Alpha Channel - How To

[nudata 10]

http://forums.avsim.net/user_files/189639.jpgThe picture shows a stark difference between the photo textures. To the right is a special 30cm/pixel photo at the highest scenery library priority and to left is 1.2m/pixel at the next lowest priority. Because of the different coloring I want to "blend" them. I have, until now, shied away from Alpha Channels. However, this seems to be a time for one. I imagine the process is simple. I have Gimp and DXTBmp. My assumption is that I need a white, tending toward grey, separate BMP to somehow become an Alpha Channel. My hi-res 30cm photo is in TIF format and is renderable with render.exe. I also assume that I need to make the 932mb TIF into a gigantic BMP file to work the magic. At that point I am looking for some guidance.

[arno 1]

Hi,TIFF files can also have an alpha channel, so I guess that is even easier. The lower resolution image does also extend under the higher one I assume? In that case it would indeed be worth a try to add a blend mask to your high resolution image.What you need to do is make add an alpha channel and use grey colours there to indicate the level of transparency you want on the edges. After that simply convert the TIFF again. It might be necessary to indicate in the INF file with channel is for the blend mask, as you can also have a water mask channel. See the SDK for more details.The process of adding the alpha channel to your image depends a bit on the image editor you use.

[Clutch Cargo 384]

nudata,why not use something like Photoshop to 'blend' two together? I was able to not only blend a few photo tiles on my project but that's how I would color correct textures that were obviously taken at different times.By the why is nudata Dick B.? If so, could you drop me an email? I have a few questions on photomesh if you don't mind.thx,Clutch(9dragonskaitak (at) gmail .com)

[arno 1]

If the two photos have a different resolution I would not blend them together into one. That would make the resulting BGL file a lot larger than needed. And of course the lower resolution part does not become higher resolution by doing so :).