RVMAT basics

Theory

Lighting

Lighting and shading are what make 3D scene appealing. In real-time render we still have to simplify so the Artist must understand how shading works in engine to be able prepare the best realistic looking surfaces.

Real Virtuality counts lighting as T * (D.o + A) + S.o:

• T = texture color
• D = diffuse lighting (color, intensity and direction. ARMA engine has just one light source of directional light - sun or moon.) D is calculated as max(L.N,0)*sunLightColor - where L is light direction, N is surface direction (normal)
• A = ambient lighting (color and intensity. It is always present at same intensity all over the scene and its value is done by overcast setting)
• S = specular (setting of material glossiness and specularity)
• o = direction of light (1 = pixel is lit, 0 = pixel is in shadow)

Simple materials count lighting per vertex by interpolating light direction between face edges (normals). It is similar to well known Gouraud shading model. More complex materials use per pixel normal orientation.

Values for shading calculations are combined from textures, effect bitmaps, engine light settings (config) and material settings (.rvmat).

Shadows

Shadows are calculated in ARMA engine two types, depending on values in Video options and each model setting.

Stencil buffer shadows are sharp and they are added after the whole scene has been drawn. Engine just subtracts diffuse light value on places where stencil shadow volume appeared. This results in speculars still being present in shadows. Also when ambient and diffuse settings of the material are not equal (and ForceDiffuse!=0) then resulting color isn't correct.

Shadow buffer makes one soft shadow map calculated on GCard for whole scene from the viewport. This affects the precision of the shadow.

Glossiness

Material specularity is defined by a curve (Bidirectional reflectance function) that says how much light is reflected under all angles. In Real Virtuality we are able to use:

• Specular Power
• Irradiance Table
• Fresnel values

in .rvmat files.

Sections

Textures and materials are linked to each face separately so artist can have various materials on surface mapped with a single texture.

Everytime when Graphics Card (GPU) is instructed to draw with new parameters, we call it scene section. It is usually when new object (*.p3d), texture or material appears. Sections are generated each time when there is need to change parameters for rendering on Graphical Card (GPU). This is always when loading information from CPU about independent OBJECT, TEXTURE, MATERIAL or bone limit is exceeded on the card. Overhead in instruction transfer between CPU and GPU then lowers rendering performance which could be used to render hundreds polygons or textures etc.

Texture (TGA) is assigned to individual faces. Material (RVMAT) is assigned to same faces separately thus it is possible use various materials on surface covered with one UV and CO map. Yet then are generated another sections. In STAGE 0 is possible change with RVMAT also difusse component texture. Sections may differ in individual LODs.

Procedural textures

Besides TGA/PAA textures, Real Virtuality can work with maps generated in real-time procedurally - see Procedural Textures.

Normal Map

The Normal maps used in Arma are Tangent-space maps with the X+ Y- orientation (same as in Unreal Engine and 3dsmax renderer default setting).

RVMAT files

Those files are a sort of config.

Basic Surface Setting

Ambient

Ambient[] = { 0.9, 0.9, 0.9, 1 };

multiplies color values (color texture R,G,B,A) of the surface that is not lit by the main directional light.

Diffuse

Diffuse[] = { 0.9, 0.9, 0.9, 1 };

multiplies color values of the surface that lit by main directional light.

ForcedDiffuse

ForcedDiffuse[] = { 0, 0, 0, 0 };

those values help to simulate so called Translucency; part of the diffuse lighting that is reflected on surface in shadow. It works similar to ambient but with different lighting component. Unfortunately some shaders do not work well with forcedDiffuse.

ambient[] = { 1, 1, 1, 1 };
Diffuse[] = { 0.5, 0.5, 0.5, 1 };
ForcedDiffuse[] = { 0.5, 0.5, 0.5, 0 };

This combination makes the same result as the old HalfLighted vertex property (surface is lit the same from all sides, it appears flat)

For foliage surfaces there are special shaders that use also forcedDiffuse Alpha value setting for calculating how much light goes through (1 = all).

Emmisive

emmisive[] = { 0, 0, 0, 0 };

Emmisive^sic - also called Luminescence. Values give amount of light that surface shines by himself. Use it for light-sources. It will appeal shining but will not lit anything around.

Specular

specular[] = { 0.3, 0.3, 0.3, 0 };

Used for making so called hotspot (in max it is Specular level+specular color). It is part of the light that is reflected from surface. Specular is calculated poer vertex or per pixel depending od specific shader.

SpecularPower

specularPower = 40;

Also called Glossiness. Defines how sharp the hot-spot will be. Some shaders use IRRADIANCE TABLE instead of this value.

ⓘ

• All above mentioned settings can be calculated in some shaders per pixel using effect bitmaps.
• All components are together used in calculation of surface shading:

pixel RGB on screen = (RVMAT ambient * RGB texture * Environment ambient)
+ (RVMAT diffuse * RGB texture * Environment diffuse * light direction)
+ (RVMAT forced diffuse * RGB texture * Environment diffuse)
+ (RVMAT emissive material * RGB texture)
+ (RVMAT specular * Environment diffuse * light direction)

Color values are usually in range 0-1, but it can be more. ARMA engine calculates light in high dynamic range, with values exceeding 0-255 RGB depth. Final RGB in monitor is calculated for each frame depending od eye/optics Aperture (shutter) settings setAperture/setApertureNew.

Realistic surfaces do not reflect 100% of incoming light. The more light is reflected as specular the less diffuse it has. Sum of diffuse, forced diffuse and reflected light should not exceed 1 BUT this is not true on ArmA real-time materials that do render just sunlight hot-spot and miss environmental light.

Diffuse for many usual surfaces is between 40%-80%. If you aim for maximum realistic surface settings, study photoreference. RVMAT settings allow you to put as much color range as possible in texture and than modify it to realistic values with maximum dynamic range.

Realistic surfaces usually reflect directional and scattered light the same way - Diffuse and Ambient are equal. Real Virtuality has environment settings with values for diffuse and ambient (scene contrast) based on real world light recording. Color Calibration. It is not wise to compensate contrast in material settings.

Lower diffuse values are used for spongy materials (some light is transfered to forceDiffuse). Lower ambient values can be used on surfaces where global ambient should be reduced, such as Interiors. It is usually made using Ambient Light maps.

Specular color

Usually we set RGB values color neutral. But sometimes it is effective to tint color in rvmat. Most obvious it is in specular settings of some glossy metal surfaces.

If I want a specific color, I count:

X = B / (Sp * Db)

B.. desired color of hot-spot

Sp.. actual Specular setting of hot-spotmaterial

Db.. color of environment light (Ambient and Diffuse change during day and overcast) O2 environment editor shows actual colors used in buldozer preview.

X ..number that i use to multiply Specular to get desired color.

RenderFlags

Special shading property that are used instead of old VERTEX LIGHTING PROPERTY settings.

renderFlags[] = { flag1, flag2 };

Flag Name	Description
NoZWrite	Face is not count in Z-buffer. Used for alpha-transparent surfaces laid over another faces to fix shadow artifacts. (for example squad logo)
NoColorWrite	Disables calculation in color channels. Face is calculated just in alpha and Z-buffer.
NoAlphaWrite	Disables calculation in alpha channels. Used for transparent glass that has 2 pass material.
AddBlend	Allows adding alpha-transparent surface color to the background. Used for fire particles.
LandShadow	For terrain.
AlphaTest32 Alphatest64 Alphatest128	Defines threshold where pixel becomes transparent at drop off to discrete alpha. The bigger value, the more pixels are used
Road
NoTiWrite
NoReceiveShadow
NoLODBlend
Dummy0

Always in Shadow can be achieved with setting RVMAT diffuse[] = { 0, 0, 0, 0 } + reasonable specular reduction.

Light Mode

Setting of various kinds of light calculation:

mainLight = "Sun";

Possible values are:

• None
• Sun
• Sky
• Horizon
• Stars
• SunObject
• SunHaloObject
• MoonObject
• MoonHaloObject

Fog Mode

Setting of various kinds of fog calculation:

fogMode = "Alpha";

Possible values are:

• none - no fog
• fog - fog used by usual opaque objects; the more the object is covered by fog, the closer its color is to fog color
• alpha - fog used by objects with alpha; the more the object is covered by fog, the more transparent it is
• fogAlpha - combination of both above approaches; used for roads (alpha-out could be quicker than fogging); can be used to fade away objects when object is not just normally fogging
• fogSky - fog for sky objects (moon, stars)

Shader-Specific Setting

Selecting shader.

PixelShaderID = "xxx";
VertexShaderID = "xxx";

Each shader uses specific "Stages".

class StageX

Each stage define parameters for shader calculation, usually as links to effect bitmaps.

• texture = (name and path to effect bitmap texture)

Must obey texture naming conventions Texture Naming Conventions otherwise there will be no proper automatic conversion made from TGA to PAA.

• Filter = "Anizotropic";

Default is Anizotropic, but in some situations you can use Point, Linear, Trilinear.

• uvSource = "tex";

can be: none, tex, tex1 (second UV set), pos, norm, worlPos, worldNorm, texShoreAnim, texCollimator, texCollimatorInv

• class uvTransform

Offset, deformation or repeating ot texture in given UV set.

Material Types

Inside O2 Material editor exist examples for most of shaders - see Oxygen 2 - Manual - MAT plugin.

Show Material Types

Wikipage	Vertex shader	Pixel shader	Notes
Material - General material	Basic	Normal
Material - DXTA material	Basic	NormalDXTA
Material - Basic detail map	Basic	Detail
	Basic	White
	Basic	WhiteAlpha
Material - Basic glass	Basic	AlphaShadow
Material - Normal map	NormalMap	NormalMap
Material - Normal map HQ specular	NormalMap	NormalMapSpecularMap	NOHQ+SM
	NormalMap	NormalMapSpecularDIMap	NOHQ+SMDI
Material - Normal map HQ detail map specular	NormalMap	NormalMapDetailSpecularMap	NOHQ+DT+SM
	NormalMap	NormalMapDetailSpecularDIMap	NOHQ+SMDI+DT
Material - Basic normal detail	NormalMapDiffuse	NormalMapDiffuse	NormalMapDetail, per vertex lit
	Water	Water
Material - Water simple	WaterSimple	WaterSimple
	NormalMapThrough	NormalMapThrough
	NormalMapThrough	NormalMapThroughSimple
Material - Basic Tree crown	NormalMapSpecularThrough	NormalMapSpecularThrough	TreeCrown - colormap must be with continuous alpha
	NormalMapSpecularThrough	NormalMapSpecularThroughSimple
	NormalMapThroughNoFade	NormalMapThrough
	NormalMapThroughNoFade	NormalMapThroughSimple
	NormalMapSpecularThroughNoFade	NormalMapSpecularThrough
	NormalMapSpecularThroughNoFade	NormalMapSpecularThroughSimple
Material - Detail macro AS	BasicAS	DetailMacroAS	DT+MC+AS
Material - Normal map macro AS	NormalMapAS	NormalMapMacroAS
Material - Normal map HQ specular macro AS	NormalMapAS	NormalMapMacroASSpecularMap	NOHQ+MC+AS+SM
	NormalMapAS	NormalMapMacroASSpecularDIMap	NOHQ+SMDI+MC+AS
Material - Normal map HQ detail specular macro AS	NormalMapAS	NormalMapDetailMacroASSpecularMap	NOHQ+DT+MC+AS+SM
	NormalMapAS	NormalMapDetailMacroASSpecularDIMap	NOHQ+SMDI+DT+MC+AS
Material - Normal map detail macro AS	NormalMapDiffuseAS	NormalMapDiffuseMacroAS	NO+DT+MC+AS
Material - Basic glass reflectance	Glass	Glass
Terrain	TerrainX		X is number from 1 to 15 and presents mask as per which is choosen combination from 4 layers
Material - Antiwater	Basic	AlphaNoShadow	in combination with empty alpha texture clears water from ship and is shadowless
Terrain	TerrainSimpleX		X is number from 1 to 15 and presents mask as per which is choosen combination from 4 layers
Super_shader	Super	Super	SM 3.0 - shader with Fresnel for Arma 2
Multimaterial	Multi	Multi	SM 3.0 - shader with multiple submaterials for Arma 2
Material - Tree	Tree	TreeNoFade	SM 3.0 - shader for Arma 2 vegetation
Material - TreePRT	TreePRT	TreePRT	SM 3.0 - shader for Arma 2 vegetation
Skin_shader

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Shaders

Pixel Shaders

Show Pixel Shaders

Shader Name	Description
Normal	diffuse color modulate, alpha replicate
NormalDXTA	diffuse color modulate, alpha replicate, DXT alpha correction
NormalMap	normal map shader
NormalMapThrough	normal map shader - through lighting
NormalMapGrass	normal map shader - through lighting
NormalMapDiffuse
Detail	detail texturing
Interpolation
Water	sea water
WaterSimple	small water
White
WhiteAlpha
AlphaShadow	shadow alpha write
AlphaNoShadow	shadow alpha (no shadow write
Dummy0
DetailMacroAS	detail with ambient shadow texture
NormalMapMacroAS	normal map with ambient shadow texture
NormalMapDiffuseMacroAS	diffuse normal map with ambient shadow texture
NormalMapSpecularMap	normal map with specular map
NormalMapDetailSpecularMap	normal map with detail and specular map
NormalMapMacroASSpecularMap	normal map with ambient shadow and specular map
NormalMapDetailMacroASSpecularMap	normal map with detail and ambient shadow and specular map
NormalMapSpecularDIMap	normal map with specular map, diffuse is inverse of specular
NormalMapDetailSpecularDIMap	normal map with detail and specular map, diffuse is inverse of specular
NormalMapMacroASSpecularDIMap	normal map with ambient shadow and specular map, diffuse is inverse of specular
NormalMapDetailMacroASSpecularDIMap	normal map with detail and ambient shadow and specular map, diffuse is inverse of specular
Terrain1	terrain - X layers
Terrain2	terrain - X layers
Terrain3	terrain - X layers
Terrain4	terrain - X layers
Terrain5	terrain - X layers
Terrain6	terrain - X layers
Terrain7	terrain - X layers
Terrain8	terrain - X layers
Terrain9	terrain - X layers
Terrain10	terrain - X layers
Terrain11	terrain - X layers
Terrain12	terrain - X layers
Terrain13	terrain - X layers
Terrain14	terrain - X layers
Terrain15	terrain - X layers
TerrainSimple1	terrainSimple - X layers
TerrainSimple2	terrainSimple - X layers
TerrainSimple3	terrainSimple - X layers
TerrainSimple4	terrainSimple - X layers
TerrainSimple5	terrainSimple - X layers
TerrainSimple6	terrainSimple - X layers
TerrainSimple7	terrainSimple - X layers
TerrainSimple8	terrainSimple - X layers
TerrainSimple9	terrainSimple - X layers
TerrainSimple10	terrainSimple - X layers
TerrainSimple11	terrainSimple - X layers
TerrainSimple12	terrainSimple - X layers
TerrainSimple13	terrainSimple - X layers
TerrainSimple14	terrainSimple - X layers
TerrainSimple15	terrainSimple - X layers
Glass	glass shader with environmental map
NonTL	very simple 2D pixel shader
NormalMapSpecularThrough	normal map shader - through with specular lighting
Grass	grass shader - alpha discretized
NormalMapThroughSimple	simple version of NormalMapThrough shader
NormalMapSpecularThroughSimple	simple version of NormalMapSpecularThrough shader
Road	road shader
Shore	shore shader
ShoreWet	shore shader for the wet part
Road2Pass	road shader - second pass
ShoreFoam	shore shader for the foam on the top of the shore
NonTLFlare	shader to be used for flares
NormalMapThroughLowEnd	substitute shader for NormalMapThrough shaders for low-end settings
TerrainGrass1	terrain grass - X layers
TerrainGrass2	terrain grass - X layers
TerrainGrass3	terrain grass - X layers
TerrainGrass4	terrain grass - X layers
TerrainGrass5	terrain grass - X layers
TerrainGrass6	terrain grass - X layers
TerrainGrass7	terrain grass - X layers
TerrainGrass8	terrain grass - X layers
TerrainGrass9	terrain grass - X layers
TerrainGrass10	terrain grass - X layers
TerrainGrass11	terrain grass - X layers
TerrainGrass12	terrain grass - X layers
TerrainGrass13	terrain grass - X layers
TerrainGrass14	terrain grass - X layers
TerrainGrass15	terrain grass - X layers
Crater1	Crater rendering - X craters
Crater2	Crater rendering - X craters
Crater3	Crater rendering - X craters
Crater4	Crater rendering - X craters
Crater5	Crater rendering - X craters
Crater6	Crater rendering - X craters
Crater7	Crater rendering - X craters
Crater8	Crater rendering - X craters
Crater9	Crater rendering - X craters
Crater10	Crater rendering - X craters
Crater11	Crater rendering - X craters
Crater12	Crater rendering - X craters
Crater13	Crater rendering - X craters
Crater14	Crater rendering - X craters
Sprite	Shader used for sprite rendering - it uses SoftParticle approach
SpriteSimple	Shader used for sprite rendering - no SoftParticle approach
Cloud	Shader used for clouds
Horizon	Shader used for the horizon
Super	Super shader
Multi	Multi shader
TerrainX	terrain - general number of layers
TerrainSimpleX	terrainSimple - general number of layers
TerrainGrassX	terrain grass - general number of layers
Tree	Tree shader
TreePRT	Tree shader - very cheap shader with PRT
TreeSimple	Tree shader - simpler version of Tree
Skin	Human skin - derived from Super shader
CalmWater	calm water surface
TreeAToC	tree with alpha to coverage
GrassAToC	grass with alpha to coverage
TreeAdv	advanced tree crown shader
TreeAdvSimple	advanced tree crown shader
TreeAdvTrunk	advanced tree shader
TreeAdvTrunkSimple	advanced tree shader
TreeAdvAToC	advanced tree crown shader
TreeAdvSimpleAToC	advanced tree crown shader
TreeSN	Tree shader width simple noise
SpriteExtTi	Sprite used for vehicles covering
TerrainSNX	terrain - general number of layers + satellite normal map
InterpolationAlpha
VolCloud	Shader used for volumetric cloud - it uses SoftParticle approach
VolCloudSimple	Shader used for volumetric cloud - no SoftParticle approach
UnderwaterOcclusion	Shader used for underwater occlusion object
SimulWeatherClouds	SimulWeather clouds
SimulWeatherCloudsWithLightning	SimulWeather clouds with lightning
SimulWeatherCloudsCPU	SimulWeather clouds with CPU distance fading
SimulWeatherCloudsWithLightningCPU	SimulWeather clouds with lightning and CPU distance fading
SuperExt	skyscraper & building, intended as super shader light version
SuperHair	super shader for hair rendering
SuperHairAtoC	super shader for hair rendering, atoc version
Caustics	shader for caustics effect
Refract	shader for refractions _ARMA3_REFRACTION
SpriteRefract	_ARMA3_REFRACTION_SPRITES - Shader used for sprite rendering with refraction - it uses SoftParticle approach
SpriteRefractSimple	_ARMA3_REFRACTION_SPRITES - Shader used for sprite rendering with refraction- no SoftParticle approach
SuperAToC	Super shader AToC variant
NonTLFlareNew	shader to be used for flares, new HDR version
NonTLFlareLight	shader to be used for flares from dynamic lights (not sun)
TerrainNoDetailX	terrainX without detail map
TerrainNoDetailSNX	terrainSNX without detail map
TerrainSimpleSNX	terrainSNX without parallax mapping
NormalPiP	shader for PiP screens
NonTLFlareNewNoOcclusion	same as NonTLFlareNew, but without occlusion test
Empty	empty shader, does not output anything (used only for depth output)
Point	Shader used for point lights
TreeAdvTrans	same as TreeAdv, but there is translucency map in alpha channel of MCA texture ( instead of AO)
TreeAdvTransAToC	same as TreeAdv, but there is translucency map in alpha channel of MCA texture ( instead of AO)
Collimator	special shader for collimator
LODDiag	shader for lod diagnostics
DepthOnly	Special replacement for AlphaOnly for priming non- alpha objects

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Vertex Shaders

Show Vertex Shaders

Shader Name	Description
Basic	N/A
NormalMap	normal map
NormalMapDiffuse	normal map + detail map
Grass
Dummy1
Dummy2
ShadowVolume	shadow volumes
Water	per-vertex water animation
WaterSimple	per-vertex water animation (without foam)
Sprite	particle effects
Point	anti-aliased points
NormalMapThrough	normal map - tree shader
Dummy3
Terrain	one pass terrain, no alpha mask - based on VSNormalMapDiffuse
BasicAS	ambient shadow
NormalMapAS	normal map with ambient shadow
NormalMapDiffuseAS	diffuse normal map with ambient shadow Glass /*glass shader*/ \
NormalMapSpecularThrough	normal map with specular - tree shader
NormalMapThroughNoFade	normal map - tree shader - without face fading
NormalMapSpecularThroughNoFade	normal map with specular - tree shader - without face fading
Shore	sea shore - similar to Terrain
TerrainGrass	grass layer - similar to Terrain
Super	Super shader - expensive shader containing all common features
Multi	Multi shader - shader with multiple layers suitable for huge surfaces like houses
Tree	Tree shader - cheap shader designed for trees and bushes
TreeNoFade	Tree shader - cheap shader designed for trees and bushes - without face fading
TreePRT	Tree shader - very cheap shader designed for trees and bushes
TreePRTNoFade	Tree shader - very cheap shader designed for trees and bushes - without face fading
Skin	Human skin - derived from Super shader
CalmWater	calm water surface - special shader
TreeAdv	advanced tree crown shader VSTreeAdv
TreeAdvTrunk	advanced tree crown shader VSTreeAdvTrunk
VolCloud	volumetric clouds
Road	roads
UnderwaterOcclusion	underwater occlusion object vertex shader
SimulWeatherClouds	simul weather clouds
SimulWeatherCloudsCPU	simul weather clouds with CPU distance fading
SpriteOnSurface	sprite on surface
TreeAdvModNormals	advanced tree crown shader with modified vertex normals
Refract	vertex shader for refractions - _ARMA3_REFRACTION
SimulWeatherCloudsGS	simul weather clouds with geom shader
BasicFade	basic with face fading (based on the angle with camera direction
Star	Similar to Point but only for drawing stars
TreeAdvNoFade	advanced tree crown shader - no face fading

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You can find More about material settings in Material Templates.

Physical Properties

Materials are also used in geometries for definition of physical properties.

Parameters for engine are saves into material tables *.bisurf and reference to them from material looks like:

surfaceInfo = "data\wood.bisurf";

Such .bisurf file with physical properties looks like:

density = 2500;				// density of homogeneous object in kg/m³ - see https://en.wikipedia.org/wiki/List_of_elements_by_density
thickness = 10;				// non-homogeneous component casing thickness in mm, implemented since Arma 2: Operation Arrowhead
rough = 0.1;
dust = 0.1;
bulletPenetrability = 150;	// distance in mm bullet (with speed 1000m/s) travels before it fully stops, simulation for calculation simplification calculate linear braking
							// (ergo on third of distance is bullet decelerated to two thirds of original speed)
soundEnviron = Empty;
isWater = false;

See more about penetration in Bullet penetrability.

When components in Your model got materials with references to physical properties then use script which sets weight.