Materials

Material decls are similar to shader files from Quake3, but they are a lot more powerful. Materials have a lot of power, especially when combined with scripts and GL programs.

Tables

In Quake3, you could do all kinds of neat things with sin waves, saw tooth waves, square waves and other types of waves, but you were pretty much screwed if you wanted any kind of non standard wave form. In Doom 3, you can define arbitrary data lookup tables, then reference them in your materials. The format of a table definiton is:

   table <tablename> { [snap] [clamp] { , , ... } }

Where [snap] is an optional key word which means "jump directly from one value to the other (don't blend between values)" and [clamp] is an optional key word which means "don't wrap around if the index is outside the range of table elements, (return the first value if less or the last value if it's more)". Both keywords are optional, and can be used together. Now, armed with this knowledge, we can easily construct a square wave lookup table:

   table squarewave { snap { 0, 1 } }

The sin table is a bit harder, but lucky for you, it's already defined shaderDemo.mtr

Materials

Every material file has a global section, followed by one or more stages. The global section, as the name implies, sets properties that affect all the stages. In Quake3 the stages were pretty easy to understand because the engine rendered them in order: stage 1, then stage 2, then stage 3, etc.. In Doom 3 the order is not quite as simple because of the way the lighting system works, but for the most part, they are still rendered in order. Let's look at a simple material (some random wall in the alpha labs):

   material textures/alphalabs/a_lfwall21b
   {
       qer_editorimage textures/alphalabs/a_lfwall21b
       bumpmap         textures/base_wall/lfwall21_local
       diffusemap      textures/alphalabs/a_lfwall21b
       specularmap     textures/alphalabs/a_lfwall21b_s
   }

The first line is the name of the material (which in this case also happens to be the name of the diffuse map). Notice the use of the 'material' keyword. This is required for all materials, unlike Doom3.

The global section begins right after the open curly brace. The first key word we see is qer_editorimage, which tells Radiant which image to use in the editor. This is the image used in the texture window, as well as in the 3D view. Next we define the bump map (normal map), the diffuse map (colors), and the specular map (gloss). This is about as basic of a material file you can get, while still using the advanced lighting features. Technically all you need is 'diffusemap', in which case the specular map is black, the bump map is blue, and the editorimage is the diffusemap. Creating an entire map with those types of materials will look roughly like Quake 3. In most cases you won't need to specify the qer_editorimage unless you specifically need something which looks different to the diffusemap.

This material looks like it doesn't have any stages, but in fact it has 3 stages. The 'bumpmap' 'diffusemap' and 'specularmap' keywords are simply shortcuts for stages as we will see later.

Shaders in Materials

ETQW has the ability to use custom GL vertex and fragment programs when rendering a stage of a material. This is mostly seen in the 'heat haze' effects around fire, in the warping effects on glass, and in the warping effects on various projectiles (like the BFG). For documentation on how to write your own renderprograms programs, see the separate Render program documentation

There is nothing stopping an artist from writing those, but I would really let a programmer handle writing the renderprogram. The main thing an artist or level designer needs to know is how to use the renderprogram in their materials. This is the material file for the hornet smoke which uses one of the heathaze effects. Using other renderprograms works in a similar way:

   material particles/penta/hornetheathaze {
       noshadows
       translucent
       nonsolid
       {
           program heatHazeWithVertex
           deformScroll 0, 0
           deformMagnitude 1
           bumpMap textures/particles/smoke/smokenormal.tga   
           maskAlpha
       }	
   }

There is a single stage in this material. It uses a special program, this means it will not render like any other material but that it will use that program to do some special effect. It also means that certain parameters are surrendly read by the engine. So the heatHazeWithVertex causes the engine to render the stage as a heathaze surface, it also looks at the values of deformScroll and deformMagnitude to define the specific strength of the heathaze effect (how much warping is going on). The engine automatically knows at which parameters to read when you use a certain program, so while you can set these parameters on any material only programs that actually use them will care about their value. Also note how the texture is specified using the bumpMap [bleh] command, altough you use the bumpmap command here it won't render like any other bumpmapped surface since the "program heatHazeWithVertex" told the engine to do special rendering for this surface.

The list of new "commands" that are available when you use a certain program is not fixed, so every new program may define new variables you can set. Most programs tend to use the default values like "map", "bumpMap", "diffuseMap", ... so most of the time you don't need to know about any special variables to use the program.

Maths and Logic

Materials in Doom 3 can contain mathematical and logical expressions. These expressions are evaluated for each material every frame, and are what cause normally boring surfaces to come alive. This is a replacement for the rather limited shader commands in Quake 3 such as tcMod scroll, rgbGen, etc. Let's take a look at a material to see these features in use:

   material models/weapons/soulcube/soulcube3fx
   {
       noSelfShadow
       translucent
       noShadows
       {
           if ( parm7 > 3 )
           blend add
           map models/weapons/soulcube/soulcube3fx
           rgb scTable[ time * .5 ] 
       }
   }

In Doom 3, certain stages of the material can be selectively turned on and off. The 'if' command in this example means "only draw this material if parm7 is greater than 3." There are a few places where parm7 can get set, one of them is in the editor with the 'shaderParm0' to 'shaderParm11' keys. Another place is in the script file (such as with weapons). Of course, it can also get set in the code.

Notice the use of a lookup table in this material. Here we are using 'time' (which is a floating point number that increases forever) to look up a value in 'scTable' (which was defined using a 'table' decl earlier).

The mathematical operators you can use in a material are %, /, *, -, and +. You can also use the boolean operators <, >, <=, >=, ==, !=, &&, and ||. The meaning of the symbols is the same as in C/C++, Java, PHP, etc. Mathematical expressions should be enclosed in parenthesis (there are cases where they don't have to be, such as when they are used as an index to a lookup table, but it never hurts to have too many. For the operands, you can use a lookup table, any numerical constant, and any of the following variables:

time: Forever increasing floating point value that returns the current time in seconds parm0-parm11: Parameters that can be set a number of ways (discussed above) global0-global7: Not used right now fragmentPrograms: Constant that is 1 if ARB fragment programs are available. This is mostly used for disabling a stage by specifying "if ( fragmentPrograms == 1 )" sound: The current sound amplitude of the entity using this material. This is used to create light materials that pulse with the sound.

New backend

The new backend slightly changes the way how shaders work, altough internally the system is very different we tried to keep external changes as small as possible. The next few topics are mainly "copy pastable" cases.

Alphatested surfaces

Unlike doom3 bump/specular/diffuse maps are not treated as separate material stages anymore, so instead of having three stages with one map each you now have one stage with the three maps specified at once. This makes for less stages and a generally more intuitive way of creating shaders. The biggest change because of this is the alpha testing. While you specified the bump and specular stages like normal stages and specified added the alphatest on the diffuse stage before, now you need one stage with has diffuse+bump+specular maps with alpha testing enabled. An alpha tested stage now looks like this:

   material textures/alphademo {    
       {
           diffusemap  textures/decals/fgrill2_d.tga
           specularmap textures/decals/fgrill2_s.tga
           bumpmap     addnormals( textures/decals/fgrill_local.tga , heightmap ( textures/decals/fgrill2_b.tga, 1 ) )	 	
           
           alphaTest 0.5
       }
   }

Clamped textures

Clamping was specified in the shader/stage body before, this is not very logical as it is actually an image parameter. Therefore clamping now has to be specified before image names.

   material textures/clampdemo {    
       {
           blend add
           map clamp textures/decals/blast.tga
       }
   }

Animated texture coordinates

Since bump/normal/specular are now part of a single stage( see alphatest information ) the texture matrices can't be specified per stage anymore, therefore there is a new "texturematrix" command you can use to specify the texture matrix of a specific texture.

   material textures/matrixdemo { 
       {
           bumpmap textures/base_wall/wire_fence2_local.tga
           specularmap textures/base_wall/a_wire_fence2_s.tga
           diffusemap textures/base_wall/a_wire_fence2_d.tga
           alphaTest 0.5
           
           textureMatrix bumpMatrix {
               translate 2, 2
           }
           
           textureMatrix specularMatrix {
               translate 4, 4
           }		
           
           textureMatrix diffuseMatrix {
               translate 2, 2
           }
   }

You can still use the old texture matrix system, but this means it will only affect the diffuse map and NOT the specular/normal map. If you are writing a non bumpmapped material you should also use the old way of specifying texture matrices.

Reference (Beware: copy paste from doom 3 out of date likely!)

Global Keywords for regular materials

qer_editorimage <map>	Image to display in the editor
description <string>	Just a simple description for people using this material
polygonOffset	[float] offset the depth buffer to combat z-fighting
noShadows	Don't cast shadows
noSelfShadow	This material doesn't cast shadows on the model it's on (but it does on other models)
forceShadows	Allows nodraw surfaces to cast shadows
noOverlays	Overlay / Decal suppression
forceOverlays	Force decal overlays for alpha tested or translucent surfaces
translucent	The engine thinks this is a translucent material (which means no ambient/zfill pass will be done for this material)
forceOpaque	Opposite forces the engine to think this is a nontranslucent material.
twoSided	Draw the front and back. Implies no-shadows, because the shadow volume would be coplanar with the surface, giving depth fighting
backSided	Draw only the back. This also implies no-shadows
mirror	Use to make mirrors
noFog	Don't fog this surface
unsmoothedTangents	Uses the single largest area triangle for each vertex, instead of smoothing all
guisurf <guifile> guisurf entity[2|3]	This surface has a gui on it. Use "somegui.gui" to specify the gui, or entity, entity2, entity3, etc for the level designer to set it in Radiant.
sort <type>	Type is one of: subview, opaque, decal, far, medium, close, almostNearest, nearest, postProcess
spectrum <int>	Spectrums are used for "invisible writing" that can only be illuminated by a light of matching spectrum
deform <type>	Type is one of: sprite, tube, flare, expand, move, turbulent, eyeBall, particle, particle2
decalInfo <staySeconds> <fadeSeconds> [start rgb] [end rgb]	Used in decal materials to set how long the decal stays, and how it fades out.
renderbump <args...>	Renderbump command options, without "renderbump" at the start
diffusemap <map>	shortcut for { blend diffusemap map <map> }
specularmap <map>	shortcut for { blend specularmap map <map> }
bumpmap <map>	shortcut for { blend bumpmap map <map> }
DECAL_MACRO	shortcut for polygonOffset 1 discrete sort decal noShadows

Global Keywords for light materials

noShadows	This light doesn't cast shadows
forceShadows	fog, blend, and ambient lights don't cast shadows by default. This forces them to cast shadows
noPortalFog	This fog volume won't ever consider a portal fogged out
fogLight	Option to fill with fog from viewer instead of light from center
blendLight	Perform simple blending of the projection, instead of interacting with bumps and textures
ambientLight	An ambient light has non-directional bump mapping and no specular
lightFalloffImage <map>	specifies the image to use for the third axis of projected light volumes

Global Surface Parameters

solid may need to override a clearSolid water used for water playerclip solid to players monsterclip solid to monsters moveableclip solid to moveable entities ikclip solid to IK blood used to detect blood decals trigger used for triggers aassolid solid for AAS aasobstacle used to compile an obstacle into AAS that can be enabled/disabled flashlight_trigger used for triggers that are activated by the flashlight nonsolid clears the solid flag nullNormal renderbump will draw as 0x80 0x80 0x80, which won't collect light from any angle areaportal divides areas qer_nocarve don't cut brushes in editor discrete surfaces should not be automatically merged together or clipped to the world, because they represent discrete objects like gui shaders mirrors, or autosprites noFragment dmap won't cut surface at each bsp boundary slick affects game physics (not implemented?) collision collision surface. if a model has no collision surfaces, then all surfaces are considered collision surfaces noimpact don't make impact explosions or marks nodamage no falling damage when hitting ladder player can climb up this surface nosteps no footstep sounds metal metal stone stone flesh flesh wood wood cardboard cardboard liquid liquid glass glass plastic plastic ricochet behaves like metal but causes a ricochet sound surftype10 not used surftype11 surftype12 surftype13 surftype14 surftype15

Stage Keywords

blend <type> blend <src>, <dst>

Blend types: Type Src Dst

blend gl_src_alpha gl_one_minus_src_alpha 
add gl_one gl_one 
filter gl_dst_color gl_zero 
modulate gl_dst_color gl_zero 
none gl_zero gl_one 
bumpmap Normal map 
diffusemap Diffuse map 
specularmap Specular map 

Source blend modes: gl_one Constant 1

gl_zero Constant 0 
gl_dst_color The color currently on the screen 
gl_one_minus_dst_color One minus the color currently on the screen 
gl_src_alpha The alpha channel of the source image 
gl_one_minus_src_alpha One minus the alpha channel of the source image 
gl_dst_alpha The alpha channel of the screen image 
gl_one_minus_dst_alpha One minus the alpha channel of the screen image 
gl_src_alpha_saturate Minimum of the source alpha and one minus screen alpha 

Destination blend modes: gl_one Constant 1

gl_zero Constant 0 
gl_src_color The color of the source image 
gl_one_minus_src_color One minus the color of the source image 
gl_src_alpha The alpha channel of the source image 
gl_one_minus_src_alpha One minus the alpha channel of the source image 
gl_dst_alpha The alpha channel of the screen image 
gl_one_minus_dst_alpha One minus the alpha channel of the screen image 

map <map> The image program to use for this stage remoteRenderMap <int> <int> Width and Height of the buffer to render a remote image in to (for cameras). The entity this material is applied to has to support remote render views. mirrorRenderMap <int> <int> Width and Height of the buffer to render a mirror in to. This of course makes this stage a mirror stage, which is different from using the 'mirror' global keyword because that makes the entire material a mirror, rather than just one stage. videomap [loop] <file> This stage uses a video stream as an image map soundmap [waveform] This stage uses a sound meter from the sound system as an image map. Specify 'waveform' to get a scope rather than bars. cubeMap <map> This stage uses a cube map as the image map. Looks for _px, _py, _pz, _nx, _ny, _nz for the positive x, y, z, and negative x, y, z sides cameraCubeMap <map> This stage uses a cube map in camera space. Looks for _forward, _back, _left, _right, _up, and _down ignoreAlphaTest Always use DEPTHFUNC_LEQUAL rather than DEPTHFUNC_EQUAL which is normally used for opaque and alpha tested surfaces nearest Use nearest texture filtering linear Use linear texture filtering clamp Same as the global keywords. Use to override a global clamp for a specific stage. zeroclamp alphazeroclamp noclamp Use to set texture repeat for a stage when global clamp is set uncompressed Do not compress this image in medium quality mode highquality forceHighQuality Do not compress this image in low quality mode nopicmip Ignore the image_downSize cvar vertexColor Multiply the pixel color by the vertex color inverseVertexColor Multiply the pixel color by one minus the vertex color privatePolygonOffset <float> Explict larger (or negative) polygon offset for this stage texGen <type> Type is one of: normal, reflect, skybox, wobbleSky <exp> <exp> <exp> scroll <exp>, <exp> Scroll the texture coordinates translate <exp>, <exp> scale <exp>, <exp> Just scales without a centering centerScale <exp>, <exp> Subtracts 0.5, then scales, then adds 0.5 shear <exp>, <exp> Subtracts 0.5, then shears, then adds 0.5 rotate <exp> Subtracts 0.5, then rotates, then adds 0.5 maskRed Don't write to the red channel maskGreen Don't write to the blue channel maskBlue Don't write to the green channel maskAlpha Don't write to the alpha channel maskColor Shortcut for maskRedmaskGreenmaskBlue maskDepth Don't write to the depth buffer alphaTest <exp> Only write if the alpha value is greater than <exp> red <exp> Set the red vertex color green <exp> Set the green vertex color blue <exp> Set the blue vertex color alpha <exp> Set the alpha vertex value rgb <exp> Shortcut for red <exp>green <exp>blue <exp> rgba <exp> Shortcut for red <exp>green <exp>blue <exp>alpha <exp> color <exp0>, <exp1>, <exp2>, <exp3> Shortcut for red exp0green exp1blue exp2alpha exp3 colored Shortcut for color parm0, parm1, parm2, parm3 if <exp> Conditionally disable stages fragmentProgram <prog> Use an ARB fragment program with this stage vertexProgram <prog> Use an ARB vertex program with this stage program <prog> Shortcut for fragmentProgram <prog>vertexProgram <prog> vertexParm <index> <exp0> [,exp1] [,exp2] [,exp3] Values to pass to the vertex program. One expression gets repeated across all 4 values. Two expressions put 0, 1 in z, w. Three expressions put 1 in w. fragmentMap <index> [options] <map> The image map to use for texture unit <index> [options] can be cubeMap, cameraCubeMap, nearest, linear, clamp, noclamp, zeroclamp, alphazeroclamp, forceHighQuality, uncompressed, highquality, or nopicmip megaTexture <mega> This stage uses a mega texture (super secret)

Parameters Key

<float> Any number <int> Any number without a fractional part <string> Any value enclosed in quotes <index> An integer number that is an index into an array <map> An image map, which may include image programs (below) <prog> A vertex / frament program. Written using the GL ARB shader language. These files are stored in the glprogs directory <exp> An expression that is evaluated every frame.

Image Program Functions

These can be used anywhere that accepts <map> and can be nested heightmap(<map>, <float>) Turns a grayscale height map into a normal map. <float> varies the bumpiness addnormals(<map>, <map>) Adds two normal maps together. Result is normalized. smoothnormals(<map>) Does a box filter on the normal map, and normalizes the result. add(<map>, <map>) Adds two images without normalizing the result scale(<map>, <float> [,float] [,float] [,float]) Scales the RGBA by the specified factors. Defaults to 0. invertAlpha(<map>) Inverts the alpha channel (0 becomes 1, 1 becomes 0) invertColor(<map>) Inverts the R, G, and B channels makeIntensity(<map>) Copies the red channel to the G, B, and A channels makeAlpha(<map>) Sets the alpha channel to an average of the RGB channels. Sets the RGB channels to white.