Prevent divide by zero when the elapsed time is too small.

diff --git a/bulletml-runner b/bulletml-runner
index de0fa5a..ec6007b 100755 (executable)
--- a/bulletml-runner
+++ b/bulletml-runner
@@ -85,12 +85,13 @@ def main(argv):
 
                 frames += 1
                 if frames % 100 == 0:
-                    seconds_per_bullet = elapsed / count
-                    bullets_per_second = count / elapsed
                     print "  Processing: %04d: %d bullets, %d active." % (
                         frames, total, count)
-                    print "  %g seconds per bullet (60Hz max: %g)." % (
-                        seconds_per_bullet, bullets_per_second / 60)
+                    if elapsed:
+                        print "  %g seconds per bullet (60Hz max: %g)." % (
+                            seconds_per_bullet = elapsed / count
+                            bullets_per_second = count / elapsed
+                            seconds_per_bullet, bullets_per_second / 60)
 
             screen.fill([0, 0, 0])
             for obj in active: