since I seem to read a lot about people complaining about the shadow tutorial screwing up on (mostly) Ati cards, I''d appreciate it if a few people with ati cards or whatnot could test this.. this is my own shadow renderer and has absolutly nothing to do with the shadows lesson, other than that it is based on some of the basic nehe windowing code, which I use whenever hacking together a feature so basically I''d like to know if it''s just the shadows lesson or non-nvidia cards that the problem is caused by. shadows just a note that the model used is copyright to a HL mod I work for, so you cannot use it for yourself. thanks.

Works OK for me.

ATI Rage Xpert 2000 Pro (a souped up Rage 128 Pro)

Looks fine over here on my Radeon (old model...64MB VIVO if you really want to know).

awesome :-)

Worked on my all in wonder (8 mb) too.

I guess it must be an issue with the shadowing tut then.

thanks all. :-)

The demo works correctly on a ATI RAGE PRO 128 32Mb but with a Matrox G400 it works slow and the shadows are drawn bad (triangles of the model disappear etc).
I have the same result with the nehe tutorial, i''ve updated the driver but nothing (it''s a long time i''ve tried it with many driver version).
There''s something particular for rendering shadows different from nehe code?

quote:

---

Original post by SoD
The demo works correctly on a ATI RAGE PRO 128 32Mb but with a Matrox G400 it works slow and the shadows are drawn bad (triangles of the model disappear etc).
I have the same result with the nehe tutorial, i've updated the driver but nothing (it's a long time i've tried it with many driver version).
There's something particular for rendering shadows different from nehe code?

---

ok.
if it's running slow it sounds like it may be reverting to the generic software renderer... Which may be the cause. It's been a while since I forced it to run in software to see how it looked (and it didn't look good)...
When I put the code through to my main project I'll post up a link. That does a lot more error checking, and sets up the window a lot better.

The methods for rendering the shadows in this demo are quite different to the nehe tut, and took me a good 4 weeks to get bang on. Most of these are optimizations, (eg, the silhouettes are rendered as a continuous strip of quads - not as individual quads) It also differs in that it switches between 3 different rendering modes, generic shadow voluming, (like the tut), reverse voluming (aka 'carmaks reverse') and another reverse mode where the caps are optimized significantly using only the silhouette. Also the code that calculates the edges is a pretty efficient rucursive loop, unlike the more common method of testing each edge 1 by 1.
basically it all boils down to 2-6 DrawElements calls that are made off a single array of data generated by the recursive loop (hence will be easy to optimize for things like VAR, etc) - edit - although it sill must use the model data for the un optimized reverse method...

I'm quite proud of it. As I didn't base it off any tuts/papers. (which is why it took so long to get right)

ohh yeah. and also, unlike the nehe tut, I add light to non shadowed areas, instead of darkening the shadowed areas. which I feel looks infinitly more realistic. (and is no slower either)

[edited by - RipTorn on July 23, 2002 10:48:06 PM]

quote:

---

Also the code that calculates the edges is a pretty efficient rucursive loop, unlike the more common method of testing each edge 1 by 1.

---

That is for closed models.
For opened models, you may be switching back to the "each edge 1 by 1" method, right ?

quote:

---

and also, unlike the nehe tut, I add light to non shadowed areas, instead of darkening the shadowed areas.

---

In NeHe tutorial, shadowing is rendered by blending a black square.
Do you mean that you enlight your scene by blending a white square, or do you use the multiple passes (with lights turned on and off) rendering ?

quote:

---

Original post by vincoof
That is for closed models.
For opened models, you may be switching back to the "each edge 1 by 1" method, right ?

---

no... because even a single triangle floating in space will still have a looping silhouette edge..

quote:

---

Original post by vincoof
In NeHe tutorial, shadowing is rendered by blending a black square.
Do you mean that you enlight your scene by blending a white square, or do you use the multiple passes (with lights turned on and off) rendering ?

---

I render the model with just lighting additive over the existing scene (I plan to go further into bump mapping)... As far as fill rate goes this is pretty much equal speed. Although more blending operations are done, when rendering a black square, you are running checks on every single pixel on screen, which would roughly even out. (although obviously it''d be faster when close in, it''d be slower when the model is far away and small on screen)