CopyTexture of compressed texture produces texture with different in-memory size.

For example:
Source 4096x4096 texture with RGB Compressed ETC2 4 bits compression on my android device


When i do:

Code (CSharp):

1. m_dst = new Texture2D(m_src.width, m_src.height, m_src.graphicsFormat, m_src.mipmapCount, UnityEngine.Experimental.Rendering.TextureCreationFlags.MipChain);
2. m_dst.name = "Copy";
3. Graphics.CopyTexture(m_src, m_dst);

i get this one on my device


Both textures are in correct compression format:


Why "Copy" texture has so different size? Is it correct? My Unity version is 2020.3.3f1.

 

Maybe try with textureFormat instead of graphicsFormat?

CopyTexture isn't your problem. The problem is when you initialize your new texture. CopyTexture is just moving data around.

 

By default textures created at runtime have the isReadable flag enabled, which causes a copy of the texture data to exist in the CPU and counts as 2x the memory used. You need to call Apply() on the texture once after creating it to discard the CPU copy:

https://docs.unity3d.com/ScriptReference/Texture2D.Apply.html

 

Well, of course, I didn't think of that at all! Thank you very much!