toad.city
That fuck shit the fascists are using
1package org.tm.archive.util;
2
3import android.graphics.PointF;
4
5import androidx.annotation.NonNull;
6
7public class MathUtils {
8
9 /**
10 * For more info:
11 * <a href="http://math.stackexchange.com/questions/190111/how-to-check-if-a-point-is-inside-a-rectangle">StackOverflow: How to check point is in rectangle</a>
12 *
13 * @param pt point to check
14 * @param v1 vertex 1 of the triangle
15 * @param v2 vertex 2 of the triangle
16 * @param v3 vertex 3 of the triangle
17 * @return true if point (x, y) is inside the triangle
18 */
19 public static boolean pointInTriangle(@NonNull PointF pt, @NonNull PointF v1,
20 @NonNull PointF v2, @NonNull PointF v3) {
21
22 boolean b1 = crossProduct(pt, v1, v2) < 0.0f;
23 boolean b2 = crossProduct(pt, v2, v3) < 0.0f;
24 boolean b3 = crossProduct(pt, v3, v1) < 0.0f;
25
26 return (b1 == b2) && (b2 == b3);
27 }
28
29 /**
30 * calculates cross product of vectors AB and AC
31 *
32 * @param a beginning of 2 vectors
33 * @param b end of vector 1
34 * @param c end of vector 2
35 * @return cross product AB * AC
36 */
37 private static float crossProduct(@NonNull PointF a, @NonNull PointF b, @NonNull PointF c) {
38 return crossProduct(a.x, a.y, b.x, b.y, c.x, c.y);
39 }
40
41 /**
42 * calculates cross product of vectors AB and AC
43 *
44 * @param ax X coordinate of point A
45 * @param ay Y coordinate of point A
46 * @param bx X coordinate of point B
47 * @param by Y coordinate of point B
48 * @param cx X coordinate of point C
49 * @param cy Y coordinate of point C
50 * @return cross product AB * AC
51 */
52 private static float crossProduct(float ax, float ay, float bx, float by, float cx, float cy) {
53 return (ax - cx) * (by - cy) - (bx - cx) * (ay - cy);
54 }
55}