curves: optimize their order for the bbox optimization

[xonotic/darkplaces.git] / curves.c

diff --git a/curves.c b/curves.c
index 910201ad791444b8ce77e503df6026a39e193be2..894683815db222e07be9490c9b4784fca6782595 100644 (file)
--- a/curves.c
+++ b/curves.c
@@ -402,18 +402,38 @@ void Q3PatchTriangleElements(int *elements, int width, int height, int firstvert
        int x, y, row0, row1;
        for (y = 0;y < height - 1;y++)
        {
-               row0 = firstvertex + (y + 0) * width;
-               row1 = firstvertex + (y + 1) * width;
-               for (x = 0;x < width - 1;x++)
+               if(y % 2)
                {
-                       *elements++ = row0;
-                       *elements++ = row1;
-                       *elements++ = row0 + 1;
-                       *elements++ = row1;
-                       *elements++ = row1 + 1;
-                       *elements++ = row0 + 1;
-                       row0++;
-                       row1++;
+                       // swap the triangle order in odd rows as optimization for collision stride
+                       row0 = firstvertex + (y + 0) * width + width - 2;
+                       row1 = firstvertex + (y + 1) * width + width - 2;
+                       for (x = 0;x < width - 1;x++)
+                       {
+                               *elements++ = row1;
+                               *elements++ = row1 + 1;
+                               *elements++ = row0 + 1;
+                               *elements++ = row0;
+                               *elements++ = row1;
+                               *elements++ = row0 + 1;
+                               row0--;
+                               row1--;
+                       }
+               }
+               else
+               {
+                       row0 = firstvertex + (y + 0) * width;
+                       row1 = firstvertex + (y + 1) * width;
+                       for (x = 0;x < width - 1;x++)
+                       {
+                               *elements++ = row0;
+                               *elements++ = row1;
+                               *elements++ = row0 + 1;
+                               *elements++ = row1;
+                               *elements++ = row1 + 1;
+                               *elements++ = row0 + 1;
+                               row0++;
+                               row1++;
+                       }
                }
        }
 }