From 3378a181a89e6e97159ad37feaf5adfa5cdc6724 Mon Sep 17 00:00:00 2001
From: Stedd <toanpa+git@pm.me>
Date: Sun, 8 Oct 2023 02:17:41 +0200
Subject: [PATCH] passing a variable to the shader

---
 Assets/Scripts/ComputeController.cs  | 29 +++++++++++++++++++++++++---
 Assets/Shaders/ColorInverter.compute |  7 +++----
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/Assets/Scripts/ComputeController.cs b/Assets/Scripts/ComputeController.cs
index 1e4c162..f28e8b4 100644
--- a/Assets/Scripts/ComputeController.cs
+++ b/Assets/Scripts/ComputeController.cs
@@ -15,12 +15,20 @@ public class ComputeController : MonoBehaviour
     [SerializeField] private float _scale = 1;
     [SerializeField] private bool _resize;
 
+    [Header("state")]
+    [SerializeField] private float sin;
+
     private int _kernelHandle;
+    private const int NumThreadX = 8;
+    private const int NumThreadY = 8;
+
+    #region ShaderVariables
+
     private static readonly int Result = Shader.PropertyToID("result");
     private static readonly int SourceTexture = Shader.PropertyToID("source_texture");
+    private static readonly int SinScaled = Shader.PropertyToID("sin_scaled");
 
-    private static readonly int _threadgroupX = 8;
-    private static readonly int _threadgroupY = 8;
+    #endregion
 
     private void Start()
     {
@@ -42,16 +50,31 @@ public class ComputeController : MonoBehaviour
         _computeShader.SetTexture(_kernelHandle, SourceTexture, _inputTexture);
         _computeShader.SetTexture(_kernelHandle, Result, _resultTexture);
 
-        _computeShader.Dispatch(_kernelHandle, _width / _threadgroupX, _height / _threadgroupY, 1);
+        DispatchShader();
+    }
+
+    private void DispatchShader()
+    {
+        _computeShader.Dispatch(_kernelHandle, _width / NumThreadX, _height / NumThreadY, 1);
     }
 
     private void OnGUI()
     {
         CheckScale();
+
+        ShaderUpdate();
+
         GUI.DrawTexture(new Rect(0, 0, _width, _height), _inputTexture);
         GUI.DrawTexture(new Rect(0, _height, _width, _height), _resultTexture);
     }
 
+    private void ShaderUpdate()
+    {
+        sin = (Mathf.Sin(Time.unscaledTime) + 1) / 2;
+        _computeShader.SetFloat(SinScaled, sin);
+        DispatchShader();
+    }
+
     private void CheckScale()
     {
         if (_resize)
diff --git a/Assets/Shaders/ColorInverter.compute b/Assets/Shaders/ColorInverter.compute
index 0987c18..1b23b3d 100644
--- a/Assets/Shaders/ColorInverter.compute
+++ b/Assets/Shaders/ColorInverter.compute
@@ -1,15 +1,14 @@
 #pragma kernel cs_main
 
-// The output texture
+Texture2D source_texture;
 RWTexture2D<float4> result;
 
-// Input texture
-Texture2D<float4> source_texture;
+float sin_scaled;
 
 [numthreads(8, 8, 1)]
 void cs_main(uint3 id : SV_DispatchThreadID)
 {
     float4 color = source_texture[id.xy];
-    color.rgb = 1 - color.rgb;
+    color.rgb = color.rgb * sin_scaled * 2;
     result[id.xy] = color;
 }