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Merge pull request #664 from Gustl22/geometry_utils

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GeometryUtils: Fix reverse clockwise check
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Emux 2019-02-19 13:31:23 +02:00 committed by GitHub
commit f6af3d7410
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2 changed files with 47 additions and 13 deletions
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45
vtm-tests/test/org/oscim/utils/GeometryTest.java Normal file
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@ -0,0 +1,45 @@
package org.oscim.utils;
import org.junit.Assert;
import org.junit.Test;
import org.oscim.utils.geom.GeometryUtils;
public class GeometryTest {
@Test
public void testIsTrisClockwise() {
float[] pA = new float[]{0, 0};
float[] pB = new float[]{1, 1};
float[] pC = new float[]{1, 0};
float area = GeometryUtils.isTrisClockwise(pA, pB, pC);
Assert.assertTrue(area > 0);
area = GeometryUtils.isTrisClockwise(pA, pC, pB);
Assert.assertTrue(area < 0);
}
@Test
public void testIsClockwise() {
float[] points = new float[]{0, 0, 1, 1, 1, 0};
float area = GeometryUtils.isClockwise(points, points.length);
Assert.assertTrue(area > 0);
points = new float[]{0, 0, 1, 0, 1, 1};
area = GeometryUtils.isClockwise(points, points.length);
Assert.assertTrue(area < 0);
}
@Test
public void testDotProduct() {
float[] p = {-1, 0, 0, 0, 0, 0};
for (int i = 0; i < 9; i++) {
p[4] = (float) Math.cos(Math.toRadians(i * 45));
p[5] = (float) Math.sin(Math.toRadians(i * 45));
System.out.println("\n> " + (i * 45) + " " + p[3] + ":" + p[4] + "\n="
+ GeometryUtils.dotProduct(p, 0, 2, 4));
}
}
}

15
vtm/src/org/oscim/utils/geom/GeometryUtils.java
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@ -322,9 +322,9 @@ public final class GeometryUtils {
public static float isClockwise(float[] points, int n) {
float area = 0f;
for (int i = 0; i < n - 2; i += 2) {
area += (points[i] * points[i + 3]) - (points[i + 1] * points[i + 2]);
area += (points[i + 1] * points[i + 2]) - (points[i] * points[i + 3]);
}
area += (points[n - 2] * points[1]) - (points[n - 1] * points[0]);
area += (points[n - 1] * points[0]) - (points[n - 2] * points[1]);
return 0.5f * area;
}
@ -418,15 +418,4 @@ public final class GeometryUtils {
}
return scaled;
}
public static void main(String[] args) {
float[] p = {-1, 0, 0, 0, 0, 0};
for (int i = 0; i < 9; i++) {
p[4] = (float) Math.cos(Math.toRadians(i * 45));
p[5] = (float) Math.sin(Math.toRadians(i * 45));
System.out.println("\n> " + (i * 45) + " " + p[3] + ":" + p[4] + "\n="
+ dotProduct(p, 0, 2, 4));
}
}
}