我正在製作一個遊戲,玩家將(在發佈鼠標點擊時)以一定的初始速度在某個方向上拍攝「星星」,該初始速度取決於在釋放前拖動鼠標的距離。我在畫布上有一個「行星」(固定圈),我想在行星上施加引力。我相信我正在使用正確的引力等公式,並且我已經部分工作 - 行星影響着行星的軌跡直到某個點,當恆星似乎無休止地加速並停止基於它的角度改變方向時到明星。 任何意見? (我知道星星不應該繞着行星運行,反過來也是如此。我把所有的名字都編碼在一起,所以原諒)。模擬恆星的引力?
主類:
shootingStar類的import acm.graphics.GCompound;
import acm.graphics.GImage;
import acm.graphics.GLabel;
import acm.graphics.GLine;
import acm.graphics.GMath;
import acm.graphics.GObject;
import acm.graphics.GPen;
import acm.graphics.GPoint;
import acm.graphics.GRect;
import acm.graphics.GOval;
import acm.graphics.GRectangle;
import acm.program.GraphicsProgram;
import acm.util.RandomGenerator;
import java.awt.Color;
import java.awt.event.MouseEvent;
import java.util.*;
public class Space extends GraphicsProgram {
public static int APPLICATION_WIDTH = 1000;
public static int APPLICATION_HEIGHT = 1000;
private int size = 15;
public static double pMass = 1000;
public static int sMass = 20;
public static double G = 200;
private RandomGenerator rand = new RandomGenerator();
GOval planet, tempstar;
shootingStar star;
GLine line;
double accel, xAccel, yAccel, xspeed, yspeed, angle;
public void init(){
planet = new GOval(APPLICATION_WIDTH/2, APPLICATION_HEIGHT/2, 30, 30);
planet.setFilled(true);
planet.setFillColor(rand.nextColor());
add(planet);
}
public void mousePressed(GPoint point) {
// draw a line
tempstar = new GOval(point.getX() - size/2, point.getY() - size/2, size, size);
tempstar.setFilled(true);
tempstar.setColor(rand.nextColor());
add(tempstar);
line = new GLine(tempstar.getX() + size/2, tempstar.getY() + size/2,
point.getX(), point.getY());
add(line);
line.setVisible(true);
}
public void mouseDragged(GPoint point) {
line.setEndPoint(point.getX(), point.getY());
}
public void mouseReleased(GPoint point){
xspeed =
-.05*GMath.cosDegrees(getAngle(line))*GMath.distance(line.getStartPoint().getX(),
line.getStartPoint().getY(), line.getEndPoint().getX(), line.getEndPoint().getY());
yspeed =
.05*GMath.sinDegrees(getAngle(line))*GMath.distance(line.getStartPoint().getX(),
line.getStartPoint().getY(), line.getEndPoint().getX(), line.getEndPoint().getY());
System.out.println(xspeed + " " + yspeed);
star = new shootingStar(xspeed, yspeed, this);
if(xspeed != 0)
add(star, tempstar.getX(), tempstar.getY());
new Thread(star).start();
remove(tempstar);
remove(line);
}
private double getAngle(GLine line) {
return GMath.angle(line.getStartPoint().getX(), line.getStartPoint().getY(),
line.getEndPoint().getX(), line.getEndPoint().getY());
}
public void checkPlanet(){
accel = .06*GMath.distance(star.getX(), star.getY(), planet.getX(),
planet.getY());
angle = correctedAngle(GMath.angle(planet.getX(), planet.getY(), star.getX(),
star.getY()));
xAccel = accel*GMath.cosDegrees(GMath.angle(planet.getX(), planet.getY(),
star.getX(), star.getY()));
yAccel = accel*GMath.sinDegrees(GMath.angle(planet.getX(), planet.getY(),
star.getX(), star.getY()));
double newX = xspeed - xAccel*.01;
double newY = yspeed + yAccel*.01;
xspeed = newX + xAccel*Math.pow(.01, 2)/2;
yspeed = newY + yAccel*Math.pow(.01, 2)/2;
star.setSpeed(xspeed, yspeed);
}
public double correctedAngle(double x) {
return (x%360.0+360.0+180.0)%360.0-180.0;
}
}
相關部分:
public void run() {
// move the ball by a small interval
while (alive) {
oneTimeStep();
}
}
// a helper method, move the ball in each time step
private void oneTimeStep() {
game1.checkPlanet();
shootingStar.move(xSpeed, ySpeed);
pause(20);
}
public void setSpeed (double xspeed, double yspeed){
xSpeed = xspeed;;
ySpeed = yspeed;
}
}
編輯:
當前主類方法:
public void checkPlanet(){
double xDistance = star.getX() - planet.getX();
double yDistance = star.getY() - planet.getY();
double distance = Math.sqrt(Math.pow(xDistance, 2) + Math.pow(yDistance, 2));
accel = G*pMass/Math.pow(distance, 2);
xAccel = accel * xDistance/distance;
yAccel = accel * yDistance/distance;
xspeed += xAccel;
yspeed += yAccel;
star.setSpeed(xspeed, yspeed);
}
當前星類的方法:
public void run() {
while (alive) {
oneTimeStep();
}
}
private void oneTimeStep() {
game1.checkPlanet();
shootingStar.move(xSpeed, ySpeed);
pause(20);
}
public void setSpeed (double xspeed, double yspeed){
xSpeed = xspeed;;
ySpeed = yspeed;
}
}
經過整整一天的閱讀TDWTF,最終停在[this](http://thedailywtf.com/Articles/Divine-by-Zero.aspx),我立刻感到有義務問你是否想要模擬引力拉或只是在它後面的數學。 –