Unity异步把图片数据从显存下载到内存（GPU-＞CPU）

Unity异步把图片数据从显存下载到内存（GPU->CPU）

1.c#核心代码

using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using UnityEditor.PackageManager.Requests;
using UnityEngine;
using UnityEngine.Rendering;namespace Tools
{/// <summary>/// RenderTexture转Bytes/// </summary>public class TextureOrBytes{private ComputeShader computeShader;private Texture srcRrenderTexture;private RenderTexture dstRenderTexture;private int kernelHandle;private bool requestPending;private NativeArray<byte> srcNativeArray;private byte[] dstRTData;private int width;private int height;private int memorySize;private int threadGroupsX;private int threadGroupsY;private object lockObject = new object();public TextureOrBytes(ComputeShader _computeShader, Texture _srcRrenderTexture){computeShader = _computeShader;srcRrenderTexture = _srcRrenderTexture; Init();}public void Update(){if (!requestPending){computeShader.Dispatch(kernelHandle, threadGroupsX, threadGroupsY, 1);AsyncGPUReadback.Request(dstRenderTexture, 0, TextureFormat.RGBA32, OnCompleteReadback);requestPending = true;}}public void Clear(){if (dstRenderTexture != null){dstRenderTexture.Release();dstRenderTexture = null;}if (srcNativeArray != null){srcNativeArray.Dispose();}dstRTData = null;lockObject = null;}private void Init(){width = srcRrenderTexture.width;height = srcRrenderTexture.height;memorySize = width * height * 4;srcNativeArray = new NativeArray<byte>(memorySize, Allocator.Temp);dstRTData = new byte[memorySize];//创建临时RTdstRenderTexture = new RenderTexture(width, height, 0, RenderTextureFormat.ARGB32);dstRenderTexture.enableRandomWrite = true;dstRenderTexture.Create();kernelHandle = computeShader.FindKernel("CSMain");computeShader.SetTexture(kernelHandle, "sourceTex", srcRrenderTexture);computeShader.SetTexture(kernelHandle, "destTex", dstRenderTexture);threadGroupsX = Mathf.CeilToInt(width / 8.0f);threadGroupsY = Mathf.CeilToInt(height / 8.0f);}private void OnCompleteReadback(AsyncGPUReadbackRequest request){if (srcNativeArray == null || dstRTData == null || lockObject == null){requestPending = false;return;}if (!request.done){Debug.Log("GPU readback hasnt done yet");return;}if (request.hasError){Debug.LogError("GPU readback error detected.");requestPending = false;return;}srcNativeArray = request.GetData<byte>(); lock (lockObject){if (srcNativeArray.Length == dstRTData.Length){srcNativeArray.CopyTo(dstRTData);}}requestPending = false;}public byte[] GetTexGPUBytesData(){lock (lockObject) {return dstRTData;}}public Texture GetTex(){return srcRrenderTexture;}public RenderTexture GetRWTex(){return dstRenderTexture;}#region 递归方式..private void StartRequestReadbacks(){computeShader.Dispatch(kernelHandle, threadGroupsX, threadGroupsY, 1);AsyncGPUReadback.Request(dstRenderTexture, 0, TextureFormat.RGBA32, OnCompleteReadback_Recursive);}private void OnCompleteReadback_Recursive(AsyncGPUReadbackRequest request){if (srcNativeArray == null || dstRTData == null || lockObject == null){requestPending = false;return;}if (!request.done){Debug.Log("GPU readback hasnt done yet");return;}if (request.hasError){Debug.LogError("GPU readback error detected.");requestPending = false;return;}srcNativeArray = request.GetData<byte>();//lock (lockObject){if (srcNativeArray.Length == dstRTData.Length){srcNativeArray.CopyTo(dstRTData);}}StartRequestReadbacks();}#endregion}}

2.ComputeShader核心代码

// Each #kernel tells which function to compile; you can have many kernels
#pragma kernel CSMain// Texture to read from
Texture2D<float4> sourceTex;
// Texture to write to
RWTexture2D<float4> destTex;[numthreads(8, 8, 1)]
void CSMain(uint3 id : SV_DispatchThreadID)
{float4 color = sourceTex[id.xy];destTex[id.xy] = color;
}

3.使用

• 在外部实例化TextureOrBytes
• 在update中调用 TextureOrBytes.Update();
• 通过TextureOrBytes.GetTexGPUBytesData()获取CPU数据