$ssbump
$ssbump
is a material shader parameter available in all Source games since Source 2007.
It is a boolean parameter that flags a $bumpmap
texture as being a self-shadowing bump map.
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, similar to Ambient Occlusion maps in modern game engines. You can read more about the technology behind it in this paper.
Example
$ssbumpmathfix
The parameter addresses an issue with SSBump Textures being too bright.
It can be found in the VMT's of Alien Swarm, Counter-Strike: Global Offensive, Left 4 Dead 2, Black Mesa and Portal 2
However the Parameter itself does not appear to be functional in some of them.
The Parameter addresses an issue where SSBump's unlike their Normal Map counter parts are non-unit Vectors.
More specifically, unlike the .x and .y components of the Bump Basis, the .z components don't cancel out.
The maximum range of the result, is equal to the sum of the .z components. 3* (1.0f / sqrt(3.0f))
or 1.73205f
This causes SSBumps to be MUCH too bright.
Luckily, this can retroactively be accounted for by multiplying the result with Desired_Range / Current_Range
or numerically1.0f / 1.73205f
1. Compare a $SSBump material using $SSBumpMathFix and a $Color value of 1.73205
, with the same material without both.
0.57735
Multiply your $Color Parameter with the Value 0.57735
, or in case you don't have $Color yet simply add it with that Value!
Limitations
The shadows cast by the bump map are permanently baked into the texture, meaning that they can only appear in one of three predefined locations. height2ssbump
generates shadows for light arriving from the right, top-left, and bottom-left of the texture.
If light arrives from between those directions (such as from the left), the nearest available baked shadows are blended between, producing an acceptable but hardly ideal image.
Additionally, in order to preserve the illusion of height, low areas of a SSBumped material will receive less light even if it arrives head-on. This can look odd if you have too intense (rugged) a SSBump.
Creation
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).
height2ssbump
is currently non-functional in Strata Source games. Use Portal 2's instead, or Counter-Strike: Global Offensive's if you still have access to it [todo tested in?]You can use normal2ssbump
, another SDK tool, to generate an SSBump from a normal bump map (as opposed to a height or displacement map) - Unlike height2ssbump
you do not need to run through the command line or use any additional parameters; simply drag-and-drop your normal map onto the program or a shortcut.
$normalmapalphaenvmapmask
material parameter.
Options
<path/filename>
- The source heightmap (TGA format).
-r <int>
- Set the number of 'rays' (default 250). More rays take more time.
-n
- Generate a conventional bump map as
<input name>-bump.tga
. -d
(in all games since )(also in )- Generate an ssbump detail texture, used with
$detailblendmode
10 and 11. - Confirm:How does this differ from a making regular SSBump? public/bitmap/float_bm.h has a description.
-A
- Generate ambient occlusion in the alpha channel.
-f <int>
- Set smoothing filter radius (default 10; 0 disables).
-D
- Write out filtered result as
filtered.tga
.
An example of a complete command is:
height2ssbump -r 275 "C:\Path\to\example-height.tga" 35
Third Party Tools
Third-party tools capable of generating SSbump maps:
- Substance Designer Utility Node
- Filter Forge 2.0
- Xnormal (In Tools, select 'Height map to normal map', then tick 'Radiosity NM')
- SSbump Generator
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