132 lines
4.0 KiB
Java
132 lines
4.0 KiB
Java
package com.hypixel.hytale.math.iterator;
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import com.hypixel.hytale.math.util.ChunkUtil;
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import com.hypixel.hytale.math.util.MathUtil;
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import java.util.NoSuchElementException;
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public class CircleSpiralIterator {
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public static final long MAX_RADIUS_LONG = (long)Math.sqrt(9.223372E18F) / 2L - 1L;
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public static final int MAX_RADIUS = (int)MAX_RADIUS_LONG;
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private boolean setup;
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private int chunkX;
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private int chunkZ;
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private long maxI;
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private long i;
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private int x;
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private int z;
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private int dx;
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private int dz;
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private long radiusFromSq;
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private long radiusToSq;
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private boolean hasNext;
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private long nextChunk;
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public void init(int chunkX, int chunkZ, int radiusTo) {
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this.init(chunkX, chunkZ, 0, radiusTo);
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}
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public void init(int chunkX, int chunkZ, int radiusFrom, int radiusTo) {
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if (radiusFrom < 0) {
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throw new IllegalArgumentException("radiusFrom must be >= 0: " + radiusFrom);
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} else if (radiusTo <= 0) {
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throw new IllegalArgumentException("radiusTo must be > 0: " + radiusTo);
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} else if (radiusTo > MAX_RADIUS) {
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throw new IllegalArgumentException("radiusTo must be < MAX_RADIUS " + MAX_RADIUS + ": " + radiusTo);
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} else if (radiusFrom >= radiusTo) {
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throw new IllegalArgumentException("radiusFrom must be < radiusTo: " + radiusFrom + " -> " + radiusTo);
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} else {
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this.chunkX = chunkX;
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this.chunkZ = chunkZ;
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this.radiusFromSq = (long)radiusFrom * radiusFrom;
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this.radiusToSq = (long)radiusTo * radiusTo;
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long widthTo = 1L + radiusTo * 2L;
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this.maxI = widthTo * widthTo;
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if (radiusFrom != 0) {
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float halfFrom = radiusFrom / 2.0F;
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float sq = halfFrom * halfFrom;
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int diagRadius = (int)Math.sqrt(sq + sq);
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long widthFrom = 1L + diagRadius * 2L;
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this.i = widthFrom * widthFrom;
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long pos = SpiralIterator.getPosFromIndex((int)this.i);
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this.x = ChunkUtil.xOfChunkIndex(pos);
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this.z = ChunkUtil.zOfChunkIndex(pos);
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this.dx = 1;
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this.dz = 0;
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} else {
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this.i = 0L;
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this.x = this.z = 0;
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this.dx = 0;
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this.dz = -1;
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}
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this.hasNext = false;
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this.prepareNext();
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this.setup = true;
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}
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}
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public void reset() {
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this.setup = false;
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this.hasNext = false;
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}
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public long next() {
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if (!this.setup) {
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throw new IllegalStateException("SpiralIterator is not setup!");
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} else {
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if (!this.hasNext) {
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this.prepareNext();
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}
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if (!this.hasNext) {
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throw new NoSuchElementException("No more positions inside the circle!");
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} else {
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this.hasNext = false;
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return this.nextChunk;
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}
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}
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}
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public boolean hasNext() {
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if (!this.setup) {
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throw new IllegalStateException("SpiralIterator is not setup!");
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} else {
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if (!this.hasNext) {
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this.prepareNext();
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}
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return this.hasNext;
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}
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}
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public int getCurrentRadius() {
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return MathUtil.ceil((Math.sqrt(this.i) - 1.0) / 2.0);
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}
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public int getCompletedRadius() {
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return (int)((Math.sqrt(this.i) - 1.0) / 2.0);
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}
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private void prepareNext() {
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while (!this.hasNext && this.i < this.maxI) {
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long rx = this.x;
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long rz = this.z;
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long radiusSq = rx * rx + rz * rz;
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if (radiusSq >= this.radiusFromSq && radiusSq <= this.radiusToSq) {
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this.nextChunk = ChunkUtil.indexChunk(this.chunkX + this.x, this.chunkZ + this.z);
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this.hasNext = true;
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}
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if (this.x == this.z || this.x < 0 && this.x == -this.z || this.x > 0 && this.x == 1 - this.z) {
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int tempDx = this.dx;
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this.dx = -this.dz;
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this.dz = tempDx;
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}
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this.x = this.x + this.dx;
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this.z = this.z + this.dz;
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this.i++;
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}
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}
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}
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