src/main/java/com/montecarlo/geometry/FigureDebf.java - master - shvidkuli/kkrjava

src/main/java/com/montecarlo/geometry/FigureDebf.java
88 строк3 KB
kroc400
first_commit
30 апр 2026, 22:44
30 апр 2026, 22:442347fdb
package com.montecarlo.geometry;

/**
 * The composite figure "debf": the union of a triangle (b–e–f) and a semicircle
 * (half-disk whose diameter is the chord f–e, opened towards point d).
 *
 * <h3>Geometry (default configuration)</h3>
 * <pre>
 *  Rectangle ABCD  = [0, 4] × [0, 4]
 *    A = (0, 0)   B = (4, 0)   C = (4, 4)   D = (0, 4)
 *    E = (4, 2)   — midpoint of side BC
 *    F = (2, 0)   — midpoint of side AB
 *
 *  Triangle  BEF  : vertices B=(4,0), E=(4,2), F=(2,0)   → area = 2
 *  Semicircle     : diameter F→E, centre=(3,1), r=√2, D-side → area = π
 *  ──────────────────────────────────────────────────────────────────────
 *  Total analytical area = 2 + π ≈ 5.14159265…
 * </pre>
 *
 * <p>The triangle and semicircle share only the chord F–E as their common boundary and
 * lie on strictly opposite sides of it, so their areas simply add without overlap.</p>
 *
 * <p>To use a different figure, change the coordinates in {@code config.ini}.  The
 * {@link com.montecarlo.utils.ConfigReader} will rebuild both components automatically.</p>
 */
public class FigureDebf implements Shape {

    private final Triangle triangle;
    private final Arc arc;

    /**
     * Constructs the figure "debf" from its two constituent shapes.
     *
     * @param triangle the filled triangle b–e–f
     * @param arc      the filled semicircle on the d-side of chord f–e
     */
    public FigureDebf(Triangle triangle, Arc arc) {
        this.triangle = triangle;
        this.arc      = arc;
    }

    /** @return the triangle component */
    public Triangle getTriangle() { return triangle; }

    /** @return the semicircle component */
    public Arc getArc() { return arc; }

    /**
     * Returns {@code true} if the point is inside the triangle OR inside the semicircle.
     *
     * @param p the point to test
     * @return {@code true} if inside the figure
     */
    @Override
    public boolean contains(Point p) {
        return triangle.contains(p) || arc.contains(p);
    }

    /**
     * Returns the exact analytical area of the figure.
     *
     * <p>Valid when the triangle and semicircle do not overlap (which is guaranteed
     * when the semicircle's diameter is exactly the hypotenuse of the triangle and
     * the semicircle opens away from the opposite vertex).</p>
     *
     * @return area(triangle) + area(semicircle)
     */
    @Override
    public double analyticalArea() {
        return triangle.analyticalArea() + arc.analyticalArea();
    }

    /**
     * Returns the smallest axis-aligned bounding box enclosing both the triangle
     * and the semicircle.
     *
     * @return merged bounding box
     */
    @Override
    public BoundingBox getBoundingBox() {
        return triangle.getBoundingBox().merge(arc.getBoundingBox());
    }

    @Override
    public String toString() {
        return String.format("FigureDebf{%s | %s}", triangle, arc);
    }
}