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How can I get pixels from unreadable textures?

Updated
Symptoms:
 
  • I want to get pixels from a Texture.
  • I do not want to set the Texture as "readable".
 
Causes:
 
To use Texture2D.GetPixels, you need to select Read/Write Enabled on Texture Import Settings to enable access to the Texture data from scripts. Sometimes you need to get pixels from a Texture without setting the Texture as readable, similar to how the Unity Editor does it to get preview images from Textures.
 
Resolution:
 
You can use a RenderTexture to do that. Take a look at the following code:
 
"texture" is the texture you want to read which is not marked as readable in the import settings:
 
// Create a temporary RenderTexture of the same size as the texture
RenderTexture tmp = RenderTexture.GetTemporary( 
                    texture.width,
                    texture.height,
                    0,
                    RenderTextureFormat.Default,
                    RenderTextureReadWrite.Linear);


// Blit the pixels on texture to the RenderTexture
Graphics.Blit(texture, tmp);


// Backup the currently set RenderTexture
RenderTexture previous = RenderTexture.active;


// Set the current RenderTexture to the temporary one we created
RenderTexture.active = tmp;


// Create a new readable Texture2D to copy the pixels to it
Texture2D myTexture2D = new Texture2D(texture.width, texture.height);


// Copy the pixels from the RenderTexture to the new Texture
myTexture2D.ReadPixels(new Rect(0, 0, tmp.width, tmp.height), 0, 0);
myTexture2D.Apply();


// Reset the active RenderTexture
RenderTexture.active = previous;


// Release the temporary RenderTexture
RenderTexture.ReleaseTemporary(tmp);


// "myTexture2D" now has the same pixels from "texture" and it's re
 
You can now get/set pixels from "myTexture2D".
 
More Information:
 
 

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