From 2ffb2376e09df0c5bb01a5170264c4efa3c0799c Mon Sep 17 00:00:00 2001
From: Ton Roosendaal <ton@blender.org>
Date: Thu, 13 Nov 2003 12:44:34 +0000
Subject: [PATCH] - bug fix #694   when using linked-duplicated mesh, with
 subsurf and tfaces (UV texture)   the render crashed.   Found out the
 renderloop makes a new displaylist for each Mesh, also when   it is linked
 multiple times. That way pointers to previous created elements   in
 displaylists become invalid. Crash!   Result now it even renders faster for
 linked-duplis. :)

---
 source/blender/makesdna/DNA_mesh_types.h      |  4 +-
 .../intern/convertBlenderScene.c              | 37 +++++++------------
 2 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/source/blender/makesdna/DNA_mesh_types.h b/source/blender/makesdna/DNA_mesh_types.h
index 89f9a0f67aa..ee00eecf151 100644
--- a/source/blender/makesdna/DNA_mesh_types.h
+++ b/source/blender/makesdna/DNA_mesh_types.h
@@ -143,9 +143,9 @@ typedef struct Mesh {
 	float rot[3];
 	
 	short smoothresh, flag;
-	short subdiv, subdivr;
+	short subdiv, subdivr, subdivdone;
 	short totcol;
-	short reserved1, reserved2, reserved3;	/* Padding */
+	short reserved1, reserved2;	/* Padding */
 
 	float cubemapsize, rtf;
 
diff --git a/source/blender/renderconverter/intern/convertBlenderScene.c b/source/blender/renderconverter/intern/convertBlenderScene.c
index 9899e2c56a3..bf816666b53 100644
--- a/source/blender/renderconverter/intern/convertBlenderScene.c
+++ b/source/blender/renderconverter/intern/convertBlenderScene.c
@@ -1114,23 +1114,17 @@ static void init_render_displist_mesh(Object *ob)
 	dl= me->disp.first;
 
 	/* Force a displist rebuild if this is a subsurf and we have a different subdiv level */
-#if 1
-	if((dl==0) || ((me->subdiv != me->subdivr))){
-		object_deform(ob);
-		subsurf_make_mesh(ob, me->subdivr);
-		dl = me->disp.first;
-		
+
+	if((dl==0) || ((me->subdiv != me->subdivr))) {
+		/* prevent subsurf called again for duplicate use of mesh, tface pointers change */
+		if(me->subdivdone!=me->subdivr) {
+			object_deform(ob);
+			subsurf_make_mesh(ob, me->subdivr);
+			me->subdivdone= me->subdivr;
+			dl = me->disp.first;
+		}
 	}
-	else{
-		makeDispList(ob);
-		dl= me->disp.first;
-	}
-#else
-	tempdiv = me->subdiv;
-	me->subdiv = me->subdivr;
-	makeDispList(ob);
-	dl= me->disp.first;
-#endif
+
 	if(dl==0) return;
 
 	if(need_orco) {
@@ -1138,10 +1132,6 @@ static void init_render_displist_mesh(Object *ob)
 		orco= me->orco;
 	}
 
-#if 0
-	me->subdiv = tempdiv;
-#endif
-
 	while(dl) {
 		if(dl->type==DL_SURF) {
 			startvert= R.totvert;
@@ -1767,8 +1757,8 @@ static void init_render_mesh(Object *ob)
 /* If lar takes more lamp data, the decoupling will be better. */
 void RE_add_render_lamp(Object *ob, int doshadbuf)
 {
-	Lamp *la, **temp;
-	LampRen *lar;
+	Lamp *la;
+	LampRen *lar, **temp;
 	float mat[4][4], hoek, xn, yn;
 	int c;
 	static int rlalen=LAMPINITSIZE; /*number of currently allocated lampren pointers*/
@@ -2770,8 +2760,9 @@ void RE_freeRotateBlenderScene(void)
 				MEM_freeN(me->orco);
 				me->orco= 0;
 			}
-			if (rendermesh_uses_displist(me) && (me->subdiv!=me->subdivr)){
+			if (rendermesh_uses_displist(me) && (me->subdiv!=me->subdivr)) {
 				makeDispList(ob);
+				me->subdivdone= 0;	/* needed to prevent multiple used meshes being recalculated */
 			}
 		}
 		else if(ob->type==OB_MBALL) {