to top
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 row x 1 column column-vectors stored in order:
``` v[offset + 0]
v[offset + 1]
v[offset + 2]
v[offset + 3]
```

## Summary

Public Constructors
Matrix()
Public Methods
static void frustumM(float[] m, int offset, float left, float right, float bottom, float top, float near, float far)
Define 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)
Multiply two 4x4 matrices together and store the result in a third 4x4 matrix.
static void multiplyMV(float[] resultVec, int resultVecOffset, float[] lhsMat, int lhsMatOffset, float[] rhsVec, int rhsVecOffset)
Multiply a 4 element vector by a 4x4 matrix and store 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)
Define 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)
Define 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)
Rotates matrix m 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 Methods

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

Define a projection matrix in terms of six clip planes

##### Parameters
m the float array that holds the perspective matrix 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)

Inverts a 4 x 4 matrix.

##### Parameters
mInv the array that holds the output inverted matrix an offset into mInv where the inverted matrix is stored. the input array an offset into m where the 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)

Computes the length of a vector

##### Parameters
x x coordinate of a vector y coordinate of a vector 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)

Multiply two 4x4 matrices together and store 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. The offset into the result array where the result is stored. The float array that holds the left-hand-side matrix. The offset into the lhs array where the lhs is stored The float array that holds the right-hand-side matrix. 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)

Multiply a 4 element vector by a 4x4 matrix and store 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. The offset into the result array where the result vector is stored. The float array that holds the left-hand-side matrix. The offset into the lhs array where the lhs is stored The float array that holds the right-hand-side vector. 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)

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)

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

#### public 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)

##### Parameters
m source matrix index into m where the matrix starts angle to rotate in degrees scale factor x scale factor y scale factor z

#### public 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)

##### Parameters
rm returns the result index into rm where the result matrix starts source matrix index into m where the source matrix starts angle to rotate in degrees scale factor x scale factor y scale factor z

#### public 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

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

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

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

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

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

Sets matrix m to the identity matrix.

##### Parameters
sm returns the result 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)

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

##### Parameters
rm returns the result index into rm where the result matrix starts eye point X eye point Y eye point Z center of view X center of view Y center of view Z up vector X up vector Y up vector Z

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

Converts Euler angles to a rotation matrix

##### Parameters
rm returns the result index into rm where the result matrix starts angle of rotation, in degrees angle of rotation, in degrees angle of rotation, in degrees

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

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

##### Parameters
rm returns the result index into rm where the result matrix starts angle to rotate in degrees scale factor x scale factor y scale factor z

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

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

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

#### public 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

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