/**
* 由标准的直线方程ax+by+c=0确定的两条直线，得到交点
*
* @return 两条直线平行的时候返回null
*/
public static Point2 crossPoint2(
double a1, double b1, double c1, double a2, double b2, double c2) {
if (isParallel2(a1, b1, a2, b2)) return null;
Point2 p = new Point2();
double fenMu = a1 * b2 - a2 * b1;
p.setX(-(c1 * b2 - c2 * b1) / fenMu);
p.setY(-(a1 * c2 - a2 * c1) / fenMu);
return p;
}
@Override
public Point2 getScreenPosition(final IsoWorldScene scene, final IsoCamera isoCamera) {
final float sensibility = 1.0f / isoCamera.getZoomFactor();
final Point2 delta = this.computeDeltaMouse(sensibility);
final float maxDistance = 500.0f;
delta.m_x = MathHelper.clamp(delta.m_x, -500.0f, 500.0f);
delta.m_y = MathHelper.clamp(delta.m_y, -500.0f, 500.0f);
Point2 point2 = delta;
point2.m_x += this.m_startCameraScreenX;
point2 = delta;
point2.m_y += this.m_startCameraScreenY;
return delta;
}
public double distanceTo(Point2 b) {
double dx = b.getX() - this.getX();
double dy = b.getY() - this.getY();
return Math.sqrt(dx * dx + dy * dy);
}
/**
* 计算两个点之间的距离
*
* @return
*/
public static double distance(Point2 a, Point2 b) {
return Math.sqrt(
(a.getX() - b.getX()) * (a.getX() - b.getX())
+ (a.getY() - b.getY()) * (a.getY() - b.getY()));
}
/**
* Evaluate a cubic Bézier curve according to control points `p0`, `p1`, `p2` and `p3` and store
* the position at parametric position `t` of the curve in `result`.
*
* @return the given reference to `result`.
*/
public static Point2 eval(Point2 p0, Point2 p1, Point2 p2, Point2 p3, double t, Point2 result) {
result.set(eval(p0.x, p1.x, p2.x, p3.x, t), eval(p0.y, p1.y, p2.y, p3.y, t));
return result;
}
/**
* Store in `result` the derivative point of a cubic Bézier curve according to control points
* `x0`, `x1`, `x2` and `x3` at parametric position `t` of the curve.
*
* @return the given reference to `result`.
*/
public static Point2 derivative(
Point2 p0, Point2 p1, Point2 p2, Point3 p3, double t, Point2 result) {
result.set(derivative(p0.x, p1.x, p2.x, p3.x, t), derivative(p0.y, p1.y, p2.y, p3.y, t));
return result;
}
