDrawObject *ccgDM_GPUObjectNew(DerivedMesh *dm)
 	CCGSubSurf *ss = ccgdm->ss;
 	GPUDrawObject *gdo;
 	DMFlagMat *faceFlags = ccgdm->faceFlags;
-	int gridSize = ccgSubSurf_getGridSize(ss);
-	int gridFaces = gridSize - 1;
+	int gridFaces = ccgSubSurf_getGridSize(ss) - 1;
 	int totmat = (faceFlags) ? dm->totmat : 1;
 	GPUMaterialInfo *matinfo;
 	int i, curmat, curelement;
 	unsigned int tot_internal_edges = 0;
-	int edgeSize = ccgSubSurf_getEdgeSize(ss);
+	int edgeVerts = ccgSubSurf_getEdgeSize(ss);
+	int edgeSize = edgeVerts - 1;
 
 	int totedge = ccgSubSurf_getNumEdges(ss);
 	int totface = ccgSubSurf_getNumFaces(ss);
@@ -2514,7 +2514,7 @@ static GPUDrawObject *ccgDM_GPUObjectNew(DerivedMesh *dm)
 	/* create the GPUDrawObject */
 	gdo = MEM_callocN(sizeof(GPUDrawObject), "GPUDrawObject");
 	gdo->totvert = 0; /* used to count indices, doesn't really matter for ccgsubsurf */
-	gdo->totedge = (totedge * gridFaces * 2 + tot_internal_edges);
+	gdo->totedge = (totedge * edgeSize + tot_internal_edges);
 
 	/* count the number of materials used by this DerivedMesh */
 	for (i = 0; i < totmat; i++) {
@@ -2578,7 +2578,7 @@ static GPUDrawObject *ccgDM_GPUObjectNew(DerivedMesh *dm)
 		CCGEdge *e = ccgdm->edgeMap[i].edge;
 
 		if (!ccgSubSurf_getEdgeNumFaces(e))
-			gdo->tot_loose_point += edgeSize;
+			gdo->tot_loose_point += edgeVerts;
 	}
 
 	MEM_freeN(mat_orig_to_new);