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- <h1>[name]</h1>
- <p class="desc">
- A class representing a 2x2
- [link:https://en.wikipedia.org/wiki/Matrix_(mathematics) matrix].
- </p>
- <h2>Code Example</h2>
- <code>
- const m = new Matrix2();
- </code>
- <h2>A Note on Row-Major and Column-Major Ordering</h2>
- <p>
- The constructor and [page:set]() method take arguments in
- [link:https://en.wikipedia.org/wiki/Row-_and_column-major_order#Column-major_order row-major]
- order, while internally they are stored in the [page:.elements elements]
- array in column-major order.<br /><br />
- This means that calling
- <code>
- m.set( 11, 12,
- 21, 22 );
- </code>
- will result in the [page:.elements elements] array containing:
- <code>
- m.elements = [ 11, 21,
- 12, 22 ];
- </code>
- and internally all calculations are performed using column-major ordering.
- However, as the actual ordering makes no difference mathematically and
- most people are used to thinking about matrices in row-major order, the
- three.js documentation shows matrices in row-major order. Just bear in
- mind that if you are reading the source code, you'll have to take the
- [link:https://en.wikipedia.org/wiki/Transpose transpose] of any matrices
- outlined here to make sense of the calculations.
- </p>
- <h2>Constructor</h2>
- <h3>[name]( [param:Number n11], [param:Number n12],
- [param:Number n21], [param:Number n22] )</h3>
- <p>
- Creates a 2x2 matrix with the given arguments in row-major order. If no arguments are provided, the constructor initializes
- the [name] to the 3x3 [link:https://en.wikipedia.org/wiki/Identity_matrix identity matrix].
- </p>
- <h2>Properties</h2>
- <h3>[property:Array elements]</h3>
- <p>
- A [link:https://en.wikipedia.org/wiki/Row-_and_column-major_order column-major] list of matrix values.
- </p>
- <h2>Methods</h2>
- <h3>
- [method:this fromArray]( [param:Array array], [param:Integer offset] )
- </h3>
- <p>
- [page:Array array] - the array to read the elements from.<br />
- [page:Integer offset] - (optional) index of first element in the array.
- Default is `0`.<br /><br />
- Sets the elements of this matrix based on an array in
- [link:https://en.wikipedia.org/wiki/Row-_and_column-major_order#Column-major_order column-major] format.
- </p>
- <h3>[method:this identity]()</h3>
- <p>
- Resets this matrix to the 2x2 identity matrix:
- </p>
- <math display="block">
- <mrow>
- <mo>[</mo>
- <mtable>
- <mtr>
- <mtd><mn>1</mn></mtd>
- <mtd><mn>0</mn></mtd>
- </mtr>
- <mtr>
- <mtd><mn>0</mn></mtd>
- <mtd><mn>1</mn></mtd>
- </mtr>
- </mtable>
- <mo>]</mo>
- </mrow>
- </math>
- <h3>
- [method:this set]( [param:Float n11], [param:Float n12], [param:Float n21], [param:Float n22] )
- </h3>
- <p>
- Sets the 2x2 matrix values to the given
- [link:https://en.wikipedia.org/wiki/Row-_and_column-major_order row-major]
- sequence of values:
- </p>
- <math display="block">
- <mrow>
- <mo>[</mo>
- <mtable>
- <mtr>
- <mtd><mi>n11</mi></mtd>
- <mtd><mi>n12</mi></mtd>
- </mtr>
- <mtr>
- <mtd><mi>n21</mi></mtd>
- <mtd><mi>n22</mi></mtd>
- </mtr>
- </mtable>
- <mo>]</mo>
- </mrow>
- </math>
- <h2>Source</h2>
- <p>
- [link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]
- </p>
- </body>
- </html>
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