Matrix44
public
class
Matrix44
extends Object
java.lang.Object | |
↳ | android.graphics.Matrix44 |
The Matrix44 class holds a 4x4 matrix for transforming coordinates. It is similar to
Matrix
, and should be used when you want to manipulate the canvas in 3D. Values are kept
in row-major order. The values and operations are treated as column vectors.
Summary
Public constructors | |
---|---|
Matrix44()
The default Matrix44 constructor will instantiate an identity matrix. |
|
Matrix44(Matrix mat)
Creates and returns a Matrix44 by taking the 3x3 Matrix and placing it on the 0 of the z-axis
by setting row [ a b c ] [ a b 0 c ] [ d e f ] -> [ d e 0 f ] [ g h i ] [ 0 0 1 0 ] [ g h 0 i ] |
Public methods | |
---|---|
Matrix44
|
concat(Matrix44 b)
Multiplies `this` matrix (A) and provided Matrix (B) in the order of A * B. |
boolean
|
equals(Object obj)
Indicates whether some other object is "equal to" this one. |
float
|
get(int row, int col)
Gets the value at the matrix's row and column. |
void
|
getValues(float[] dst)
Copies matrix values into the provided array in row-major order. |
int
|
hashCode()
Returns a hash code value for the object. |
boolean
|
invert()
Inverts the Matrix44, then return true if successful, false if unable to invert. |
boolean
|
isIdentity()
Returns true if Matrix44 is equal to identity matrix. |
float[]
|
map(float x, float y, float z, float w)
Multiplies (x, y, z, w) vector by the Matrix44, then returns the new (x, y, z, w). |
void
|
map(float x, float y, float z, float w, float[] dst)
Multiplies (x, y, z, w) vector by the Matrix44, then returns the new (x, y, z, w). |
void
|
reset()
Sets the Matrix44 to the identity matrix. |
Matrix44
|
rotate(float deg, float xComp, float yComp, float zComp)
Applies a rotation around a given axis, then returns self. |
Matrix44
|
scale(float x, float y, float z)
Applies scaling factors to `this` Matrix44, then returns self. |
void
|
set(int row, int col, float val)
Sets the value at the matrix's row and column to the provided value. |
void
|
setValues(float[] src)
Replaces the Matrix's values with the values in the provided array. |
String
|
toString()
Returns a string representation of the object. |
Matrix44
|
translate(float x, float y, float z)
Applies a translation to `this` Matrix44, then returns self. |
Inherited methods | |
---|---|
Public constructors
Matrix44
public Matrix44 ()
The default Matrix44 constructor will instantiate an identity matrix.
Matrix44
public Matrix44 (Matrix mat)
Creates and returns a Matrix44 by taking the 3x3 Matrix and placing it on the 0 of the z-axis
by setting row 2
and column 2
to the identity as seen in the following
operation:
[ a b c ] [ a b 0 c ] [ d e f ] -> [ d e 0 f ] [ g h i ] [ 0 0 1 0 ] [ g h 0 i ]
Parameters | |
---|---|
mat |
Matrix : A 3x3 Matrix to be converted (original Matrix will not be changed)
This value cannot be null . |
Public methods
concat
public Matrix44 concat (Matrix44 b)
Multiplies `this` matrix (A) and provided Matrix (B) in the order of A * B. The result is saved in `this` Matrix.
Parameters | |
---|---|
b |
Matrix44 : The second Matrix in the concatenation operation
This value cannot be null . |
Returns | |
---|---|
Matrix44 |
A reference to this Matrix, which can be used to chain Matrix operations
This value cannot be null . |
equals
public boolean equals (Object obj)
Indicates whether some other object is "equal to" this one.
The equals
method implements an equivalence relation
on non-null object references:
- It is reflexive: for any non-null reference value
x
,x.equals(x)
should returntrue
. - It is symmetric: for any non-null reference values
x
andy
,x.equals(y)
should returntrue
if and only ify.equals(x)
returnstrue
. - It is transitive: for any non-null reference values
x
,y
, andz
, ifx.equals(y)
returnstrue
andy.equals(z)
returnstrue
, thenx.equals(z)
should returntrue
. - It is consistent: for any non-null reference values
x
andy
, multiple invocations ofx.equals(y)
consistently returntrue
or consistently returnfalse
, provided no information used inequals
comparisons on the objects is modified. - For any non-null reference value
x
,x.equals(null)
should returnfalse
.
An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.
Parameters | |
---|---|
obj |
Object : the reference object with which to compare. |
Returns | |
---|---|
boolean |
true if this object is the same as the obj
argument; false otherwise. |
get
public float get (int row, int col)
Gets the value at the matrix's row and column.
Parameters | |
---|---|
row |
int : An integer from 0 to 3 indicating the row of the value to get
Value is between 0 and 3 inclusive |
col |
int : An integer from 0 to 3 indicating the column of the value to get
Value is between 0 and 3 inclusive |
Returns | |
---|---|
float |
getValues
public void getValues (float[] dst)
Copies matrix values into the provided array in row-major order.
Parameters | |
---|---|
dst |
float : The float array where values will be copied, must be of length 16
This value cannot be null . |
Throws | |
---|---|
IllegalArgumentException |
if the destination float array is not of length 16 |
hashCode
public int hashCode ()
Returns a hash code value for the object. This method is
supported for the benefit of hash tables such as those provided by
HashMap
.
The general contract of hashCode
is:
- Whenever it is invoked on the same object more than once during
an execution of a Java application, the
hashCode
method must consistently return the same integer, provided no information used inequals
comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. - If two objects are equal according to the
equals
method, then calling thehashCode
method on each of the two objects must produce the same integer result. - It is not required that if two objects are unequal
according to the
equals
method, then calling thehashCode
method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Returns | |
---|---|
int |
a hash code value for this object. |
invert
public boolean invert ()
Inverts the Matrix44, then return true if successful, false if unable to invert.
Returns | |
---|---|
boolean |
true on success, false otherwise |
isIdentity
public boolean isIdentity ()
Returns true if Matrix44 is equal to identity matrix.
Returns | |
---|---|
boolean |
map
public float[] map (float x, float y, float z, float w)
Multiplies (x, y, z, w) vector by the Matrix44, then returns the new (x, y, z, w). Users
should set w
to 1 to indicate the coordinates are normalized.
Parameters | |
---|---|
x |
float |
y |
float |
z |
float |
w |
float |
Returns | |
---|---|
float[] |
An array of length 4 that represents the x, y, z, w (where w is perspective) value
after multiplying x, y, z, 1 by the matrix
This value cannot be null . |
map
public void map (float x, float y, float z, float w, float[] dst)
Multiplies (x, y, z, w) vector by the Matrix44, then returns the new (x, y, z, w). Users
should set w
to 1 to indicate the coordinates are normalized.
Parameters | |
---|---|
x |
float |
y |
float |
z |
float |
w |
float |
dst |
float : This value cannot be null . |
rotate
public Matrix44 rotate (float deg, float xComp, float yComp, float zComp)
Applies a rotation around a given axis, then returns self.
x
, y
, z
represent the axis by which to rotate around.
For example, pass in 1, 0, 0
to rotate around the x-axis.
The axis provided will be normalized.
Parameters | |
---|---|
deg |
float : Amount in degrees to rotate the matrix about the x-axis |
xComp |
float : X component of the rotation axis |
yComp |
float : Y component of the rotation axis |
zComp |
float : Z component of the rotation axis |
Returns | |
---|---|
Matrix44 |
A reference to this Matrix, which can be used to chain Matrix operations
This value cannot be null . |
scale
public Matrix44 scale (float x, float y, float z)
Applies scaling factors to `this` Matrix44, then returns self. Pass 1s for no change.
Parameters | |
---|---|
x |
float : Scaling factor for the x-axis |
y |
float : Scaling factor for the y-axis |
z |
float : Scaling factor for the z-axis |
Returns | |
---|---|
Matrix44 |
A reference to this Matrix, which can be used to chain Matrix operations
This value cannot be null . |
set
public void set (int row, int col, float val)
Sets the value at the matrix's row and column to the provided value.
Parameters | |
---|---|
row |
int : An integer from 0 to 3 indicating the row of the value to change
Value is between 0 and 3 inclusive |
col |
int : An integer from 0 to 3 indicating the column of the value to change
Value is between 0 and 3 inclusive |
val |
float : The value the element at the specified index will be set to |
setValues
public void setValues (float[] src)
Replaces the Matrix's values with the values in the provided array.
Parameters | |
---|---|
src |
float : A float array of length 16. Floats are treated in row-major order
This value cannot be null . |
Throws | |
---|---|
IllegalArgumentException |
if the destination float array is not of length 16 |
toString
public String toString ()
Returns a string representation of the object.
Returns | |
---|---|
String |
a string representation of the object. |
translate
public Matrix44 translate (float x, float y, float z)
Applies a translation to `this` Matrix44, then returns self.
Parameters | |
---|---|
x |
float : Translation for the x-axis |
y |
float : Translation for the y-axis |
z |
float : Translation for the z-axis |
Returns | |
---|---|
Matrix44 |
A reference to this Matrix, which can be used to chain Matrix operations
This value cannot be null . |