Making a custom breakable surface

Note:This so far has only been tested in Half-Life 2 in the 2009 branch of the Source Engine, but in other Source games that support DirectX 8/9, and where this entity is fully programmatically functional, this should still work.

Todo: Test with other surface properties

What you need

You will need:

• A VTF editor/maker (VTFEdit was used in the making of this tutorial, but VTEX can be used also.) to make the textures VTF files

• A VTF texture to represent the intact material

• A VTF texture with an alpha channel (8-bit alpha for semi-transparent surfaces) to represent the damaged material

A mask for both textures is optional.

Handling the material/texture files

• After you've got your 2 masks and/or textures, place them in the appropriate game/mod materials directory (and whatever subfolders you wish to put them in) (e.g Half-Life 2/hl2/materials).

• Create 2 text documents in the same folder your VTFs are in, with each one having the same file name. Make sure you have extensions visible in your computer's file browser, and change the file extension of one file to .vmt, or save a text document with a .vmt file extension in whatever text editor you're using.

Note:It's good practice to name your materials (whatever)001a for the first frame then (whatever)001b for the second frame and so on when you are switching between said materials on a brush face(s) in game (in this instance, an intact and broken material

The intact texture

After you have created the material/textures in the appropriate paths, copy, paste and fill the "(...)" enclosed strings with the paths to the respective VTF files into your intact material VMT:

"LightmappedGeneric"
{
	"$basetexture" "(VTF NAME HERE)"
	"$envmap" "env_cubemap"
	"$surfaceprop" "(Surface properties goes here, it's glass by default)"
	"$envmapmask" "(VTF MASK NAME GOES HERE)"
	"$translucent" 1
	"$multipass" 1
	"$nocull" 1
	"$crackmaterial" "(DAMAGED MATERIAL PATH GOES HERE)"

	"LightmappedGeneric_hdr_dx9"
	{
		"$envmaptint" "[.08 .08 .08]" 
	}
}

Note:If you are not using a texture mask, comment out (type // behind) the line $envmapmask is on.

Insert the appropriate paths where $basetexture, $envmapmask and $crackmaterial are specified

Save the VMT in the same folder as your first (intact) VTF file

The damaged texture

The damaged texture needs to have an alpha channel otherwise skybox/black texture will appear when the surface breaks.

Copy and paste the following code into your damaged material VMT

"ShatteredGlass"
{
	"$basetexture" "(VTF NAME GOES HERE)"
	"$detail" "(VTF NAME GOES HERE)"
	"$envmap" "env_cubemap"
	"$surfaceprop" "(Surface properties goes here, it's glass by default)"
	"$envmapmask" "(TEXTURE MASK GOES HERE)"
	"$translucent" 1
	"$basetexturetransform" "scale .7 .7"
	"$detailscale" 0.7
	"$unlitfactor" 0.0

	"ShatteredGlass_DX8"
	{
		"$unlitfactor" 0.3

		// This is roughly equal to the average value of envmapmask of the unbroken texture
		"$envmaptint" "{201 201 201}"
	}

	// On the low end, envmaptint + lightmap tint both use the average alpha value 
	"ShatteredGlass_DX7"
	{
		// This is roughly equal to the average value of alpha channel of the unbroken basetexture
		"$lightmaptint" "{128 128 128}"

		// This is roughly equal to the average value of envmapmask of the unbroken texture
		// times the average value of the alpha value of the unbroken base texture
		"$envmaptint" "{100 100 100}"

	}

	"$nocull" 1

	"Proxies"
	{
		"BreakableSurface"
		{
		}
	}
}

Note:If you are not using a texture mask, comment out (type // behind) the line $envmapmask is on.

End

Provided you have done everything right, you should now have a texture that works fully with the func_breakable_surf brush entity provided all except 1 side is Nodraw.

Modifications to the independent parameters (e.g $lightmaptint) can be made without any loss of functionality, however since func_breakable_surf is mostly used for glass, it has been optimised as such (hopefully).