我想使用手机加速计来滚动球中的球。运动有效 正确的是,问题在于球撞到墙时。我怎样才能顺利滚动 球沿着大球内侧滑动的动画?
这是我当前移动球并检查交点的代码:
onSuccess: function(acceleration) {
var xPos = this.xPos + (-1 * (acceleration.x * 0.5));
var yPos = this.yPos + (acceleration.y * 0.5);
var intersect = this.intersection(xPos + 32,
yPos + 32,
32,
self.canvas.width * 0.5,
self.canvas.height * 0.5,
self.canvas.width * 0.5);
if (!intersect) {
this.yPos = yPos;
this.xPos = xPos;
}
this.cnv.clearRect(0.0, 0.0, this.canvas.width, this.canvas.height);
this.cnv.drawImage(this.target, this.xPos, this.yPos);
},
intersection: function(x0, y0, r0, x1, y1, r1) {
var a, dx, dy, d, h, rx, ry;
var x2, y2;
/* dx and dy are the vertical and horizontal distances between
* the circle centers.
*/
dx = x1 - x0;
dy = y1 - y0;
/* Determine the straight-line distance between the centers. */
d = Math.sqrt((dy*dy) + (dx*dx));
/* Check for solvability. */
if (d > (r0 + r1)) {
/* no solution. circles do not intersect. */
return false;
}
if (d < Math.abs(r0 - r1)) {
/* no solution. one circle is contained in the other */
return false;
}
/* 'point 2' is the point where the line through the circle
* intersection points crosses the line between the circle
* centers.
*/
/* Determine the distance from point 0 to point 2. */
a = ((r0*r0) - (r1*r1) + (d*d)) / (2.0 * d) ;
/* Determine the coordinates of point 2. */
x2 = x0 + (dx * a/d);
y2 = y0 + (dy * a/d);
/* Determine the distance from point 2 to either of the
* intersection points.
*/
h = Math.sqrt((r0*r0) - (a*a));
/* Now determine the offsets of the intersection points from
* point 2.
*/
rx = -dy * (h/d);
ry = dx * (h/d);
/* Determine the absolute intersection points. */
var xi = x2 + rx;
var xi_prime = x2 - rx;
var yi = y2 + ry;
var yi_prime = y2 - ry;
return [xi, xi_prime, yi, yi_prime];
}
};
感谢您的帮助:)
最佳答案
在只是滑动的情况下使用参数圆方程
x=x0+r*cos(a)
y=y0+r*sin(a)
地点:
x0,y0
为大圆圆心r = R0-R1
R0
是大圆半径R1
是小圆半径
现在 Angular a
最简单的方法是放置a=重力方向
:
a=atanxy(acceleration.x,acceleration.y)
atanxy
是 atan2
,它是 4 象限切线弧。如果您没有,请使用我的
并修正与坐标系的 Angular (可能取反或添加一些 90 度倍数)
[注释]
如果屏幕和设备加速度计之间具有兼容的坐标系,则只需将加速度矢量缩放到大小 |r|
并向其添加 (x0,y0)
即可没有任何测 Angular 函数的相同结果...
为了正确进行模拟,请使用 D'ALember 方程 + 圆边界
所以2D运动非常简单:
// in some timer with interval dt [sec]
velocity.x+=acceleration.x*dt;
velocity.y+=acceleration.y*dt;
position.x+=velocity.x*dt;
position.y+=velocity.y*dt;
现在 if (|position-big_circle_center|>big_circle_radius)
发生碰撞,因此当您不希望任何反弹(所有能量都被吸收)时,则:
position-=big_circle_center;
position*=big_circle_radius/|position|;
position+=big_circle_center;
现在您需要删除径向速度并仅保留切向速度:
normal=position-big_circle_center; // normal vector to surface
normal*=dot(velocity,normal); // this is the normal speed part
velocity-=normal; // now just tangential speed should be left
所以在这之后,速度的切线(黄色)部分仍然存在......希望我没有忘记一些东西(比如制作单位向量或+/-某处......)
关于javascript - 加速度计 - 球中滚动,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26216173/