//function to remove cannon balls if they are out of screen or remain stationary for a long time
void removeUselessBall(CannonBall ball, ArrayList ballList)
{
if (ball.getPosition().x < leftBoundary || ball.getPosition().x > rightBoundary || ball.getPosition().y < bottonBoundary)
{
//when out of scree, remove the ball from the ball list and destroy it
ballList.Remove(ball);
Destroy(ball.GetGameObject());
}
else if (Mathf.Abs(ball.getVelocity().x) < 0.0001f)
{
//the ball's x-velocity is really small (caused by friction), remove the ball from the ball list and destroy it
//note that it must been a long time for the ball staying on the ground to have such a small x-velocty
ballList.Remove(ball);
Destroy(ball.GetGameObject());
}
}
//function to detect and handle collision bewtween cannon ball and collision lines (water, terrain and balloons)
//taking one cannon ball and an array of points of the line (line with corners) as paramters, detect the collsion
void handleCannonBallCollision(CannonBall ball, Vector3[] linePoints, ColliderType type)
{
GameObject ballObject = ball.GetGameObject();
//check that if any line segment of the line is collided with the cannon ball
for (int i = 0; i < linePoints.Length - 1; i++)
{
//if the line which the ball is colliding with is terrain
if (type == ColliderType.TERRAIN)
{
// if the cannon ball is collided with the line
if (CollisionCalculation.isCircleCollidesLine(linePoints[i].x, linePoints[i].y, linePoints[i + 1].x, linePoints[i + 1].y, ballObject.transform.position.x, ballObject.transform.position.y, ball.getRadius()))
{
//if the ball is colliding with horizontal ground
if (linePoints[i].y - linePoints[i + 1].y == 0)
{
//apply an inverse acceleration to the gravity to cancel out the gravity
ball.updateVelocity(Time.deltaTime, new Vector2(0, -gravity));
//apply a friction to the ball when rolling on horizontal ground
applyFrictionOfGround(ball);
}
else //when the ball is not colliding with the horizontal terrain, push it back by a small amount to avoid triggering continuous collision detection
{
//push the ball away from the terrain line in its normal vector direction by a small
//amount to avoid penetration
Vector2 unitNormal = CollisionCalculation.getNormal(linePoints[i].x, linePoints[i].y, linePoints[i + 1].x, linePoints[i + 1].y);
ball.translatePosition(Time.deltaTime, unitNormal * 1);
}
//handle the collision on terrain
bouncingAfterTerrainCollision(ball, linePoints[i].x, linePoints[i].y, linePoints[i + 1].x, linePoints[i + 1].y);
}
}
else //if the line which the ball is colliding with is water
{
// if the cannon ball is collided with the line
if (CollisionCalculation.isCircleCollidesLine(linePoints[i].x, linePoints[i].y, linePoints[i + 1].x, linePoints[i + 1].y, ballObject.transform.position.x, ballObject.transform.position.y, ball.getRadius()))
{
//handle the collision on water
disappearAfterWaterCollision(ball, cannonBallsList);
}
}
}
}
//function for the disappearing solution of collison on water
void disappearAfterWaterCollision(CannonBall ball, ArrayList ballList)
{
//when fall in water, remove the ball from the ball list and destroy it
ballList.Remove(ball);
Destroy(ball.GetGameObject());
}
//this function will handle the collision between cannon ball and any ballon body
void handleBalloonCollision(CannonBall cb, ArrayList balloonList)
{
//vectors that store the position of points that construct the balloons
Vector3[] bodyPositions;
Vector3[] stringPositions;
//get every ballon as line segment
for (int k = 0; k < balloonsList.Count; k++)
{
bodyPositions = ((Balloon)balloonsList[k]).getBodyLinePositions();
stringPositions = ((Balloon)balloonsList[k]).getStringLinePositions();
//iterate through the Points to check if the cannon ball collided any line segment of the balloon string
for (int i = 0; i < stringPositions.Length - 1; i++)
{
// if the cannon ball is collided with the line segment of a balloon string
if (CollisionCalculation.isCircleCollidesLine(stringPositions[i].x, stringPositions[i].y, stringPositions[i + 1].x, stringPositions[i + 1].y, cb.GetGameObject().transform.position.x, cb.GetGameObject().transform.position.y, cb.getRadius()))
{
//handle the collision by moving the string to avoid intersecting with the cannon ball
movingAfterCannonBallCollision(cb, ((Balloon)balloonsList[k]), stringPositions[i], stringPositions[i + 1]);
}
}
//iterate through the Points to check if the cannon ball collided any line segment of the balloon body
for (int i = 0; i < bodyPositions.Length - 1; i++)
{
// if the cannon ball is collided with the line segment of a balloon body
if (CollisionCalculation.isCircleCollidesLine(bodyPositions[i].x, bodyPositions[i].y, bodyPositions[i + 1].x, bodyPositions[i + 1].y, cb.GetGameObject().transform.position.x, cb.GetGameObject().transform.position.y, cb.getRadius()))
{
//handle the collision by destroy the balloon which has been collided
destroyAfterCannonBallCollision(((Balloon)balloonsList[k]), balloonList);
break; //break since the balloon with current positions array is destroyed, so no further check has to be made
}
}
}
}