Question

我正在尝试将球（椭圆形）移动到最近单击鼠标的位置，但是我不希望它跳到那里，我希望它以某个速度移动到那里。这是我的代码

int BallX = 200;
int BallY = 150;
final int BALL_SIZE = 30; // size of the ball
final int SPEED = 10; // the ball should move at this speed
void setup(){
 size(500 , 500); //canvas size
}
 void draw(){
  drawBall();
 }
void drawBall(){
fill(255);
ellipse(BallX , BallY ,BALL_SIZE,BALL_SIZE); // the ball
}
void mouseClicked(){
golfBallX = pmouseX;
golfBallY = pmouseY;
}

Answer 1

要生成平滑的运动，我建议使用浮点值（double）进行计算：

您必须声明球的位置和球应到达的目标位置的变量。在初始状态下，两个位置必须相同：

double  BallX = 200.0;
double  BallY = 150.0;
double  targetBallX = 200.0;
double  targetBallY = 150.0;

计算draw function中球的当前位置和目标位置之间的距离：

double deltaX = targetBallX - BallX;
double deltaY = targetBallY - BallY;
double dist = Math.sqrt(deltaX*deltaX + deltaY*deltaY);

如果当前位置与目标位置不同，则朝目标方向执行一个步骤：

if ( dist > 0.0 ) {
    double step = Math.min(dist, SPEED);
    BallX += step * deltaX / dist;
    BallY += step * deltaY / dist;
}

完整代码如下：

double  BallX = 200.0;
double  BallY = 150.0;
double  targetBallX = 200.0;
double  targetBallY = 150.0;

final int    BALL_SIZE = 30; // size of the ball
final double SPEED = 10.0; // the ball should move at this speed

void setup(){
   size(500 , 500); //canvas size
}

void draw(){

    double deltaX = targetBallX - BallX;
    double deltaY = targetBallY - BallY;
    double dist = Math.sqrt(deltaX*deltaX + deltaY*deltaY);
    if ( dist > 0.0 ) {
        double step = Math.min(dist, SPEED);
        BallX += step * deltaX / dist;
        BallY += step * deltaY / dist;
    }

    drawBall();
}

void drawBall(){ 
    background(128);
    fill(255);
    ellipse((int)BallX, (int)BallY, BALL_SIZE, BALL_SIZE); // the ball
}

void mouseClicked(){
    targetBallX = (double)pmouseX;
    targetBallY = (double)pmouseY;
}

以一定速度将球（椭圆形）移动到单击鼠标的位置-处理3

1 个答案: