alpha channels

FEMTO

hi,

just a quick question about alpha channels. when making a texture that uses an alpha channel...does it have to be on a seperate piece of texture or can i include it on teh main texture also?

oh and just one thing....if i want to use a texture map the size of 512x256 how can i make the blue square in the 3d max unwrap tool to be of that size? rather than being a square. i am using max 7 btw

Eric Chadwick

1. Same texture. In a 32-bit texture there are four channels of pixel info... red, green, blue, and alpha. Most graphics hardware will convert every 24bit texture (red/green/blue, JPG, TGA, etc.) into a 32bit one before rendering it, so you you might as well include alpha anyway since you're paying the cost of that alpha wheterh you add it to your texture or not.

It's different if you use a non-24-bit texture, like a 8-bit (256-color) GIF or TGA or whatever. Then the hardware generally doesn't convert this to 32bit, so you don't get a separate alpha channel.

2. This thread might help (or not).
http://boards.polycount.net/showflat.php?Cat=0&Board=3&Number=47315