[游戏开发]Unity Computer shader后效

使用范围：像素处理、粒子效果、大规模同步无依赖运算。
1\检测是否支持：
SystemInfo.supportsComputeShaders

2\创建Computer Shader
click>Create>Shader>Compute Shader

直接上代码

using UnityEngine;

public class CBW : MonoBehaviour
{
    public ComputeShader shader;
    public Camera cam;
    public RenderTexture rt;

    private void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        if(rt == null)
        {
            RenderTexture camTex = cam.activeTexture;
            if (camTex == null) return;
            rt = new RenderTexture(camTex.descriptor);
            rt.enableRandomWrite = true;
            rt.Create();
        }

        if (shader == null|| rt == null) return;

        Graphics.Blit(source, rt);
        int kernel = shader.FindKernel("CSMain");
        uint shaderThreadX, shaderThreadY, shaderThreadZ;
        shader.GetKernelThreadGroupSizes(kernel,out shaderThreadX,out shaderThreadY,out shaderThreadZ);

        int dispathXF = Mathf.CeilToInt(source.width / shaderThreadX)+1;
        int dispathYF = Mathf.CeilToInt(source.height / shaderThreadY)+1;

        shader.SetTexture(kernel, "InOutputTexture", rt);    
        shader.Dispatch(kernel,dispathXF,dispathYF,1);

        Graphics.Blit(rt,destination);
    }
}

Computer Shader

// Each #kernel tells which function to compile; you can have many kernels
#pragma kernel CSMain

// Create a RenderTexture with enableRandomWrite flag and set it
// with cs.SetTexture
RWTexture2D<float4> InOutputTexture;

[numthreads(8,8,1)]
void CSMain (uint3 id : SV_DispatchThreadID)
{
    // TODO: insert actual code here!
    float4 color = InOutputTexture[id.xy];

    //Result[id.xy] = float4(id.x & id.y, (id.x & 15)/15.0, (id.y & 15)/15.0, 0.0);
    float c = color.r * 0.30 + color.g * 0.59 + color.b * 0.11;
    InOutputTexture[id.xy] = float4(c, c, c,color.a);

}

说明：
使用默认管线，如果是URP管线，需要使用Feature进行操作

使用Computer shader 前后