RegTest: Improve -maxframes option

Grab the last N frames instead of first N. Better for showing crashes.

scripts/check_regression_tests.py

@@ -310,8 +310,9 @@ def check_regression_test(baselinedir, testdir, name):
 
         has_any = True
         if not compare_frames(path1, path2):
-            diff_frames.append(framenum)
+            diff_frames.append((framenum, path1, path2))
 
+    for (framenum, path1, path2) in diff_frames[-MAX_DIFF_FRAMES:]:
         if first_fail:
             write("<div class=\"item\">")
             write("<h1>{}</h1>".format(name))
@@ -323,14 +324,11 @@ def check_regression_test(baselinedir, testdir, name):
         write("<tr><td colspan=\"2\">Frame %d</td></tr>" % (framenum))
         write("<tr><td><img class=\"before\" src=\"%s\" /></td><td><img class=\"after\" src=\"%s\" /></td></tr>" % (imguri1, imguri2))
 
-            if len(diff_frames) == MAX_DIFF_FRAMES:
-                break
-
     if not first_fail:
         write("</table>")
-        write("<pre>Difference in frames [%s] for %s</pre>" % (",".join(map(str, diff_frames)), name))
+        write("<pre>Difference in frames [%s] for %s</pre>" % (",".join(map(lambda x: str(x[0]), diff_frames)), name))
         write("</div>")
-        print("*** Difference in frames [%s] for %s" % (",".join(map(str, diff_frames)), name))
+        print("*** Difference in frames [%s] for %s" % (",".join(map(lambda x: str(x[0]), diff_frames)), name))
         #assert has_any
 
     return len(diff_frames) == 0

scripts/run_regression_tests.py

@@ -55,8 +55,6 @@ def run_regression_tests(runner, gamedir, destdir, dump_interval, frames, parall
         for filename in pool.imap_unordered(func, gamepaths, chunksize=1):
             completed += 1
             print("[%u%% %u/%u] %s" % ((completed * 100) // len(gamepaths), completed, len(gamepaths), filename))
-
-        pool.map(func, gamepaths, chunksize=1)
         pool.close()