/// <summary>
/// return global rotation in radians
/// </summary>
/// <returns></returns>
public float GetRotate()
{
return(globalTransform.GetRotateZ());
}
/// <summary>
/// moves the tank and performs actions based on player location and randomised numbers
/// </summary>
/// <param name="deltaTime"></param>
public override void OnUpdate(float dT)
{
//find angle from the turret to the player
float turretAngle = (float)Math.Atan2(turret.Position.y - Game.player.Position.y, turret.Position.x - Game.player.Position.x);
//getParent angle in radians relative to world space
float parentAngle = GetRotate();
//set the turret's rotation to the turretAngle - parentAngle to compensate for hierachy. Also flip it cuz it ends up backwards otherwise
turret.SetRotate(turretAngle + (float)Math.PI - parentAngle);
//if we are near the middle of the screen
if (collider.Overlaps(Game.arenaBox))
{
if (shootTimer > 0)
{
//keep waiting to shoot
shootTimer--;
}
else
{
//ready to shoot
Shoot();
}
if (moveTimer > 0)
{
//keep waiting to change direction
moveTimer--;
//keep moving to in the same direction
Move(dT);
}
else
{
//randomise movement directions
move = Game.Random.Next(0, 2);
turn = Game.Random.Next(0, 2);
//reset waiting period
moveTimer = Game.Random.Next(30, 100);
}
}
//if we are leaving the screen
else
{
//create new temperary matrix3
Matrix3 angleToCenter = new Matrix3();
//rotate in 180 degrees
angleToCenter.SetRotateZ((float)Math.PI);
//get angle we need to go to
angleToCenter.RotateZ((float)Math.Atan2(Position.y - Game.arenaBox.Center.y, Position.x - Game.arenaBox.Center.x));
//determine if we need to turn left or right
if (angleToCenter.GetRotateZ() < GetRotate())
{
//turn left quickly
Rotate(-rotationSpeed * 3);
}
else
{
//turn right quickly
Rotate(rotationSpeed * 3);
}
//move forward
Vector3 facing = new Vector3(localTransform.m1, localTransform.m2, 1) * dT * 100;
Translate(facing * speed);
}
//if we are completely outside of the map
if (!collider.Overlaps(Game.totalMapBox))
{
//flip 180 to point at home
Rotate(3.14f);
//move forwards quickly
Vector3 facing = new Vector3(localTransform.m1, localTransform.m2, 1) * dT * 100;
Translate(facing * speed * 4);
}
//update tank collider
collider.Fit(cornersGlobalPosition);
//update turret collider
turret.collider.Fit(turret.cornersGlobalPosition);
}