PixiJS

Namespace: groupD8

PIXI.groupD8

Implements the dihedral group D8, which is similar to group D4; D8 is the same but with diagonals, and it is used for texture rotations.

The directions the U- and V- axes after rotation of an angle of a: GD8Constant are the vectors (uX(a), uY(a)) and (vX(a), vY(a)). These aren't necessarily unit vectors.

Origin: This is the small part of gameofbombs.com portal system. It works.

See:

Members

PIXI.groupD8.E number staticreadonly

Rotation Direction
0° East
Default Value:
  • 0

PIXI.groupD8.MAIN_DIAGONAL number staticreadonly

Reflection about the main diagonal.

Default Value:
  • 10

PIXI.groupD8.MIRROR_HORIZONTAL number staticreadonly

Reflection about X-axis.

Default Value:
  • 12

PIXI.groupD8.MIRROR_VERTICAL number staticreadonly

Reflection about Y-axis.

Default Value:
  • 8

PIXI.groupD8.N number staticreadonly

Rotation Direction
-90°/270°↻ North
Default Value:
  • 6

PIXI.groupD8.NE number staticreadonly

Rotation Direction
-45°/315°↻ Northeast
Default Value:
  • 7

PIXI.groupD8.NW number staticreadonly

Rotation Direction
-135°/225°↻ Northwest
Default Value:
  • 5

PIXI.groupD8.REVERSE_DIAGONAL number staticreadonly

Reflection about reverse diagonal.

Default Value:
  • 14

PIXI.groupD8.S number staticreadonly

Rotation Direction
90°↻ South
Default Value:
  • 2

PIXI.groupD8.SE number staticreadonly

Rotation Direction
45°↻ Southeast
Default Value:
  • 1

PIXI.groupD8.SW number staticreadonly

Rotation Direction
135°↻ Southwest
Default Value:
  • 3

PIXI.groupD8.W number staticreadonly

Rotation Direction
180° West
Default Value:
  • 4

Methods

PIXI.groupD8.add (rotationSecond, rotationFirst) PIXI.GD8Symmetry static

groupD8.ts:247

Composes the two D8 operations.

Taking ^ as reflection:

E=0 S=2 W=4 N=6 E^=8 S^=10 W^=12 N^=14
E=0 E S W N E^ S^ W^ N^
S=2 S W N E S^ W^ N^ E^
W=4 W N E S W^ N^ E^ S^
N=6 N E S W N^ E^ S^ W^
E^=8 E^ N^ W^ S^ E N W S
S^=10 S^ E^ N^ W^ S E N W
W^=12 W^ S^ E^ N^ W S E N
N^=14 N^ W^ S^ E^ N W S E

This is a Cayley table

Name Type Description
rotationSecond PIXI.GD8Symmetry

Second operation, which is the row in the above cayley table.
rotationFirst PIXI.GD8Symmetry

First operation, which is the column in the above cayley table.
Returns:
Type Description
PIXI.GD8Symmetry Composed operation

PIXI.groupD8.byDirection (dx, dy) PIXI.GD8Symmetry static

groupD8.ts:300

Approximates the vector V(dx,dy) into one of the eight directions provided by groupD8.

Name Type Description
dx number

X-component of the vector
dy number

Y-component of the vector
Returns:
Type Description
PIXI.GD8Symmetry Approximation of the vector into one of the eight symmetries.

PIXI.groupD8.inv (rotation) PIXI.GD8Symmetry static

groupD8.ts:231
Name Type Description
rotation PIXI.GD8Symmetry

symmetry whose opposite is needed. Only rotations have opposite symmetries while reflections don't.
Returns:
Type Description
PIXI.GD8Symmetry The opposite symmetry of rotation

PIXI.groupD8.isVertical (rotation) boolean static

groupD8.ts:292

Checks if the rotation angle is vertical, i.e. south or north. It doesn't work for reflections.

Name Type Description
rotation PIXI.GD8Symmetry

The number to check.
Returns:
Type Description
boolean Whether or not the direction is vertical

PIXI.groupD8.matrixAppendRotationInv (matrix, rotation, tx, ty) void static

groupD8.ts:345

Helps sprite to compensate texture packer rotation.

Name Type Default Description
matrix PIXI.Matrix

sprite world matrix
rotation PIXI.GD8Symmetry

The rotation factor to use.
tx number 0

sprite anchoring
ty number 0

sprite anchoring

PIXI.groupD8.rotate180 (rotation) number static

groupD8.ts:284

Adds 180 degrees to rotation, which is a commutative operation.

Name Type Description
rotation number

The number to rotate.
Returns:
Type Description
number Rotated number

PIXI.groupD8.sub (rotationSecond, rotationFirst) PIXI.GD8Symmetry static

groupD8.ts:274

Reverse of add.

Name Type Description
rotationSecond PIXI.GD8Symmetry

Second operation
rotationFirst PIXI.GD8Symmetry

First operation
Returns:
Type Description
PIXI.GD8Symmetry Result

PIXI.groupD8.uX (ind) PIXI.GD8Symmetry static

groupD8.ts:203
Name Type Description
ind PIXI.GD8Symmetry

sprite rotation angle.
Returns:
Type Description
PIXI.GD8Symmetry The X-component of the U-axis after rotating the axes.

PIXI.groupD8.uY (ind) PIXI.GD8Symmetry static

groupD8.ts:210
Name Type Description
ind PIXI.GD8Symmetry

sprite rotation angle.
Returns:
Type Description
PIXI.GD8Symmetry The Y-component of the U-axis after rotating the axes.

PIXI.groupD8.vX (ind) PIXI.GD8Symmetry static

groupD8.ts:217
Name Type Description
ind PIXI.GD8Symmetry

sprite rotation angle.
Returns:
Type Description
PIXI.GD8Symmetry The X-component of the V-axis after rotating the axes.

PIXI.groupD8.vY (ind) PIXI.GD8Symmetry static

groupD8.ts:224
Name Type Description
ind PIXI.GD8Symmetry

sprite rotation angle.
Returns:
Type Description
PIXI.GD8Symmetry The Y-component of the V-axis after rotating the axes.