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Half Life 2 Graphics Technology

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Has anyone seen the half life 2 demos? What´s going on in there ? Those demos were incredible! Anyone has any idea about what were the gfx techniques used in that game? There is some kind of cool out of focus effect. The lighting is somewhat different ... per vertex ? per pixel ? All I know is that the game looks great... and the physics ....

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I loved the demo, but a few things (good and bad) struck out in my view:

The Good:
The water rendering was abso-fucking-lutely amazing. It had proper light refraction, and just looked amazing.
The lip-syncing system looks great in practice. Each face has ~40 muscles (whatever the demo said), and they obviously put a lot of work into the system, and it shows.
The material system in place (wood acts like wood, metal acts like metal) was also very incredible.
The AI seems to be very good, as does the "scale" of the game.

The Bad:
The enemies did NOT react correctly after being shot. I watched the demo as the player shot one of the zombies in the torso, and the enemy made a general "jolt backwards" animation, and then I witnessed an enemy getting hit in the leg, and it had the same general "jolt backwards" animation.
Doom 3''s "blood" system blows HL2 out of the water. Their blood looks amazing, and when it splats on to the wall, it looks totally realistic. This was best witnessed when playing the leaked alpha that was out a while back, not that I tried it or anything...
Other than the water and facial animation, nothing graphically "stood out" for me. I mean, everything looked good, no doubt, but it just wasn''t amazing. I mean, the lighting was pretty traditional, the textures were standard, the character models were alright, etc. Nothing was simply awe-inspring.

However, the rest of the game (and its accompanying engine) looks very rugged, and well-done. Valve put a lot of work into the engine/game, and it really shows. However, try to remember that the Valve guys have probably been working on this engine for years (under very tight wraps, obviously), so don''t think they whipped it all together in a year or two.

Trent Polack
trent.codershq.com
trent@codershq.com
Author of Focus on 3D Terrain Programming

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I was quite ammused by the fact that everyone in the IRC channels i live in apon seeing the HL2 videos seemed to go into some kinda orgasmic frenzy... at times i wonder if i''m the only person on the planet who isnt getting like that

As a side note, its HW2 and GC2 i''m looking forward to the most this yeah, both look lovely and i really enjoyed the first games in the series for ''em

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See my post in the lounge regarding my thoughts on the lighting of half-life 2.

quote:

Look in e32k3-halflife2_pce32003)1dn_wt.mov, 3:13 into the movie, in the room where there's a camera tripod pointed at the gman. Notice that the tripod doesn't cast a shadow. Now, notice that when the headcrab jumps at it, the headcrab and the camera do cast shadows. This occurs in other scenes as well - rather than having the lights that light the level geometry cast chadows, a "virtual" shadow caster is selected, and shadows come from that. For example, in the intro of that same movie, where he throws the mattress into the water, the intitial light doesn't cast shadows onto the barrels - the angle is wrong.

The gun muzzle flashes are really bad, as far as lighting quality goes. It looks like an alpha blended sphere - no lighting term evaluated, and definitely no shadows. Compare that to the Doom 3 video from E3m about 1:55 into it, where a monster makes a fireball to throw at you. The fireball causes the monster to cast a shadow! And it's a real light source - the lighting equation is evaluated for it. Look again at 2:24 into the movie for the same thing. Monster throws a projectile, which lights up the scene correctly and casts shadows.

Does that make Half life 2 a bad game? Of course not. I'm going to buy it and play it, and I suspect it will blow me away, just like the first one.

My point is that Doom 3 has a superior lighting engine. As a computer graphics programmer, it really stands out to me.



The materials are very cool. Physics effects are well done. I liked their shaders, but the Doom3 lighting just blows it out of the water.

[edited by - sjelkjd on May 27, 2003 1:33:02 AM]

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The physics and the overall production values blow me away. The lighting looks like standard precomputed radiosity lightmaps for the most part, although the characters supposedly use some per pixel stuff (normal maps.)

The combination of the size (evident in the dune buggy video) and the detail of the levels was pretty impressive. I wonder if they''re still using a standard BSP\Portal engine or something different?

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quote:
Original post by Fistandantilus
What´s going on in there ? Those demos were incredible!

Anyone has any idea about what were the gfx techniques used in that game?

There is some kind of cool out of focus effect. The lighting is somewhat different ... per vertex ? per pixel ?


Some guesses based on the current "flavour of the month" techniques for realtime graphics:

- Depth of field ("cool out of focus effect"?), realtime methods and sample code presented by IHVs like nVidia a few years ago.

- HDR (High Dynamic Range). cf. Paul Debevec: http://www.debevec.org. Though from the screenshots and low res MPEGs it doesn''t seem to be being used too much.

- Some nice effects/tricks used in Wreckless presented at GDC. Masaki Kawase, (http://www.daionet.gr.jp/~masa/) revealed how some were implemented: http://www.daionet.gr.jp/~masa/column/2003-03-21.html [page is in Japanese, presentation is in English]


- Spherical Harmonics, Irradiance Maps, Image Based Lighting etc:

"Ramamoorthi,R., Hanrahan,P. 2002. Frequency Space Environment Map Rendering. SIGGRAPH 2002, p517"
http://graphics.stanford.edu/~hanrahan/

"Sloan,P-P., Kautz,J., Snyder,J. 2002. Precomputed Radiance Transfer for Real-Tim Rendering in Dynamic, Low-Frequency Lighting Environments. SIGGRAPH 2002, p527"
http://research.microsoft.com/~ppsloan/

"Green,R. 2003. Spherical Harmonic Lighting: The Gritty Details"
http://research.scea.com


quote:
and the physics ....


The use of physics middleware comes of age: http://www.havok.com


--
Simon O''Connor
Creative Asylum Ltd
www.creative-asylum.com

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That''s probably exactly it. I am very glad that Doom3 is making this step though - hopefully it will wake people up and make them see how awesome correct lighting is. Stencil shadows ARE expensive, but a unified lighting model is worth it.

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I''m impressed by Half-Life2, much more appealing to me than yet another IDSoftware game... (seen enough doom and quake for a long time)

-* So many things to do, so little time to spend. *-

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Guest Anonymous Poster
id Software leads, others follow. Although, since id lost Romero, Steed, American McGee and one or two other top bods id''s products have turned more into graphics tech demos more than games.

Quake 1 was when id was at it''s peak I feel, the graphics, physics, sound, extensibility, net code of the game were absolutely superb, the only thing not so solid at the time was the story line, but that was made up for by the billion or so fun and quick to download mods.

Valve on the other hand always sucked and still suck with their buggy engines (What the hell was that half assed attempt at changing the mod source to be object oriented - either do it right, or leave it procedural). Valve has always had cool ideas but their implementation has been appalling, I''ve always been left with a feeling of extremely buggy, poorly written games when I''ve played anything from them, I think they''ve done like many newer game dev companies and try to fit too much in without making sure it all works properly before moving onto the next cool feature. I''m still waiting for TF2 from them, it''s only what, 5yrs late now?

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http://gameinfowire.com/image.asp?iid=18580&gid=712&pg=&pid=6

The water isn''t all that fantastic. It looks awsome, but it seems to behave very surrealisticly. Notice how the surface of the water is unaffected when touched and how the water''s edge is always a perfectly straight line.

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I was looking at the screenshots in the site above , and one of then shows one ally (I believe) shooting at some kind of bug (I believe) behind him the gun fire illuminated the walls in what appeared per vertex shading. The gun in the ally hand didn´t cast any shadow.

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Anyway, it's the whole engine that gives you the 'appeal'.
Physic rocks, graphics are good, art is good...

I've seen the out of focus effets made with fragment programs, on some kind of plane. Not sure exactly how it was done, it's based p, in-game image investigation.

(Fistandantilus : DragonLance fan ?)

-* So many things to do, so little time to spend. *-


[edited by - Ingenu on May 27, 2003 2:59:40 PM]

[edited by - Yann L on May 27, 2003 6:30:45 PM]

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I'm guessing half life 2 uses perspective shadow maps with one directional light source, which is somewhere up in the sky. This would provide good performance, and look somewhat reasonable outdoors. It would also explain some of the shadow anomolies I saw.

Unfortunately the interview posted doesn't bother asking any interesting technological questions.


[edited by - Yann L on May 27, 2003 6:31:31 PM]

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The Half Life 2 video really made an impression on me, though there are a few things that caught my mind.
First of all, it lagged a few times Not really what I would want to see after seeing no lag in Doom3-videos.
I wonder how this "apply-and-play" thingy works for materials, is it based on what the textures "look like"? What if we have a metallic-sprayed wooden plank?
The graphics aren''t very close to what we can see in Doom3 (or Virtual Tales'' stuff ), but still, it''s way ahead of the games today.

Other than that, and perhaps a few more things, Half Life 2 is really, really nice. The lip-synching was superb as was the physics interaction.
Still, I don''t wanna say too much about the game, I''ll wait till Nov when it''s out...

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quote:
Original post by Rian
http://gameinfowire.com/image.asp?iid=18580&gid=712&pg=&pid=6

The water isn''t all that fantastic. It looks awsome, but it seems to behave very surrealisticly. Notice how the surface of the water is unaffected when touched and how the water''s edge is always a perfectly straight line.


Hmmm couldnt see any water on the page above, however the page it links to does have some fire on it... and it looks... i dunno.. out of place in the scene... more real i guess while the rest of the scene doesnt match upto it...

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You two (you know who you are), would you mind fighting out your personal disputes via email ? Let''s keep this thread flame free and technical. Thanks.

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My 4c:
Because of the above comparisons with Doom 3, I''ll tell my opinion. Doom 3 looks and feels like yet another tech-demo - sure in Q1 there was much atmosphere, it was one of the first truly 3d games and ambient sounds rocks. Q2 bored me to death. Dunno about Doom 3, but I can''t see any gameplay there, again - just walkn'' shoot. Graphics - stencil shadows on and over everything + good bumpmaps. Too dark, too narrow, too static.
I like it, and I''ll play it, but in comparison it looks nothing that can stand even close to what was shown from HL2.
Very nice lighting (even without proper shadows characters looks real), very, I repeat very complex and good-looking design of the levels. The overall look is about something well polished, well scripted and the sound is great. Physics rocks too.
And the single fact that it don''t cast shadows on everything and don''t shade all geometry the same way can''t drag me away from that marvelous game. And for masses that really matters nothing, the tech behind is important just to get the proper look of the game, don''t you think?
Of the titles I saw, Halo 2 too catches my attention, and I think it beats Doom 3 too (it looks like movie sometimes).
Btw, talking about ''artefacts'' - don''t you think those particles (smoke trails) from weapons in Doom 3 are lame?
Large flashes (like in CS with fusion pack) are much-much better and convincing...

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Zemedelec
*********

and if i going to play a shooter for a while, i stareing at my monitor and got something like a "tunnelview" especially in some titles from Id. u said it...just walkn'' shoot.

so i''m waiting for half-life 2 too and i hopeing its just as good as halflife(the feeling, story etc.)

bye there

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Guest Anonymous Poster
quote:
Original post by Anonymous Poster

Valve on the other hand always sucked and still suck with their buggy engines (What the hell was that half assed attempt at changing the mod source to be object oriented - either do it right, or leave it procedural). Valve has always had cool ideas but their implementation has been appalling, I''ve always been left with a feeling of extremely buggy, poorly written games when I''ve played anything from them, I think they''ve done like many newer game dev companies and try to fit too much in without making sure it all works properly before moving onto the next cool feature. I''m still waiting for TF2 from them, it''s only what, 5yrs late now?


Actually, i wish you can come out with something better :D

Secondly everything they did not have time too fully implement and TEST in the engine as been pullet out ( a year ago ) engine been made since 4 year, and they will be in the already announced Half-Life III :D .... and imagine TF 2 with this engine :D ...

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