Physics-game/wall_physics2.html at master · mikeherring/Physics-game · GitHub

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<!doctype html>
<html>
<head>
    <title>Wall Physics</title>
    <script src="vector2.js" type="text/javascript"></script>
    <script src="models4.js" type="text/javascript"></script>
</head>
<body onload="init();">

    <table>
        <tr valign="top">
            <td>
                <canvas id="myCanvas" width="500" height="300" style="border:1px solid black;"></canvas><br />
                <button onclick="go();">Go</button>
                <button onclick="stop();">Stop</button>
                <button onclick="animate();">Step</button>
            </td>
            <td>
                <a href="index.html">Home</a>
	            <h1>Wall Physics 2</h1>
                <p>New Features</p>
                <ul>
                    <li>Better class organization</li>
                    <li>Structures made of several walls</li>
                    <li>Solid drawn structures</li>
                </ul>
            </td>
        </tr>
    </table>


    <script type="text/javascript">

        var canvas = null;
        var context = null;
        var looper = null;
        var b = null;
        var walls = [];
        var worldFriction = 0.000;
        var wallCollisionDampening = 0.0;

        function init()
        {
            canvas = document.getElementById("myCanvas");
            context = canvas.getContext("2d");

            b = new Agent(new Point(50, 50), 10, 1, new Vector(5, 0), 'blue');

            //walls[0] = new Wall(new Point(300, 30), new Point(325, 90));
            //walls[1] = new Wall(new Point(325, 90), new Point(325, 150));
            //walls[2] = new Wall(new Point(325, 150), new Point(275, 150));
            //walls[3] = new Wall(new Point(275, 150), new Point(300, 30));
            //walls[4] = new Wall(new Point(300, 300), new Point(500, 200));
            //walls[5] = new Wall(new Point(0, 200), new Point(300, 300));

            walls[0] = new Wall(new Point(100, 50), new Point(200, 0));
            walls[1] = new Wall(new Point(100, 50), new Point(200, 100));

            draw();
            go();
        }

        function draw()
        {
            b.draw(context);
            for (var i = 0; i < walls.length; i++)
            {
                walls[i].draw(context);
            }
        }

        function go()
        {
            looper = setInterval(animate, 30);
        }

        function animate()
        {
            update();
            checkCollisions();
            bounding();
            clear();
            draw();
        }

        function clear()
        {
            context.clearRect(0, 0, canvas.width, canvas.height);
        }

        function bounding()
        {
            var hit = false;

            if (b.p.x <= b.r) { b.p.x = b.r; b.v.x *= -1; hit = true; }
            if (b.p.y <= b.r) { b.p.y = b.r; b.v.y *= -1; hit = true; }
            if (b.p.x >= canvas.width - b.r) { b.p.x = canvas.width - b.r; b.v.x *= -1; hit = true; }
            if (b.p.y >= canvas.height - b.r) { b.p.y = canvas.height - b.r; b.v.y *= -1; hit = true; }

            if (hit)
            {
                b.v = b.v.scale(1.0 - wallCollisionDampening);
            }
        }

        function checkCollisions()
        {
            Collision firstCollision = null;

            // find the collision with the shortest distance
            for (var i = 0; i < walls.length; i++)
            {
                var w = walls[i];
                var c = w.checkCollision(b);
                if (c != null)
                {
                    if (firstCollision == null || c.dist < firstCollision.dist)
                    {
                        firstCollision = c;
                    }
                }
            }

            // These are all possible collisions, but one had to be first
            if (firstCollision != null)
            {
                resolveCollision(firstCollision);
            }
        }

        // switch to handling Collision objects
        function resolveCollision(w)
        {
            // calculate normal and tangent vectors
            var vn = w.norm.scale(b.v.dot(w.norm)); // the normal component of the ball's velocity
            var vt = b.v.sub(vn); // the tangent component of the ball's velocity

            // de-overlap first
            var distance = w.distance(b.p);
            b.p = b.p.add(b.v.scale((distance - b.r) / vn.mag()));

            // calculate new velocity
            b.v = vt.sub(vn).scale(1.0 - wallCollisionDampening); // keep the same tangent component and reflect the normal
        }

        function update()
        {
            b.move(worldFriction);
        }

        function stop()
        {
            clearInterval(looper);
        }

    </script>

</body>
</html>