From b036cac6168acba4a14a84f816656021d5137eca Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Fri, 23 Feb 2018 02:36:12 +0900
Subject: [PATCH] graphics: Fix screen filter calculation

---
 internal/graphics/shader.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/internal/graphics/shader.go b/internal/graphics/shader.go
index 03227ac0e..37eaf9e19 100644
--- a/internal/graphics/shader.go
+++ b/internal/graphics/shader.go
@@ -162,7 +162,7 @@ void main(void) {
   vec4 c3 = texture2D(texture, p1);
   // Texels must be in the source rect, so it is not necessary to check that like linear filter.
 
-  vec2 rate = min(max(1.0 - ((1.0 - fract(pos * source_size)) * scale), 0.0), 1.0);
+  vec2 rate = min(max((fract(pos * source_size) - 0.5) * scale, 0.0), 1.0);
   vec4 color = mix(mix(c0, c1, rate.x), mix(c2, c3, rate.x), rate.y);
 #endif