63 lines
1.8 KiB
Java
63 lines
1.8 KiB
Java
package com.mojang.math;
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import java.util.Arrays;
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import net.minecraft.Util;
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import org.joml.Matrix3f;
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import org.joml.Matrix3fc;
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/**
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* The symmetric group S3, also known as all the permutation orders of three elements.
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*/
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public enum SymmetricGroup3 {
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P123(0, 1, 2),
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P213(1, 0, 2),
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P132(0, 2, 1),
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P231(1, 2, 0),
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P312(2, 0, 1),
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P321(2, 1, 0);
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private final int[] permutation;
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private final Matrix3fc transformation;
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private static final int ORDER = 3;
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private static final SymmetricGroup3[][] CAYLEY_TABLE = Util.make(
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new SymmetricGroup3[values().length][values().length],
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symmetricGroup3s -> {
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for (SymmetricGroup3 symmetricGroup3 : values()) {
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for (SymmetricGroup3 symmetricGroup32 : values()) {
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int[] is = new int[3];
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for (int i = 0; i < 3; i++) {
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is[i] = symmetricGroup3.permutation[symmetricGroup32.permutation[i]];
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}
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SymmetricGroup3 symmetricGroup33 = (SymmetricGroup3)Arrays.stream(values())
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.filter(symmetricGroup3x -> Arrays.equals(symmetricGroup3x.permutation, is))
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.findFirst()
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.get();
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symmetricGroup3s[symmetricGroup3.ordinal()][symmetricGroup32.ordinal()] = symmetricGroup33;
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}
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}
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}
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);
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private SymmetricGroup3(final int first, final int second, final int third) {
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this.permutation = new int[]{first, second, third};
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Matrix3f matrix3f = new Matrix3f().zero();
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matrix3f.set(this.permutation(0), 0, 1.0F);
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matrix3f.set(this.permutation(1), 1, 1.0F);
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matrix3f.set(this.permutation(2), 2, 1.0F);
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this.transformation = matrix3f;
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}
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public SymmetricGroup3 compose(SymmetricGroup3 other) {
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return CAYLEY_TABLE[this.ordinal()][other.ordinal()];
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}
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public int permutation(int element) {
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return this.permutation[element];
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}
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public Matrix3fc transformation() {
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return this.transformation;
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}
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}
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