Don't override GTEST_DIR if it already is set.

[movit] / mix_effect.h

diff --git a/mix_effect.h b/mix_effect.h
index 8032062077491e7b545fc0df5e208d0b13f20a45..c6739653b398b7cd9791af5361d32197dd3d8499 100644 (file)
--- a/mix_effect.h
+++ b/mix_effect.h
@@ -1,7 +1,8 @@
 #ifndef _MIX_EFFECT_H
 #define _MIX_EFFECT_H 1
 
-// Combine two images: a*x + b*y. (If you set a within [0,1] and b=1-a, you will get a fade.)
+// Combine two images: a*x + b*y. If you set a within [0,1] and b=1-a,
+// you will get a fade; if not, you may get surprising results (consider alpha).
 
 #include "effect.h"