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CDSmith

Getting more bits in the Alpha channel...

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Does anyone know of a way to get more than 8-bits in the Alpha channel? I am trying to create a texture that will be used as an overlay to some digital terrain data and use the alpha bits to hold altitude information in the overlay. That way I can use a quick alpha test to remove the portions of the texture that I don''t want to see. This works fine except that the resolution of the data is such that 8-bits in the alpha is just not enough. Does anyone know of a way to get more resolution in the alpha channel?

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There really isn''t a way to add more alpha bits, but you can always cheat.

Instead of having your alpha represent 1 altitude unit, you can use them to represent 2 altitude units.

A*2 = your information.

I''m not sure what kind of terrain you are using, but you can cheat a lot of different ways. Instead of using the raw alpha information, you can also plug the information into a formula.

If you use a spline, you can set your accuracy better for some elevations than others.

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Thanks for the reply,

I pretty much came to the same conclusion. Unfortunatly, trying to cheat by using multiplication, or even normalizing the data will not work too well because I really need more than 8-bits for the resoultion of the data that I am using....

I guess it comes down to this... I am trying to make a monocrome texture (remember, this is an overlay) in such a way that I can quickly remove portions of the texture from being displayed (so I didn''t have to keep recalculating and reloading the texture). I saw that a quick alpha test worked... but the resolution was poor. Since I only cared about it being one color, I wondered if anyone knew of a way to get to those extra bits that I didn''t care about or knew of another way of doing what I am trying to do... I hope I am making sense...

Any help would be appriciated.

Chris

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