net.rim.device.api.math
Class VecMath

java.lang.Object
  net.rim.device.api.math.VecMath

public final class VecMath
extends Object

Implementations of a stack for use in matrix multiplication. Does matrix multiplication on 3x3 matrices.

NOTE: All matrix elements must be Fixed32 integers, that is, 32-bit ints that use the 16.16 convention to fix the decimal point. Use Fixed32.toFP(int) and Fixed32.toInt(int) to convert between normal integers and Fixed32 integers.

Since:

BlackBerry API 4.0.0

Field Summary
static int[]	IDENTITY_3X3 3 x 3 identity matrix.

Method Summary
static boolean	intersects(int ax0, int ay0, int ax1, int ay1, int bx0, int by0, int bx1, int by1) Does line segment A intersection line segment B?
static boolean	isIdentity(int[] source, int index) Determines if this matrix is the indentity matrix.
static boolean	isTranslation(int[] source, int index) Determine if the matrix represented by the integer array is a translation.
static void	multiply3x3(int[] a, int aStartIndex, int[] b, int bStartIndex) Deprecated. use multiply3x3(int[],int,int[],int,int[],int) and pass B as the destination matrix.
static void	multiply3x3(int[] a, int aStartIndex, int[] b, int bStartIndex, int[] dest, int destStartIndex) Multiplies 2 3x3 matrices (A x B).
static void	multiply3x3Affine(int[] a, int aStartIndex, int[] b, int bStartIndex, int[] dest, int destStartIndex) Multiplies 2 affine 3x3 matrices (A x B).
static long	multiplyPoint(int[] matrix, int pos, int x, int y) Multiplies a given (x, y) point by a given matrix, and returns the result as a long number: the first 32 bits represent the resulting x-coordinate, and the second 32 bits represent the resulting y-coordinate So, resultX = (int) result resultY = (int) (result >>> 32) This method does the same as VecMath.pointMultiply3x3(int[], int, int, int, int[], int), but it does not require an array to store the return values.
static void	pointMultiply3x3(int[] a, int aStartIndex, int x, int y, int[] dest, int destStartIndex) Multiplies a given x,y point by a given 3x3 matrix.
static void	transformPoints(int[] matrix, int matrixOffset, int[] coordsX, int[] coordsY, int[] destX, int[] destY) Transforms an array of x,y coordinates represented by normal integers.
static void	transformPoints32(int[] matrix, int matrixOffset, int[] coordsX, int[] coordsY, int[] destX, int[] destY) Transforms an array of x,y coordinates represented by Fixed32 integers.
static void	transformPoints32(int[] matrix, int matrixOffset, int[] coordsX, int[] coordsY, int[] destX, int[] destY, int length) Transforms an array of x,y coordinates represented by Fixed32 integers.

Methods inherited from class java.lang.Object

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

Field Detail

IDENTITY_3X3

public static final int[] IDENTITY_3X3

3 x 3 identity matrix.

Since:

BlackBerry API 4.0.0

Method Detail

multiplyPoint

public static long multiplyPoint(int[] matrix,
                                 int pos,
                                 int x,
                                 int y)

Multiplies a given (x, y) point by a given matrix, and returns the result as a long number: the first 32 bits represent the resulting x-coordinate, and the second 32 bits represent the resulting y-coordinate So, resultX = (int) result resultY = (int) (result >>> 32)

This method does the same as VecMath.pointMultiply3x3(int[], int, int, int, int[], int), but it does not require an array to store the return values.

Parameters:

matrix - the array containing the matrix to multiply.

pos - the index in a where the matrix begins.

x - the x coordinate (in Fixed 32 notation).

y - the y coordinate (in Fixed 32 notation).

Returns:

the long number representing the resulting (x, y) point.

Since:

BlackBerry API 4.0.0

transformPoints

public static void transformPoints(int[] matrix,
                                   int matrixOffset,
                                   int[] coordsX,
                                   int[] coordsY,
                                   int[] destX,
                                   int[] destY)

Transforms an array of x,y coordinates represented by normal integers.

Parameters:

matrix - The transformation matrix used to transform the input coordinates. The matrix elements are in fixed-32 (15.16) format.

matrixoffset - The offset to the first point to be transformed in the matrix array.

coordsX - An array containing normal integers that represent the x coordinates to be transformed.

coordsY - An array containing normal integers that represent the Y coordinates to be transformed.

destX - The array into which the transformed x coordinates are returned as normal integers.

destY - The array into which the transformed y coordinates are returned as normal integers.

Since:

BlackBerry API 4.0.0

transformPoints32

public static void transformPoints32(int[] matrix,
                                     int matrixOffset,
                                     int[] coordsX,
                                     int[] coordsY,
                                     int[] destX,
                                     int[] destY)

Transforms an array of x,y coordinates represented by Fixed32 integers.

Parameters:

matrix - The transformation matrix used to transform the input coordinates. The matrix elements are in fixed-32 (15.16) format.

matrixoffset - The offset to the first point to be transformed in the matrix array.

coordsX - An array containing normal integers that represent the x coordinates to be transformed.

coordsY - An array containing normal integers that represent the Y coordinates to be transformed.

destX - The array into which the transformed x coordinates are returned as normal integers.

destY - The array into which the transformed y coordinates are returned as normal integers.

Since:

BlackBerry API 4.0.2

transformPoints32

public static void transformPoints32(int[] matrix,
                                     int matrixOffset,
                                     int[] coordsX,
                                     int[] coordsY,
                                     int[] destX,
                                     int[] destY,
                                     int length)

Transforms an array of x,y coordinates represented by Fixed32 integers.

Parameters:

matrix - The transformation matrix used to transform the input coordinates. The matrix elements are in fixed-32 (15.16) format.

matrixoffset - The offset to the first point to be transformed in the matrix array.

coordsX - An array containing normal integers that represent the x coordinates to be transformed.

coordsY - An array containing normal integers that represent the Y coordinates to be transformed.

destX - The array into which the transformed x coordinates are returned as normal integers.

destY - The array into which the transformed y coordinates are returned as normal integers.

length - If length is -1, then all the values in the input arrays are processed; otherwise, the first length values in the input arrays are processed.

Since:

BlackBerry API 4.0.2

isIdentity

public static final boolean isIdentity(int[] source,
                                       int index)

Determines if this matrix is the indentity matrix.

Parameters:

source - Integer array containing the matrix.

index - Offset inside the matrix

Returns:

True if it is the identity.

Since:

BlackBerry API 4.0.0

isTranslation

public static final boolean isTranslation(int[] source,
                                          int index)

Determine if the matrix represented by the integer array is a translation.

Parameters:

source - Integer array containing the matrix.

index - Offset inside the matrix

Returns:

True if the matrix is a translation, otherwise false.

Since:

BlackBerry API 4.1.0

intersects

public static boolean intersects(int ax0,
                                 int ay0,
                                 int ax1,
                                 int ay1,
                                 int bx0,
                                 int by0,
                                 int bx1,
                                 int by1)

Does line segment A intersection line segment B? It receives the x and y coordinates of every line segment This method assumes integer parameters ONLY (non-fixed32). Passing fixed32 values to this method could cause overflow.

Returns:

True is the line intersect.

Since:

BlackBerry API 4.0.0

multiply3x3

public static void multiply3x3(int[] a,
                               int aStartIndex,
                               int[] b,
                               int bStartIndex)

Deprecated. use multiply3x3(int[],int,int[],int,int[],int) and pass B as the destination matrix.

Multiplies 2 3x3 matrices (A x B). The result overwrites the second matrix (B). Please note, no bounds checks are made by this method. It assumes that the arrays are non-null and contain enough values for a 3x3 matrix.

Parameters:

a - the array containing matrix A

aStartIndex - the index of the start of matrix A

b - the array containing matrix B

bStartIndex - the index of the start of matrix B

Since:

BlackBerry API 4.0.0

multiply3x3

public static void multiply3x3(int[] a,
                               int aStartIndex,
                               int[] b,
                               int bStartIndex,
                               int[] dest,
                               int destStartIndex)

Multiplies 2 3x3 matrices (A x B). The result is stored in the specified destination array. Please note, no bounds checks are made by this method. It assumes that the arrays are non-null and contain enough values/space for a 3x3 matrix. If A or B would be overwritten by the operation, A or B is first copied to a temporary array before the calculation.

Parameters:

a - the array containing matrix A

aStartIndex - the index of the start of matrix A

b - the array containing matrix B

bStartIndex - the index of the start of matrix B

dest - the array to store the result of the multiplication

destStartIndex - the index at which to store the first value in the matrix.

Since:

BlackBerry API 4.0.0

multiply3x3Affine

public static void multiply3x3Affine(int[] a,
                                     int aStartIndex,
                                     int[] b,
                                     int bStartIndex,
                                     int[] dest,
                                     int destStartIndex)

Multiplies 2 affine 3x3 matrices (A x B). An affine matrix has the following form:
A C E
B D F
0 0 1

The result is stored in the specified destination array. Please note, no bounds checks are made by this method. It assumes that the arrays are non-null and contain enough values/space for a 3x3 matrix. Also this method is optimized for affine matrices. Using it with non-affine matrices give incorrect and undefined behavior.

Parameters:

a - the array containing matrix A

aStartIndex - the index of the start of matrix A

b - the array containing matrix B

bStartIndex - the index of the start of matrix B

dest - the array to store the result of the multiplication

destStartIndex - the index at which to store the first value in the matrix.

Since:

BlackBerry API 4.0.0

pointMultiply3x3

public static void pointMultiply3x3(int[] a,
                                    int aStartIndex,
                                    int x,
                                    int y,
                                    int[] dest,
                                    int destStartIndex)

Multiplies a given x,y point by a given 3x3 matrix. (A x P) The resulting x point is stored at dest[destStartIndex] and the resulting y point is stored at dest[destStartIndex + 1]. It is assumed that the arrays are of sufficient length.

Parameters:

a - the array containing the matrix to multiply.

aStartIndex - the index in a where the matrix begins.

x - the x coordinate (in Fixed 32 notation).

y - the y coordinate (in Fixed 32 notation).

dest - the array in which to store the results.

destStartOffset - the index in dest where the results should be stored.

Since:

BlackBerry API 4.0.0