I have a 2048x2048 ATF texture for PVRTC 4bpp, no mipmaps. It is a texture atlas created using TexturePacker tool.
I am loading the texture atlas using starling AssetManager.
According to my calculations 2048x2048 ATF texture with PVRTC 4bpp should take 2Mb of GPU memory ( 2048 * 2048 * 0.5 bytes ).But when I profile my application using Adobe Scout, it shows GPU memory to be around 6Mb. To be more specific it shows Base(Compressed) inside Textures under GPU memory to be around 6Mb, which is 3 times of the calculated value.
I played around with several other sizes and ATF textures and all are showing roughly 3 times my calculated value.
Any ideas what I am doing wrong ?. Either I am missing something in my calculations or there is some behaviour of stage3d or Flash/AIR that I am unaware of.
Please help me in understanding what I may be doing wrong