kayjaydee
8d868a28ca
- Vec3.lerp(other, t) for linear interpolation between two points - ParticleTrail.sample(from, to, density) emits density-based interpolated points strictly between endpoints (endpoints excluded by construction) - TRAIL_DENSITY = 4.0 particles per block - 6 ParticleTrail tests + 3 Vec3.lerp tests, all green - Zero Hytale imports — chain/ frontier preserved
83 lines
2.6 KiB
Java
83 lines
2.6 KiB
Java
package com.mythlane.chainlightning.chain;
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import java.util.List;
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import org.junit.jupiter.api.Test;
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import static org.junit.jupiter.api.Assertions.assertEquals;
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import static org.junit.jupiter.api.Assertions.assertTrue;
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final class ParticleTrailTest {
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private static final double EPS = 1e-9;
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@Test
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void zeroDistance() {
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Vec3 p = new Vec3(2, 3, 4);
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List<Vec3> out = ParticleTrail.sample(p, p, 4.0);
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assertTrue(out.isEmpty());
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}
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@Test
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void subBlockDistance() {
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// distance 0.5 along X with density 4 → ceil(2.0) = 2
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Vec3 from = new Vec3(0, 0, 0);
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Vec3 to = new Vec3(0.5, 0, 0);
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List<Vec3> out = ParticleTrail.sample(from, to, 4.0);
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assertEquals(2, out.size());
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// Both points strictly between endpoints
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for (Vec3 v : out) {
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assertTrue(from.distanceSquared(v) > EPS, "sample equals from");
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assertTrue(to.distanceSquared(v) > EPS, "sample equals to");
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}
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}
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@Test
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void integerDistanceCount() {
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Vec3 from = new Vec3(0, 0, 0);
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Vec3 to = new Vec3(5, 0, 0);
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List<Vec3> out = ParticleTrail.sample(from, to, 4.0);
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assertEquals(20, out.size());
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}
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@Test
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void fractionalDistanceCount() {
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Vec3 from = new Vec3(0, 0, 0);
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Vec3 to = new Vec3(3.7, 0, 0);
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List<Vec3> out = ParticleTrail.sample(from, to, 4.0);
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// ceil(3.7 * 4) = ceil(14.8) = 15
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assertEquals(15, out.size());
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}
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@Test
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void endpointsExcluded() {
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Vec3 from = new Vec3(1, 2, 3);
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Vec3 to = new Vec3(7, 8, 9);
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List<Vec3> out = ParticleTrail.sample(from, to, 4.0);
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assertTrue(out.size() > 0);
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for (Vec3 v : out) {
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assertTrue(from.distanceSquared(v) > EPS, "sample equals from endpoint");
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assertTrue(to.distanceSquared(v) > EPS, "sample equals to endpoint");
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}
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}
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@Test
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void uniformSpacing() {
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Vec3 from = new Vec3(0, 0, 0);
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Vec3 to = new Vec3(5, 0, 0);
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List<Vec3> out = ParticleTrail.sample(from, to, 4.0);
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assertEquals(20, out.size());
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double total = from.distance(to);
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double expectedSpacing = total / (out.size() + 1);
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// from -> first
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assertEquals(expectedSpacing, from.distance(out.get(0)), EPS);
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// last -> to
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assertEquals(expectedSpacing, out.get(out.size() - 1).distance(to), EPS);
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// consecutive
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for (int i = 1; i < out.size(); i++) {
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assertEquals(expectedSpacing, out.get(i - 1).distance(out.get(i)), EPS);
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}
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}
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}
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