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{"version":3,"file":"groupD8.mjs","sources":["../src/groupD8.ts"],"sourcesContent":["// Your friendly neighbour https://en.wikipedia.org/wiki/Dihedral_group\n//\n// This file implements the dihedral group of order 16, also called\n// of degree 8. That's why its called groupD8.\n\nimport { Matrix } from './Matrix';\n\n/*\n * Transform matrix for operation n is:\n * | ux | vx |\n * | uy | vy |\n */\n\nconst ux = [1, 1, 0, -1, -1, -1, 0, 1, 1, 1, 0, -1, -1, -1, 0, 1];\nconst uy = [0, 1, 1, 1, 0, -1, -1, -1, 0, 1, 1, 1, 0, -1, -1, -1];\nconst vx = [0, -1, -1, -1, 0, 1, 1, 1, 0, 1, 1, 1, 0, -1, -1, -1];\nconst vy = [1, 1, 0, -1, -1, -1, 0, 1, -1, -1, 0, 1, 1, 1, 0, -1];\n\n/**\n * [Cayley Table]{@link https://en.wikipedia.org/wiki/Cayley_table}\n * for the composition of each rotation in the dihederal group D8.\n * @type {number[][]}\n * @private\n */\nconst rotationCayley: number[][] = [];\n\n/**\n * Matrices for each `GD8Symmetry` rotation.\n * @type {PIXI.Matrix[]}\n * @private\n */\nconst rotationMatrices: Matrix[] = [];\n\n/*\n * Alias for {@code Math.sign}.\n */\nconst signum = Math.sign;\n\n/*\n * Initializes `rotationCayley` and `rotationMatrices`. It is called\n * only once below.\n */\nfunction init(): void\n{\n for (let i = 0; i < 16; i++)\n {\n const row: number[] = [];\n\n rotationCayley.push(row);\n\n for (let j = 0; j < 16; j++)\n {\n /* Multiplies rotation matrices i and j. */\n const _ux = signum((ux[i] * ux[j]) + (vx[i] * uy[j]));\n const _uy = signum((uy[i] * ux[j]) + (vy[i] * uy[j]));\n const _vx = signum((ux[i] * vx[j]) + (vx[i] * vy[j]));\n const _vy = signum((uy[i] * vx[j]) + (vy[i] * vy[j]));\n\n /* Finds rotation matrix matching the product and pushes it. */\n for (let k = 0; k < 16; k++)\n {\n if (ux[k] === _ux && uy[k] === _uy\n && vx[k] === _vx && vy[k] === _vy)\n {\n row.push(k);\n break;\n }\n }\n }\n }\n\n for (let i = 0; i < 16; i++)\n {\n const mat = new Matrix();\n\n mat.set(ux[i], uy[i], vx[i], vy[i], 0, 0);\n rotationMatrices.push(mat);\n }\n}\n\ninit();\n\ntype GD8Symmetry = number;\n/**\n * @memberof PIXI\n * @typedef {number} GD8Symmetry\n * @see PIXI.groupD8\n */\n\n/**\n * Implements the dihedral group D8, which is similar to\n * [group D4]{@link http://mathworld.wolfram.com/DihedralGroupD4.html};\n * D8 is the same but with diagonals, and it is used for texture\n * rotations.\n *\n * The directions the U- and V- axes after rotation\n * of an angle of `a: GD8Constant` are the vectors `(uX(a), uY(a))`\n * and `(vX(a), vY(a))`. These aren't necessarily unit vectors.\n *\n * **Origin:**\n * This is the small part of gameofbombs.com portal system. It works.\n * @see PIXI.groupD8.E\n * @see PIXI.groupD8.SE\n * @see PIXI.groupD8.S\n * @see PIXI.groupD8.SW\n * @see PIXI.groupD8.W\n * @see PIXI.groupD8.NW\n * @see PIXI.groupD8.N\n * @see PIXI.groupD8.NE\n * @author Ivan @ivanpopelyshev\n * @namespace PIXI.groupD8\n * @memberof PIXI\n */\nexport const groupD8 = {\n /**\n * | Rotation | Direction |\n * |----------|-----------|\n * | 0° | East |\n * @readonly\n */\n E: 0,\n\n /**\n * | Rotation | Direction |\n * |----------|-----------|\n * | 45°↻ | Southeast |\n * @readonly\n */\n SE: 1,\n\n /**\n * | Rotation | Direction |\n * |----------|-----------|\n * | 90°↻ | South |\n * @readonly\n */\n S: 2,\n\n /**\n * | Rotation | Direction |\n * |----------|-----------|\n * | 135°↻ | Southwest |\n * @readonly\n */\n SW: 3,\n\n /**\n * | Rotation | Direction |\n * |----------|-----------|\n * | 180° | West |\n * @readonly\n */\n W: 4,\n\n /**\n * | Rotation | Direction |\n * |-------------|--------------|\n * | -135°/225°↻ | Northw
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