From 3d878cf6a6761a2e25629e11fa46f9d98da3201c Mon Sep 17 00:00:00 2001
From: Marisa Kirisame <marisa@sayachan.org>
Date: Mon, 6 Dec 2021 16:46:09 +0100
Subject: [PATCH] Finetune retrofx math.

---
 shaders/glsl/mfx_retrofx.fp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/shaders/glsl/mfx_retrofx.fp b/shaders/glsl/mfx_retrofx.fp
index df8c580..c8196d6 100644
--- a/shaders/glsl/mfx_retrofx.fp
+++ b/shaders/glsl/mfx_retrofx.fp
@@ -5,6 +5,9 @@
 void main()
 {
 	// far more simplified when the actual scale calculations are on the zscript side
-	ivec2 ncoord = ivec2((floor(TexCoord*bresl)/bresl)*textureSize(InputTexture,0));
-	FragColor = texelFetch(InputTexture,ncoord,0);
+	vec2 ncoord = floor(TexCoord*bresl)/bresl;
+	FragColor = vec4(textureGather(InputTexture,ncoord,0).y,
+		textureGather(InputTexture,ncoord,1).y,
+		textureGather(InputTexture,ncoord,2).y,
+		textureGather(InputTexture,ncoord,3).y);
 }