$ssbump

Comparing SSBump with standard bump mapping and no mapping at all.

$ssbump is a boolean material parameter that flags a $bumpmap texture as being self-shadowing. It is only supported with LightmappedGeneric and requires the Orange Box.

Standard bump maps only darken texels that are facing away from a light source. Self-shadowing bump maps darken both texels facing away and also any texels which are 'behind' them. You can read more about the technology behind it in this paper.

Tip:Self-shadowed normal mapping is actually faster than the standard method!

Example

rockwall_cave_02a_height-ssbump.vtf

LightmappedGeneric
{
	$basetexture	nature/rockwall_cave02a
	$surfaceprop	concrete
	$bumpmap	nature/rockwall_cave_02a_height-ssbump
	$ssbump		1
}

Limitations

The shadows cast by the bump map are baked into the texture, meaning that they can only appear in one of three predefined locations. If a light is arriving on the surface between these angles the nearest available shadows will be blended between, producing an acceptable but hardly ideal image.

It's therefore best to consider the direction from which your material will be predominantly lit from when creating it, bearing in mind that at least one of its edges will have to do without proper shadowing!

Creation

Bug:Only the version of height2ssbump in the current SDK Beta works.  [todo tested in ?]

You need to use height2ssbump, a command line SDK tool. The command is:

height2ssbump <options> <path\to\heightmap.tga> <float|bumpscale>

The output is <input name>-ssbump.tga, in the same folder as the input file. Bumpscale controls the intensity of the ssbump (i.e. coarseness of the surface); 60 is a good starting value.

Note:Bizarrely, the tool examines only the alpha channel of the input TGA. The original alpha channel will be passed on to the output TGA, but serves no purpose and should be deleted.

Options

<path/filename>

The source heightmap (TGA format).

-r <int>

Set the number of 'rays' (default 250). More rays take more time.

-f <int>

Set smoothing filter radius (default 10; 0 disables).

-n

Generate a conventional bump map as <input name>-bump.tga.

-A

Generate ambient occlusion in the alpha channel.

-D

Write out filtered result as filtered.tga.

Creating ssbumps manually

Here are the different ways of manually creating ssbumps without the real tools.

• SSbump Generator 3.0 (now with GUI) - Third Party tool