```java.lang.Object
de.grogra.graph.impl.Edge
de.grogra.graph.impl.Node
```
All Implemented Interfaces:
Icon, IconSource, ChannelMap, ColorMap, Manageable, PersistenceCapable, Shareable, RenderedIcon, Scattering, Shader, UserFields, XObject, Map, java.io.Serializable

`public class Phongextends Material`

A `Phong` shader represents a Phong-like reflector. Its bidirectional reflection/transmission distribution functions are as follows:

At a given point x, let cd be the diffuse color (components R, G, B) at that point, α the alpha-component of the diffuse color and ct the transparency color. For each color component, set

cαt = 1 + α (ct - 1)
Let cs be the specular color and n the shininess exponent. Let r be the reflection coefficient as computed by `Math2.fresnel(javax.vecmath.Vector3f, javax.vecmath.Vector3f, float, javax.vecmath.Vector3f, javax.vecmath.Vector3f)`.
• Now if `interpolatedTransparency` is `true`, set
kd = (1 - cαt) cd
ks = (1 - cαt) cs + r cαt
kt = (1 - r) cαt
• Otherwise, set
kd = cd
ks = cs + r cαt
kt = (1 - r) cαt
The bidirectional reflection distribution function is
BRDF(x, ωi, ωo) = kd / π + ks (n + 2) max(cos β, 0)n / 2π
where β is the angle between ωi and the direction of ideal reflection of ωo.

The bidirectional transmission distribution function is

BTDF(x, ωi, ωt) = ktt / ηi)2 δω+i - T(ωt))
where η stands for the index of refraction, T for the direction of transmission according to Fresnel's formulas, and δω+ is the δ-distribution with respect to projected solid angle ω+.

Author:
Ole Kniemeyer
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` `ambient\$FIELD`

`static ColorMap` `DEFAULT_AMBIENT`

`static ColorMap` `DEFAULT_DIFFUSE`

`static ColorMap` `DEFAULT_DIFFUSE_TRANSPARENCY`

`static ColorMap` `DEFAULT_EMISSIVE`

`static float` `DEFAULT_SHININESS`

`static ColorMap` `DEFAULT_SPECULAR`

`static ColorMap` `DEFAULT_TRANSPARENCY`

`static float` `DEFAULT_TRANSPARENCY_SHININESS`

`static Node.NType.Field` `diffuse\$FIELD`

`static Node.NType.Field` `diffuseTransparency\$FIELD`

`static Node.NType.Field` `emissive\$FIELD`

`static Node.NType.Field` `interpolatedTransparency\$FIELD`

`static float` `MAX_SHININESS`

`static Node.NType.Field` `shininess\$FIELD`

`static Node.NType.Field` `specular\$FIELD`

`static Node.NType.Field` `transparency\$FIELD`

`static Node.NType.Field` `transparencyShininess\$FIELD`

`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`

`LAMBERTIAN_VARIANCE`

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.icon.Icon
`DEFAULT, DISABLED`

Fields inherited from interface de.grogra.util.Map
`DEFAULT_VALUE, EMPTY_MAP`

Constructor Summary
`Phong()`

Method Summary
` void` `accept(ChannelMapNodeVisitor visitor)`

` void` `accept(ShaderVisitor visitor)`

` Phong` `clone()`

` float` ```computeBSDF(Environment env, Vector3f in, Spectrum specIn, Vector3f out, boolean adjoint, Spectrum bsdf)```
Evaluates bidirectional scattering distribution function for given input.
` void` ```computeMaxRays(Environment env, Vector3f out, Spectrum outSpec, 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.
`static float` `convertShininess(float x)`

`static Phong` `createPhong()`

` 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.
` ChannelMap` `getAmbient()`

` int` `getAverageColor()`
Returns an average color for the scattering entity.
` ChannelMap` `getDiffuse()`

` ChannelMap` `getDiffuseTransparency()`

` ChannelMap` `getEmissive()`

` int` `getFlags()`

`protected  Node.NType` `getNTypeImpl()`
This method returns the `Node.NType` which describes the managed fields of the class of this node.
` ChannelMap` `getShininess()`

` ChannelMap` `getSpecular()`

` ChannelMap` `getTransparency()`

` ChannelMap` `getTransparencyShininess()`

` boolean` `isInterpolatedTransparency()`

` boolean` `isTransparent()`

`static void` `main(java.lang.String[] args)`

`protected  Node` `newInstance()`
This method returns a new instance of the class of this node.
` void` `setAmbient(ChannelMap value)`

` void` `setDiffuse(ChannelMap value)`

` void` `setDiffuseTransparency(ChannelMap value)`

` void` `setEmissive(ChannelMap value)`

` void` `setInterpolatedTransparency(boolean value)`

` void` `setShininess(ChannelMap value)`

` void` `setSpecular(ChannelMap value)`

` void` `setTransparency(ChannelMap value)`

` void` `setTransparencyShininess(ChannelMap value)`

` void` ```shade(Environment env, RayList rays, Vector3f out, Spectrum outSpec, Tuple3d outColor)```
Computes color of outgoing light ray for given input.

`renderLine, renderLine`

`drawImage, getIcon, getIconBounds, getIconSource, getImage, getImage, getImageSource, getInputData, getPreferredIconSize, getRenderedImage, getSizeRatio, isMutable, paintIcon, prepareIcon, renderImage`

`accept, getFloatValue, getInput, getObjectValue, setInput`

Methods inherited from class de.grogra.graph.impl.Node
`addEdgeBitsTo, addReference, appendBranchNode, appendBranchNode, appendReferencesTo, 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`

### ambient\$FIELD

`public static final Node.NType.Field ambient\$FIELD`

### DEFAULT_AMBIENT

`public static final ColorMap DEFAULT_AMBIENT`

### DEFAULT_DIFFUSE

`public static final ColorMap DEFAULT_DIFFUSE`

### DEFAULT_DIFFUSE_TRANSPARENCY

`public static final ColorMap DEFAULT_DIFFUSE_TRANSPARENCY`

### DEFAULT_EMISSIVE

`public static final ColorMap DEFAULT_EMISSIVE`

### DEFAULT_SHININESS

`public static final float DEFAULT_SHININESS`
Constant Field Values

### DEFAULT_SPECULAR

`public static final ColorMap DEFAULT_SPECULAR`

### DEFAULT_TRANSPARENCY

`public static final ColorMap DEFAULT_TRANSPARENCY`

### DEFAULT_TRANSPARENCY_SHININESS

`public static final float DEFAULT_TRANSPARENCY_SHININESS`
Constant Field Values

### diffuse\$FIELD

`public static final Node.NType.Field diffuse\$FIELD`

### diffuseTransparency\$FIELD

`public static final Node.NType.Field diffuseTransparency\$FIELD`

### emissive\$FIELD

`public static final Node.NType.Field emissive\$FIELD`

### interpolatedTransparency\$FIELD

`public static final Node.NType.Field interpolatedTransparency\$FIELD`

### MAX_SHININESS

`public static final float MAX_SHININESS`
Constant Field Values

### shininess\$FIELD

`public static final Node.NType.Field shininess\$FIELD`

### specular\$FIELD

`public static final Node.NType.Field specular\$FIELD`

### transparency\$FIELD

`public static final Node.NType.Field transparency\$FIELD`

### transparencyShininess\$FIELD

`public static final Node.NType.Field transparencyShininess\$FIELD`
Constructor Detail

### Phong

`public Phong()`
Method Detail

### accept

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

### accept

`public void accept(ShaderVisitor visitor)`

### clone

`public Phong clone()`
Overrides:
`clone` in class `Node`

### computeBSDF

```public float computeBSDF(Environment env,
Vector3f in,
Spectrum specIn,
Vector3f out,
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) `specIn`i) 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) `specIn`o) 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.

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

### computeMaxRays

```public void computeMaxRays(Environment env,
Vector3f out,
Spectrum outSpec,
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.

Parameters:
`env` - the environment for scattering
`out` - the (negated) direction unit vector of the incoming ray (i.e., pointing away from the surface)
`outSpec` - 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`

### convertShininess

`public static float convertShininess(float x)`

### createPhong

`public static Phong createPhong()`

### generateRandomRays

```public void generateRandomRays(Environment env,
Vector3f out,
Spectrum specOut,
RayList rays,
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(ωi, νi; ωo, νo) in the following way:
• If `adjoint` is `false`, `out` = ωo describes the direction of an outgoing light ray. In this case, the integration is with respect to ωi. Let g(ω, ν; `out`, μ) = BSDF(ω, ν; `out`, μ)
• Otherwise, `adjoint` is `true`. In this case, `out` = ωi describes the direction of an outgoing importance ray (an inverse light ray). Now the integration is with respect to ωo. Let g(ω, ν; `out`, μ) = BSDF(`out`, μ; ω, ν)
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.

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

### getAmbient

`public ChannelMap getAmbient()`

### 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.

Returns:
an average color in Java's default sRGB color space, encoded as an int (0xAARRGGBB).

### getDiffuse

`public ChannelMap getDiffuse()`

### getDiffuseTransparency

`public ChannelMap getDiffuseTransparency()`

### getEmissive

`public ChannelMap getEmissive()`

### getFlags

`public int getFlags()`

### 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

### getShininess

`public ChannelMap getShininess()`

### getSpecular

`public ChannelMap getSpecular()`

### getTransparency

`public ChannelMap getTransparency()`

### getTransparencyShininess

`public ChannelMap getTransparencyShininess()`

### isInterpolatedTransparency

`public boolean isInterpolatedTransparency()`

### isTransparent

`public boolean isTransparent()`

### main

`public static void main(java.lang.String[] args)`

### 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

### setAmbient

`public void setAmbient(ChannelMap value)`

### setDiffuse

`public void setDiffuse(ChannelMap value)`

### setDiffuseTransparency

`public void setDiffuseTransparency(ChannelMap value)`

### setEmissive

`public void setEmissive(ChannelMap value)`

### setInterpolatedTransparency

`public void setInterpolatedTransparency(boolean value)`

### setShininess

`public void setShininess(ChannelMap value)`

### setSpecular

`public void setSpecular(ChannelMap value)`

### setTransparency

`public void setTransparency(ChannelMap value)`

### setTransparencyShininess

`public void setTransparencyShininess(ChannelMap value)`

```public void shade(Environment env,
RayList rays,
Vector3f out,
Spectrum outSpec,
Tuple3d outColor)```
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.

Parameters:
`env` - the environment for scattering
`rays` - the incoming rays
`out` - the direction unit vector of the outgoing ray (i.e., pointing away from the surface)
`outSpec` - spectrum of outgoing ray
`outColor` - the output color will be placed in here