1 files changed, 3 insertions, 2 deletions
diff --git a/src/code/PreRender.c b/src/code/PreRender.c
index df71d059e..e960acfec 100644
--- a/src/code/PreRender.c
+++ b/src/code/PreRender.c
@@ -659,11 +659,12 @@ void PreRender_AntiAliasFilter(PreRender* this, s32 x, s32 y) {
         }
     }
 
-    // The background color is determined by averaging the penultimate minimum and maximum pixels, and subtracting the
+    // The background color is determined by adding the penultimate minimum and maximum pixels, and subtracting the
     // ForeGround color:
-    //      BackGround = (pMax + pMin) - (ForeGround) * 2
+    //      BackGround = (pMax + pMin) - ForeGround
 
     // OutputColor = cvg * ForeGround + (1.0 - cvg) * BackGround
+    //             = ForeGround + (1.0 - cvg) * (BackGround - ForeGround)
     invCvg = 7 - buffCvg[7];
     outR = buffR[7] + ((s32)(invCvg * (pmaxR + pminR - (buffR[7] * 2)) + 4) >> 3);
     outG = buffG[7] + ((s32)(invCvg * (pmaxG + pminG - (buffG[7] * 2)) + 4) >> 3);