//function for changing the string motion after it's collided with cannon ball (the string shouldn't intersect will cannon ball)
//the paramters are the cannon ball and the balloon whose string is collided with, and also the position of the two end of the line segment of the string
void movingAfterCannonBallCollision(CannonBall ball, Balloon balloon, Vector3 startPoint, Vector3 endPoint)
{
//find the 2 Point objects of the balloon string according to the startPoint and endPoint
//Balloon.Point point1 = null;
Balloon.Point point2 = null;
ArrayList strPoints = balloon.getStringPoints();
for (int i = 0; i < strPoints.Count; i++)
{
/*
* if( ((Balloon.Point) strPoints[i]).getPosition().Equals(startPoint))
* {
* point1 = (Balloon.Point) strPoints[i];
* }*/
if (((Balloon.Point)strPoints[i]).getPosition().Equals(endPoint))
{
point2 = (Balloon.Point)strPoints[i];
}
}
Vector2 unitNormal = CollisionCalculation.getNormal(startPoint.x, startPoint.y, point2.getPosition().x, point2.getPosition().y); //calculate the unit normal of the line
float epsilon = 0.1f; //the coefficient of restitution (0~1, when it's 1 we have perfect bouncing)
float mass = 1f; //mass of the string
float VnCollided = unitNormal.x * ball.getVelocity().x + unitNormal.y * ball.getVelocity().y; //Vn-: the normal component of collided velocity = dot product of normal and velocity
float j = -(1 + epsilon) * mass * VnCollided; //the impulse scalar j = -(1+epsilon) * m * Vn-
Vector2 impulse = -j * unitNormal; //the force will apply to the line, not the cannon ball, so we use negative of the impulse
point2.setAcceleration((impulse / mass)); //update the acceleration based on the impulse
}
//function for changing the balloon point motion after it's collided with line (the balloon Point shouldn't intersect will terrain)
//the paramters are the balloon and the points of a line which the balloon is collided with, and also the position of the two end of the line segment
void movingAfterLineCollision(Balloon balloon, Vector3 collidedPoint, Vector3 lineStart, Vector3 lineEnd)
{
//find the 2 Point objects of the balloon string according to the startPoint and endPoint
//Balloon.Point point1 = null;
Balloon.Point cPoint = null;
ArrayList strPoints = balloon.getStringPoints();
ArrayList bodyPoints = balloon.getBodyPoints();
//iterate to find the contact point
for (int i = 0; i < strPoints.Count; i++)
{
if (((Balloon.Point)strPoints[i]).getPosition().Equals(collidedPoint))
{
cPoint = (Balloon.Point)strPoints[i];
}
}
for (int i = 0; i < bodyPoints.Count; i++)
{
if (((Balloon.Point)bodyPoints[i]).getPosition().Equals(collidedPoint))
{
cPoint = (Balloon.Point)bodyPoints[i];
}
}
Vector2 unitNormal = CollisionCalculation.getNormal(lineStart.x, lineStart.y, lineEnd.x, lineEnd.y); //calculate the unit normal of the line segment
float epsilon = 1f; //the coefficient of restitution (0~1, when it's 1 we have perfect bouncing)
float mass = 0.1f; //mass of the string
float VnCollided = unitNormal.x * cPoint.getMovingDirection().x + unitNormal.y * cPoint.getMovingDirection().y; //Vn-: the normal component of collided velocity = dot product of normal and velocity
float multiplier = 30f;
float j = -(1 + epsilon) * mass * -VnCollided * multiplier; //the impulse scalar j = -(1+epsilon) * m * Vn-
Vector2 impulse = -j * unitNormal; //the force will apply to the line, not the cannon ball, so we use negative of the impulse
foreach (Balloon.Point p in bodyPoints)
{
p.setAcceleration((impulse / mass)); //update the acceleration based on the impulse
}
foreach (Balloon.Point p in strPoints)
{
p.setAcceleration((impulse / mass)); //update the acceleration based on the impulse
}
//cPoint.setAcceleration((impulse / mass)); //update the acceleration based on the impulse
}
