Real Time Soft Shadow Demo

[Cryect]

Got curious looking around at the state of the art in Real Time soft shadows and found these interesting demos here. I find they are buggy as hell on my computer (basically if I try to change anything in the engine it crashes on me forcing me to change the objects it loads by changing filenames).

The physics in the demo are nice as well. You can pick up items with left mouse and right mouse (left mouse button when you click and hold it kinda makes it drag around while right mouse button when you click and hold pulls the object towards you and when you release you throw/kick the object wherever you are looking).

Its fun taking the cardboard boxes and knock over a tower of them then watch the soft shadows react realistically!

http://www.ce.chalmers.se/old/staff/tomasm/soft/

 

[Mintmaster]

I was looking at those papers just a few days ago. Their technique is very interesting, but there are a few flaws.

It's silhouette based, so you can get some sudden drastic changes in the shadow as the light moves (because the edge casting the soft shadow jumps). Parts of a model that are behind other parts can also create sudden changes to the shadow once they are just barely visible to the light.

I also figured out a way to make the pixel shader way faster (several multiples faster than even their optimized method), but I want to try it out properly before I share it. Didn't notice they had source code, so it should be pretty easy now.

If these soft shadow methods lost the drawbacks I mentioned, they could become quite effective and popular.

 

[Cryect]

Yeah, when I was reading the paper noticed that those issues should occur as well. It seemed to me that you should be able to fix the issue by doing a few multisamples to more correctly define the soft shadow area. Not sure how many would be optimum for avoiding those issues though. Was planning to look at trying out modifying it with that.

Also, unfortunately whenever almost every pixel on the screen is a soft shadow pixel, hehe the framerate dies practically. But, seems to me a couple years this method with modifications would be very practical for usage in games.

Some images below of some of my playing around with it. And I would definately be interested in seeing your demo when you are done Mintmaster ^_^

 

[991060]

Looks like there's a bug in the DirectX version demo, after clicking "2", the light source changed to flat square, but the shadow completely messed up.
http://bbs.gzeasy.com/index.php?act=Attach&type=post&id=151819

 

[Cryect]

Heh I just have to say they write buggy code. I didn't try the DirectX version after couldn't get the OpenGL source to compile (didn't like my version of MSVS and I didn't feel like figuring out what it was doing that was screwing up the queue header file).

Edit: BTW I think those might be the shadow penumbras it put in and was just screwing up.