Emissive material question

[ajr2764]

Okay im not sure if Im doing this right or if its the best workflow. I have a mesh with diffuse, spec, normal textures are 1024 each. I have parts of the mesh that are lights that will need to be turned on and off in kismet.

I've isolated the lights parts and put them in a alpha channel and exported a 1024 32 bit targa. Is it better to have the emissive parts on a seperate lower rez texture? When I setup my material I tried to plug the emissive into the alpha but the parts just turn pure white and I get no diffuse in those areas.

Im not sure if Im doing something wrong in photoshop or the material editor.

Thanks.

[moose]

I'd use a seperate texture for you emissive instead of using an alpha channel. DXT5's are more expensive, and generally speaking you can get more use out of making a mask texture (putting your grayscale masks/alphas into the RGB channels and using them individually) or a straight up emissive texture for you material as a 512 or 256.

You can crop the emissive to the area where it exists on the texture, but you will have to do some multiplication and addition with a 2 vector constant to the material through a texture coordinate to position it poroperly on the texture, as well as set your cropped emissive texture to CLAMP in the texture properties. This takes up less memory, but can be a hassle :)

keeping it simple, have 4 textures for your material; Diffuse, Spec, Normal, and Emissive. Multiply the emissive by a single vector and convert it to a parameter that Kismet/matinee will control.

[ajr2764]

Thanks for the help. It would be interesting if I can get the more of a hassle method working..which I'll try. I figured it was more expensive using the 1k 32bit texture.