Question about shadows

[MMhardKy]

A really stupid question but I'm not sure. Sorry if this was discussed before but do the characters in HL2 throw shadows on themself? I cannot see it in the latest DX9 video. I know it doesn't contain such shadowing technology like Doom3, but I think the shadowing in HL2 will be also good. Anybody could explain which "shadowing technology" does HL2 use?

 

[spitcodfry]

Originally posted by MMhardKy
A really stupid question but I'm not sure. Sorry if this was discussed before but do the characters in HL2 throw shadows on themself? I cannot see it in the latest DX9 video. I know it doesn't contain such shadowing technology like Doom3, but I think the shadowing in HL2 will be also good. Anybody could explain which "shadowing technology" does HL2 use?

Half-Life 2 has its own dynamic lighting system...but unlike Doom III, it only affects moving objects such as enemies. Static objects such as telephone poles and boxes do not possess dynamic lighting attributes. So if you put a swinging lamp in a room, don't expect for the shadows of static objects to bend.

 

[LoneDeranger]

Yes, the characters self-shadow. You can't see it in the latest vid because there really are no characters there. It's pretty obvious in Kleiner's lab.

 

[Xtasy0]

i believe it was said that "characters eyes self shadow..". for their faces they have normal mapping which creates the illusion of lightness/dakrness depending on the lighting in the enviroment.

and the characters and any dynamic objects cast a projected shadow, which won't show up on other dynamic objects (unless they've changed that)

 

[LoneDeranger]

There is some proof of dynamic shadows in some videos, where 1/2 of a character is in the shadow, and the other 1/2 is not. Then again, there are ones that don't show any dynamic shadowing.

 

[Xtasy0]

Originally posted by LoneDeranger
There is some proof of dynamic shadows in some videos, where 1/2 of a character is in the shadow, and the other 1/2 is not. Then again, there are ones that don't show any dynamic shadowing.

yeah, but i believe those are shadows from static lights, and not self shadows.

 

[RoyGBiv]

models don't self shadow in hl2.

 

[LoneDeranger]

there is some wierd model-on-model shadow behavior in half-life 2 though (i.e. scanner on top of the table).

 

[Xtasy0]

Originally posted by LoneDeranger
there is some wierd model-on-model shadow behavior in half-life 2 though (i.e. scanner on top of the table).

thats cause the table and the scanner on top of it are dynamic objects, just like characters are, they cant shadow onto each other, not with projected shadows at least..

same with the table and the box that blocks the door in traptown.

 

[LoneDeranger]

yeah. i wonder if there is some way they could detect if one object's shadow is to overlap with another's and then not display it. Hopefully they'll think of something like that.

 

[Athlon7]

Knowing Gabe and company they have Or will.

 

[Apos]

They said that issues with shadows was one of things they were going to work on towards the end. I think their shadowing system is a really good mix of static and dynamic lighting to give the best look for the least performance hit. It gets all the important stuff in (objects can be differentially illuminated by static lights, and they can convicing shadows).

The stuff it lacks is too bad, but a) not as important and b) we don't know for sure that it's not fixable
-Projected shadows on objects certainly hasn't worked in what we've seen (I wonder why not tho: why are objects like tables different than static geometry which can have shadows cast on it?), and it might not.
-Some screenshots have shown problems with multiple overlapping shadows having an additive "overlap" effect, which looks odd. Again hopefully something they can fix (and again, I don't get why it was a problem, technically: why not give all projected shadow outcomes the same darkness value no matter how many are cast on a single spot?)

 

[Xtasy0]

Projected Shadows project the vertices of the occluder onto the ground/wall plane based on the location of the light source

Convex hull of projected vertices form the shadow polygon

The shadow polygon can then be rendered in “shadow” color

The Main drawback of projected shadows is that they only project properly onto flat surfaces

don't ask me i found it on google.

[edit]

heres the link to the PPT in HTML format if anyone wants to read it, it talks about tons of different types of shadowing in games.

http://www.google.ca/search?q=cache...ojected+shadows+static+objects&hl=en&ie=UTF-8



[edit #2]

HEY check this out, this sounds hopeful.

The main feature, of course, is the whole light and shadow system. With the implementation of the light map, dynamic lights, and projected shadows, we were able to create an atmosphere on the PS2 that was true to the essence of the game. The lighting of the character changes gradually depending on the light position and the visibility indicator.

Specifically, the engine supports the following:

* Prerendered vertex color light.
* Real-time light for spotlights and breakable lights (the light map is recalculated in real time when the light is switched on or off).
* Shadow-casting light that casts a white spot on the places it can reach. In the game editor, graphics designers set which objects need to cast shadow and which objects need to receive shadows. By rearranging the rendering pipeline, we are able to render shadows on characters and static objects.

notice the bold parts.. they were able to get projected shadows onto characters, so there is hope, BTW thats from splinter cell preview on gamespot, heres a link http://www.gamespot.com/gamecube/action/splintercell/preview_6024440-2.html

 

[Apos]

I'm just happy that they project seamlessly from the ground up onto a wall. That "lobster" creature's shadow looks great.

 

[Apos]

No, there definately IS hope. One of the Valve team (I forget which) said in the info thread that they would be taking another look at how shadows work before the game shipped: tho they werent making any promises.

 

[Xtasy0]

heres another article about shadows.

http://www.extremetech.com/article2/0,3973,1158311,00.asp

 

[Ahnteis]

My understanding is that shadows on characters is a directX 9 function. So if you have a directX 9 graphics card, you get it. If not, no go.

 

[Joneleth]

there is some wierd model-on-model shadow behavior in half-life 2 though (i.e. scanner on top of the table).

Hot model-on-model action? Where?!

Oh, wait, you were talking about something else... :cheese:

 

[Xtasy0]

Originally posted by Ahnteis
My understanding is that shadows on characters is a directX 9 function. So if you have a directX 9 graphics card, you get it. If not, no go.

no, its not a dx9 feature, they're simple projected shadows, and they can only be cast on static objects [Read: walls and floors]

 

[Apos]

Soft shadows are what are Dx9 only.

 

[Xtasy0]

Originally posted by Apos
Soft shadows are what are Dx9 only.

yes.

 

[JaG]

it was noticed in some early screenshots that the weapons in HL2 do not cast shadows (i know: the bugbait demo is at least e3 old)

it seems not to have been fixed, as you can see in the attached shot

only the character cast the shadow but not the weapon he is holding

hopefully also they get rid of obvious clipping issues before they ship the game

 

[Dagobert]

Characters and objects in Half-Life 2 do not self shaowd, as the system is projected textures which does not allow this function. However the light sources for the shadows can move and we would see the resultant change in the shadow.

Self shadowing is a DX8 function.