From: Ian Jackson <ian@davenant.relativity.greenend.org.uk>
Date: Mon, 31 Dec 2007 02:25:15 +0000 (+0000)
Subject: sort triangles by centroids
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=3228a46c1c7d345262324cad037d65cf7bbd62a4;p=moebius2.git

sort triangles by centroids
---

diff --git a/project.c b/project.c
index a2e3f91..266237f 100644
--- a/project.c
+++ b/project.c
@@ -76,10 +76,14 @@ static void generate_display_list(void) {
 }    
 
 static int dl_compare(const void *tav, const void *tbv) {
+  int i;
   const Triangle *const *tap= tav, *ta= *tap;
   const Triangle *const *tbp= tbp, *tb= *tbp;
-  double za= ta->vertex[0][2];
-  double zb= tb->vertex[0][2];
+  double za=0, zb=0;
+  for (i=0; i<3; i++) {
+    za += ta->vertex[i][2];
+    zb += tb->vertex[i][2];
+  }
   return za > zb ? -1 :
          za < zb ? +1 : 0;
 }