球體的XYZ座標

Question

Android初學者，有人能指導我嗎？

我確實有距離，角度和原點。

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

相反的，這是沒有任何默認的API，我可以依賴於Android的

Answer 1

你的問題不明確：你不瞭解Android或極座標表達式嗎？

後者很簡單：

/** 
* 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; 
} 

Answer 2

如果沒有記錯一些簡單的三角函數會幫助你在這裏：

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); 
}