de.grogra.imp3d.objects
Class SpotLight

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

All Implemented Interfaces:

Raytraceable, Manageable, Shareable, Emitter, Light, Scattering

public class SpotLight
extends PointLight
implements Raytraceable

This class implements a spot light. Light rays are cast from the local origin, the central direction of the spot light is the local z-axis. Light rays with an angle α to the z-axis less than innerAngle have a maximal intensity, the intensity falls off to zero when the angle reaches outerAngle. The fall-off is governed by a cubic spline: Let

t = (cos α - cos outerAngle) / (cos innerAngle - cos outerAngle) then the interpolation factor is (3 - 2 t) t²

Author:

Ole Kniemeyer

Nested Class Summary

static class

SpotLight.Type

Field Summary

static SpotLight.Type	$TYPE
static SCOType.Field	innerAngle$FIELD
static SCOType.Field	outerAngle$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

SpotLight()

Method Summary

void	accept(LightVisitor visitor)
RaytracerLeaf	createRaytracerLeaf(java.lang.Object object, boolean asNode, long pathId, GraphState gs)
protected void	draw(Tuple3f color, RenderState rs)
void	generateRandomRays(Environment env, Vector3f out, Spectrum specOut, RayList rays, boolean photon, java.util.Random rnd) Pseudorandomly generates, for the given input, a set of scattered rays.
protected float	getDensityAt(Vector3f direction)
float	getInnerAngle()
ManageableType	getManageableType()
float	getOuterAngle()
void	setInnerAngle(float value)
void	setOuterAngle(float value)

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

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

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

completeRay, 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 SpotLight.Type $TYPE

innerAngle$FIELD

public static final SCOType.Field innerAngle$FIELD

outerAngle$FIELD

public static final SCOType.Field outerAngle$FIELD

Constructor Detail

SpotLight

public SpotLight()

Method Detail

accept

public void accept(LightVisitor visitor)

Overrides:

accept in class PointLight

createRaytracerLeaf

public RaytracerLeaf createRaytracerLeaf(java.lang.Object object,
                                         boolean asNode,
                                         long pathId,
                                         GraphState gs)

Specified by:

createRaytracerLeaf in interface Raytraceable

Overrides:

createRaytracerLeaf in class PointLight

draw

protected void draw(Tuple3f color,
                    RenderState rs)

Overrides:

draw in class LightBase

generateRandomRays

public void generateRandomRays(Environment env,
                               Vector3f out,
                               Spectrum specOut,
                               RayList rays,
                               boolean photon,
                               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

photon - 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

getInnerAngle

public float getInnerAngle()

getManageableType

public ManageableType getManageableType()

Specified by:

getManageableType in interface Manageable

Overrides:

getManageableType in class PointLight

getOuterAngle

public float getOuterAngle()

setInnerAngle

public void setInnerAngle(float value)

setOuterAngle

public void setOuterAngle(float value)