Transform4¶

Overview¶

Forward and inverse transforms with 4x4 matrices, allowing flexibility including affine and perspective transformations.

Methods starting with 'transform' will apply the transform from our primary matrix, while methods starting with 'inverse' will apply the transform from the inverse of our matrix.

Generally, this means transform.inverseThing( transform.transformThing( thing ) ).equals( thing ).

@author Jonathan Olson <jonathan.olson@colorado.edu>

Class Transform4¶

import { Transform4 } from 'scenerystack/dot';

Constructor¶

new Transform4( matrix )¶

Instance Methods¶

setMatrix( matrix )¶

Sets the value of the primary matrix directly from a Matrix4. Does not change the Matrix4 instance of this Transform4. @public

@param {Matrix4} matrix

invalidate()¶

This should be called after our internal matrix is changed. It marks the other dependent matrices as invalid, and sends out notifications of the change. @private

prepend( matrix )¶

Modifies the primary matrix such that: this.matrix = matrix * this.matrix. @public

@param {Matrix4} matrix

append( matrix )¶

Modifies the primary matrix such that: this.matrix = this.matrix * matrix @public

@param {Matrix4} matrix

prependTransform( transform )¶

Like prepend(), but prepends the other transform's matrix. @public

@param {Transform4} transform

appendTransform( transform )¶

Like append(), but appends the other transform's matrix. @public

@param {Transform4} transform

applyToCanvasContext( context )¶

Sets the transform of a Canvas context to be equivalent to the 2D affine part of this transform. @public

@param {CanvasRenderingContext2D} context

copy()¶

Creates a copy of this transform. @public

@returns {Transform4}

getMatrix()¶

Returns the primary matrix of this transform. @public

@returns {Matrix4}

getInverse()¶

Returns the inverse of the primary matrix of this transform. @public

@returns {Matrix4}

getMatrixTransposed()¶

Returns the transpose of the primary matrix of this transform. @public

@returns {Matrix4}

getInverseTransposed()¶

Returns the inverse of the transpose of matrix of this transform. @public

@returns {Matrix4}

isIdentity()¶

Returns whether our primary matrix is known to be an identity matrix. If false is returned, it doesn't necessarily mean our matrix isn't an identity matrix, just that it is unlikely in normal usage. @public

@returns {boolean}

isFinite()¶

Returns whether any components of our primary matrix are either infinite or NaN. @public

@returns {boolean}

transformPosition3( v )¶

Transforms a 3-dimensional vector like it is a point with a position (translation is applied). @public

For an affine matrix \(M\), the result is the homogeneous multiplication \(M\begin{bmatrix} x \\ y \\ z \\ 1 \end{bmatrix}\).

@param {Vector3} v @returns {Vector3}

transformDelta3( v )¶

Transforms a 3-dimensional vector like position is irrelevant (translation is not applied). @public

@param {Vector3} v @returns {Vector3}

transformNormal3( v )¶

Transforms a 3-dimensional vector like it is a normal to a surface (so that the surface is transformed, and the new normal to the surface at the transformed point is returned). @public

@param {Vector3} v @returns {Vector3}

transformDeltaX( x )¶

Returns the x-coordinate difference for two transformed vectors, which add the x-coordinate difference of the input x (and same y,z values) beforehand. @public

@param {number} x @returns {number}

transformDeltaY( y )¶

Returns the y-coordinate difference for two transformed vectors, which add the y-coordinate difference of the input y (and same x,z values) beforehand. @public

@param {number} y @returns {number}

transformDeltaZ( z )¶

Returns the z-coordinate difference for two transformed vectors, which add the z-coordinate difference of the input z (and same x,y values) beforehand. @public

@param {number} z @returns {number}

transformRay( ray )¶

Returns a transformed ray. @public

@param {Ray3} ray @returns {Ray3}

inversePosition3( v )¶

Transforms a 3-dimensional vector by the inverse of our transform like it is a point with a position (translation is applied). @public

For an affine matrix \(M\), the result is the homogeneous multiplication \(M^{-1}\begin{bmatrix} x \\ y \\ z \\ 1 \end{bmatrix}\).

This is the inverse of transformPosition3().

@param {Vector3} v @returns {Vector3}

inverseDelta3( v )¶

Transforms a 3-dimensional vector by the inverse of our transform like position is irrelevant (translation is not applied). @public

This is the inverse of transformDelta3().

@param {Vector3} v @returns {Vector3}

inverseNormal3( v )¶

Transforms a 3-dimensional vector by the inverse of our transform like it is a normal to a curve (so that the curve is transformed, and the new normal to the curve at the transformed point is returned). @public

This is the inverse of transformNormal3().

@param {Vector3} v @returns {Vector3}

inverseDeltaX( x )¶

Returns the x-coordinate difference for two inverse-transformed vectors, which add the x-coordinate difference of the input x (and same y,z values) beforehand. @public

This is the inverse of transformDeltaX().

@param {number} x @returns {number}

inverseDeltaY( y )¶

Returns the y-coordinate difference for two inverse-transformed vectors, which add the y-coordinate difference of the input y (and same x,z values) beforehand. @public

This is the inverse of transformDeltaY().

@param {number} y @returns {number}

inverseDeltaZ( z )¶

Returns the z-coordinate difference for two inverse-transformed vectors, which add the z-coordinate difference of the input z (and same x,y values) beforehand. @public

This is the inverse of transformDeltaZ().

@param {number} z @returns {number}

inverseRay( ray )¶

Returns an inverse-transformed ray. @public

This is the inverse of transformRay()

@param {Ray3} ray @returns {Ray3}

Source Code¶

See the source for Transform4.js in the dot repository.