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Android APIs
public class

Matrix

extends Object
java.lang.Object
   ↳ android.opengl.Matrix

Class Overview

Matrix math utilities. These methods operate on OpenGL ES format matrices and vectors stored in float arrays.

Matrices are 4 x 4 column-vector matrices stored in column-major order: 

        m[offset +  0] m[offset +  4] m[offset +  8] m[offset + 12]
  m[offset +  1] m[offset +  5] m[offset +  9] m[offset + 13]
  m[offset +  2] m[offset +  6] m[offset + 10] m[offset + 14]
  m[offset +  3] m[offset +  7] m[offset + 11] m[offset + 15]
Vectors are 4 x 1 column vectors stored in order: 
        v[offset + 0]
 v[offset + 1]
 v[offset + 2]
 v[offset + 3]

Summary

Public Constructors
Matrix ()
This constructor was deprecated in API level 19. All methods are static, do not instantiate this class.
Public Methods
static void frustumM (float[] m, int offset, float left, float right, float bottom, float top, float near, float far)
Defines a projection matrix in terms of six clip planes.
static boolean invertM (float[] mInv, int mInvOffset, float[] m, int mOffset)
Inverts a 4 x 4 matrix.
static float length (float x, float y, float z)
Computes the length of a vector.
static void multiplyMM (float[] result, int resultOffset, float[] lhs, int lhsOffset, float[] rhs, int rhsOffset)
Multiplies two 4x4 matrices together and stores the result in a third 4x4 matrix.
static void multiplyMV (float[] resultVec, int resultVecOffset, float[] lhsMat, int lhsMatOffset, float[] rhsVec, int rhsVecOffset)
Multiplies a 4 element vector by a 4x4 matrix and stores the result in a 4-element column vector.
static void orthoM (float[] m, int mOffset, float left, float right, float bottom, float top, float near, float far)
Computes an orthographic projection matrix.
static void perspectiveM (float[] m, int offset, float fovy, float aspect, float zNear, float zFar)
Defines a projection matrix in terms of a field of view angle, an aspect ratio, and z clip planes.
static void rotateM (float[] m, int mOffset, float a, float x, float y, float z)
Rotates matrix m in place by angle a (in degrees) around the axis (x, y, z).
static void rotateM (float[] rm, int rmOffset, float[] m, int mOffset, float a, float x, float y, float z)
Rotates matrix m by angle a (in degrees) around the axis (x, y, z).
static void scaleM (float[] sm, int smOffset, float[] m, int mOffset, float x, float y, float z)
Scales matrix m by x, y, and z, putting the result in sm.
static void scaleM (float[] m, int mOffset, float x, float y, float z)
Scales matrix m in place by sx, sy, and sz.
static void setIdentityM (float[] sm, int smOffset)
Sets matrix m to the identity matrix.
static void setLookAtM (float[] rm, int rmOffset, float eyeX, float eyeY, float eyeZ, float centerX, float centerY, float centerZ, float upX, float upY, float upZ)
Defines a viewing transformation in terms of an eye point, a center of view, and an up vector.
static void setRotateEulerM (float[] rm, int rmOffset, float x, float y, float z)
Converts Euler angles to a rotation matrix.
static void setRotateM (float[] rm, int rmOffset, float a, float x, float y, float z)
Creates a matrix for rotation by angle a (in degrees) around the axis (x, y, z).
static void translateM (float[] m, int mOffset, float x, float y, float z)
Translates matrix m by x, y, and z in place.
static void translateM (float[] tm, int tmOffset, float[] m, int mOffset, float x, float y, float z)
Translates matrix m by x, y, and z, putting the result in tm.
static void transposeM (float[] mTrans, int mTransOffset, float[] m, int mOffset)
Transposes a 4 x 4 matrix.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public Matrix ()

Added in API level 1

This constructor was deprecated in API level 19.
All methods are static, do not instantiate this class.

Public Methods

public static void frustumM (float[] m, int offset, float left, float right, float bottom, float top, float near, float far)

Added in API level 1

Defines a projection matrix in terms of six clip planes.

Parameters
m the float array that holds the output perspective matrix
offset the offset into float array m where the perspective matrix data is written

public static boolean invertM (float[] mInv, int mInvOffset, float[] m, int mOffset)

Added in API level 1

Inverts a 4 x 4 matrix.

mInv and m must not overlap.

Parameters
mInv the array that holds the output inverted matrix
mInvOffset an offset into mInv where the inverted matrix is stored.
m the input array
mOffset an offset into m where the input matrix is stored.
Returns
  • true if the matrix could be inverted, false if it could not.

public static float length (float x, float y, float z)

Added in API level 1

Computes the length of a vector.

Parameters
x x coordinate of a vector
y y coordinate of a vector
z z coordinate of a vector
Returns
  • the length of a vector

public static void multiplyMM (float[] result, int resultOffset, float[] lhs, int lhsOffset, float[] rhs, int rhsOffset)

Added in API level 1

Multiplies two 4x4 matrices together and stores the result in a third 4x4 matrix. In matrix notation: result = lhs x rhs. Due to the way matrix multiplication works, the result matrix will have the same effect as first multiplying by the rhs matrix, then multiplying by the lhs matrix. This is the opposite of what you might expect.

The same float array may be passed for result, lhs, and/or rhs. However, the result element values are undefined if the result elements overlap either the lhs or rhs elements.

Parameters
result The float array that holds the result.
resultOffset The offset into the result array where the result is stored.
lhs The float array that holds the left-hand-side matrix.
lhsOffset The offset into the lhs array where the lhs is stored
rhs The float array that holds the right-hand-side matrix.
rhsOffset The offset into the rhs array where the rhs is stored.
Throws
IllegalArgumentException if result, lhs, or rhs are null, or if resultOffset + 16 > result.length or lhsOffset + 16 > lhs.length or rhsOffset + 16 > rhs.length.

public static void multiplyMV (float[] resultVec, int resultVecOffset, float[] lhsMat, int lhsMatOffset, float[] rhsVec, int rhsVecOffset)

Added in API level 1

Multiplies a 4 element vector by a 4x4 matrix and stores the result in a 4-element column vector. In matrix notation: result = lhs x rhs

The same float array may be passed for resultVec, lhsMat, and/or rhsVec. However, the resultVec element values are undefined if the resultVec elements overlap either the lhsMat or rhsVec elements.

Parameters
resultVec The float array that holds the result vector.
resultVecOffset The offset into the result array where the result vector is stored.
lhsMat The float array that holds the left-hand-side matrix.
lhsMatOffset The offset into the lhs array where the lhs is stored
rhsVec The float array that holds the right-hand-side vector.
rhsVecOffset The offset into the rhs vector where the rhs vector is stored.
Throws
IllegalArgumentException if resultVec, lhsMat, or rhsVec are null, or if resultVecOffset + 4 > resultVec.length or lhsMatOffset + 16 > lhsMat.length or rhsVecOffset + 4 > rhsVec.length.

public static void orthoM (float[] m, int mOffset, float left, float right, float bottom, float top, float near, float far)

Added in API level 1

Computes an orthographic projection matrix.

Parameters
m returns the result

public static void perspectiveM (float[] m, int offset, float fovy, float aspect, float zNear, float zFar)

Defines a projection matrix in terms of a field of view angle, an aspect ratio, and z clip planes.

Parameters
m the float array that holds the perspective matrix
offset the offset into float array m where the perspective matrix data is written
fovy field of view in y direction, in degrees
aspect width to height aspect ratio of the viewport

public static void rotateM (float[] m, int mOffset, float a, float x, float y, float z)

Added in API level 1

Rotates matrix m in place by angle a (in degrees) around the axis (x, y, z).

Parameters
m source matrix
mOffset index into m where the matrix starts
a angle to rotate in degrees
x X axis component
y Y axis component
z Z axis component

public static void rotateM (float[] rm, int rmOffset, float[] m, int mOffset, float a, float x, float y, float z)

Added in API level 1

Rotates matrix m by angle a (in degrees) around the axis (x, y, z).

m and rm must not overlap.

Parameters
rm returns the result
rmOffset index into rm where the result matrix starts
m source matrix
mOffset index into m where the source matrix starts
a angle to rotate in degrees
x X axis component
y Y axis component
z Z axis component

public static void scaleM (float[] sm, int smOffset, float[] m, int mOffset, float x, float y, float z)

Added in API level 1

Scales matrix m by x, y, and z, putting the result in sm.

m and sm must not overlap.

Parameters
sm returns the result
smOffset index into sm where the result matrix starts
m source matrix
mOffset index into m where the source matrix starts
x scale factor x
y scale factor y
z scale factor z

public static void scaleM (float[] m, int mOffset, float x, float y, float z)

Added in API level 1

Scales matrix m in place by sx, sy, and sz.

Parameters
m matrix to scale
mOffset index into m where the matrix starts
x scale factor x
y scale factor y
z scale factor z

public static void setIdentityM (float[] sm, int smOffset)

Added in API level 1

Sets matrix m to the identity matrix.

Parameters
sm returns the result
smOffset index into sm where the result matrix starts

public static void setLookAtM (float[] rm, int rmOffset, float eyeX, float eyeY, float eyeZ, float centerX, float centerY, float centerZ, float upX, float upY, float upZ)

Added in API level 8

Defines a viewing transformation in terms of an eye point, a center of view, and an up vector.

Parameters
rm returns the result
rmOffset index into rm where the result matrix starts
eyeX eye point X
eyeY eye point Y
eyeZ eye point Z
centerX center of view X
centerY center of view Y
centerZ center of view Z
upX up vector X
upY up vector Y
upZ up vector Z

public static void setRotateEulerM (float[] rm, int rmOffset, float x, float y, float z)

Added in API level 1

Converts Euler angles to a rotation matrix.

Parameters
rm returns the result
rmOffset index into rm where the result matrix starts
x angle of rotation, in degrees
y angle of rotation, in degrees
z angle of rotation, in degrees

public static void setRotateM (float[] rm, int rmOffset, float a, float x, float y, float z)

Added in API level 1

Creates a matrix for rotation by angle a (in degrees) around the axis (x, y, z).

An optimized path will be used for rotation about a major axis (e.g. x=1.0f y=0.0f z=0.0f).

Parameters
rm returns the result
rmOffset index into rm where the result matrix starts
a angle to rotate in degrees
x X axis component
y Y axis component
z Z axis component

public static void translateM (float[] m, int mOffset, float x, float y, float z)

Added in API level 1

Translates matrix m by x, y, and z in place.

Parameters
m matrix
mOffset index into m where the matrix starts
x translation factor x
y translation factor y
z translation factor z

public static void translateM (float[] tm, int tmOffset, float[] m, int mOffset, float x, float y, float z)

Added in API level 1

Translates matrix m by x, y, and z, putting the result in tm.

m and tm must not overlap.

Parameters
tm returns the result
tmOffset index into sm where the result matrix starts
m source matrix
mOffset index into m where the source matrix starts
x translation factor x
y translation factor y
z translation factor z

public static void transposeM (float[] mTrans, int mTransOffset, float[] m, int mOffset)

Added in API level 1

Transposes a 4 x 4 matrix.

mTrans and m must not overlap.

Parameters
mTrans the array that holds the output transposed matrix
mTransOffset an offset into mTrans where the transposed matrix is stored.
m the input array
mOffset an offset into m where the input matrix is stored.