HDR Graphics...An amazing technology.

[Spiffae]

First, read this:

http://www.anandtech.com/video/showdoc.html?i=1656&p=10

Ok. There is much more to know about HRD technology than that single page explains, but that covers the basics. I just want to explain an idea i had for HL2, if not for a mod.

Gabe Newell has said on a couple occaisons that High Dynamic Range technology had been added to HL2. It's a DirectX 9 only feature, and he never really said how it was being worked in. Here's a brief description.

You're walking around with a camcorder. when you walk outside, everything looks fine. the sun shines on the street, and the video looks just like what you see. when you point that camera at the entrance to your house, however, all the camera can see is blackness. walk into the doorway, and it will be black right up until you walk in the door, at which point the camera will change it's exposure and things will lighten up until you can see indoors again. point the camera from inside the room at a window or door? it will be blown out completely white.

why is this? because the world has a high dynamic range, (like HDR graphics) and the camcorder has a limited range (like your monitor). If everything in HL2 was programmed with a realistic range of values, with the sun at the brightest, and dark night at the darkest, then with HDR technology, it's possible that we could get a camcorder (or human pupil) effect. this would be a HUGE step in the direction of photorealistic graphics. i don't really know how to explain this in a better way, but i feel like the potential is enormous.

If you don't understand, forgive my excited rambling, but if you do, i think you'll realize the significance of HDR. I've e-mailed Gabe twice about this, and both times i've gotten no response.

I submitted a question to the interview thread as well.

 

[FoB_Ed]

hmmmm fascinating

 

[nsxownzme]

hi

 

[Axxron]

I can see it now... Anyway, thanks for the link.

 

[Xtasy0]

doesnt that japanese, now translated to english interview say something about HDR, and points out a few screenshots that display HDR?

 

[LoneDeranger]

not to mention it probably also improves performance as you don't have to render what's inside the house.

 

[alco]

So, it is in HL2? Lighting is essential to graphics. Glad to hear Half-Life 2 will boast something this advanced.

 

[Xtasy0]

heres that japanese translated to english interview, it mentions HDR on the first page.

http://www.4gamer.net/specials/hl2int/hl2int_e1.html

 

[Spiffae]

here's a normal image

 

[palindrome]

Originally posted by nsxownzme
hi

hello

 

[Spiffae]

thanks for that interview...looks like pupil dilation won't be in...a mod then?

here's my conception of HDR

 

[kelisis]

Wow, that's very interesting and cool....You got me another topic to rant about.

 

[FictiousWill]

Actually I might find that intensly annoying. People's eyes adjust differently, and unless the effect was done very expertly, I think it could be a detrimental effect.

 

[Guest]

Besides, wont your eyes automatically adjust to the bright outdoors in HL-2 anyways? Why should they have to code it in?

 

[CordlessPen]

I first feared this may be just like Lens Flare, a nice-looking effect that serves no real purpose because the human eye is not a camera (have you ever seen a lens flare effect without a camera?), but after reading, it makes sense, and it souds like it has a great potential.

 

[kelisis]

Yes, if they lead the technology in the right direction, it could be revolutionary, but if not it could turn out to totally be useless.

 

[Spiffae]

Originally posted by schweppes
Besides, wont your eyes automatically adjust to the bright outdoors in HL-2 anyways? Why should they have to code it in?

because your eyes don't adjust to the outdoors in hl2 because they are dim dim dim. every tried playing a game with sun shining on the monitor? impossible, right? that's because the sun is bright, causing your pupils to contract, and then you can't really see the dim screen. computer screens are extremely dim. look at the sun in any game. is it bright? does it hurt your eyes? no. because it's about a quarter as bright as a light bulb.

 

[Anthraxxx]

Originally posted by CordlessPen
I first feared this may be just like Lens Flare, a nice-looking effect that serves no real purpose because the human eye is not a camera (have you ever seen a lens flare effect without a camera?), but after reading, it makes sense, and it souds like it has a great potential.

Have I ever seen lens flare without a camera? Yes. I have. Of course, I wear glasses and that is why I do get lens flare when looking at something bright, like the sun. Correct me if I'm wrong, but doesn't Gordon Freeman wear glasses too? So it would be correct for there to be lens flare in HL2 because of Gordon's glasses....

 

[Guest]

wow dudde... thats like the best inerview right thanks!

 

[Anthraxxx]

Originally posted by kelisis
Yes, if they lead the technology in the right direction, it could be revolutionary, but if not it could turn out to totally be useless.

HDR technology in games would add to the immersion level of games adding to the realism....having something in-game that you have actually experienced first hand definitely(sp?) adds to the overall effect.

 

[dscowboy]

Ok, everyone should check this out for a great application of HDR. Here's the movie:
http://www2.ati.com/misc/demos/ATI-9700-rnl-Movie-v1.0.mpg
And here's the page with the link to the exe on it (if you own a 9700 or 9800)
http://ati.com/developer/demos/r9700.html

See how the light has a much more realistic effect? Especially when other objects pass in front of it. Essentially, HDR allows differences in light intensity to be realistically modeled.

 

[Guest]

Originally posted by Anthraxxx
Have I ever seen lens flare without a camera? Yes. I have. Of course, I wear glasses and that is why I do get lens flare when looking at something bright, like the sun. Correct me if I'm wrong, but doesn't Gordon Freeman wear glasses too? So it would be correct for there to be lens flare in HL2 because of Gordon's glasses....

OWNED haha he does wear glasses

 

[Spiffae]

those ATI demos are modeled on the work of Paul Debevec. Look up his SIGGRAPH work for good explanations and implementations of HDR.

 

[mad max]

The image rendered in HDR looks good to me. Its essentially offer a wide range of brightness levels (as the Anandtech's article says each color component can now be represented by, in effect, an unlimited number of values, giving you a truly dynamic range of brightness).

 

[Xtasy0]

also, check this out, its a real time demo, you need a DX9 GPU to run it, http://www.daionet.gr.jp/~masa/rthdribl/

DX9 Real-Time High-Dynamic Range Image-Based Lighting

 

[Spiffae]

Originally posted by Anthraxxx
Have I ever seen lens flare without a camera? Yes. I have. Of course, I wear glasses and that is why I do get lens flare when looking at something bright, like the sun. Correct me if I'm wrong, but doesn't Gordon Freeman wear glasses too? So it would be correct for there to be lens flare in HL2 because of Gordon's glasses....

well, actually, no, you probably haven't. Lens flares as they have been typified in games are the product of a bright light (the sun) shining through a multi-element lens. If you've ever taken apart a video camera or SLR lens, you'll see that there are between 3 and 20 glass elements between the film or CCD and the front objective lens. every time the light passes through, a tiny percentage of that light is reflected, rather than being refracted. in normal situations, that tiny percentage is invisible, but the sun is so bright that .05 percent of the sun's brightess is still enough to be printed on the film or video. a realistic rendering of the sun's effect is seen in IL-2 sturmovik. from first person view, if you look at the sun, there is a huge glare effect, but no further elements. there is just a big glare around the sun. in third person view, the sun's glare is still present, but the flare also has many added elements to simulate a true camera flare. check out the demo if you want to see more.

to get back to my main point you can't see a lens flare with your naked eye, glasses or not. (well, unless you were looking through an SLR lens.)

 

[Spiffae]

notice how this looks very bright? it's no brighter than the white text on your desktop. it's just the glare effect that can fool your eye. imagine if some weapon in HL2 had an effect like this. you'd squint when it went off! that'd be incredible!

http://www.daionet.gr.jp/~masa/rthdribl/Image/27.jpg

 

[Tyl3n0L]

Originally posted by palindrome
hello

Hey

 

[dscowboy]

It's interesting that the japanese article said HDR would be in HL2 because I don't recall seeing anything in the videos that looks like HDR. Maybe their use of it is more subtle.

 

[Spiffae]

or maybe they aren't showing anything to us because they want to surprise us. That realtime directx 9 demo that someone linked to shows just about everything i was trying to explain.

 

[Apos]

Wait, I'm confused. I thought that HDR was designed to FIX exactly the sort of artifacts that the OP describes it as CREATING. HDR is supposed to fix the phenomenon of over or under exposure, not create it, as far as I knew.

 

[Apos]

I'm also confused by that article (at least they TRIED to translate it, even if it's really about as confusing as the BABELFISH version). It says that self-shadowing isn't in the game... yet we've heard several times that it is, and that models self-shadow. If I understand the feature correctly, we can even SEE it happening on characters like Alyx and Kliener in the lab video.

 

[jhero]

ZEN:
When I see "Half-Life2" graphics, expressions like HDR rendering(*1) will be seen in some places. May I think that "Half-Life2" engine has employed HDR rendering technique?

BVB:
Yes. About the HDR rendering, it was implemented by the cooperation of a certain GPU vender, although I can't tell the vender's name. That's why HDR rendering-expression will be seen here and there when you play "Half-Life2".


My bet is on ATi.

 

[RoyGBiv]

it doesn't have self shadowing. the kleiner vid you just see the models being illuminated but not casting shadows. and it sounds like when it is dark it's using a different darker texture, but who knows with that one.

 

[x84D80Yx]

this whole thing is kinda confusing...i got a g4 ti4200 so i dont have dx9. i guess i wont have this HDR stuff.

that lil video clip was good...but wouldnt it get annoying being blinded by the sun? i think thats why games dont put it in, even tho its really realistic.

design decision, not a technical limitation?

 

[nw909]

Originally posted by x84D80Yx
this whole thing is kinda confusing...i got a g4 ti4200 so i dont have dx9. i guess i wont have this HDR stuff.

that lil video clip was good...but wouldnt it get annoying being blinded by the sun? i think thats why games dont put it in, even tho its really realistic.

design decision, not a technical limitation?

Games making you blind from looking at the sun would have a whole lotta lawsuits on their asses.

 

[jhero]

Games making you die 50 billion times will have a whole lotta lawsuits on their ass. Damn dirty Raven Shield :flame: :angry:

 

[Apos]

Gabe, in the original e3 vids, says that the gman is "self-shadowing"

That video makes my player crash. Can anyone tell me what it shows?

 

[dscowboy]

Apos, the models are surface shaded but they don't cast shadows on themselves. There's a distinct difference. Surface shading works by determining the difference between the lightsource vector and the surface normal. So surfaces facing away from the light source are automatically dark, and surfaces facing toward it are automatically light. If the models could self-shadow, G-man's nose could cast a shadow on his face, which would be separate from the surface shading.

You could see self shadowing in the Doom3 alpha. The doom-guy's face had distinct shadows on it from his nose and eyebrows. tbh it looks kind of stupid, because the surface shading is so blended and the shadows are so sharp, they didn't match up at all. Dynamic shadows in HL2 appear to be sharp also, so self-shading models (or at least faces) would look kind of lame.

On a side note, it appears that the smoothness of the surface shading for the HL2 characters is the result of normal-mapping their faces (but not the rest of their models). Normal-mapping only works in DX8 and 9, so beware DX6 and 7 people, the faces in HL2 will probably look blocky like they do in most games.

 

[RoyGBiv]

On a side note, it appears that the smoothness of the surface shading for the HL2 characters is the result of normal-mapping their faces (but not the rest of their models). Normal-mapping only works in DX8 and 9, so beware DX6 and 7 people, the faces in HL2 will probably look blocky like they do in most games.

they will probably look like alyx did in the making of video when you see her with no eyes in xsi... flat.