Changes from August-November 2006 -- detailed history was lost.

[vor.git] / dust.c

diff --git a/dust.c b/dust.c
index 5ee9e20..7b62867 100644 (file)
--- a/dust.c
+++ b/dust.c
@@ -32,13 +32,34 @@ move_dust(float ticks)
        int i;
        float xscroll = screendx * ticks;
        float yscroll = screendy * ticks;
+
+       // Originally this code was much simpler, but it would crash sometimes
+       // because the floating point numbers wouldn't always round the same
+       // direction, and we'd ocanially try to draw off the screen.
+       
        for(i=0; i<N_DUST_MOTES; i++) {
                motes[i].x -= xscroll / (1.3 + motes[i].z);
                motes[i].y -= yscroll / (1.3 + motes[i].z);
-               if(motes[i].x >= XSIZE) motes[i].x -= XSIZE;
-               else if(motes[i].x < 0) motes[i].x += XSIZE;
-               if(motes[i].y >= YSIZE) motes[i].y -= YSIZE;
-               else if(motes[i].y < 0) motes[i].y += YSIZE;
+
+               if(motes[i].x < 0) {
+                       motes[i].x += XSIZE;
+               }
+               if(motes[i].x > (XSIZE - 0.000001)) {
+                       motes[i].x -= XSIZE;
+                       if(motes[i].x < 0) {
+                               motes[i].x = 0;
+                       }
+               }
+
+               if(motes[i].y < 0) {
+                       motes[i].y += YSIZE;
+               }
+               if(motes[i].y > (YSIZE - 0.000001)) {
+                       motes[i].y -= YSIZE;
+                       if(motes[i].y < 0) {
+                               motes[i].y = 0;
+                       }
+               }
        }
 }