Question

我正在试图弄清楚如何使用PhysicsJS。我首先想要简单地弄清楚如何改变让我们说点击对象的位置或速度......但我只是想弄明白了！

( function()
{
    var viewWidth = 500,
    viewHeight = 300,
    renderer = Physics.renderer( 'canvas', 
    {
        el: 'viewport',
        width: viewWidth,
        height: viewHeight,
        meta: false,
        styles: 
        {
            'circle' : 
            {
                strokeStyle: 'hsla(60, 37%, 17%, 1)',
                lineWidth: 1,
                fillStyle: 'hsla(60, 37%, 57%, 0.8)',
                angleIndicator: 'hsla(60, 37%, 17%, 0.4)'
            }
        }
    }),
    viewportBounds = Physics.aabb(0, 0, viewWidth, viewHeight),
    constraint = {
        aabb: viewportBounds,
        restitution: 0.99,
        cof: 0.99
    },
    ballOptions = {
        x: 100,         // x-coordinate
        y: 100,         // y-coordinate
        vx: 0.0,    // velocity in x-direction
        vy: 0.0,    // velocity in y-direction
        radius: 20
    },
    gravity = Physics.behavior('constant-acceleration', 
    {
        acc: { x : 0, y: 0.0004 } 
    }),
    ball = Physics.body('circle', ballOptions );

    Physics( function( world )
    {

    // add the renderer
    world.add( renderer );
    // add circle
    world.add( ball );

    // subscribe to ticker to advance the simulation
    Physics.util.ticker.subscribe(function( time, dt )
    {
        world.step( time );
    });

    // on every step...
    world.subscribe( 'step', function()
    {
        world.render();
    });

    world.subscribe( 'collisions:detected', function( $collision )
    {

    });

    var onElementClick = function()
    {
        // do something
    };

    document.getElementById( 'viewport' ).addEventListener( 'click', onElementClick, false );

    // Lets GO!
    Physics.util.ticker.start();

});
})();

任何非常感谢的帮助

Answer 1

一种选择是获取已创建但从未添加到世界的重力并执行该操作。

world.add(gravity);

在您询问有关更改对象的位置或速度的意义上，这是作弊。为此，请修改球的状态。 See the docs on Bodies，特别是属性。您可以设置state.pos来移动它。要使其运动，请设置速度：

ball.state.vel.set(.1,-.5); // move right and upward

jsfiddle that sets velocity

PhysicsJS - 移动一个物体

1 个答案: