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Anti-aliasing

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I would really appreciate a few opinions on how to go about performing anti-aliasing in real time. I already have info on wu-lines and such but I am more interested in applying the technique to a "sprite'n'tile" situation. Description of algorithms preffered, I'd like to come up with the code myself Edited by - WytRaven on 2/22/00 4:34:29 PM

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alphablend the edges of the sprites with the backbuffer

this isnt anti-aliasing, but it produces good images and can be done in real time.

the algorithms for true edge anti-aliasing is similar but looks better at a much greater cost. you''d have to take several pixels from the backbuffers and sprite and compute an average color to replace the edge of the sprite on the backbuffer. there are other methods too, but most are slower. look some up in a graphics book or graphics website.

if you meant full scene aa... then you gotta do with hardware like a v5 for realtime.

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Thanks Trixter,

I''ll give it a shot.

Please excuse my ignorance, but just out of curiosity, what is a v5?

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I see this comment a lot:

''Alphablend the edge pixels''.

That makes sense.. except how do you find which pixels are on the edge?

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I was thinking of using a mask but if anyone else has any better ideas i would be very interested

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Most of today 3D accelerators have anti aliasing.
Full scene for PowerVR, Glaze3D and Voodoo5, edge for some other cards.
You should better use those hardware features, which are faster and easy to use.
(at least using D3D)
:o)

-* Sounds, music and story makes the difference between good and great games *-

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If you add an alpha channel to your images then you can render onto that via most 3D rendering programs (if that is how you are creating your images). If you have antialiasing enabled in your 3D program it will usually use the alpha channel to provide alphablending around the edge pixels. If you write graphics code to handle this then you can also do some neat effects with transparent areas of images, etc, not just around the edges.

Good luck

Starfall

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quote:
Original post by Ingenu

Most of today 3D accelerators have anti aliasing.
Full scene for PowerVR, Glaze3D and Voodoo5, edge for some other cards. You should better use those hardware features, which are faster and easy to use.



Most of those aren''t even available yet, much less commonplace with users, so banking on support there is limiting your customer base severely, hence NOT a good idea.


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PowerVR Serie2 (the one in the dreamcast) is available since september for the PC.
Voodoo4 and Glaze3D will support anti aliasing and is going to ship.
I think that NV10 supports AA...

Even if todays accelerators don''t support this feature, by the time you''ll release your engine/program, it''ll be and maybe became a standard

You can do AA via full scene oversampling, and shrunking it to the resolution, altought I think you''ll lost some quality.
Forget about finding edges, it''s far too slow.

-* Sounds, music and story makes the difference between good and great games *-

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You could store the edge-alpha information in with the bitmap though ( storing as an RGBA bmp instead ), meaning there''s no realtime calculation to be done.
After all we''re talking 2D tiling.

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