我做了一些东西来模拟绳子，当绳子抓住的东西在绳子抓住的东西下面时，它会出现故障。这在不在for循环中时有效，它只是一个片段，但我希望能够模拟多个片段。
代码：
//Declaring variables
int linkCount = 3;
float Rotation = 0;
float R = radians(Rotation);
float x[] = new float[linkCount];
float y[] = new float[linkCount];
float xVel[] = new float[linkCount];
float yVel[] = new float[linkCount];
float ropeLength = 50;
float velMX;
float velMY;
float spring = 1;
void setup() {
size(1280, 500, P3D);
stroke(0);
fill(0);
}
void draw() {
background(255);
// Updating velocitys
for(int i=1; i < linkCount; i++) {
x[i] = x[i] + xVel[i];
y[i] = y[i] + yVel[i];
}
// The two lines below are not needed and will most likely will be used in the futre
velMX = pmouseX - mouseX;
velMY = pmouseY - mouseY;
// Setting the start of the rope to the mouse
x[0] = mouseX;
y[0] = mouseY;
// if(mousePressed) {
calcRopes();
// }
}
void calcRopes() {
for(int i = 1; i < linkCount; i++) {
// Getting a radian that points toward the last subrope
R = atan2(-(x[i] - x[i-1]), -(y[i] - x[i-1]));
// Drawing the rope
line(x[i], y[i], x[i - 1], y[i - 1]);
// If the segment is farther than the rope length it moves it inside the rope length based on the R radian
if(dist(x[i], y[i], x[i - 1], y[i - 1]) > ropeLength) {
x[i] = x[i] + ((dist(x[i], y[i], x[i - 1], y[i - 1]) - (ropeLength)) * sin(R));
y[i] = y[i] + ((dist(x[i], y[i], x[i - 1], y[i - 1]) - (ropeLength)) * cos(R));
// xVel[i] = ((dist(x[i], y[i], x[i-1], y[i-1]) - (ropeLength + 10)) * sin(R));
// yVel[i] = ((dist(x[i], y[i], x[i-1], y[i-1]) - (ropeLength + 10)) * cos(R));
}
}
}
我如何解决这个问题？
首先：不要使用变量来设置屏幕尺寸，处理2.2.1不喜欢这样，处理3甚至不允许这样。
其次：
line(x[i], y[i], x[i--], y[i--]);
calcRope（）中这样的语句将导致ArrayIndexOutOfBoundsException。你为什么使用i--for？每次你使用它，i都会减少一次。所以从i=2开始，在“line（x[i]， y[i]，x[i--]，y[i--]）”之后，i的值变为-1；
编辑：这对我有用，但我认为它还需要一些调整。
int linkCount = 10;
float Rotation = 0;
float R = radians(Rotation);
float x[] = new float[linkCount];
float y[] = new float[linkCount];
float xVel[] = new float[linkCount];
float yVel[] = new float[linkCount];
float ropeLength = 100;
float velMX;
float velMY;
float spring = 1;
void setup() {
size(1280, 500); //CHANGED THIS***********************
}
void draw() {
stroke(0);
fill(0);
background(255);
for (int i=0; i < linkCount; i++) {
x[i] = x[i] + xVel[i];
y[i] = y[i] + yVel[i];
}
velMX = pmouseX - mouseX;
velMY = pmouseY - mouseY;
x[1] = mouseX;
y[1] = mouseY;
// if(mousePressed) {
calcRopes();
// }
}
//REPLACED ALL i-- with i-1 (just to see if it works)***********************
void calcRopes() {
for (int i = 1; i < linkCount; i++) {
if (i<x.length && i<y.length) {
R = atan2(-(x[i] - mouseX), -(y[i] - mouseY));
line(x[i], y[i], x[i-1], y[i-1]);
if (dist(x[i], y[i], x[i - 1], y[i - 1]) > ropeLength) {
xVel[i] = ((dist(x[i], y[i], x[i-1], y[i-1]) - (ropeLength - 1)) * sin(R)) / spring;
yVel[i] = ((dist(x[i], y[i], x[i-1], y[i-1]) - (ropeLength - 1)) * cos(R)) / spring;
}
}
}
}
我发现了这一行：
R = atan2(-(x[i] - x[i-1]), -(y[i] - x[i-1]));
有一个错误导致它错误地计算了弧度
R = atan2(-(x[i] - x[i-1]), -(y[i] - y[i-1]));
这是我想要的。我仍然无法使它看起来真实，但我可以自己解决。
