From 519ae68848b599b7a72b7e06fac35076d7727d3e Mon Sep 17 00:00:00 2001
From: Samuel Bouchet <contact@samuel-bouchet.fr>
Date: Fri, 13 Oct 2023 10:40:35 +0200
Subject: [PATCH] Add curvature to CRT shader effect.

Also add a 'curvatureScale' property to provides control for the level of curvature simulated by the CRT shader.
---
 .../Editor/CRTPostEffecterEditor.cs           |  2 ++
 .../SimpleCRTShader/Script/CRTPostEffecter.cs |  5 +++++
 Assets/SimpleCRTShader/material/CRT.mat       |  8 ++++++--
 Assets/SimpleCRTShader/shader/CRT.shader      | 19 +++++++++++++++++--
 4 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/Assets/SimpleCRTShader/Editor/CRTPostEffecterEditor.cs b/Assets/SimpleCRTShader/Editor/CRTPostEffecterEditor.cs
index 938c1b6..37bd162 100644
--- a/Assets/SimpleCRTShader/Editor/CRTPostEffecterEditor.cs
+++ b/Assets/SimpleCRTShader/Editor/CRTPostEffecterEditor.cs
@@ -13,6 +13,8 @@ public override void OnInspectorGUI()
         CRTPostEffecter effect = target as CRTPostEffecter;
         effect.material = (Material)EditorGUILayout.ObjectField("Effect Material", effect.material, typeof(Material), false);
 
+        effect.curvatureScale = EditorGUILayout.FloatField("Curvature", effect.curvatureScale);
+
         using (new HorizontalScope(GUI.skin.box))
         {
             effect.whiteNoiseFrequency = EditorGUILayout.IntField("White Noise Freaquency (x/1000)", effect.whiteNoiseFrequency);
diff --git a/Assets/SimpleCRTShader/Script/CRTPostEffecter.cs b/Assets/SimpleCRTShader/Script/CRTPostEffecter.cs
index 3e4e3b6..53af836 100644
--- a/Assets/SimpleCRTShader/Script/CRTPostEffecter.cs
+++ b/Assets/SimpleCRTShader/Script/CRTPostEffecter.cs
@@ -4,6 +4,7 @@
 public class CRTPostEffecter : MonoBehaviour
 {
     public Material material;
+    public float curvatureScale = -0.1f;
     public int whiteNoiseFrequency = 1;
     public float whiteNoiseLength = 0.1f;
     private float whiteNoiseTimeLeft;
@@ -54,6 +55,7 @@ public enum LeterBoxType
     public Vector2Int resolutions;
 
     #region Properties in shader
+    private int _CurvatureScale;
     private int _WhiteNoiseOnOff;
     private int _ScanlineOnOff;
     private int _MonochormeOnOff;
@@ -83,6 +85,7 @@ public enum LeterBoxType
 
     private void Start()
     {
+        _CurvatureScale = Shader.PropertyToID("_CurvatureScale");
         _WhiteNoiseOnOff = Shader.PropertyToID("_WhiteNoiseOnOff");
         _ScanlineOnOff = Shader.PropertyToID("_ScanlineOnOff");
         _MonochormeOnOff = Shader.PropertyToID("_MonochormeOnOff");
@@ -127,6 +130,8 @@ private void OnRenderImage(RenderTexture src, RenderTexture dest)
         }
         //////
         
+        material.SetFloat(_CurvatureScale, curvatureScale); 
+        
         material.SetInteger(_LetterBoxOnOff, isLetterBox ? 0 : 1); 
         //material.SetInteger(_LetterBoxEdgeBlurOnOff, isLetterBoxEdgeBlur ? 0 : 1); 
         material.SetInteger(_LetterBoxType, (int)letterBoxType);
diff --git a/Assets/SimpleCRTShader/material/CRT.mat b/Assets/SimpleCRTShader/material/CRT.mat
index 93a39e7..004d771 100644
--- a/Assets/SimpleCRTShader/material/CRT.mat
+++ b/Assets/SimpleCRTShader/material/CRT.mat
@@ -2,20 +2,24 @@
 %TAG !u! tag:unity3d.com,2011:
 --- !u!21 &2100000
 Material:
-  serializedVersion: 6
+  serializedVersion: 8
   m_ObjectHideFlags: 0
   m_CorrespondingSourceObject: {fileID: 0}
   m_PrefabInstance: {fileID: 0}
   m_PrefabAsset: {fileID: 0}
   m_Name: CRT
   m_Shader: {fileID: 4800000, guid: fd1d99cddfb7f5644bbd3d844f92ab11, type: 3}
-  m_ShaderKeywords: 
+  m_Parent: {fileID: 0}
+  m_ModifiedSerializedProperties: 0
+  m_ValidKeywords: []
+  m_InvalidKeywords: []
   m_LightmapFlags: 4
   m_EnableInstancingVariants: 0
   m_DoubleSidedGI: 0
   m_CustomRenderQueue: -1
   stringTagMap: {}
   disabledShaderPasses: []
+  m_LockedProperties: 
   m_SavedProperties:
     serializedVersion: 3
     m_TexEnvs:
diff --git a/Assets/SimpleCRTShader/shader/CRT.shader b/Assets/SimpleCRTShader/shader/CRT.shader
index 1ba885a..1431f08 100644
--- a/Assets/SimpleCRTShader/shader/CRT.shader
+++ b/Assets/SimpleCRTShader/shader/CRT.shader
@@ -36,6 +36,8 @@ Shader "Simple CRT"
             float4 _MainTex_ST;
             float4 _MainTex_TexelSize;
 
+            float _CurvatureScale;
+            
             int _WhiteNoiseOnOff;
             int _ScanlineOnOff;
             int _MonochormeOnOff;
@@ -75,7 +77,16 @@ Shader "Simple CRT"
             float GetRandom(float x);
             float EaseIn(float t0, float t1, float t);
 
-            v2f vert (appdata v)
+            float2 Distort(float2 uv)
+            {
+                float2 center = float2(0.5, 0.5);
+                uv = uv - center;
+                float len = length(uv);
+                uv = uv / (1.0 + len * _CurvatureScale);
+                return uv * (1 + (_CurvatureScale * 0.5)) + center;
+            }
+
+            v2f vert(appdata v)
             {
                 v2f o;
                 o.vertex = UnityObjectToClipPos(v.vertex);
@@ -86,7 +97,11 @@ Shader "Simple CRT"
 
             fixed4 frag (v2f i) : SV_Target
             {
-                float2 uv = i.uv;
+                float2 uv = Distort(i.uv);
+                if (uv.x < 0.0 || uv.x > 1.0 || uv.y < 0.0 || uv.y > 1.0)
+                {
+                    return fixed4(0.0, 0.0, 0.0, 1.0); // Return black color for outbound pixels
+                }
 
                 /////Jump noise
                 uv.y = frac(uv.y + _ScreenJumpLevel);