Texture Compression

[Pickle]

at this point the game could end up looking like crud and if it runs I would have some satisfaction. Reality there are only a few cases where 1 bit could not be used for alpha. I recall some images like smoke or clouds that have non-0/1 alpha. If I can i can leave them as 32 bpp.
First test will probably be with everything at 5551 to see if the game runs (at all).

[lb]

Again, what speaks against the easy solution of using a separate texture for alpha? This uses less than 16 bits per pixel, but provides better quality and full alpha.

[Pickle]

Again, what speaks against the easy solution of using a separate texture for alpha? This uses less than 16 bits per pixel, but provides better quality and full alpha.

There are a couple of issues, but mainly I dont have a 2.0 es render path yet (although im working on it).
Then if I have a 2.0 es render then I will need to make a script to separate images into the 2 images. Then I could use the PVR tex tool to make the ETC1 images.
But then I have to add code to handle loading 2 textures anytime one texture is loaded and write the GLSL code to handle them.

Trying 5551 is a simple PVR Tex tool script change and small changes to the texture loading.

I think your idea has some merit, but im not even close to being able to try it yet.

[lb]

Well, a 2D plane/sprite renderer is really simple to do with ES 2.0, there is none of the somewhat complex transformation math involved, and you can easily apply various effects to the sprites with a fragment shader.

ARM's Mali Development Center has some nice examples, including conversion tools. They present various alternatives to alpha+compression. Check it out:
http://www.malideveloper.com/files/AlphaChannels.zip

[Pickle]

Thanks, had a look at the pdf and if I get that point that will be useful