Specular + Bump maps

[Rassilon]

LOL well suppose I could start using that but will it really make a difference relitive to size? png or 2 jpg files....I'll look into it I suppose

[Rassilon]

Yes it works quite nicely Chris! Thank you

[chris]

LOL well suppose I could start using that but will it really make a difference relitive to size? png or 2 jpg files....I'll look into it I suppose

It can . . . But if you use two png or jpg files--one for specular and one for color--you'll end up using twice as much texture memory as if you combine them in a single texture. However, you can usually get away with using a half-resolution texture for specular. The big win with separate specular textures is when you're using compressed textures. With a combined spec/color texture, you have to use DXT5, which is twice the size of a DXT1 texture. With separate textures, you can use DXT1 for both. There's no advantage if they're the same size, but if you use a half res spec texture, you'll use 37.5% less texture memory . . .

It works like this (and I'll ignore mipmaps for these calculations)

Let's say you have an 8k x 4k texture . . .

Uncompressed color map:
8k x 4k x 32bpp = 128 M
Uncompressed color+spec map - same as color only - 128 M
Uncompressed spec map:
8k x 4k x (32 or 8 bpp) = 128 or 32 M (depends on if your graphics card supports luminance textures)
Uncompressed half res spec map:
4k x 2k x (32 or 8 bpp) = 32 or 8 M

DXT1 color map:
8k x 4k x 4bpp = 16 M
DXT1 spec map - same as DXT1 color map - 16 M
DXT1 half res spec map:
4k x 2k x 4bpp = 4 M

DXT5 color+spec:
8k x 4k x 8bpp = 32 M

Uncompressed 8k x 4k uses 128 M, which is not going to happen on any current consumer graphics hardware.
DXT5 color+spec is 32 M total
DXT1 color + DXT1 spec uses 16 M for color and 16 M for spec, or 32 M total
DXT1 color + DXT1 half res spec uses 16 M for color and 4 M for spec, or 20 M total

The main reason that I added support for separate specular maps is for the DXT1 color + DXT1 half res specular case. It's an excellent way to save a lot of texture memory on your planets that need specular highlights. Also, if the entire planet is reflective (e.g. an ocean planet), you can omit the specular texture completely.

--Chris

[Rassilon]

The thing is Chris Im not even using DXT compression yet...If I did then I would be making them for myself alone The current formats Im using is JPG uncompressed 2048x1024 color 1024x512 spec and bump...which saves me alot of space compared to one PNG file which averages to be 4.5 megs at 2048 x 1024....Today I made a planet using a color 2048 x 1024 jpg = 852k...1024 x 512 jpg spec = 207k and the 1024 x 512 jpg bump = 317k totals to 1376k...Looks as good as if I made the 4.5 meg png file....but almost quarter the size!....so for now I am totally stoked by the memory I am saving

Oh and btw...I just tried compressing the specular...and it loses very little resolution...cut that down to 100k hehe....I suppose the DXT compression is the best for single files....so I can definately see what your saying there

[Rassilon]

Heres those textures in action...

[Buzz]

My 8k specular reflection map for Earth is finally there. I started with the spec map in NASA's 8k texture and added lakes. It's really nice to see these lakes suddenly appear when the sunlight hits them at the right angle. I sent it to Bruckner, but he hasn't updated the repository on his site for some time. If there is anyone else who is willing to host this map (837 KB), please let me know!
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[Darkmiss]

Hey Don

I cant get access to your downloads.

Im really interested in your Blue Mars, with spec, non bumped.
I tried all last night, and again this morning.
Is your site down, or is it the server

What times is it available

[Buzz]

I'm going to quote myself, sorry

My 8k specular reflection map for Earth is finally there. I started with the spec map in NASA's 8k texture and added lakes. It's really nice to see these lakes suddenly appear when the sunlight hits them at the right angle.

I have now set up a web page... I added the spec map to a dds texture. Here's a screenshot:

You can download the spec map here:
http://home.tiscali.nl/celestia