View Full Version : HDR impact on normal maps
08-23-2007, 11:55 AM
I'm working on an official map for the pvkii mod.
The problem I encountered is the quite big difference of the intensity of normals maps with and without HDR.
I've done this animated gif to demonstrate the difference directly: "HDR with bloom effect", "HDR without bloom effect" and "no HDR, no bloom effect"
have a look at the gif and you'll see what I mean.
See how the normal map is way weaker as long as HDR is turned on? (you can see that very good on the white rock)
Plus, it still is weaker with the bloom effect off, so it is not weaker because the bloom effect overlays the materials.
The problem is that if I adjust the normal maps for the HDR version, they are too strong for the LDR version and vice versa.
08-29-2007, 09:30 AM
isn't it clear what the problem is or why does nobody answer?
I think this is a quite big problem and I guess it concerns everyone.
No idea, anyone?
08-29-2007, 09:45 AM
I am not sure that I am qualified to give advice to someone making official mod maps, but whilst googling "Normal Maps" I came accross an article/forum/tutorial (i can't rmembber which) that simply said when normals and bumps are compiled in HDR that they always come out looking less "3D".
The only suggestion I have is increasing the "intensity" of your normal maps to compensate for the "lessening" effect in HDR. Maybe a normal map that would be too much when compiled in LDR (you know that kind of glossy effect you can get when your normal maps are too much) would be okay in HDR.
Anyway, from what I read its not a problem with your textures, but simply an effect of using HDR, and something you cannot change, I think.
Hope this helps
08-30-2007, 10:13 AM
hehey I'm just human aswell, of course you can give me advice! ;)
yea I already thought it was a problem with the engine and not with my textures.
When I make more intense normal maps for the HDR version, alot of people who have older GPUs will only get to see the LDR version with waaay too strong normals maps which, as you said, looks crappy.
I would have liked it if I someone from Valve got aware of this problem. I mean, it's pretty annoying... a special parameter for the .vmt to regulate the intensity of normal maps would suffice.
there alreaady is a way to define settings of a material for HDR only.
08-31-2007, 05:38 AM
Is there not some way of using the "$bumpscale" .vmt parameter to change the intensity of the normal maps depending on whether LDR or HDR is used. Can you not create some kind of "fallback" system like when you turn off normal/bump/mips on computers working on Directx8 or Directx7? Or maybe create your normal maps so they look good in HDR and turn them off totally LDR.
Hope you find a solution.
08-31-2007, 09:18 AM
sad to say the bumpscale parameter is for the parallax shader only and does not affect the actual intensity scaling of the normal map
I'll think about turning off the bump maps for LDR...
09-01-2007, 09:28 AM
I wasnt sure, I've never tried using it myself... I have only made a few Normal maps and dont have much experience. Seems a shame that there is no .vmt command to control the intensity of Normal maps. I found it very frustrating making normal maps because its difficult to get the intensity right, if you bump too much it looks terrible and if you dont do it enough... well theres no point. I had no luck finding a good tutorial explaining how to make Normals based upon a texture.
I came up with this technique: I make a 2 layer image in photoshop, the background layer totally black and the second layer my texture. I adjust the contrast, colour etc on my texture image to bring out the areas I want bumped. Then I put both layers through the Normal map filter and lastly adjust the opacity of the "texture" layer to about 30 or 40 percent, so its "diluted" into the black layer behind. Then I flatten the image to finish my normal map. This seems to work okay, but Im sure there must be a better way of do it...
If you know of any good tutorials, I would really appriciate the link.
09-02-2007, 12:05 PM
if you find it hard to create a good normal map from texture you should definitely check out CrazyBump!
It's a little program that is quite effective in creating normal maps from textures. It analyzes the image and looks for possible 3d structures. I used it a couple of times and it seemed to work very well.
09-03-2007, 04:36 AM
You'll probably find that it's to do with brightness. Use the BrightnessHDR value of the light shining on the rockface.
09-06-2007, 04:23 AM
mh no, the BrightnessHDR value does not affect the normal maps. thanks anyway, I appreciate all possible solutions!
09-06-2007, 10:31 AM
It looks better with HDR.
The stone plating does.
Actually nvm it was at LDR.
09-06-2007, 02:36 PM
In this particular case, it looks like you have a bright surface (high reflectivity) being directly lit in the scene. When you add HDR tonemapping, it increases the relative brightness of that surface (that's part of what HDR does). I would expect that this same surface without the normal map would have the same effect, probably even more so.
Your options would be:
- Lower the brightness/reflectivity of the basexture.
- Adjust the range of tonemapping exposure settings so the surface does not get that bright (this is global, however).
- Reduce the bloomscale (also global).
- A combination of these.
09-07-2007, 06:54 AM
yes, the basetexture is quite bright, infact it is very bright as I wanted the normal map to give the material contrast.
mh maybe I didn't give out enough information about the material. none of the cracks in the rock are part of the basetexture. Wait, I'll show you the maps of the material for better understanding.
okay, let me get this straight.
I see that the bloom effect increases the brightness and it can't get any brighter than white, so the contrast of the final image decreases.
But without bloom the intensity of the normal map(!) is decreased eventhough it isn't overexposed. See the big crack which zigzags up the rock? it's done by the normal map only. You can see how it is barely visible with HDR and bloom. that's okay, we know this is caused by the bloom effect. But the difference between no HDR and HDR without bloom effect still is a mystery to me. You can see that the image without HDR is even more overexposed than the one with HDR and no bloom but still has a stronger normal map.
@ vcool: yea but that's not the point. some people will only be able to play the LDR version and I want the map to look good for everyone.
09-07-2007, 11:34 AM
isn't it also possible, if this is a reflectivity issue, to address ldr and hdr individually in the .vmt?
"LightmappedGeneric_DX9_hdr" within the vmt.
this link on the wiki has some notes on it:
09-08-2007, 04:39 AM
ah hehe no, I think you missunterstood him, Jeff was talking about the reflectivity of colors, like bright colors reflect more light than dark colors etc. This materials does not use a specular map.
09-08-2007, 05:52 AM
add light entity near this rock
09-10-2007, 10:31 PM
Like I said, Im no expert, but I have read a little about HDR, as I understand it HDR is a way of enhancing an image by including information about the "luminance" of a sceen.
So, as the "colour" (therefore luminance) information is contained in the base texture, this is the information that is being enhanced by HDR rendering, however the normal map is ignored in this process, no?. By using HDR are you not effectively "strengthening" the rendering of your base texture which results in a weakening of the Normal maps effect.
Like you said your base texture does not even contain the crack in the surface... so if the texture itself is being rendered more "intensely" then I can understand that the Normal map will have less impact.
I say this simply as regards to HDR, ignoring the bloom thing.
Maybe this is not true, just that you were looking for an explaination, and it seemed plausible.
09-17-2007, 03:27 AM
add light entity near this rock
that won't help.
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