com.samrj.devil.geo2d.Box.java Source code

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Here is the source code for com.samrj.devil.geo2d.Box.java

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/*
 * Copyright (c) 2015 Sam Johnson
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.samrj.devil.geo2d;

import com.samrj.devil.math.Util;
import com.samrj.devil.math.Vec2;
import org.lwjgl.opengl.GL11;

/**
 * 2D unaligned box. Rotates around its origin. {@code rx} is its half-width
 * along {@code dir}. {@code ry} is its half-width along an axis perpendicular
 * to {@code dir}. {@code dir} is always assumed to be a unit vector.
 * 
 * @author Samuel Johnson (SmashMaster)
 */
public final class Box {
    public static Box lineBox(Vec2 a, Vec2 b, float padTan, float padNrm) {
        if (a.equals(b))
            return new Box(padTan, padNrm, a);

        Box out = new Box();
        out.dir.set(b).sub(a);
        out.pos.set(a).add(b).mult(0.5f);
        float len = out.dir.length();
        out.dir.div(len);
        out.rx = len / 2f + padTan;
        out.ry = padNrm;
        return out;
    }

    public static Box lineBox(Line line, float padTan, float padNrm) {
        return lineBox(line.a, line.b, padTan, padNrm);
    }

    public static Box fromAngle(float w, float h, Vec2 pos, float angle) {
        Box out = new Box();
        out.dir.set((float) Math.cos(angle), (float) Math.sin(angle));
        out.pos.set(pos);
        out.rx = w / 2f;
        out.ry = h / 2f;
        return out;
    }

    public static Box fromAAB(AAB2 aab) {
        Box out = new Box();
        out.pos.set(aab.center());
        Vec2 size = aab.size().div(2f);
        out.rx = size.x;
        out.ry = size.y;
        return out;
    }

    public static Box fromCorners(Vec2 a, Vec2 b, Vec2 c) {
        Box out = new Box();
        out.pos.set(Vec2.add(a, c).mult(0.5f));
        Vec2 dir = Vec2.sub(b, a);
        float sizeX = dir.length();
        out.rx = sizeX / 2f;
        dir.div(sizeX);
        out.ry = c.dist(b) / 2f;
        out.dir.set(dir);
        return out;
    }

    public final Vec2 pos = new Vec2();
    public final Vec2 dir = new Vec2(1f, 0f);
    public float rx = 0f, ry = 0f;

    public Box() {
    }

    public Box(float w, float h) {
        rx = w / 2f;
        ry = h / 2f;
    }

    public Box(float w, float h, Vec2 p) {
        this(w, h);
        pos.set(p);
    }

    public Box(float w, float h, Vec2 p, Vec2 d) {
        this(w, h, p);
        Vec2.normalize(d, dir);
    }

    public Box(Box box) {
        set(box);
    }

    public Box set(Box box) {
        pos.set(box.pos);
        dir.set(box.dir);
        rx = box.rx;
        ry = box.ry;
        return this;
    }

    public Box translate(Vec2 v) {
        pos.add(v);
        return this;
    }

    public boolean touches(Box box) {
        ConvexPoly thisPoly = new ConvexPoly(this);
        ConvexPoly boxPoly = new ConvexPoly(box);

        return thisPoly.touches(boxPoly);
    }

    public boolean contains(Vec2 v) {
        v = Vec2.sub(v, pos);
        v.set(v.x * dir.y - v.y * dir.x, v.x * dir.x + v.y * dir.y);
        return Util.isZero(v.x, ry) && Util.isZero(v.y, rx);
    }

    public Vec2[] vertices() {
        Vec2 x = Vec2.mult(dir, rx);
        Vec2 y = new Vec2(-dir.y, dir.x).mult(ry);

        Vec2[] out = { Vec2.negate(x).sub(y).add(pos), Vec2.negate(x).add(y).add(pos), Vec2.add(x, y).add(pos),
                Vec2.sub(x, y).add(pos) };

        return out;
    }

    public void glVertex() {
        for (Vec2 v : vertices())
            GL11.glVertex2f(v.x, v.y);
    }

    @Override
    public Box clone() {
        return new Box(this);
    }
}