Material Files

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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 Dark Mod parser might complain (e.g. no "&" (ampersand) or "-" (dash) characters, etc.)

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.

Note: If there is no specular map then substitute _black, and if there is no bumpmap then use _flat instead.
        // 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.

See also