Matrix Methods
taccgl™ includes various matrix operations. Each matrix is
represented as a javaScript array. A 3x3 matrix is
represented as an array with 9 elements indexed 0..8 and a
4x4 matrix as an array with 16 elements indexed from 0..15.
Normally a matrix is stored in row major order, i.e. m[0]
contains the first element of the first row and m[1] contains
the second element of the first row.
Using the representation it is easily possible to create a
matrix using javaScript e.g. m=[1,0,0, 0,1,0,
0,0,1] is the 3x3 identity matrix.
Some matrix functions create a new a javascript object for the
result (copying functions) while other matrix functions (in-place
funcitions) in-place modify one of the array objects passed to it as
parameter. The latter is useful to reduce the number of array
objects objects created, but needs careful programming since often
one might not expect that these functions change their arguments.
When using these latter functions it is neccessary to copy the array
object of a matrix, which can be done using the javaScript slice
function e.g. m.slice(0).
Vector functions usually start with 'v', matrix functions with 'm'.
In-place functions then use an 'i' in their name, copying functions do not.
Some functions handle arbitrary sized vectors or matrices, others fixed size.
Fixed size functions have 32, 33, or 44 in their name for 4x2, 3x3, or 4z4 matrices.
m33I Library Method
Short Description: 3x3 Identity Matrix
Signature: taccgl.m33I
Class: taccgl Class
Creates and returns a 3x3 identity matrix.
<script > document.write(taccgl.m33I()); </script> |
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m33Add Library Method
Short Description: 3x3 Matrix Addition
Signature: taccgl.m33Add (a,b)
Class: taccgl Class
Adds the 3x3 matrix b on the matrix a.
It allocates a new matrix object for the result and does not modify its arguments.
<script > document.write(taccgl.m33Add(taccgl.m33I(),taccgl.m33I()) ); </script> |
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mi33Add Library Method
Short Description: 4x4 Translation Matrix
Signature: taccgl.mi33Add (a,b)
Class: taccgl Class
Adds the 3x3 matrix b on the matrix a.
It modifies the matrix a thereby and returns the modified matrix a.
<script > document.write(taccgl.mi33Add(taccgl.m33I(),taccgl.m33I()) ); </script> |
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m33Mul Library Method
Short Description: 3x3 Matrix Multiplication
Signature: taccgl.m33Mul (a,b)
Class: taccgl Class
Multiplies the 3x3 matrix a with the matrix b.
It allocates a new matrix object for the result and does not modify its arguments.
<script > document.write(taccgl.m33Mul([1,1,1,0,1,0,0,0,1], [2,3,1,0,1,0,0,0,1])) </script> |
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mi33Mul Library Method
Short Description: 4x4 Translation Matrix
Signature: taccgl.mi33Mul (a,b)
Class: taccgl Class
Multiplies the 3x3 matrix a with the matrix b.
It modifies the matrix a thereby and returns the modified matrix a.
<script > document.write(taccgl.mi33Mul([1,1,1,0,1,0,0,0,1], [2,3,1,0,1,0,0,0,1])) </script> |
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m33T Library Method
Short Description: Transpose 3x3 Matrix
Signature: taccgl.m33T (a)
Class: taccgl Class
Transposes the 3x3 matrix a and returns it.
It allocates a new matrix object for the result and does not modify its arguments.
<script > document.write(taccgl.m33T([2,3,1,0,1,0,0,0,1])) </script> |
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mi33T Library Method
Short Description: 4x4 Translation Matrix
Signature: taccgl.mi33T (a)
Class: taccgl Class
Transposes the 3x3 matrix a and returns it. Note that this function
modifies the matrix object a and does not create a new matrix.
<script > document.write(taccgl.mi33T([2,3,1,0,1,0,0,0,1])) </script> |
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m33Inverse Library Method
Short Description: 3x3 Matrix Inverse
Signature: taccgl.m33Inverse (a)
Class: taccgl Class
Returns a new matrix contains the inverse matrix of the 3x3 matrix a.
<script > document.write(taccgl.m33Inverse([2,3,1,0,1,0,0,0,1])) </script> |
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m33Rotation Library Method
Short Description: 3x3 Rotation Matrix
Signature: taccgl.m33Rotation (alpha,va)
Class: taccgl Class
Returns a rotation matrix around the va axis and the angle alpha.
alpha must be given in radians.
<script > document.write(taccgl.m33Rotation(Math.PI,[0,0,1])) </script> |
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m44I Library Method
Short Description: 4x4 Identity Matrix
Signature: taccgl.m44I
Class: taccgl Class
Creates and returns a 4x4 identity matrix.
<script > document.write(taccgl.m44I()); </script> |
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m44Add Library Method
Short Description: 4x4 Matrix Addition
Signature: taccgl.m44Add (a,b)
Class: taccgl Class
Adds the 4x4 matrix b on the matrix a.
It allocates a new matrix object for the result and does not modify its arguments.
mi44Add Library Method
Short Description: 4x4 Translation Matrix
Signature: taccgl.mi44Add (a,b)
Class: taccgl Class
Adds the 4x4 matrix b on the matrix a.
It modifies the matrix a thereby and returns the modified matrix a.
m44Mul Library Method
Short Description: 4x4 Matrix Multiplication
Signature: taccgl.m44Mul (a,b)
Class: taccgl Class
Multiplies the 4x4 matrix a with the matrix b.
It allocates a new matrix object for the result and does not modify its arguments.
mi44Mul Library Method
Short Description: 4x4 Translation Matrix
Signature: taccgl.mi44Mul (a,b)
Class: taccgl Class
Multiplies the 4x4 matrix a with the matrix b.
It modifies the matrix a thereby and returns the modified matrix a.
m44MulV Library Method
Short Description: 4x4 Matrix and Vector Multiplication
Signature: taccgl.m44MulV (a,v)
Class: taccgl Class
Multiplies the 4x4 matrix a with the vector v.
v must have exaclty 4 elements. The function returns a new vector of 4 elements.
m44T Library Method
Short Description: Transpose 4x4 Matrix
Signature: taccgl.m44T (a)
Class: taccgl Class
Transposes the 4x4 matrix a and returns it.
It allocates a new matrix object for the result and does not modify its arguments.
mi44T Library Method
Short Description: 4x4 Translation Matrix
Signature: taccgl.mi44T (a)
Class: taccgl Class
Transposes the 4x4 matrix a and returns it. Note that this function
indeed modifies the matrix object a and does not create a new matrix.
m44FromM33 Library Method
Short Description: Extend 3x3 Matrix to 4x4 Matrix
Signature: taccgl.m44FromM33 (a,x,y,z)
Class: taccgl Class
The parameter a must be a 3x3 Matrix and x,y,z numbers. The 3x3 matrix a is converted
into a 4x4 matrix by adding a 4th row containing [0,0,0,1] and a 4th column containing [x,y,z,1].
<script > document.write(taccgl.m44FromM33([2,2,2,2,2,2,2,2,2],3,4,5)) </script> |
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m33FromM44 Library Method
Short Description: Take 3x3 Matrix from 4x4 Matrix
Signature: taccgl.m33FromM44 (a,x,y,z)
Class: taccgl Class
The parameter a must be a 4x4 Matrix. It is converted
into a 3x3 matrix by removing the last row and the last column.
m44Translation Library Method
Short Description: 4x4 Translation Matrix
Signature: taccgl.m44Translation (dx,dy,dz)
Class: taccgl Class
Returns a translation matrix that moves coordinates by the vector dx,dy,dz.
<script > document.write(taccgl.m44Translation(2,3,4)) </script> |
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