Author: rambetter

[xonotic/netradiant.git] / regression_tests / q3map2 / disappearing_sliver3 / README.txt

diff --git a/regression_tests/q3map2/disappearing_sliver3/README.txt b/regression_tests/q3map2/disappearing_sliver3/README.txt
index 9fda8b0cc249e861ebc6c83e69e3c96f3b50af95..839bd692f1d57eafbcea608a6169432cae0c0398 100644 (file)
--- a/regression_tests/q3map2/disappearing_sliver3/README.txt
+++ b/regression_tests/q3map2/disappearing_sliver3/README.txt
@@ -14,4 +14,36 @@ compile for any Q3 mod.
 SOLUTION TO PROBLEM:
 ====================
 
-None yet.  Probably due to sloppy math code.
+More work has been done to BaseWindingForPlane() to make it more accurate.
+This function is in polylib.c.  The changes to fix this regression test were
+committed in revision 377; however, those changes are not "good enough".
+
+
+IN-DEPTH DISCUSSION:
+====================
+
+This is the problem triangle:
+
+  In ParseRawBrush() for brush 0
+      Side 0:
+          (6144.000000 16122.000000 -2048.000000)
+          (6144.000000 16083.000000 -2048.000000)
+          (6784.000000 16241.000000 -2048.000000)
+
+Computed winding before fix:
+
+  (6784.16406250 16241.04101562 -2048.00000000)
+  (6144.00000000 16122.00976562 -2048.00000000)
+  (6144.00000000 16083.00000000 -2048.00000000)
+
+Obviously the 6784.16406250 is beyond epsilon error.
+
+After revision 377:
+
+  (6783.85937500 16240.96484375 -2048.00000000)
+  (6144.00000000 16121.99218750 -2048.00000000)
+  (6144.00000000 16083.00000000 -2048.00000000)
+
+Even though this fixes the regression test, the error in 6783.85937500 is
+still greater than epsilon (but fortunately in the opposite direction).  So
+I don't consider this test case to be fixed quite yet.