From c4522ea1a3212f3dafe3c4f55de4a17228902bcf Mon Sep 17 00:00:00 2001
From: Luke Hubmayer-Werner <mongoose41@gmail.com>
Date: Tue, 25 Jul 2023 14:49:32 +0930
Subject: [PATCH] GLES2 mode

---
 load_sprites.gd             |  6 +++---
 project.godot               |  1 +
 shaders/palette_shader.tres | 12 +++++++++---
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/load_sprites.gd b/load_sprites.gd
index 5226521..4cdeaec 100644
--- a/load_sprites.gd
+++ b/load_sprites.gd
@@ -23,7 +23,6 @@ var weapon_textures = {}
 func texture_from_image(image: Image, flags: int = 0) -> ImageTexture:
 	var tex = ImageTexture.new()
 	tex.create_from_image(image, flags)
-	tex.flags = Texture.FLAG_CONVERT_TO_LINEAR
 	return tex
 
 func bgr555_to_color(short: int) -> Color:
@@ -46,7 +45,8 @@ func generate_palette_rgbf(rom: File, offset: int, length: int = 16) -> Image:
 	return img
 
 func generate_palette_rgb8(rom: File, offset: int, length: int = 16) -> Image:
-	# Implicit sRGB -> linear conversion on ImageTexture creation from RGB8 Image ruins this
+	# Safe for GLES2 only!
+	# Implicit sRGB -> linear conversion on ImageTexture creation from RGB8 Image ruins this in GLES3 mode
 	rom.seek(offset)
 	var data = ByteArray(length*3)
 	# img.lock()
@@ -76,7 +76,7 @@ func generate_palette_rgb5_a1(rom: File, offset: int, length: int = 16) -> Image
 	return img
 
 func generate_palette(rom: File, offset: int, length: int = 16) -> Image:
-	return generate_palette_rgb5_a1(rom, offset, length)
+	return generate_palette_rgb8(rom, offset, length)
 
 func ByteArray(size: int) -> PoolByteArray:
 	var arr = PoolByteArray()
diff --git a/project.godot b/project.godot
index 75c6e65..d7dd57f 100644
--- a/project.godot
+++ b/project.godot
@@ -35,5 +35,6 @@ color=false
 
 [rendering]
 
+quality/driver/driver_name="GLES2"
 environment/default_clear_color=Color( 0, 0, 0.517647, 1 )
 environment/default_environment="res://default_env.tres"
diff --git a/shaders/palette_shader.tres b/shaders/palette_shader.tres
index 5a2441d..f37265d 100644
--- a/shaders/palette_shader.tres
+++ b/shaders/palette_shader.tres
@@ -3,13 +3,19 @@
 [resource]
 code = "shader_type canvas_item;
 //uniform usampler2D tex;
-uniform sampler2D palette: hint_normal;
+uniform sampler2D palette;
+const float index_scale = 255.0 / 16.0;
 
 void fragment() {
-	//uint color_idx = textureLod(tex, UV, 0.0).r;
-	uint color_idx = uint(textureLod(TEXTURE, UV, 0.0).r * 255.0);
+	// GLES3
+	/*uint color_idx = uint(textureLod(TEXTURE, UV, 0.0).r * 255.0);
 	COLOR = texelFetch(palette, ivec2(int(color_idx), 0), 0);
 	if (color_idx == uint(0))
+		COLOR.a = 0.0;*/
+	// GLES2
+	float color_idx = texture(TEXTURE, UV).a * index_scale;
+	COLOR = texture(palette, vec2(color_idx, 0.5));
+	if (color_idx == 0.0)
 		COLOR.a = 0.0;
 }
 "