de.javagl.jgltf.model

Class MathUtils

java.lang.Object

de.javagl.jgltf.model.MathUtils

public class MathUtils
extends java.lang.Object

Mathematical utility methods. These methods are mainly related to computations on arrays that represent matrices.

Unless otherwise noted, the matrices are assumed to be in column-major order.

Unless otherwise noted, none of the arguments to these methods may be null.

Unless otherwise noted, each 4x4 matrix is assumed to have a length of at least 16, and each 3x3 matrix is assumed to have a length of at least 9. Points in 3D are assumed to have a length of at least 3. TODO This class should not be considered as part of the public API!

Method Summary

Modifier and Type	Method and Description
static java.lang.String	createFormattedMatrixString(float[] array) Create a string representation of the given array, as a matrix, interpreting it as a matrix that is stored in column-major order.
static float[]	createIdentity4x4() Creates a 4x4 identity matrix
static java.lang.String	createMatrixString(float[] array) Create a string representation of the given array, as a matrix, interpreting it as a matrix that is stored in column-major order.
static void	getRotationScale(float[] sourceMatrix4x4, float[] targetMatrix3x3) Obtains the upper 3x3 matrix (which describes the rotation- and scaling part of the transformation) of the given 4x4 source matrix, and writes it into the given target 3x3 matrix.
static void	infinitePerspective4x4(float fovyDeg, float aspect, float zNear, float[] m) Fill the given matrix to describe an infinite perspective projection with the given parameters.
static void	invert3x3(float[] m, float[] inv) Inverts the given matrix and writes the result into the given target matrix.
static void	invert4x4(float[] m, float[] inv) Inverts the given matrix and writes the result into the given target matrix.
static void	mul4x4(float[] a, float[] b, float[] m) Fills the given result matrix with the product of the given matrices.
static void	perspective4x4(float fovyDeg, float aspect, float zNear, float zFar, float[] m) Fill the given matrix to describe a perspective projection with the given parameters.
static void	quaternionToMatrix4x4(float[] q, float[] m) Fills the given matrix, with the values for the rotation that is described by the given quaternion.
static void	setIdentity4x4(float[] m) Set the given matrix to be the identity matrix.
static void	transformPoint3D(float[] matrix4x4, float[] point3D, float[] result3D) Transform the given 3D point with the given 4x4 matrix (thus, treating the non-present fourth component of the point as being 1.0), and write the result into the given result array.
static void	translate(float[] m, float x, float y, float z, float[] result) Writes the given matrix into the given result matrix, with the given values added to the translation component
static void	transpose4x4(float[] m, float[] t) Transpose the given matrix, and write the result into the given target matrix.

Methods inherited from class java.lang.Object

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

Method Detail

createIdentity4x4

public static float[] createIdentity4x4()

Creates a 4x4 identity matrix

Returns:

The matrix

setIdentity4x4

public static void setIdentity4x4(float[] m)

Set the given matrix to be the identity matrix.

Parameters:

m - The matrix

getRotationScale

public static void getRotationScale(float[] sourceMatrix4x4,
                                    float[] targetMatrix3x3)

Obtains the upper 3x3 matrix (which describes the rotation- and scaling part of the transformation) of the given 4x4 source matrix, and writes it into the given target 3x3 matrix.

Parameters:

sourceMatrix4x4 - The source matrix

targetMatrix3x3 - The target matrix

transpose4x4

public static void transpose4x4(float[] m,
                                float[] t)

Transpose the given matrix, and write the result into the given target matrix.

Parameters:

m - The input matrix

t - The target matrix

mul4x4

public static void mul4x4(float[] a,
                          float[] b,
                          float[] m)

Fills the given result matrix with the product of the given matrices.

Parameters:

a - The first matrix

b - The second matrix

m - The result matrix

quaternionToMatrix4x4

public static void quaternionToMatrix4x4(float[] q,
                                         float[] m)

Fills the given matrix, with the values for the rotation that is described by the given quaternion. None of the arguments may be null. The quaternion must have at least length 4.

Parameters:

q - The quaternion

m - The matrix

invert4x4

public static void invert4x4(float[] m,
                             float[] inv)

Inverts the given matrix and writes the result into the given target matrix. If the given matrix is not invertible, then the target matrix will be set to identity.

Parameters:

m - The input matrix

inv - The inverse matrix

invert3x3

public static void invert3x3(float[] m,
                             float[] inv)

Inverts the given matrix and writes the result into the given target matrix. If the given matrix is not invertible, then the target matrix will be set to identity.

Parameters:

m - The input matrix

inv - The inverse matrix

translate

public static void translate(float[] m,
                             float x,
                             float y,
                             float z,
                             float[] result)

Writes the given matrix into the given result matrix, with the given values added to the translation component

Parameters:

m - The input matrix

x - The x-translation

y - The y-translation

z - The z-translation

result - The result matrix

infinitePerspective4x4

public static void infinitePerspective4x4(float fovyDeg,
                                          float aspect,
                                          float zNear,
                                          float[] m)

Fill the given matrix to describe an infinite perspective projection with the given parameters.

Parameters:

fovyDeg - The Field-Of-View, in y-direction, in degrees

aspect - The aspect ratio

zNear - The z-value of the near clipping plane

m - The matrix to fill

perspective4x4

public static void perspective4x4(float fovyDeg,
                                  float aspect,
                                  float zNear,
                                  float zFar,
                                  float[] m)

Fill the given matrix to describe a perspective projection with the given parameters.

Parameters:

fovyDeg - The Field-Of-View, in y-direction, in degrees

aspect - The aspect ratio

zNear - The z-value of the near clipping plane

zFar - The z-value of the far clipping plane

m - The matrix to fill

transformPoint3D

public static void transformPoint3D(float[] matrix4x4,
                                    float[] point3D,
                                    float[] result3D)

Transform the given 3D point with the given 4x4 matrix (thus, treating the non-present fourth component of the point as being 1.0), and write the result into the given result array.

Parameters:

matrix4x4 - The matrix

point3D - The input point

result3D - The result point

createMatrixString

public static java.lang.String createMatrixString(float[] array)

Create a string representation of the given array, as a matrix, interpreting it as a matrix that is stored in column-major order. The given array may be null. If it is not null, then it must either have 3x3 elements or 4x4 elements.

Parameters:

array - The array

Returns:

The string representation

createFormattedMatrixString

public static java.lang.String createFormattedMatrixString(float[] array)

Create a string representation of the given array, as a matrix, interpreting it as a matrix that is stored in column-major order. The given array may be null. If it is not null, then it must either have 3x3 elements or 4x4 elements.

The individual elements of the matrix will be formatted (in an unspecified way) so that the matrix entries are aligned.

Parameters:

array - The array

Returns:

The string representation