T2 Screenshots.

Game Engine, Players & Web Plug-in, Virtual Reality, support for other engines

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alien-xmp
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T2 Screenshots.

Post by alien-xmp » Mon Aug 09, 2004 4:17 pm

Multipass shadows:
Lights will fill in other light's shadows.
Image
Big version

Playing with the accum buffer:
Image
Big Version

Anaglyph stereo:
Image
Big Version

GLSL Shaders:
Image
Spotlight shader, toon shader on the alien, and OrenNayar Blinn on the girl.
Big Version

ada89
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Post by ada89 » Mon Aug 09, 2004 5:14 pm

:shock: :shock: That's it, i am going to buy a new gfx card!!!

jm
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Post by jm » Mon Aug 09, 2004 6:09 pm

the shadows is realy cool. I want it :cry:

jm

Doc_Holiday
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Post by Doc_Holiday » Tue Aug 10, 2004 3:26 am

:shock: I cant belief my Eyes.
Is it possible to bake such Shadows to a Shadowmap for static Objects?

alien-xmp
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Post by alien-xmp » Tue Aug 10, 2004 4:35 am

Doc_Holiday wrote::shock: I cant belief my Eyes.
Is it possible to bake such Shadows to a Shadowmap for static Objects?
Not currently. The 'shadowmap' is simply the z buffer from the light's point of view. So, if you set a lamp as a camera, and use the show z sequence plugin, you will get a shadow map.

Panther
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Post by Panther » Tue Aug 10, 2004 9:49 am

I can't beleive it... 3 replies, and not one of them said thanks !!! :wink:

Great work ( as always ) Kester, can't wait to see what you come up with next - The shader stuff looks very promising. :)

Will you be attending the Blender Conference this year ???

alien-xmp
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Post by alien-xmp » Tue Aug 10, 2004 11:56 am

Panther wrote:Will you be attending the Blender Conference this year ???
Not the Euro one - the continent of Asia thwarts me again!

I'm considering the .au one though.

dmao
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Post by dmao » Wed Aug 11, 2004 5:06 pm

:shock: Excellent work as always! I can't wait to play around with this (and buy a new video card :cry:)

I remember a while back on Elysiun you asked for feedback on the shadow mapping. I had nothing to add back then, but I checked out the Unreal Engine 3 the other day and noticed they say they oversample their shadow buffers 16x. It looks great (of course :)) and might be a good solution to the aliasing problem?

http://www.unrealtechnology.com/screens/SoftShadows.jpg

z3r0_d
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Post by z3r0_d » Wed Aug 11, 2004 11:16 pm

dmao wrote::shock: Excellent work as always! I can't wait to play around with this (and buy a new video card :cry:)

I remember a while back on Elysiun you asked for feedback on the shadow mapping. I had nothing to add back then, but I checked out the Unreal Engine 3 the other day and noticed they say they oversample their shadow buffers 16x. It looks great (of course :)) and might be a good solution to the aliasing problem?

http://www.unrealtechnology.com/screens/SoftShadows.jpg
were you aware that the unreal 3 engine is slow on current hardware?

as in, unusuably slow...

I think this is quite an improvement [over the other shadow method], and as I am not working on anything better [for runtime graphics] at the moment I have no reason to complain.

R2Blend
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Post by R2Blend » Thu Aug 12, 2004 3:25 am

All I have to say is wow.

wow. :shock:

With all of those combined, and all of the bugs fixed, and many more logic bricks, then Blender's engine would be PERFECT. :)

levon
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Post by levon » Thu Aug 12, 2004 12:01 pm

R2Blend wrote:All I have to say is wow.

wow. :shock:

With all of those combined, and all of the bugs fixed, and many more logic bricks, then Blender's engine would be PERFECT. :)
what new logic bricks do you think could be put in to the game engine?

levon
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Post by levon » Thu Aug 12, 2004 12:02 pm

R2Blend wrote:All I have to say is wow.

wow. :shock:

With all of those combined, and all of the bugs fixed, and many more logic bricks, then Blender's engine would be PERFECT. :)
what new logic bricks do you think could be put in to the game engine?

dmao
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Post by dmao » Thu Aug 12, 2004 4:49 pm

z3r0_d wrote:were you aware that the unreal 3 engine is slow on current hardware?

as in, unusuably slow...
Lol, yes... To be fair though, the Geforce 6800 is current hardware ;). In any case, the shadowmapping in UE3 isn't what kills the speed, rather the fact that every surface has per-pixel lighting.

I tried out shadowmapping in T2 and it was very fast, even on my modest Geforce 3 ti200. Having the option to oversample it to 4 or maybe even 8x would still give acceptable performance.
z3r0_d wrote:I think this is quite an improvement [over the other shadow method], and as I am not working on anything better [for runtime graphics] at the moment I have no reason to complain.
Every method has its pros and cons. Buffered shadows are fast and great for when you want a localized soft shadow, but you can't light a large area with them. Conversely, stencil shadows (assuming that's what you meant) are like raytraced shadows and can shadow large areas very accurately, but they're always perfectly sharp and can get very slow with complex geometry.

Like the raytraced and shadow buffered shadows in the linear part of Blender, there's an advantage to having both.

Btw, I wasn't complaining at all. Kester asked for feedback on the usability of the shadows, esp. with respect to aliasing, and I offered a suggestion.

alien-xmp
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Post by alien-xmp » Fri Aug 13, 2004 2:09 pm

The shadow method (shadowmapping) is the same as the previous shadows, only I'm not taking any shortcuts. :wink: The GPU generates a mask, which is applied to the diffuse & specular lighting passes.

Soft shadows are a bit harder - I tried doing multiple samples in a shader, but it didn't look too good.

Shadow mapping vs stencil shadows:

Shadow Mapping:
+ No geometry processing
+ Works with alpha stenciled polys (tree leaves)
- Aliasing
- No point light sources (needs 6 light render passes, and 6 texture slots per light! GeforceFX/Radeon9500 can only do this with a shader)

Stencil Shadows:
+ Point light sources
+ No aliasing
- Meshes must be manifold
- Expensive geometry processing

But there is no reason for making a choice! Both methods can be used at the same time.

z3r0_d
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Post by z3r0_d » Sat Aug 14, 2004 3:08 am

alien-xmp wrote:The shadow method (shadowmapping) is the same as the previous shadows, only I'm not taking any shortcuts. :wink: The GPU generates a mask, which is applied to the diffuse & specular lighting passes.

Soft shadows are a bit harder - I tried doing multiple samples in a shader, but it didn't look too good.

Shadow mapping vs stencil shadows:

Shadow Mapping:
+ No geometry processing
+ Works with alpha stenciled polys (tree leaves)
- Aliasing
- No point light sources (needs 6 light render passes, and 6 texture slots per light! GeforceFX/Radeon9500 can only do this with a shader)

Stencil Shadows:
+ Point light sources
+ No aliasing
- Meshes must be manifold
- Expensive geometry processing

But there is no reason for making a choice! Both methods can be used at the same time.
... I feel I should ramble about my knowledge of the shadow methods

there are more than just those two, and variations on them

you probably could've guessed the rendering to a texture, and mapping that onto [just landscape] geometry, and projecting blobs onto the landscape...

but anyway, here are a couple sortof variations on those methods

an indexed shadow map. it suffers from problems of both methods, but will work on low end cards [even those without stencil buffers]. the method is as follows
render the objects from the lamp's point of view onto a texture, but altering the alpha channel only. make it so that further objects [if you want self shadowing make this convex regions of faces] end up with a lower alpha value, closer objects have a higher alpha value.
then, render this texture [so the colors are essentially a lamp cookie I guess they call it] projected from the lamp as adding to the existing faces, but also use alpha testing. when rendering each region of faces, change the alpha testing value.

exe and code:
http://www.daionet.gr.jp/~masa/ishadowmap/
[there is a link to an english .txt which explains it better there]

now then, for stencil shadows there are the more understood things (carmak-reverse instead of traditional stencil changing), but there are a couple other interesting things

one is a way to accelerate calculating shadow volumes (if done on a cpu, I don't know if it can currently be done on a gpu because of the numbers of jumps required)
pretty much you store an edge structure of the mesh, and on each frame you decide to do this you find the edges which are no longer the shilouette edges and traverse the mesh in the proper direction until you find the result.
I don't know where to find the paper right now


the other interesting thing is to do stencil shadows, but using an alpha channel instead of a stencil buffer. instead of adding 1 you multiply by two, and subtracting 1 you divide by two. [somehow I figure this could cause problems with an only 8 bit alpha channel [especially because you are essentially shifting left and right], but I haven't tried it myself and I figure they would have experienced them if it did].

well anway, one of the things this allows is that you can [usually have to somewhat anway...] render the shadows at a lower resolution than the screen [you'd usually have to because the screen isn't usually a square power of two]. this reduces the demand on fill-rate, with an understandable sacrafice in shadow quality.

http://www.vis.uni-stuttgart.de/~roettg ... HADOWS.PDF


while searching for these things I found a whole bunch of other stuff... I was hoping to leave my computer after i finnished writing this post... :(

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