Material Files
Originally written by Fingernail & greebo on http://forums.thedarkmod.com/topic/127
What the Heck is a Material File?
The material files (.mtr) contain lists of 'material definitions' that tell the engine where to find the source files for the specified textures and what features it should have. All material files should be located in the darkmod/materials folder and have the extension .mtr.
In fact, it's the material (=shader) which gets applied to surfaces of brushes, patches and models, not the actual TGA/DDS texture image. A TGA file cannot be applied to surfaces, it's the shader name which gets used.
Polygons ==> Shader ==> Image(s) + Processing => Appearance
Material definitions apply to a single 'texture', though it may be made up of multiple texture files blended together. A simple material definition looks like this:
textures/darkmod/stone/brick/redbrick_with_mortar
{
qer_editorimage textures/darkmod/custom/redbrick_ed
diffusemap textures/darkmod/custom/redbrick
bumpmap textures/darkmod/custom/redbrick_local
specularmap textures/darkmod/custom/redbrick_s
}
If you're using the material called textures/darkmod/stone/brick/redbrick_with_mortar in your map, Doom looks up the name in the material definition and loads the according image files (as specified by the Map Expressions). Note that you don't need to specify the file extension, the engine is automatically adding it (depending on your quality setting) and finds the according texture file. You also don't need to include the dds/ prefix in the path, this is also added automatically.
A single material file contains lots of material definitions. This is useful as textures that logically belong to each other are summarized in one material file (e.g. materials/tdm_stone_brick.mtr)
The .mtr files are read upon launching Doom 3 - changing your material file therefore requires either restarting Doom or typing reloadDecls in the console.
Create a new Texture Definition
Provided you already saved your texture source file (the .tga or .dds) in the appropriate folder, you can go on and create your texture definition. You cannot use your textures without this step.
Open up or create your personal material file with a text editor. There are existing guidelines for where texture definitions should go, for the sake of organization, but the engine doesn't care what the filename is as long as it's in the materials folder and has a .mtr extension.
First, specify the name of your new material. If it is not a model texture, then the name should include the path to the texture files used. Example:
textures/darkmod/stone/brick/redbrick_with_mortar
Note: Do not use special characters for your shader name or the Doom 3 parser might complain (e.g. no & characters)
Then, open up a squiggly bracket ({), and start to fill in the texture paths as below, changing the paths and names for your texture.
textures/darkmod/stone/brick/redbrick_with_mortar
{
qer_editorimage textures/darkmod/stone/brick/redbrick_with_mortar_ed // editor image
diffusemap textures/darkmod/stone/brick/redbrick_with_mortar // diffuse map
bumpmap textures/darkmod/stone/brick/redbrick_with_mortar_local // normal map
specularmap textures/darkmod/stone/brick/redbrick_with_mortar_s // specular map
}
Close the definition with a close squiggly bracket (}).
Save the file. Now you can load your new texture in DoomEdit or DarkRadiant provided you did it all correctly.
Alternatively you can also have a look a the existing material files and learn from them.
Add the Ambient Light Stage
This should go on all Dark Mod textures - see Virtual Ambient Light Textures.
// TDM Ambient Method Related
{
if (global5 == 1)
blend add
map <mappath/name>
scale 1, 1
red global2
green global3
blue global4
}
Add the Frob Highlight Stage
All materials need to have a conditional shader stage added to let the material highlight when the objects are frobbed. The technical details are of minor interest here, just copy and paste such a stage from other materials and adjust the diffusemap and bumpmap references.
Full example
Here is the full example with the final material definition:
textures/darkmod/stone/brick/redbrick_with_mortar
{
// Use on of the predefined surface types like:
// none, metal, stone, flesh, glass, wood
stone
// Or use "surftype15" and add the surface type as the first (or only) word of the description,
// the following are possible:
// tile, carpet, dirt, gravle, grass, rock, twigs, foliage, sand, mud, brokeglass, snow, ice, squeakboard,
// puddle, moss, cloth, ceramic, slate, straw, armor_leath, armor_chain, armor_plate, climbable, paper, hardwood
//surftype15
//description "carpet This is a carpet texture."
qer_editorimage textures/darkmod/stone/brick/redbrick_with_mortar_ed
bumpmap textures/darkmod/stone/brick/redbrick_with_mortar_local
diffusemap textures/darkmod/stone/brick/redbrick_with_mortar
specularmap textures/darkmod/stone/brick/redbrick_with_mortar_s
// This is the code required for frob highlighting this texture
{
if ( parm11 > 0 )
blend gl_dst_color, gl_one
map _white.tga
rgb 0.40 * parm11
}
{
if ( parm11 > 0 )
blend add
map textures/darkmod/stone/brick/redbrick_with_mortar
rgb 0.15 * parm11
}
// TDM Ambient Method Related
{
if (global5 == 1)
blend add
map textures/darkmod/stone/brick/redbrick_with_mortar
scale 1, 1
red global2
green global3
blue global4
}
}
AS OF TDM 2.0 the old Enhanced Ambient stage:
{
if (global5 == 2)
blend add
program ambientEnvironment.vfp
vertexParm 0 1, 1, 1, 1 // UV Scales for Diffuse and Bump
vertexParm 1 1, 1, 1, 1 // (X,Y) UV Scale for specular
vertexParm 2 global2, global3, global4, 1
fragmentMap 0 cubeMap env/gen1
fragmentMap 1 textures/darkmod/stone/brick/redbrick_with_mortar_local // Bump
fragmentMap 2 textures/darkmod/stone/brick/redbrick_with_mortar // Diffuse
fragmentMap 3 _black // Specular
}
is no longer needed as ambient rendering has it's own dedicated function in the renderer now.
Special Keywords
There are also some special keywords you can use:
- noshadows - surface does not cast a shadow
- noselfshadows - casts shadows, but not on itself
- translucent - for things like glass
- twosided - the surface will be duplicated and flipped, this causes it to be rendered twice. Useful for half-transparent things that should be visible from both sides. Normally surfaces are only visible from the front side (see note below)
- noFog - do not render fog on this surface
- Discrete - Dmap will not merge brushes with this material applied
- NoFragment - Dmap will not split brushes with the material applied
- nopicmip - The image_downsize settings will not affect this texture. Use sparingly, as low-end users need to use image_downsize to load larger maps.
Note:
http://www.iddevnet.com/doom3/materials.php
twoSided Draw the front and back. Implies no-shadows, because the shadow volume would be coplanar with the surface, giving depth fighting
Use a nodraw surface with forceShadows to address this.
