How to capture a camera at power-of-two size in unity free

Hi.

I need to be able to use GL.Viewport to make the camera smaller, then capture the tex at that size, then be able to stretch the viewport back to normal screen size. How could I go about doing this? I am currently trying this, but it nly captures the bottom-left corner...

 

And i want the captured tex to be at the correct aspect.

 

Example (using Unity Pro feature):

Code (CSharp):

1.         void LateUpdate ()
2.         {
3.                 if (Input.GetKeyDown (KeyCode.S)) {
4.                         int rw = (int)Mathf.Round (camera.pixelWidth / 4);
5.                         int rh = (int)Mathf.Round (camera.pixelHeight / 4);
6.                         RenderTexture rt = new RenderTexture (rw, rh, 24);
7.                         camera.targetTexture = rt;
8.                         Texture2D ss = new Texture2D (rw, rh, TextureFormat.RGB24, false);
9.                         camera.Render ();
10.                         RenderTexture.active = rt;
11.                         ss.ReadPixels (new Rect (0, 0, rw, rh), 0, 0);
12.                         camera.targetTexture = null;
13.                         RenderTexture.active = null;
14.                         Destroy (rt);
15.                         byte[] bytes = ss.EncodeToPNG ();
16.                         string filename = "screenshot.png";
17.                         System.IO.File.WriteAllBytes (filename, bytes);
18.                         Debug.Log (string.Format ("Took screenshot to: {0}", filename));
19.                 }
20.         }

 

Oh, and i forgot to mention, I don't have Unity pro... But i can still use this, so thanks for the code!

 

This code doesn't make it power-of-two size...

 

Surely you can manage that yourself?

 

Of course. If you want power of two and save aspect ratio you have to set fixed size you like and make all empty space transparent.

Say if you render on the screen 1280 x 720 then render 512 x 512 and make top 224 rows of pixels transparent.

 

I did mean this:
basically, perhaps the camera is like this:

I want it to be like this:

That way, I can capture the screen at power-of-two size. understand now? I know my question wasn't very obvious, but if you know something about the above, please let me know! Also note how the apsect ratio isn't lost, it is just squished together, like a powr-of-two rendertexture in Unity Pro

 

Are you asking for help, or do you just want us to do it for you?

Have you tried playing around with the supplied code? Changing it to be a power of two size isn't a big deal - find where the size is specified and change it to be what you want it to be.

 

No, no. I am asking how to do it. and I can easily make any texture power-of-two size, the real problem is trying to capture the WHOLE viewport at that size without chopping off the edges or capturing the bottom-left corner...

thanks for the fast rply BTW! I also tried the TextureScale script on the wiki, but that is dead slow for realtime performance...

 

Right, so the issue is that you can't use the RenderTexture part?

 

Yes, I have Unity Free. In unity pro, it is possible to render into a POT texture, right?

In free version, we have ReadPixels, which captures a viewport as a rect. the workaround would be to squish the aspect ratio so that it is preserved in the POT texture, but all my attempts fail with the bottom-left corner problem. (and that measn that the viewport is STILL at NPOT size!)

 

Have you had a look at the documentation for the camera's aspect property?

 

I had no idea about the aspect property. If you mean setting the apsect ratio manually, this won't work, as I need the POT texture to hold, say 16:9 aspect, so that when I draw to the screen, the 16:9 aspect lines up with the camera.

I will have a look at the aspect property...

EDIT: Ok, this worked for me, thank you very much!

 

Ok, I now have the aspect working. now how would I go about adjusting the aspect so that I can squish the image to preserve it? Thank you for your help so far!

EDIT: got that fixed, but I have a problem: resetting the aspect after capturing the screen results in the apsect being lost, help!

 

Why mess around with changing the settings on one single camera? Could you set up a second, dormant camera just for the purpose of capturing and leave your normal one alone? Why mess with something you don't need to mess with?

 

Strangely, if i remove the aspect ratio reset, the camera capturees properly, only problem is, the camera is not stretched. (which is intentional, this is what readpixels is supposed to capture!)

 

And there's that, but i was sure a second camera ruined the framerate... But still you never know... unless you try! may give this a go later, as I have an exam after lunch.

 

That's why it should be dormant. You don't want it rendering every frame, just the ones you want to capture.

Just merely existing won't ruin your framerate.

 

Ok, I got everything working. again thanks for your help!

If you wish to find out the reason why I am attempting this, click the link in my signature for more info. if you wish also, I can put you in the credits for helping capture screen at power-of-two size.