public void update() {
for (int j = 0; j < parti_num; ++j) {
Parti_obj obj = parti_obj[INNER][j];
obj.x += obj.speedX;
obj.y += obj.speedY;
obj.speedX += obj.accX;
obj.speedY += obj.accY;
if (obj.x < width / 3
|| obj.x > width * 2 / 3
|| obj.y - height / 4 > height / 2 * Math.sin(((obj.x - width / 3) / Math.PI * 3 / width))
|| obj.y < 0) {
reset(obj, INNER);
}
}
for (int j = 0; j < parti_num; ++j) {
Parti_obj obj = parti_obj[MID][j];
obj.x += obj.speedX;
obj.y += obj.speedY;
obj.speedX += obj.accX;
obj.speedY += obj.accY;
if (obj.x >= width * 2 / 3 || obj.x <= width / 3) {
if (obj.x < 0
|| obj.x > width
|| obj.y - height / 4 > height * 3 / 4 * Math.sin((obj.x * Math.PI / width))
|| obj.y < 0) {
reset(obj, MID);
}
} else {
if (obj.y - height / 4 > height * 3 / 4 * Math.sin((obj.x * Math.PI / width))
|| obj.y + height / 4
< height / 2 * Math.sin(((obj.x - width / 3) / Math.PI * 3 / width))
|| obj.y < 0) {
reset(obj, MID);
}
}
}
for (int j = 0; j < parti_num; ++j) {
Parti_obj obj = parti_obj[OUTER][j];
obj.x += obj.speedX;
obj.y += obj.speedY;
obj.speedX += obj.accX;
obj.speedY += obj.accY;
if (obj.x < 0
|| obj.x > width
|| obj.y - height / 4 > height * Math.sin((obj.x * Math.PI / width))
|| obj.y + height / 4 < height * 3 / 4 * Math.sin((obj.x * Math.PI / width))
|| obj.y < 0) {
reset(obj, OUTER);
}
}
}
public void reset(Parti_obj obj, int type) {
// initialize the inner particles
if (type == INNER) {
obj.x = width / 3 + (float) (width / 3 * Math.random());
obj.y = Math.random() * height / 2 * Math.sin(((obj.x - width / 3) * Math.PI * 3 / width));
}
// initialize the middle particles
else if (type == MID) {
obj.x = (float) (width * Math.random());
if (obj.x >= width * 2 / 3 || obj.x <= width / 3) {
obj.y = Math.random() * height * 3 / 4 * Math.sin((obj.x * Math.PI / width));
} else {
obj.y =
height / 2 * Math.sin(((obj.x - width / 3) / Math.PI * 3 / width))
+ Math.random()
* (height * 3 / 4 * Math.sin((obj.x * Math.PI / width))
- height / 2 * Math.sin(((obj.x - width / 3) / Math.PI * 3 / width)));
}
}
// initialize the outer particles
else if (type == OUTER) {
obj.x = (float) (width * Math.random());
obj.y =
height * 3 / 4 * Math.sin((obj.x * Math.PI / width))
+ Math.random() * (height / 4 * Math.sin((obj.x * Math.PI / width)));
}
obj.life = (int) Math.random() * 100;
if (obj.x % 2 == 0) {
obj.speedX = 5 * Math.random();
obj.speedY = 5 * Math.random();
} else {
obj.speedX = -5 * Math.random();
obj.speedY = -5 * Math.random();
}
if (obj.y % 2 == 0) {
obj.accX = Math.random();
obj.accY = Math.random();
} else {
obj.accX = -Math.random();
obj.accY = -Math.random();
}
}