Casting Shadows

How about shadows? I want to have a light that only illuminates a picture I have on my wall, so I created a light, and then a shade, but the shade has no effect, and neither do my walls. I know shadows are tough, but from a 3d perspective, this sucks. I don't see why this would add any difficulty on the simulation or bandwidth end. Couldn't this just be a client side thing (and also client side option, so people with slower computers could turn it off)?

-Pat Murphy

Or maybe I'm the only one who cares about lighting and shadows? Oh well, I'll live.

I vote for directional lighting, otherwise the landscape just ends up looking bleached, having layers of light and dark against each other is what makes the outdoors really beautiful.

yah, shadows are cool, I would like them indoors too. I figure this is probably in the works, but yet to be implemented kinda thing.

BBC

Yes, shadows can be done better, and is a client side computation... but it is a CPU-resource problem. Shadows are nice, but usable frames-per-second is a _must_.

Who wants 0.5 frames a second on their P4 w/ GeForce_4_4600?

Well really... eventually graphics cards will have wonderful hardware acceleration for ray-tracing and volumetric occlusion. When that happens video games (and Second Life, of course) will be fast approaching photo-realism.

Don't most modern games have of some kind of shadowing where lights don't go through objects? What I mean is that if there is a light on one side of a wall, objects on the other side of the wall don't get illuminated. Maybe this isn't true "shadow casting," but as far as I can tell SL doesn't do this, the light in my house illuminates everything in the vicinity, including the ground outside. This seems kind of weird, but I'm not a 3d graphics programmer, just a 3d graphics artist.

-Pat Murphy

Yes, we don't do shadow casting like other games. This is because other games have the entire set of "level data" available during development. When each level is done, they run a very time consuming (days of CPU time) process to patch up all the textures with good looking lighting.

In Second Life, anybody can put an object anywhere at any time. So the client does the best it can. Currently there are some bugs in our shadow code, which we're working on. The lighting model is pretty simple -- big shapes are supposed to cast shadows on the ground (but may not, due to bugs), and lights brighten things up in a radius around themselves.

So, yup, boxes don't cast sharp shadows on other boxes. If you really want the effect, you can make a custom texture with the shadow "baked in" and apply it to the object.

Cheers,

James

Old style shadowed games used precomputed lighting and shadows baked into the textures as James mentioned. Other techniques are used for flickering lighting and such. There are a lot of clever tricks that can be employed when the level content is static or mostly static (for lighting and visibility culling) to make a game fast.

Some modern games are coming out with new shadow technology, however the level content is still mostly static, so they can use extra CPU cycles for better shadows on small subsets of the objects/content.

Ray-tracing is the way to go, but is still in the future. We do limited ray-tracing and occlusion culling for lights, but can't crank it up yet.

some day, i will be able to walk through the valley of N7, and as the sun sets, the shadows will track me down, envelope me, and all that you will be able to see will be my hair and eyes...

seriously though, I don't know why I was worried about shadows, I live 20m beneath the sea, not much light gets down there you know

This would be cool.

I saw a demo of this in EQ2 and it looks freaking fantastic. Basically light coming in from the bars of a window which overlay on top of objects which lie in the shadow path.

I tried to get this to work in SL, but couldn't. Is it just my video card or can you do this in SL?

When Radeon 9800s and geForce 6800s are $60 US, this will become feasible.

Or, it could be included as an option on the client side for 1.6/1.7....

In the mean time, Jimmy Thompson has done a sort of mini-tutorial in the texture forum on how to fake it... at least on your own property.

How does EQ2 do it? The machine I was on wasn't that advanced.. The shadows weren't 'baked in' as Andrew talks about above.. they really are casting against dynamic objects.

Yeah, those tricks Jimmy comes up with... pretty tasty stuff. It's a workaround and not the same as having the features implemented from the getgo, but the results show themselves and look pretty awesome, i.e. in the art gallery he did and even in Sim Horror before that.

*looks at original date of thread... whoa!*