Question about displacement maps / bump maps

[Samuel]

Question about displacement maps / bump maps, in the tech demo we saw are section where the floor list dynamically altered, I think it had spikes rising up out of the ground?

Anyway, my question is, do you think we are going to be able to create effects like craters with this? Eg, a morter shell comes in, where it hits the ground you could dynamically "dig" that part of the ground out. You could also set a time to die on these so it did not bog peoples machines down so much.

If you are able to do this, think of the possibilites, foot prints, trails in the sand/dirt, claw marks in things.

 

[dawdler]

In theory, yes on the craters, I beleive one can do that... It might be tricky getting it to work dynamicly (ie when you fire a mortar), but would be very easy to script a blast and displaced terrain. You could have some of the coolest WW2 scenes seen in a game

However, foot prints, trails in the sand/dirt and claw marks are not possible. It would require a mesh so high poly you couldnt fit the displacement map in memory. Having such things as footprints that almost look like a foot would require something 20-30 times as detailed as BF1942 at least. Claw marks about 100 times more detailed. Not a single system today can handle it. That's why you use decals, maybe they can normal mapped too

 

[johnshafft]

from what I've read and understand the displacemnt map is not 'dynamic' or 'free form' like Red Faction's Geo Mod engine.

Its something the mapper has implement. which means it would have to be scripted into a sequence to trigger the displacement map

 

[dawdler]

Originally posted by johnshafft
from what I've read and understand the displacemnt map is not 'dynamic' or 'free form' like Red Faction's Geo Mod engine.

Its something the mapper has implement. which means it would have to be scripted into a sequence to trigger the displacement map

Ah, but it should be easy to call such a script from an ingame enviroment. For example (note, its a stupid theory, not anything to be taken as fact):
If you use a terrain displacement map, similar to say BF1942, then ingame you use something like this: if a projectile hit an area on the map, you find out which intersections is closest, then you redraw the displacement map with a "bump" around the correct pixel. Then after that you rerender the mesh for just that area, using animation between old positions and new positions, effectivly doing a crater in realtime (note, animation is like 0.2 seconds anyway, so its not much).
Or even simpler (if you can call it that ), you make a mesh system you can manipulate realtime and have set radius/falloff/strenght values for terrain bumps, you never even bother with a displacemement map.

In any way, its something that should in theory be possible dynamicly with the help of a really good coder. But true it isnt like Red Faction, it doesnt even use displacement maps, you just blow chunks out of everything

 

[IchI]

Originally posted by Samuel

If you are able to do this, think of the possibilites, foot prints, trails in the sand/dirt, claw marks in things.

You normally do all those with textures. Use a bump map for this and u wouldn't even need a 3d ingravment and wasting polgon mesh count.

The part with the holes is even possible in hl1 so its definatlly possible with hl2. Its just done with displacment maps instead of your old hl1 way.

 

[johnshafft]

Originally posted by dawdler
Ah, but it should be easy to call such a script from an ingame enviroment. For example (note, its a stupid theory, not anything to be taken as fact):
If you use a terrain displacement map, similar to say BF1942, then ingame you use something like this: if a projectile hit an area on the map, you find out which intersections is closest, then you redraw the displacement map with a "bump" around the correct pixel. Then after that you rerender the mesh for just that area, using animation between old positions and new positions, effectivly doing a crater in realtime (note, animation is like 0.2 seconds anyway, so its not much).
Or even simpler (if you can call it that ), you make a mesh system you can manipulate realtime and have set radius/falloff/strenght values for terrain bumps, you never even bother with a displacemement map.

In any way, its something that should in theory be possible dynamicly with the help of a really good coder. But true it isnt like Red Faction, it doesnt even use displacement maps, you just blow chunks out of everything

Thats in theory, without having the game engine as Valve is going to put out we cant make any real decisions if this is possible. The script may also get very complex in relationship to vertical surfaces, and actually cratering the the target and not just adding this displacment map turned object .

real time mesh deformation will supposedly be possible to implement. But I wonder what the performance hit, and network issues will be

but either way I dont think you can actually create a concave suface that goes deeper than the existing brush(es), with actually modifying the bsp tree in real time with out having a pre-built system availble to the modder. And talk about some network issues....



*note I haven't looked at the leaks, out of respect. sure wish I had the legit sdk