de.grogra.imp3d.shading
Class SunSkyLight

java.lang.Object
  extended by de.grogra.graph.impl.Edge
      extended by de.grogra.graph.impl.Node
          extended by de.grogra.imp3d.shading.ChannelMapNode
              extended by de.grogra.imp3d.shading.ColorMapNode
                  extended by de.grogra.imp3d.shading.Material
                      extended by de.grogra.imp3d.shading.SunSkyLight
All Implemented Interfaces:
Icon, IconSource, ChannelMap, ColorMap, Manageable, PersistenceCapable, Shareable, RenderedIcon, Emitter, Light, Scattering, Shader, UserFields, XObject, Map, java.io.Serializable

public class SunSkyLight
extends Material
implements Light

See Also:
Serialized Form

Nested Class Summary
 
Nested classes/interfaces inherited from class de.grogra.graph.impl.Node
Node.AccessorBridge, Node.FieldAttributeAccessor, Node.NType
 
Nested classes/interfaces inherited from interface de.grogra.util.Map
Map.Chain
 
Field Summary
static Node.NType $TYPE
           
static Node.NType.Field disableLight$FIELD
           
static Node.NType.Field disableSun$FIELD
           
static Node.NType.Field radianceFactor$FIELD
           
static Node.NType.Field sun$FIELD
           
static Node.NType.Field turbidity$FIELD
           
 
Fields inherited from class de.grogra.imp3d.shading.ChannelMapNode
AMBIENT, COLOR, COLOR_2, DIFFUSE_TRANSPARENCY, DISPLACEMENT, EMISSIVE, FIRST_OP, INPUT, input$FIELD, MIN_UNUSED_SPECIAL_OF_TARGET, SECOND_OP, SHININESS, SPECULAR, TRANSPARENCY, TRANSPARENCY_SHININESS
 
Fields inherited from class de.grogra.graph.impl.Node
ADDITIONAL_FIELDS, bits, DELETED, EXTENT_BIT, EXTENT_MASK, extentIndex$FIELD, extentTail$FIELD, HAS_OBSERVERS, IS_INTERPRETIVE, isInterpretive$FIELD, LAST_EXTENT_INDEX, layer$FIELD, MARK, mark$FIELD, MIME_TYPE, MIN_UNUSED_SPECIAL_OF_SOURCE, name$FIELD, USED_BITS
 
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
 
Fields inherited from interface de.grogra.ray.physics.Shader
LAMBERTIAN_VARIANCE
 
Fields inherited from interface de.grogra.icon.Icon
DEFAULT, DISABLED
 
Fields inherited from interface de.grogra.util.Map
DEFAULT_VALUE, EMPTY_MAP
 
Constructor Summary
SunSkyLight()
           
 
Method Summary
 void accept(ChannelMapNodeVisitor visitor)
           
 void accept(LightVisitor visitor)
           
 void accept(ShaderVisitor visitor)
           
 double completeRay(Environment env, Point3d vertex, Ray out)
           
 float computeBSDF(Environment env, Vector3f in, Spectrum specIn, Vector3f out, boolean adjoint, Spectrum bsdf)
          Evaluates bidirectional scattering distribution function for given input.
 double computeExitance(Environment env, Spectrum exitance)
          Evaluates the exitance function for given input.
 void computeMaxRays(Environment env, Vector3f in, Spectrum specIn, Ray reflected, Tuple3f refVariance, Ray transmitted, Tuple3f transVariance)
          Computes, for the given input, the reflected and transmitted importance rays for which the reflection/transmission probability densities (integrated over the spectrum) attain a maximum.
 void generateRandomOrigins(Environment env, RayList out, java.util.Random random)
          Pseudorandomly generates, for the given input, a set of origins for this emitter.
 void generateRandomRays(Environment env, Vector3f out, Spectrum specOut, RayList rays, boolean adjoint, java.util.Random random)
          Pseudorandomly generates, for the given input, a set of scattered rays.
 int getAverageColor()
          Returns an average color for the scattering entity.
 int getFlags()
           
 int getLightType()
          Determines the type of light source which is represented by this light.
protected  Node.NType getNTypeImpl()
          This method returns the Node.NType which describes the managed fields of the class of this node.
 float getRadianceFactor()
           
 Vector3d getSun()
           
 double getTotalPower(Environment env)
          Computes the total power of this light source which is emitted to the region defined by env.bounds.
 float getTurbidity()
           
 boolean isDisableLight()
           
 boolean isDisableSun()
           
 boolean isIgnoredWhenHit()
          Determines whether the light source shall be ignored when a shot ray happens to hit the geometry of the light source.
 boolean isShadowless()
          Determines whether the light source casts shadows or not.
 boolean isTransparent()
           
protected  Node newInstance()
          This method returns a new instance of the class of this node.
 void setDisableLight(boolean value)
           
 void setDisableSun(boolean value)
           
 void setRadianceFactor(float value)
           
 void setSun(Vector3d value)
           
 void setTurbidity(float value)
           
 void shade(Environment env, RayList in, Vector3f out, Spectrum specOut, Tuple3d color)
          Computes color of outgoing light ray for given input.
 
Methods inherited from class de.grogra.imp3d.shading.Material
renderLine, renderLine
 
Methods inherited from class de.grogra.imp3d.shading.ColorMapNode
drawImage, getIcon, getIconBounds, getIconSource, getImage, getImage, getImageSource, getInputData, getPreferredIconSize, getRenderedImage, getSizeRatio, isMutable, paintIcon, prepareIcon, renderImage
 
Methods inherited from class de.grogra.imp3d.shading.ChannelMapNode
accept, getFloatValue, getInput, getObjectValue, setInput
 
Methods inherited from class de.grogra.graph.impl.Node
addEdgeBitsTo, addReference, appendBranchNode, appendBranchNode, appendReferencesTo, clone, clone, cloneGraph, dump, dumpTree, dup, dupUnmanagedFields, edgeChanged, fieldModified, findAdjacent, get, getAccessor, getAccessor, getAttributes, getAxisParent, getBoolean, getBranch, getBranchLength, getBranchNode, getBranchTail, getByte, getChar, getCommonAncestor, getCurrentGraphState, getDirectChildCount, getDouble, getEdgeAttributeAccessor, getEdgeAttributes, getEdgeBitsTo, getEdgeTo, getExtentIndex, getFirst, getFirstEdge, getFloat, getGraph, getId, getIndex, getInstantiator, getInt, getLayer, getLong, getManageableType, getName, getNeighbor, getNext, getNType, getObject, getOrCreateEdgeTo, getOrNull, getPersistenceManager, getPredecessor, getProvider, getShort, getSource, getStamp, getSuccessor, getSymbol, getSymbolColor, getTarget, getTransaction, getUserField, getUserFieldCount, getXClass, getXData, hasName, initProvider, initXClass, insertBranchNode, insertBranchNode, instantiateGraph, isAncestorOf, isDirection, isManagingInstance, isMarked, isRoot, isSource, isTarget, manageableReadResolve, manageableWriteReplace, paramString, removeAll, removeEdgeBitsTo, removeFromChain, removeFromChain, removeReference, setBranch, setBranch, setExtentIndex, setGraphForDeserialization, setLayer, setMark, setName, setSuccessor, setSuccessor, specialEdgeAdded, specialEdgeRefModified, specialEdgeRemoved, toString, writeReplace
 
Methods inherited from class de.grogra.graph.impl.Edge
addEdgeBits, getBitMark, getEdgeBits, getObjectMark, getSpecialEdgeDescriptor, parseEdgeKeys, remove, removeEdgeBits, setBitMark, setEdgeBits, setObjectMark, testEdgeBits
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface de.grogra.math.ChannelMap
accept, getFloatValue, getObjectValue, getStamp
 
Methods inherited from interface de.grogra.pf.ui.RenderedIcon
getStamp
 
Methods inherited from interface de.grogra.persistence.PersistenceCapable
getBitMark, getObjectMark, setBitMark, setObjectMark
 

Field Detail

$TYPE

public static final Node.NType $TYPE

disableLight$FIELD

public static final Node.NType.Field disableLight$FIELD

disableSun$FIELD

public static final Node.NType.Field disableSun$FIELD

radianceFactor$FIELD

public static final Node.NType.Field radianceFactor$FIELD

sun$FIELD

public static final Node.NType.Field sun$FIELD

turbidity$FIELD

public static final Node.NType.Field turbidity$FIELD
Constructor Detail

SunSkyLight

public SunSkyLight()
Method Detail

accept

public void accept(ChannelMapNodeVisitor visitor)
Overrides:
accept in class ChannelMapNode

accept

public void accept(LightVisitor visitor)

accept

public void accept(ShaderVisitor visitor)

completeRay

public double completeRay(Environment env,
                          Point3d vertex,
                          Ray out)
Specified by:
completeRay in interface Emitter

computeBSDF

public float computeBSDF(Environment env,
                         Vector3f in,
                         Spectrum specIn,
                         Vector3f out,
                         boolean adjoint,
                         Spectrum bsdf)
Description copied from interface: Scattering
Evaluates bidirectional scattering distribution function for given input.

The computed spectrum is an integral over the spectrum of the following product:

|cos θ| BSDF(ωi, νi; ωo, νo)
where BSDF is the bidirectional scattering distribution function (= BRDF + BTDF) at the point env.point, ωi the (negated) direction of the incoming light ray, νi the frequency where the incoming ray is sampled, ωo the direction of the outgoing light ray, νo the frequency where the outgoing ray is sampled, and θ the angle between the surface normal and out.

If adjoint is false, in and out describe true light rays from light sources to sensors. In this case, ωi = in, ωo = out, and the integral is

bsdf(ν) = |cos θ| ∫ BSDF(in, νi; out, ν) specIni) dνi
Otherwise, adjoint is true. in and out then describe importance rays (inverse light rays from sensors to light sources). In this case, ωi = out, ωo = in, and the integral is
bsdf(ν) = |cos θ| ∫ BSDF(out, ν; in, νo) specIno) dνo

If this Scattering instance is in fact a Light source, adjoint is false, and the BSDF is defined as BSDF(in, 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, in is not used.

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

The computation should be physically valid. This excludes, e.g., ambient or emissive light contributions.

The returned value is the value of the probability density pω that would be calculated by Scattering.generateRandomRays(de.grogra.ray.physics.Environment, javax.vecmath.Vector3f, de.grogra.ray.physics.Spectrum, de.grogra.ray.util.RayList, boolean, java.util.Random) if the ray happened to be one of the randomly generated rays.

Specified by:
computeBSDF in interface Scattering
Parameters:
env - the environment for scattering
in - the (negated) direction unit vector of the incoming ray (i.e., pointing away from the surface)
specIn - the spectrum of the incoming ray
out - the direction unit vector of the outgoing ray (i.e., pointing away from the surface)
adjoint - light ray or importance ray?
bsdf - the computed spectrum of the outgoing ray will be placed in here
Returns:
the value of the probability density for the ray direction

computeExitance

public double computeExitance(Environment env,
                              Spectrum exitance)
Description copied from interface: Emitter
Evaluates the exitance function for given input. The computed value is the spectrum of the radiant exitance (emitted power per area) L0j(x, ν) at the point env.point in case of light sources, or the corresponding function W0j(x, ν) in case of sensors.

The returned value is the value of the probability density px that would be calculated by Emitter.generateRandomOrigins(de.grogra.ray.physics.Environment, de.grogra.ray.util.RayList, java.util.Random) if env.point happened to be one of the randomly generated origins.

Specified by:
computeExitance in interface Emitter
Parameters:
env - the environment for scattering
exitance - the exitance values will be placed in here
Returns:
the value of the probability density for the ray origin

computeMaxRays

public void computeMaxRays(Environment env,
                           Vector3f in,
                           Spectrum specIn,
                           Ray reflected,
                           Tuple3f refVariance,
                           Ray transmitted,
                           Tuple3f transVariance)
Description copied from interface: Shader
Computes, for the given input, the reflected and transmitted importance rays for which the reflection/transmission probability densities (integrated over the spectrum) attain a maximum. The reflection probability density (measured with respect to solid angle) for the outgoing importance direction (i.e., incoming light direction) ω, given a fixed incident direction in, is
pr(ω) = cos θ BRDF(ω, in) / R
where BRDF is the bidirectional reflectivity distribution function, θ the angle between the surface normal and ω, and R the total reflectivity for the incident direction, i.e., the integral over cos θ BRDF(ω, in). The transmission probability density is defined correspondingly.

The color-fields are set to the total reflectivity/transparency for the incident direction for each color component R, G, B. Thus, for physically plausible BRDF/BTDF, the component-wise sum of reflected.color and transmitted.color lies in the interval [0, 1], and the difference to 1 is the amount absorbed.

The color may be zero if there is no reflected or transmitted ray, respectively, i.e., if the surface is fully transparent, opaque, or absorbing. The origin-fields of the rays will never be set.

The computed variances are defined to be, for each color component, (approximations for) the angular mean quadratic deviations of the densities from the returned maximal ray directions. E.g., for perfect reflection/transmission, these variances are zero, whereas for a perfect lambertian reflector, the variance of reflection is ∫ cos θ (1 / π) θ2 dω = (π2 - 4) / 8. This is the value of Shader.LAMBERTIAN_VARIANCE.

The ray properties which are not mentioned are neither used nor modified. These are the origin and its density, and the direction density.

Specified by:
computeMaxRays in interface Shader
Parameters:
env - the environment for scattering
in - the (negated) direction unit vector of the incoming ray (i.e., pointing away from the surface)
specIn - spectrum of incoming ray
reflected - the reflected ray with maximal probability
refVariance - the angular mean quadratic deviation from reflected
transmitted - the transmitted ray with maximal probability
transVariance - the angular mean quadratic deviation from transmitted

generateRandomOrigins

public void generateRandomOrigins(Environment env,
                                  RayList out,
                                  java.util.Random random)
Description copied from interface: Emitter
Pseudorandomly generates, for the given input, a set of origins for this emitter. They are generated such that they can be used for Monte Carlo-based photon tracing algorithms in the following way.

At first, we consider the case where the emitter is in fact a light source. Let L(x, ω, ν) be the emitted spectral radiance for the frequency ν at the light's surface point x in direction ω. The radiant exitance (emitted spectral power per area) at x is defined as

L0(x, ν) = ∫ cos θ L(x, ω, ν) dω
where θ is the angle between the surface normal and ω. Now the directional distribution of the emitted radiance at x can be described by the density
L1(x, ω, ν) = L(x, ω, ν) / L0(x, ν)
so that the radiance is split into
L(x, ω, ν) = L0(x, ν) L1(x, ω, ν)
Let oi and si denote the origins and spectra of the N generated rays (N = rays.size). Then for a function f(x, ν) which is to be integrated over the light surface, the sum
1 / N ∑i si(ν) f(oi, ν)
is an unbiased estimate for the integral
∫ L0(x, ν) f(x, ν) dA
The integral ranges over the whole surface A of the light source. As a consequence, the spectrum of a ray is to be considered as the ray's radiant spectral power.

Now if the emitter is a sensor, let W(x, ω, ν) be the emitted spectral importance for frequency ν at the sensors's surface point x in direction ω. The quantities W0(x, ν) and W1(x, ω, ν) are defined similarly to the case of light sources:

W0(x, ν) = ∫ cos θ W(x, ω, ν) dω
W(x, ω, ν) = W0(x) W1(x, ω, ν)
The formulas for light sources are valid for sensors if the L-quantites are replaced by the corresponding W-quantities.

Let px be the probability density used for the ray origin, then the field originDensity is set to px(oi) for each ray. For emitters which are concentrated at a single point (e.g., point lights) px is not a regular function, the value originDensity 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 direction and its density.

Specified by:
generateRandomOrigins in interface Emitter
Parameters:
env - the environment
out - the outgoing rays to be generated
random - pseudorandom generator

generateRandomRays

public void generateRandomRays(Environment env,
                               Vector3f out,
                               Spectrum specOut,
                               RayList rays,
                               boolean adjoint,
                               java.util.Random random)
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(ωi, νi; ωo, νo) in the following way: Let di and si denote the directions and spectra of the N generated rays (N = rays.size). Then, for every frequency ν the sum
1 / N ∑i si(ν) f(di; 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 pω 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 pω(di). For ideal specular reflection or transmission, or for directional lights or sensors, pω 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
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?
random - 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)

getAverageColor

public int getAverageColor()
Description copied from interface: Scattering
Returns an average color for the scattering entity. This color is used for simplified graphical representations of the corresponding objects.

Specified by:
getAverageColor in interface ColorMap
Specified by:
getAverageColor in interface Scattering
Returns:
an average color in Java's default sRGB color space, encoded as an int (0xAARRGGBB).

getFlags

public int getFlags()
Specified by:
getFlags in interface Scattering

getLightType

public int getLightType()
Description copied from interface: Light
Determines the type of light source which is represented by this light.

Specified by:
getLightType in interface Light
Returns:
one of Light.NO_LIGHT, Light.POINT, Light.AREA, Light.DIRECTIONAL, Light.SKY, Light.AMBIENT.

getNTypeImpl

protected Node.NType getNTypeImpl()
Description copied from class: Node
This method returns the Node.NType which describes the managed fields of the class of this node. This method has to be implemented in every concrete subclass.

Overrides:
getNTypeImpl in class Node
Returns:
type describing the managed fields of the class of this node

getRadianceFactor

public float getRadianceFactor()

getSun

public Vector3d getSun()

getTotalPower

public double getTotalPower(Environment env)
Description copied from interface: Light
Computes the total power of this light source which is emitted to the region defined by env.bounds. Note that the computed value is not necessarily exact: It should be used just as a hint, e.g., when one of a set of lights has to be chosen randomly on the basis of their relative power.

Specified by:
getTotalPower in interface Light
Parameters:
env - environment which defines the bounds of the scene
Returns:
total power emitted to the region env.bounds

getTurbidity

public float getTurbidity()

isDisableLight

public boolean isDisableLight()

isDisableSun

public boolean isDisableSun()

isIgnoredWhenHit

public boolean isIgnoredWhenHit()
Description copied from interface: Light
Determines whether the light source shall be ignored when a shot ray happens to hit the geometry of the light source.

Specified by:
isIgnoredWhenHit in interface Light
Returns:
true iff the light source shall be ignored

isShadowless

public boolean isShadowless()
Description copied from interface: Light
Determines whether the light source casts shadows or not.

Specified by:
isShadowless in interface Light
Returns:
true iff the light source does not cast shadows

isTransparent

public boolean isTransparent()
Specified by:
isTransparent in interface Shader

newInstance

protected Node newInstance()
Description copied from class: Node
This method returns a new instance of the class of this node. This method has to be implemented in every concrete subclass.

Overrides:
newInstance in class Node
Returns:
new instance of class of this node

setDisableLight

public void setDisableLight(boolean value)

setDisableSun

public void setDisableSun(boolean value)

setRadianceFactor

public void setRadianceFactor(float value)

setSun

public void setSun(Vector3d value)

setTurbidity

public void setTurbidity(float value)

shade

public void shade(Environment env,
                  RayList in,
                  Vector3f out,
                  Spectrum specOut,
                  Tuple3d color)
Description copied from interface: Shader
Computes color of outgoing light ray for given input. The computed value is, for each color component j = R, G, B, the following sum over all incident rays k:
k |cos θk| BSDFjk, out) ck,j
where BSDFj is the bidirectional scattering distribution function (= BRDF + BTDF) at the point env.point, ωk and ck the direction and color of ray k, and θk the angle between the surface normal and ωk.

The computation may include physically invalid contributions, which may not fit into the formula above, e.g., ambient or emissive light contributions.

Specified by:
shade in interface Shader
Parameters:
env - the environment for scattering
in - the incoming rays
out - the direction unit vector of the outgoing ray (i.e., pointing away from the surface)
specOut - spectrum of outgoing ray
color - the output color will be placed in here