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View Full Version : Odd shadows in Doom 3 - EnPron


Wavern
08-13-04, 01:21 PM
In the Enpron level, you meet up with a soldier that gives you an access card of some sort (transmission card?) and soon thereafter gets eaten by a demon. In that same room, there's an area with a large shadow of an X on it. Looking up shows you that 2 beams with a light above them creates this X shadow. Makes sense, right?

Take a look at these screenshots. I thought shadows were 100% dynamic but this is the 2nd case I've seen where they seem to be painted on.

http://www.wavern.com/hosted/images/shot00009.png
http://www.wavern.com/hosted/images/shot00010.png
http://www.wavern.com/hosted/images/shot00011.png

Ludic
08-13-04, 01:23 PM
The game isn't perfect, but it doesn't appear that you're using "high" quality, which may explain what you're seeing.

Wavern
08-13-04, 01:25 PM
I am using High Quality. 1600x1200 with nvidia controlled 2xQ AA. Everything but vsync is on.

Zeta
08-13-04, 01:53 PM
WOW! Looks like a painted on shadow to me. I will have to load that part and see if it does the same thing for me.

Zeno
08-13-04, 03:59 PM
In the Enpron level, you meet up with a soldier that gives you an access card of some sort (transmission card?) and soon thereafter gets eaten by a demon. In that same room, there's an area with a large shadow of an X on it. Looking up shows you that 2 beams with a light above them creates this X shadow. Makes sense, right?

Take a look at these screenshots. I thought shadows were 100% dynamic but this is the 2nd case I've seen where they seem to be painted on.

http://www.wavern.com/hosted/images/shot00009.png
http://www.wavern.com/hosted/images/shot00010.png
http://www.wavern.com/hosted/images/shot00011.png

Man, you guys and these shadow topics. The shadow is not baked in. It may look a bit off for 2 reasons: 1) Stencil shadows are pixel-accurate in screen space. The textures in this scene are being magnified (there is less than one texel per pixel)...this discontinuity in resolution gives an illusion that the shadow is not "attached" to the surface. 2) The shadow conforms only to the geometry, not to the bump maps, so the countours of the shadow don't follow the bump.

Wavern
08-13-04, 04:45 PM
Man, you guys and these shadow topics. The shadow is not baked in. It may look a bit off for 2 reasons: 1) Stencil shadows are pixel-accurate in screen space. The textures in this scene are being magnified (there is less than one texel per pixel)...this discontinuity in resolution gives an illusion that the shadow is not "attached" to the surface. 2) The shadow conforms only to the geometry, not to the bump maps, so the countours of the shadow don't follow the bump.

My appologies if this has been discussed before. I just find it strange that only some shadows act this way.

Nv40
08-13-04, 07:15 PM
In the Enpron level, you meet up with a soldier that gives you an access card of some sort (transmission card?) and soon thereafter gets eaten by a demon. In that same room, there's an area with a large shadow of an X on it. Looking up shows you that 2 beams with a light above them creates this X shadow. Makes sense, right?

Take a look at these screenshots. I thought shadows were 100% dynamic but this is the 2nd case I've seen where they seem to be painted on.

http://www.wavern.com/hosted/images/shot00009.png
http://www.wavern.com/hosted/images/shot00010.png
http://www.wavern.com/hosted/images/shot00011.png


Doom3 lighting is 100% dynamic (generated always in realtime), Doom3 shadows can be 100% dynamic or can be a mix between dynamic and static. Doom3 doesnt have shadow maps ,nor baked shadows in textures.. what you see many times as very nice softshadows is a FIlter (static texture) atached to a dynamic light (not atached to game textures). this is very elegant IMHO because is like a filter added to a dynamic light ..its the same effect you will get in real life is someone paint with ink part of the lens of a flashlight ,the output will be a diferent light shape .and its optional.any level designer can use the shadow look they want .ironically this FIlters that looks like softshadows can be also dynamic since you can animated them. the rotating softshadows that you see in the floor of Fans in the ceiling are an example of this technique. So if something is Dynamic or not doesnt say the whole story ,because static textures animated are also dynamic ,a better word is to know if a shadow is real time generated or not. and there is nothing painted in Doom3. thats the job of shadowmaps which most games use. the X in the floor is hard edge ,means is most likely realtime generated,if you change the light position in that level the X will move instantly since is generated by a dynamic light.

Edge
08-13-04, 10:25 PM
You know, you could just turn on the player shadow and see if you cast a shadow on that light rather than making a forum topic about it...
If more people did this simple step, I think we'd have far less topics about the shadows on this board (though then I'm sure we'd see a lot of "why does my shadow look strange in this circumstance" topics...)

And these "anomalies" have nothing to do with the shadows. It's entirely because of the perspective certain things are viewed at, and due to the other effects used in the game (such as bump mapping and specularity). The shadows themselves are perfect, but the lighting is point based, which is why it looks so strange sometimes. If there were point-lights in real life, it would look exactly the same.

Wavern
08-14-04, 03:04 AM
Doom3 lighting is 100% dynamic (generated always in realtime), Doom3 shadows can be 100% dynamic or can be a mix between dynamic and static. Doom3 doesnt have shadow maps ,nor baked shadows in textures.. what you see many times as very nice softshadows is a FIlter (static texture) atached to a dynamic light (not atached to game textures). this is very elegant IMHO because is like a filter added to a dynamic light ..its the same effect you will get in real life is someone paint with ink part of the lens of a flashlight ,the output will be a diferent light shape .and its optional.any level designer can use the shadow look they want .ironically this FIlters that looks like softshadows can be also dynamic since you can animated them. the rotating softshadows that you see in the floor of Fans in the ceiling are an example of this technique. So if something is Dynamic or not doesnt say the whole story ,because static textures animated are also dynamic ,a better word is to know if a shadow is real time generated or not. and there is nothing painted in Doom3. thats the job of shadowmaps which most games use. the X in the floor is hard edge ,means is most likely realtime generated,if you change the light position in that level the X will move instantly since is generated by a dynamic light.

In most tests, pointing the flashlight at a shadow lights up the texture to match surrounding unshadowed textures. That's what threw me off here. I'm not saying the shadow shouldn't have been there, just that it appeared to be unequally affected by the flashlight. I didn't make that clear.