From 7fcd05816cf1bd9ff287139e0ee7e3a9208a16b9 Mon Sep 17 00:00:00 2001
From: Luke Hubmayer-Werner <mongoose41@gmail.com>
Date: Wed, 26 Jul 2023 22:49:17 +0930
Subject: [PATCH] Update palette shader for 16x16 palettes (GLES2)

---
 palette_mat.tres                                       |  2 +-
 .../{palette_shader.tres => palette_shader.gdshader}   | 10 ++++------
 2 files changed, 5 insertions(+), 7 deletions(-)
 rename shaders/{palette_shader.tres => palette_shader.gdshader} (74%)

diff --git a/palette_mat.tres b/palette_mat.tres
index 899f2dc..d7f53a7 100644
--- a/palette_mat.tres
+++ b/palette_mat.tres
@@ -1,6 +1,6 @@
 [gd_resource type="ShaderMaterial" load_steps=2 format=2]
 
-[ext_resource path="res://shaders/palette_shader.tres" type="Shader" id=1]
+[ext_resource path="res://shaders/palette_shader.gdshader" type="Shader" id=1]
 
 [resource]
 shader = ExtResource( 1 )
diff --git a/shaders/palette_shader.tres b/shaders/palette_shader.gdshader
similarity index 74%
rename from shaders/palette_shader.tres
rename to shaders/palette_shader.gdshader
index f37265d..096abfb 100644
--- a/shaders/palette_shader.tres
+++ b/shaders/palette_shader.gdshader
@@ -1,7 +1,4 @@
-[gd_resource type="Shader" format=2]
-
-[resource]
-code = "shader_type canvas_item;
+shader_type canvas_item;
 //uniform usampler2D tex;
 uniform sampler2D palette;
 const float index_scale = 255.0 / 16.0;
@@ -14,8 +11,9 @@ void fragment() {
 		COLOR.a = 0.0;*/
 	// GLES2
 	float color_idx = texture(TEXTURE, UV).a * index_scale;
-	COLOR = texture(palette, vec2(color_idx, 0.5));
+	float row = trunc(color_idx) / 16.0;
+	float col = fract(color_idx);
+	COLOR = texture(palette, vec2(col, row));
 	if (color_idx == 0.0)
 		COLOR.a = 0.0;
 }
-"