Just like the engine doing for ETC1, I want to support S3TC\DXT... . The textures are stored as .jpg\.png, and will be dynamic compressed to specific format rely to GL-extension in runtime.
Is there any hook\method to do this ?
No, there's no way of doing this, i'm afraid.
Could you support the common texture compression or add interfaces to do the extension by third party, please.
I'm not sure how to do this is a good way and i'm also not sure if the benefit justifies the amount that it woudl cost. Why do you want to use that kind of compression instead of the default OpenGL ES ETC1?