de.grogra.imp3d.objects
Class PhysicalLight

java.lang.Object
  de.grogra.persistence.ShareableBase
      de.grogra.imp3d.objects.LightBase
          de.grogra.imp3d.objects.PointLight
              de.grogra.imp3d.objects.PhysicalLight

All Implemented Interfaces:

Raytraceable, Manageable, Shareable, Emitter, Light, Scattering

public class PhysicalLight
extends PointLight

Nested Class Summary

static class

PhysicalLight.Type

Field Summary

static PhysicalLight.Type	$TYPE
static SCOType.Field	distribution$FIELD

Fields inherited from class de.grogra.imp3d.objects.PointLight

attenuationDistance$FIELD, attenuationExponent$FIELD, power$FIELD

Fields inherited from class de.grogra.imp3d.objects.LightBase

color$FIELD, shadowless$FIELD

Fields inherited from interface de.grogra.ray.physics.Light

AMBIENT, AREA, DIRECTIONAL, NO_LIGHT, POINT, SKY

Fields inherited from interface de.grogra.ray.physics.Scattering

DELTA_FACTOR, IS_NON_OPAQUE, MIN_UNUSED_FLAG, NEEDS_NORMAL, NEEDS_POINT, NEEDS_TANGENTS, NEEDS_TRANSFORMATION, NEEDS_UV, RANDOM_RAYS_GENERATE_ORIGINS

Constructor Summary

PhysicalLight()
physical light constructor

PhysicalLight(double[][] distribution)
physical light constructor

PhysicalLight(LightDistribution distribution)
physical light constructor

Method Summary

void	generateRandomRays(Environment env, Vector3f out, Spectrum specOut, RayList rays, boolean adjoint, java.util.Random rnd) Pseudorandomly generates, for the given input, a set of scattered rays.
protected float	getDensityAt(Vector3f direction)
LightDistribution	getDistribution()
ManageableType	getManageableType()
void	setDistribution(double[][] distribution) sets the light emission dsitribution
void	setDistribution(Light light) sets the light emission dsitribution by discretizing the emission distribution of an existing light source
void	setDistribution(LightDistribution value)

Methods inherited from class de.grogra.imp3d.objects.PointLight

accept, computeBSDF, computeExitance, createRaytracerLeaf, generateRandomOrigins, getAttenuationDistance, getAttenuationExponent, getLightType, getPower, getTotalPower, setAttenuationDistance, setAttenuationExponent, setPower

Methods inherited from class de.grogra.imp3d.objects.LightBase

completeRay, draw, getAverageColor, getColor, getFlags, isIgnoredWhenHit, isShadowless, setShadowless

Methods inherited from class de.grogra.persistence.ShareableBase

addReference, appendReferencesTo, fieldModified, getProvider, getStamp, initProvider, manageableReadResolve, manageableWriteReplace, removeReference

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

$TYPE

public static final PhysicalLight.Type $TYPE

distribution$FIELD

public static final SCOType.Field distribution$FIELD

Constructor Detail

PhysicalLight

public PhysicalLight()

physical light constructor

PhysicalLight

public PhysicalLight(double[][] distribution)

physical light constructor

Parameters:

distribution - is the 2D discretized light emission distribution over the unit sphere

PhysicalLight

public PhysicalLight(LightDistribution distribution)

physical light constructor

Parameters:

distribution - is the light emission distribution over the unit sphere

Method Detail

generateRandomRays

public void generateRandomRays(Environment env,
                               Vector3f out,
                               Spectrum specOut,
                               RayList rays,
                               boolean adjoint,
                               java.util.Random rnd)

Description copied from interface: Scattering

Pseudorandomly generates, for the given input, a set of scattered rays. The scattered rays are generated such that they can be used for a Monte Carlo integration of a function f(ω;ν) over cos θ BSDF(ω_i, ν_i; ω_o, ν_o) in the following way:

• If adjoint is false, out = ω_o describes the direction of an outgoing light ray. In this case, the integration is with respect to ω_i. Let g(ω, ν; out, μ) = BSDF(ω, ν; out, μ)
• Otherwise, adjoint is true. In this case, out = ω_i describes the direction of an outgoing importance ray (an inverse light ray). Now the integration is with respect to ω_o. Let g(ω, ν; out, μ) = BSDF(out, μ; ω, ν)

Let d_i and s_i denote the directions and spectra of the N generated rays (N = rays.size). Then, for every frequency ν the sum 1 / N ∑_i s_i(ν) f(d_i; ν) is an unbiased estimate for the integral ∫ cos θ f(ω; ν) g(ω, ν; out, μ) specOut(μ) dμ dω θ is the angle between the surface normal and ω. The domain of integration is the whole sphere, since the bidirectional scattering distribution includes both reflection and transmission (BSDF = BRDF + BTDF).

If this Scattering instance is in fact a Light source, adjoint is true, and the BSDF is defined as BSDF(out, μ; ω, ν) = L¹(ω, ν) δ(μ - ν), i.e., the directional distribution of the emitted radiance at env.point, see Emitter. In this case, out is not used.

If this Scattering instance is in fact a Sensor, adjoint is false, and the BSDF is defined as BSDF(ω, ν; out, μ) = W¹(ω, ν) δ(μ - ν), i.e., the directional distribution of the emitted importance at env.point, see Emitter. In this case, out is not used.

Let p_ω be the probability density used for the ray direction (measured with respect to solid angle ω), then the field directionDensity of the ray i is set to p_ω(d_i). For ideal specular reflection or transmission, or for directional lights or sensors, p_ω is not a regular function, the value directionDensity will be set to a multiple of Scattering.DELTA_FACTOR.

The ray properties which are not mentioned in the given formulas are neither used nor modified. These are the origin and its density.

Specified by:

generateRandomRays in interface Scattering

Overrides:

generateRandomRays in class PointLight

Parameters:

env - the environment for scattering

out - the direction unit vector of the outgoing ray (i.e., pointing away from the surface)

specOut - the spectrum of the outgoing ray

rays - the rays to be generated

adjoint - represents out a light ray or an importance ray?

rnd - pseudorandom generator

See Also:

Scattering.computeBSDF(de.grogra.ray.physics.Environment, javax.vecmath.Vector3f, de.grogra.ray.physics.Spectrum, javax.vecmath.Vector3f, boolean, de.grogra.ray.physics.Spectrum)

getDensityAt

protected float getDensityAt(Vector3f direction)

Overrides:

getDensityAt in class PointLight

getDistribution

public LightDistribution getDistribution()

getManageableType

public ManageableType getManageableType()

Specified by:

getManageableType in interface Manageable

Overrides:

getManageableType in class PointLight

setDistribution

public void setDistribution(double[][] distribution)

sets the light emission dsitribution

Parameters:

distribution - is the 2D discretized light emission distribution over the unit sphere

setDistribution

public void setDistribution(Light light)

sets the light emission dsitribution by discretizing the emission distribution of an existing light source

Parameters:

light - is used to construct a discretized emission distribution

setDistribution

public void setDistribution(LightDistribution value)