com.jme3.environment.util

Class EnvMapUtils

java.lang.Object

com.jme3.environment.util.EnvMapUtils

public class EnvMapUtils
extends java.lang.Object

This class holds several utility method useful for Physically Based Rendering. It allows us to compute useful prefiltered maps from an env map.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	EnvMapUtils.FixSeamsMethod
static class	EnvMapUtils.GenerationType

Field Summary

Fields

Modifier and Type	Field and Description
static int	NUM_SH_COEFFICIENT
static float[]	shBandFactor

Method Summary

Modifier and Type	Method and Description
static TextureCubeMap	createIrradianceMap(int size, Image.Format imageFormat) initialize the irradiance map
static TextureCubeMap	createPrefilteredEnvMap(int size, Image.Format imageFormat) initialize the pem map
static TextureCubeMap	duplicateCubeMap(TextureCubeMap sourceMap) Make a duplicate of this cube Map.
static void	evalShBasis(Vector3f texelVect, float[] shDir) Computes SH coefficient for a given textel dir The method used is the one from this article : http://graphics.stanford.edu/papers/envmap/envmap.pdf
static Node	getCubeMapCrossDebugView(TextureCubeMap cubeMap, AssetManager assetManager) Creates a debug Node of the given cube map to attach to the gui node the cube map is layered this way :
static Node	getCubeMapCrossDebugViewWithMipMaps(TextureCubeMap cubeMap, AssetManager assetManager)
static int	getCubemapFaceTexCoordFromVector(Vector3f texelVect, int mapSize, Vector2f store, EnvMapUtils.FixSeamsMethod fixSeamsMethod) Computes the texture coordinates and the face of the cube map from the given vector
static Vector4f	getHammersleyPoint(int i, int nbrSample, Vector4f store)
static float	getMipFromRoughness(float roughness, int miptot)
static float	getRoughnessFromMip(int mipLevel, int miptot)
static int	getSampleFromMip(int mipLevel, int miptot)
static Vector3f[]	getSphericalHarmonicsCoefficents(TextureCubeMap cubeMap) same as getSphericalHarmonicsCoefficents(com.jme3.texture.TextureCubeMap, com.jme3.environment.util.EnvMapUtils.FixSeamsMethod) the fix method used is EnvMapUtils.FixSeamsMethod.Wrap
static Vector3f[]	getSphericalHarmonicsCoefficents(TextureCubeMap cubeMap, EnvMapUtils.FixSeamsMethod fixSeamsMethod) Returns the Spherical Harmonics coefficients for this cube map.
static Vector3f	getVectorFromCubemapFaceTexCoord(int x, int y, int mapSize, int face, Vector3f store, EnvMapUtils.FixSeamsMethod fixSeamsMethod) Computes the 3 component vector coordinates for the given face and coords
static Vector3f	importanceSampleGGX(Vector4f xi, float a2, Vector3f normal, Vector3f store, TempVars vars)
static TextureCubeMap	makeCubeMap(Image rightImg, Image leftImg, Image upImg, Image downImg, Image backImg, Image frontImg, Image.Format format) Creates a cube map from 6 images
static void	prepareShCoefs(Vector3f[] shCoefs)

Methods inherited from class java.lang.Object

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

Field Detail

NUM_SH_COEFFICIENT

public static final int NUM_SH_COEFFICIENT

See Also:

Constant Field Values

shBandFactor

public static float[] shBandFactor

Method Detail

makeCubeMap

public static TextureCubeMap makeCubeMap(Image rightImg,
                                         Image leftImg,
                                         Image upImg,
                                         Image downImg,
                                         Image backImg,
                                         Image frontImg,
                                         Image.Format format)

Creates a cube map from 6 images

Parameters:

leftImg - the west side image, also called negative x (negX) or left image

rightImg - the east side image, also called positive x (posX) or right image

downImg - the bottom side image, also called negative y (negY) or down image

upImg - the top side image, also called positive y (posY) or up image

backImg - the south side image, also called positive z (posZ) or back image

frontImg - the north side image, also called negative z (negZ) or front image

format - the format of the image

Returns:

a cube map

duplicateCubeMap

public static TextureCubeMap duplicateCubeMap(TextureCubeMap sourceMap)

Make a duplicate of this cube Map. That means that it's another instant od TextureCubeMap, but the underlying buffers are duplicates of the original ones. see ByteBuffer.duplicate() Use this if you need to read from the map from multiple threads, it should guaranty the thread safety. Note that if you want to write to the cube map you have to make sure that the different thread do not write to the same area of the buffer. The position, limit and mark are not an issue.

Parameters:

sourceMap - the map to be copied (not null, unaffected)

Returns:

a new instance

getVectorFromCubemapFaceTexCoord

public static Vector3f getVectorFromCubemapFaceTexCoord(int x,
                                                        int y,
                                                        int mapSize,
                                                        int face,
                                                        Vector3f store,
                                                        EnvMapUtils.FixSeamsMethod fixSeamsMethod)

Computes the 3 component vector coordinates for the given face and coords

Parameters:

x - the x texture coordinate

y - the y texture coordinate

mapSize - the size of a face of the cube map

face - the face to consider

store - a vector3f where the resulting vector will be stored

fixSeamsMethod - the method to fix the seams

Returns:

either store or a new vector

getCubemapFaceTexCoordFromVector

public static int getCubemapFaceTexCoordFromVector(Vector3f texelVect,
                                                   int mapSize,
                                                   Vector2f store,
                                                   EnvMapUtils.FixSeamsMethod fixSeamsMethod)

Computes the texture coordinates and the face of the cube map from the given vector

Parameters:

texelVect - the vector to fetch texels from the cube map

fixSeamsMethod - the method to fix the seams

mapSize - the size of one face of the cube map

store - a Vector2f where the texture coordinates will be stored

Returns:

the face from which to fetch the texel

getSampleFromMip

public static int getSampleFromMip(int mipLevel,
                                   int miptot)

getRoughnessFromMip

public static float getRoughnessFromMip(int mipLevel,
                                        int miptot)

getMipFromRoughness

public static float getMipFromRoughness(float roughness,
                                        int miptot)

getSphericalHarmonicsCoefficents

public static Vector3f[] getSphericalHarmonicsCoefficents(TextureCubeMap cubeMap)

same as getSphericalHarmonicsCoefficents(com.jme3.texture.TextureCubeMap, com.jme3.environment.util.EnvMapUtils.FixSeamsMethod) the fix method used is EnvMapUtils.FixSeamsMethod.Wrap

Parameters:

cubeMap - the environment cube map to compute SH for

Returns:

an array of 9 vectors representing the coefficients for each RGB channel

getSphericalHarmonicsCoefficents

public static Vector3f[] getSphericalHarmonicsCoefficents(TextureCubeMap cubeMap,
                                                          EnvMapUtils.FixSeamsMethod fixSeamsMethod)

Returns the Spherical Harmonics coefficients for this cube map. The method used is the one from this article: http://graphics.stanford.edu/papers/envmap/envmap.pdf Another good resource for spherical harmonics: http://dickyjim.wordpress.com/2013/09/04/spherical-harmonics-for-beginners/

Parameters:

cubeMap - the environment cube map to compute SH for

fixSeamsMethod - method to fix seams when computing the SH coefficients

Returns:

an array of 9 vectors representing the coefficients for each RGB channel

evalShBasis

public static void evalShBasis(Vector3f texelVect,
                               float[] shDir)

Computes SH coefficient for a given textel dir The method used is the one from this article : http://graphics.stanford.edu/papers/envmap/envmap.pdf

Parameters:

texelVect - the input texel (not null, unaffected)

shDir - storage for the results

prepareShCoefs

public static void prepareShCoefs(Vector3f[] shCoefs)

getHammersleyPoint

public static Vector4f getHammersleyPoint(int i,
                                          int nbrSample,
                                          Vector4f store)

importanceSampleGGX

public static Vector3f importanceSampleGGX(Vector4f xi,
                                           float a2,
                                           Vector3f normal,
                                           Vector3f store,
                                           TempVars vars)

getCubeMapCrossDebugView

public static Node getCubeMapCrossDebugView(TextureCubeMap cubeMap,
                                            AssetManager assetManager)

Creates a debug Node of the given cube map to attach to the gui node the cube map is layered this way :

         _____
        |     |
        | +Y  |
   _____|_____|_____ _____
  |     |     |     |     |
  | -X  | +Z  | +X  | -Z  |
  |_____|_____|_____|_____|
        |     |
        | -Y  |
        |_____|

Parameters:

cubeMap - the cube map

assetManager - the asset Manager

Returns:

a new Node

getCubeMapCrossDebugViewWithMipMaps

public static Node getCubeMapCrossDebugViewWithMipMaps(TextureCubeMap cubeMap,
                                                       AssetManager assetManager)

createIrradianceMap

public static TextureCubeMap createIrradianceMap(int size,
                                                 Image.Format imageFormat)

initialize the irradiance map

Parameters:

size - the size of the map

imageFormat - the format of the image

Returns:

the initialized Irradiance map

createPrefilteredEnvMap

public static TextureCubeMap createPrefilteredEnvMap(int size,
                                                     Image.Format imageFormat)

initialize the pem map

Parameters:

size - the size of the map

imageFormat - the format of the image

Returns:

the initialized prefiltered env map