From 2980d902b94bddac0a9ebcb6023343b18f1a482e Mon Sep 17 00:00:00 2001
From: Nicholas Bishop <nicholasbishop@gmail.com>
Date: Fri, 11 Jun 2010 07:57:43 +0000
Subject: [PATCH] Fixed bug #21348, Hide selection in Edit Mode not working
 with some modifiers (VBOs)

Was actually a couple bugs:
* VBO bug was that hidden faces weren't being skipped correctly. Fixed that and rewrote this bit of VBO drawing code more clearly (less duplication, less unecessary state, and comments even)
* Second bug was that CCGDerivedMesh wasn't outputing ORIGINDEX data for faces. (it's not doing it for edges or verts either, but I don't know that we need it to.) At any rate, we do need this data for faces so that additional DerivedMeshes on top of subsurf know what faces in the editmesh are hidden.
---
 .../blender/blenkernel/intern/cdderivedmesh.c | 44 ++++++++-----------
 .../blender/blenkernel/intern/subsurf_ccg.c   |  5 +++
 2 files changed, 24 insertions(+), 25 deletions(-)

diff --git a/source/blender/blenkernel/intern/cdderivedmesh.c b/source/blender/blenkernel/intern/cdderivedmesh.c
index cadf5f375b5..80f39531b34 100644
--- a/source/blender/blenkernel/intern/cdderivedmesh.c
+++ b/source/blender/blenkernel/intern/cdderivedmesh.c
@@ -853,47 +853,41 @@ static void cdDM_drawMappedFaces(DerivedMesh *dm, int (*setDrawOptions)(void *us
 		}
 	}
 	else { /* use OpenGL VBOs or Vertex Arrays instead for better, faster rendering */
-		int state = 1;
-		int prevstate = 1;
 		int prevstart = 0;
 		GPU_vertex_setup(dm);
 		GPU_normal_setup(dm);
 		if( useColors && mc )
 			GPU_color_setup(dm);
 		if( !GPU_buffer_legacy(dm) ) {
+			int tottri = dm->drawObject->nelements/3;
 			glShadeModel(GL_SMOOTH);
-			for( i = 0; i < dm->drawObject->nelements/3; i++ ) {
+
+			for( i = 0; i < tottri; i++ ) {
 				int actualFace = dm->drawObject->faceRemap[i];
 				int drawSmooth = (mf[actualFace].flag & ME_SMOOTH);
-				int dontdraw = 0;
+				int draw = 1;
+
 				if(index) {
 					orig = index[actualFace];
 					if(setDrawOptions && orig == ORIGINDEX_NONE)
-						dontdraw = 1;
+						draw = 0;
 				}
 				else
 					orig = actualFace;
-				if( dontdraw ) {
-					state = 0;
+
+				if(setDrawOptions && !setDrawOptions(userData, orig, &drawSmooth))
+					draw = 0;
+
+				/* Goal is to draw as long of a contiguous triangle
+				   array as possible, so draw when we hit either an
+				   invisible triangle or at the end of the array */
+				if(!draw || i == tottri - 1) {
+					if(prevstart != i)
+						/* Add one to the length (via `draw')
+						   if we're drawing at the end of the array */
+						glDrawArrays(GL_TRIANGLES,prevstart*3, (i-prevstart+draw)*3);
+					prevstart = i + 1;
 				}
-				else {
-					if(!setDrawOptions || setDrawOptions(userData, orig, &drawSmooth)) {
-						state = 1;
-					}
-					else {
-						state = 0;
-					}
-				}
-				if( prevstate != state && prevstate == 1 ) {
-					if( i-prevstart > 0 ) {
-						glDrawArrays(GL_TRIANGLES,prevstart*3,(i-prevstart)*3);
-					}
-					prevstart = i;
-				}
-				prevstate = state;
-			}
-			if(state==1) {
-				glDrawArrays(GL_TRIANGLES,prevstart*3,dm->drawObject->nelements-prevstart*3);
 			}
 			glShadeModel(GL_FLAT);
 		}
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index 53206bb3970..0d7738353df 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -2328,6 +2328,7 @@ static CCGDerivedMesh *getCCGDerivedMesh(CCGSubSurf *ss,
 	int gridInternalEdges;
 	MEdge *medge = NULL;
 	MFace *mface = NULL;
+	int *orig_indices;
 	FaceVertWeight *qweight, *tweight;
 
 	DM_from_template(&ccgdm->dm, dm, DM_TYPE_CCGDM,
@@ -2437,6 +2438,7 @@ static CCGDerivedMesh *getCCGDerivedMesh(CCGSubSurf *ss,
 
 	faceFlags = ccgdm->faceFlags = MEM_callocN(sizeof(char)*2*totface, "faceFlags");
 
+	orig_indices = (int*)ccgdm->dm.getFaceDataArray(&ccgdm->dm, CD_ORIGINDEX);
 	for(index = 0; index < totface; ++index) {
 		CCGFace *f = ccgdm->faceMap[index].face;
 		int numVerts = ccgSubSurf_getFaceNumVerts(f);
@@ -2450,6 +2452,9 @@ static CCGDerivedMesh *getCCGDerivedMesh(CCGSubSurf *ss,
 		ccgdm->faceMap[index].startEdge = edgeNum;
 		ccgdm->faceMap[index].startFace = faceNum;
 
+		if(orig_indices)
+			orig_indices[faceNum] = origIndex;
+
 		/* set the face base vert */
 		*((int*)ccgSubSurf_getFaceUserData(ss, f)) = vertNum;