Shady.Lighting

Lighting/shading. Adapted from Vertigo.

Documentation

data LightInfo

Info about how one light affects a given point. The surface lighter decides what to do with the light info. Attenuation and relation of light position (if finitely distant) to surface position are already accounted for. liDir is the direction to the light (normalized).

Constructors

LI

Fields

liColor :: Color

liDir :: Dir3E

type Light = R3E -> LightInfo

A light is something that provides light info to every point in space (though to some points it provides blackness), independent of obstructions. Should probably also take an atmosphere argument.

data View

Viewing environment: ambient, eye, lights

Constructors

View

Fields

viewAmbient :: Color

viewEye :: R3E

viewLights :: [Light]

data SurfInfo

Info about a surface at a point: position, normal, color

Constructors

SurfInfo

Fields

surfPos :: R3E

surfNormal :: Dir3E

surfColor :: Color

type Lighter a = View -> SurfInfo -> a

View-dependent lighter

type LLighter a = LightInfo -> Lighter a

Light- and view-dependent lighter

ambient :: Lighter Color

Ambient color

eye :: Lighter R3E

Eye point

lights :: Lighter [Light]

Lights

surfP :: Lighter R3E

Surface point

surfN :: Lighter Dir3E

Surface normal

intrinsic :: Lighter Color

Surface Color

colorL :: LLighter Color

Light color

dirL :: LLighter R3E

Direction to light

illuminance :: (AdditiveGroup a, IfB BoolE a) => LLighter a -> Lighter a

Combine contributions from multiple lights. Patterned after Renderman's illuminance construct.

diffuse :: Lighter Color

Pure diffuse

ambDiff :: (Color, Color) -> Lighter Color

Weighted combination of ambient and diffuse

eyeDir :: Lighter Dir3E

The Stanford rtsl version, with ambient and weights:

surface float4 lightmodel_diffuse (float4 ka, float4 kd) { perlight float diffuse = dot(N,L); perlight float4 fr = kd * select(diffuse > 0, diffuse, 0); return ka * Ca + integrate(fr * Cl); }

Direction from surface point to eye

eyeLight :: LLighter Dir3E

Eye/light vector average (CGPP p 731)

reflection :: LLighter Dir3E

Reflection vector (CGPP p 730)

specularG :: LLighter FloatE -> FloatE -> Lighter Color

Pure specular. Ignores intrinsic surface color. There are different ways to compute the power base.

specularRV :: FloatE -> Lighter Color

specularNH :: FloatE -> Lighter Color

Or the N.H model:

type BasicSh = (Color, Color, Color, FloatE) -> Lighter Color

surface floatv lightmodel_specular (floatv s, floatv e, float sh) { perlight float diffuse = dot(N,DIRL); perlight float specular = pow(max(dot(N,H),0),sh); perlight floatv fr = select(diffuse > 0, s * specular, Zero); return integrate(fr * Cl) + e; }

basic :: LLighter FloatE -> BasicSh

Combine intrinsic, ambient, diffuse and specular, with weightings

basicRV :: BasicSh

basicNH :: BasicSh

class Liftable k f where

surface float4 lightmodel (float4 a, float4 d, float4 s, float4 e, float sh) { perlight float diffuse = dot(N,DIRL); perlight float specular = pow(max(dot(N,H),0),sh); perlight float4 fr = d * max(diffuse, 0) + s * select(diffuse > 0, specular, 0); return a * Ca + integrate(fr * Cl) + e; }

Methods

lift :: k -> f

Instances

Liftable a a

Liftable d (a -> b -> c -> d)

Liftable c (a -> b -> c)

Liftable b (a -> b)

type Dir3E = R3E

Direction. Assumed normalized.

dirLight :: Color -> Dir3E -> Light

Directional light, given the direction from the light (opposite dirL)

pointLight :: Color -> R3E -> Light

Point light

stdViewPos :: R3E

stdView :: R3E -> [Light] -> View

View with white ambient light and given eye position and lights

view1 :: R3E -> View

View with white ambient light, one directional light, and given eye position. For now, light position is like eye position but more so.

ma :: Color

md :: Color

ms :: Color

msh :: FloatE

basicStd :: Lighter Color