Unity Compute Shader 入门

Compute Shader

• 创建Shader
• 设置参数
• Dispatch()
• 获取结果

参考

代码

• ComputeNoise.cs

  using System.Collections;
  using System.Collections.Generic;
  using UnityEditor;
  using UnityEngine;
  
  [ExecuteInEditMode]
  [RequireComponent(typeof(MeshRenderer))]
  public class ComputeNoise : MonoBehaviour
  {
      public int resolution = 512;
      public Color color = Color.white;
      [Range(0, 100)] public float seed;
  
      private ComputeShader m_computeShader;
      private Material m_material;
      private RenderTexture m_texture;
  
      void OnEnable()
      {
          m_material = new Material(Shader.Find("Unlit/Texture"));
          GetComponent<MeshRenderer>().material = m_material;
  
          CreateNoise();
      }
  
      private void CreateNoise()
      {
          if (!m_computeShader)
          {
  #if UNITY_EDITOR
              const string computeShaderFile = "Assets/Dev/Shader/Compute/NoiseTexture.compute";
              m_computeShader = AssetDatabase.LoadAssetAtPath<ComputeShader>(computeShaderFile);
  #endif
          }
  
          if (!m_computeShader.HasKernel("CSMain")) return;
          int id = m_computeShader.FindKernel("CSMain");
  
          bool bCreateNewTexture = false;
          if (m_texture == null)
          {
              bCreateNewTexture = true;
          }
          else if (m_texture.width != resolution || m_texture.enableRandomWrite == false)
          {
              bCreateNewTexture = true;
              m_texture.Release();
          }
  
          if (bCreateNewTexture)
          {
              m_texture = new RenderTexture(resolution, resolution, 24);
              m_texture.enableRandomWrite = true;
              m_texture.Create();
          }
  
          m_computeShader.SetTexture(id, "Result", m_texture);
          m_computeShader.SetVector("Color", color);
          m_computeShader.SetFloat("Seed", seed);
  
          m_computeShader.GetKernelThreadGroupSizes(id, out uint groupNumX, out uint groupNumY, out _);
          int numX = Mathf.CeilToInt(resolution / (float) groupNumX);
          int numY = Mathf.CeilToInt(resolution / (float) groupNumY);
  
          m_computeShader.Dispatch(id, numX, numY, 1);
  
          if (m_material) m_material.SetTexture("_MainTex", m_texture);
      }
  }

• NoiseTexture.compute

  #pragma kernel CSMain
  
  float hash2d_value(float2 uv, float seed = 0)
  {
      uint x = (uint)uv.x << 4;
      uint y = (uint)uv.y << 6;
      return frac(sin(dot(uv, float2(12.9898 + seed + x * y, 78.233))) * 43758.5453);
  }
  
  RWTexture2D<float4> Result;
  float3 Color;
  float Seed;
  
  [numthreads(8,8,1)]
  void CSMain(uint3 id : SV_DispatchThreadID)
  {
      uint w, h;
      Result.GetDimensions(w, h);
      if (id.x < w && id.y < h)
      {
          float2 uv = id.xy / float2(w, h);
  
          float randValue = hash2d_value(uv, Seed);
          Result[id.xy] = float4(randValue * Color, 1);
      }
  }