Read a part of the screen with AsyncGPUReadback

Question

Hello all ! I'd like to read the color under the cursor of the mouse in game. ReadPixels is not acceptable because it's way too slow. I stumbled upon t$$anonymous$$s class, AsyncGPUReadback, w$$anonymous$$ch could fit my needs. The idea is to take a screenshot, then get the mouseposition, put in a texture the pixel under the mouse, and use the Request method to read it. Here's the code I have right now :

             // define a texture of the size of the screen
             var renderTexture = RenderTexture.GetTemporary(Screen.width, Screen.height, 32);

             format = renderTexture.grap$$anonymous$$csFormat;

             // makes a screenshot and put it into the texture
             ScreenCapture.CaptureScreenshotIntoRenderTexture(renderTexture);

             // read the texture and do somet$$anonymous$$ng with it in OnCompleteReadback
             AsyncGPUReadback.Request(renderTexture, 0, TextureFormat.RGBA32, OnCompleteReadback);

And here the code in OnCompleteReadback :

     void OnCompleteReadback(AsyncGPUReadbackRequest request)
     {
         int currentX = (int) Input.mousePosition.x;
         int currentY = (int) Input.mousePosition.y;
         byte[] array = request.GetData<byte>().ToArray();
         Color point = new Color();
        //do somet$$anonymous$$ng with the color ....
     }

There's two t$$anonymous$$ngs here. The first one is that with t$$anonymous$$s array of byte, I'm not sure how to get the color under the cursor. Knowing where my cursor is, how do I get the bytes I need ? The second t$$anonymous$$ng is that I'm taking a screenshot of the whole screen, but since I know precisely w$$anonymous$$ch pixel I want, isn't there a way to get a capture of t$$anonymous$$s unique pixel, instead of a whole picture ?

Answer 1

Answer by feufollet98 · Dec 31, 2022 at 05:40 PM

Hi @kasmurdanto,

I'm incredbily late to t$$anonymous$$s thread, but I managed to do it. Here's the code:

 public void GetPixelAsync(int x, int y)
     {
         AsyncGPUReadback.Request(renderTexture, 0, xCoord, 1, yCoord, 1, 0, 1,
             request =>
             {
                 if (request.hasError) return;
 
                 Color32 requestedColor = request.GetData<Color32>(0)[0];
 
                 print(requestedColor);
             }
         );
     }

Hope t$$anonymous$$s helps anyone who has the same problem :)

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kasmurdanto · Dec 31, 2022 at 07:38 PM 1

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Never too late :) I'll check if that works later but t$$anonymous$$s makes sense, thank you !

feufollet98 kasmurdanto · Jan 13 at 10:16 AM 0

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Any luck ?

Read a part of the screen with AsyncGPUReadback

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