Lee Elliott wrote:

On Sunday 26 Jun 2005 23:03, Vivian Meazza wrote:
Frederic Bouvier

2 stranges things that I know are inherent to the shadow
volume technique

1. even when surfaces are smoothed, the shadows are hard and
apply to a whole quad when a fuselage shadows itself ( try
the A320, look at the airframe and press t to see what I
mean ).
Cool I didn't know about time warp ;) I'll see what I can do for that problem.
What we see is the projected shadow that is received by the caster itself.

2. transparent surfaces ( the suspension chains of the
bridges, or the metallic structures ) produce filled
shadows.
There is no real solution for that because it's the surface that cast shadow and not the texture.

Yes, I can see that. The markings on the Hunter are on
separate transparent object: these throw a shadow. It seems as
if I'm going to abandon that method if shadows are to be
usable with that model. Pity; it saves a huge amount of
artwork and texture.
Don't change your model for that. If it's not a problem to rename your objects you can add a 'noshadow' prefix to your markings, they won't caste shadow ('mydecal' => 'noshadow.mydecal').

The edges of the shadows are a bit too
hard; a little penumbra would be good
ahem ;) so you have too much fps ? this can be done with a fragment shader.

Let wait the hardware to catch up a hit, and we could have
clouds and mountains casting shadows ;-)
We could use a simple ovale for clouds, it's just that the shadow would be as dark as the other type
of shadows - perhaps too dark then but not sure.

Nice if aircraft could throw shadow on cloud.
I didn't enable writes in the depth buffer while rendering clouds, that's why they don't catch shadows. I can't remember if that gave a visual glitch or if it was just for performance.

Altogether it's a nice enhancement.

V.

thanks ;)

Yep - I've used the same texturing technique on a few a/c as well:( Then again, I've already stopped using it:) It did save a lot of texture space though.

Re the 1st problem Fred referred to, it seems to happen when an object puts itself in shadow. Shadows cast by other objects seem to be ok. Generally, the old shading code did a good enough job of shading each individual object in a model, according to the sun pos, so I wonder if the new shadows might work better if they were only applied to other objects, and let the old code shade each individual object...

LeeE

I'll check that.

Harald.


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