球体的XYZ坐标

Question

Android初学者，有人可以指导我吗？

我确实有距离，角度和原点。

newx = (distance * cosθ) + origin.x;
newy = (distance * sinθ) + origin.y;

而不是这个，我可以在Android中依赖默认的API

Answer 1

如果内存服务，一些简单的三角函数将帮助你：

public static PointF getPoint(PointF origin, float distance, float angle)
{
  float x = Math.cos(angle)*distance;
  float y = Math.sin(angle)*distance;

  return origin.offset(x,y);
}

Answer 2

你的问题不明确：你不了解Android或极坐标的表达式吗？

后者很简单：

/**
 * Factory for PointF 
 * @param origin of the coordinate system (not needed)
 * @param distance this really means "radius"
 * @param angle from the x-axis in radians; positive increases in the counterclockwise direction 
 */
public static PointF getPoint(PointF origin, float distance, float angle)
{
    PointF newPoint = new PointF();
    newPoint.x = origin.x + distance*Math.cos(angle);
    newPoint.y = origin.y + distance*Math.sin(angle);
    return newPoint;
}