[EXPERIMENT] Some questions about Glide Anti Aliasing. Adding HW AA to Glide games.

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rkk
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Joined: Wed Apr 08, 2015 12:58 pm

[EXPERIMENT] Some questions about Glide Anti Aliasing. Adding HW AA to Glide games.

Postby rkk » Fri Feb 12, 2016 4:27 pm

Since nGlide 1.05 supports Anti Aliasing I was wondering if I could implement some hardware AA into a Glide 2 game.

To see how it would look I just swapped all the Glide functions used in-game to their AA versions (where available). The results are quite interesting.. Here are some pics.

URP2 - 3 - Everything with AA 2016-02-12 16-22-20-82.png
AA works just in the distance
URP2 - 3 - Everything with AA 2016-02-12 16-22-20-82.png (929.34 KiB) Viewed 2373 times


First of all it seems that AA is just working in the far. Even if I swapped all non AA functions with their AA counterparts.

URP2 - 3 - Everything with AA 2016-02-12 16-21-39-73.png
AA works just in the distance
URP2 - 3 - Everything with AA 2016-02-12 16-21-39-73.png (1.1 MiB) Viewed 2373 times


Maybe it's fog-related? When it's close to where the fog starts, then AA works. Or is there some kind of limit for the amount of Anti Aliased vertices?

Anti Aliasing doesn't seem to like fog as seen on the next picture..
URP2 - 3 - Everything with AA 2016-02-12 16-53-31-16.jpg
AA doesn't play nice with fog
URP2 - 3 - Everything with AA 2016-02-12 16-53-31-16.jpg (336.39 KiB) Viewed 2373 times

Is Glide AA compatible with fog or is it just a nGlide limit?

Anybody here with some Glide knowledge could give some info about what's going on here? Is there any way to fix this or make it look better?

Greetings and thanks.

rkk
Posts: 23
Joined: Wed Apr 08, 2015 12:58 pm

Re: [EXPERIMENT] Some questions about Glide Anti Aliasing. Adding HW AA to Glide games.

Postby rkk » Fri Feb 12, 2016 4:28 pm

Here is the modified EXE for the game Ulim@te Race Pro (1.50) in case somebody wants to try it out. Anybody here with a real Voodoo 2 to see how it looks?

Ultim@te Race Pro - AA.zip
(622.55 KiB) Downloaded 264 times

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Zeus
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Re: [EXPERIMENT] Some questions about Glide Anti Aliasing. Adding HW AA to Glide games.

Postby Zeus » Sat Feb 27, 2016 1:27 am

The concept of edge AA is based on alpha channel, so you have to ensure alpha combine unit/blend is setup properly for all AA-enabled primitives.

You won't see a smooth transition if you'll render something with alpha blending disabled or if vertex alpha won't be selected as an alpha source.

To avoid "glitches" on semi-transparent objects (that's not fog) make sure to enable AA only for outer edges. For example, if you're going to render a quad, render it as a polygon with 4 vertices, not as 2 triangles or do not enable AA on edges inside.

rkk
Posts: 23
Joined: Wed Apr 08, 2015 12:58 pm

Re: [EXPERIMENT] Some questions about Glide Anti Aliasing. Adding HW AA to Glide games.

Postby rkk » Sat Feb 27, 2016 2:55 pm

Thanks for the input Zeus.

I'll try it out. I wish I could make the Glide SDK work on Visual Studio 2015 to test out the stuff before trying to make it work in assembly. But the Glide.lib file refuses to work and the linking fails. Anyone got the Glide SDK working on modern IDEs?


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