From 8a00a7aa025073b32ae2112d20bc233316af06bc Mon Sep 17 00:00:00 2001
From: Thomas Wessel <turpleturtle12@gmail.com>
Date: Tue, 4 Mar 2025 18:34:12 -0800
Subject: [PATCH] Add contrast filter

---
 .../ContrastFilter/ContrastFilter.gdshader    | 10 ++++++++++
 Globals/ContrastFilter/ContrastFilter.tscn    | 19 +++++++++++++++++++
 Globals/StageProducer.cs                      | 11 +++++++++++
 scenes/Options/OptionsMenu.cs                 |  1 +
 4 files changed, 41 insertions(+)
 create mode 100644 Globals/ContrastFilter/ContrastFilter.gdshader
 create mode 100644 Globals/ContrastFilter/ContrastFilter.tscn

diff --git a/Globals/ContrastFilter/ContrastFilter.gdshader b/Globals/ContrastFilter/ContrastFilter.gdshader
new file mode 100644
index 00000000..b6f2754d
--- /dev/null
+++ b/Globals/ContrastFilter/ContrastFilter.gdshader
@@ -0,0 +1,10 @@
+shader_type canvas_item;
+
+uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap;
+
+void fragment() {
+	vec4 screen = texture(SCREEN_TEXTURE, SCREEN_UV);
+
+	COLOR.rgb =vec3(0.6 * screen.r + 0.6 * screen.g + 0.2 * screen.b);
+}
+
diff --git a/Globals/ContrastFilter/ContrastFilter.tscn b/Globals/ContrastFilter/ContrastFilter.tscn
new file mode 100644
index 00000000..5529050f
--- /dev/null
+++ b/Globals/ContrastFilter/ContrastFilter.tscn
@@ -0,0 +1,19 @@
+[gd_scene load_steps=3 format=3 uid="uid://b6bblgxtfs020"]
+
+[ext_resource type="Shader" path="res://Globals/ContrastFilter/ContrastFilter.gdshader" id="1_4bhca"]
+
+[sub_resource type="ShaderMaterial" id="ShaderMaterial_i6hl4"]
+shader = ExtResource("1_4bhca")
+
+[node name="CanvasLayer" type="CanvasLayer"]
+layer = 128
+
+[node name="Filter" type="ColorRect" parent="."]
+z_index = 4096
+material = SubResource("ShaderMaterial_i6hl4")
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+grow_horizontal = 2
+grow_vertical = 2
+mouse_filter = 2
diff --git a/Globals/StageProducer.cs b/Globals/StageProducer.cs
index d9f64292..2ce7a7de 100644
--- a/Globals/StageProducer.cs
+++ b/Globals/StageProducer.cs
@@ -23,6 +23,8 @@ public partial class StageProducer : Node
     //TODO: Allow for permanent changes and battle temporary stat changes.
     public static PlayerStats PlayerStats;
 
+    public static CanvasLayer ContrastFilter;
+
     public override void _EnterTree()
     {
         InitFromCfg();
@@ -36,6 +38,12 @@ private void InitFromCfg()
         TranslationServer.SetLocale(
             SaveSystem.GetConfigValue(SaveSystem.ConfigSettings.LanguageKey).As<string>()
         );
+        ContrastFilter = GD.Load<PackedScene>("res://Globals/ContrastFilter/ContrastFilter.tscn")
+            .Instantiate<CanvasLayer>();
+        ContrastFilter.Visible = SaveSystem
+            .GetConfigValue(SaveSystem.ConfigSettings.HighContrast)
+            .AsBool();
+        GetTree().Root.CallDeferred("add_child", ContrastFilter);
     }
 
     public void StartGame()
@@ -101,6 +109,7 @@ public void TransitionFromRoom(int nextRoomIdx)
 
     public void TransitionStage(Stages nextStage, int nextRoomIdx = -1)
     {
+        GetTree().Root.RemoveChild(ContrastFilter);
         switch (nextStage)
         {
             case Stages.Title:
@@ -139,6 +148,8 @@ public void TransitionStage(Stages nextStage, int nextRoomIdx = -1)
                 break;
         }
 
+        //Apply grayscale shader to all scenes
+        GetTree().Root.AddChild(ContrastFilter);
         _curStage = nextStage;
     }
 
diff --git a/scenes/Options/OptionsMenu.cs b/scenes/Options/OptionsMenu.cs
index 5396175c..587cb621 100644
--- a/scenes/Options/OptionsMenu.cs
+++ b/scenes/Options/OptionsMenu.cs
@@ -95,6 +95,7 @@ public static void ChangeVolume(double value)
 
     private void HighContrastChanged(bool toggled)
     {
+        StageProducer.ContrastFilter.Visible = toggled;
         SaveSystem.UpdateConfig(SaveSystem.ConfigSettings.HighContrast, toggled);
     }
 }