protected override void Update(GameTime gameTime)
{
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
{
this.Exit();
}
float Elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds;
cannonCooldown = Math.Max(0, cannonCooldown - Elapsed);
ProcessInput(Elapsed);
UpdateViewMatrix();
float height;
Vector3 temp;
LinkedList <Shell> delete = new LinkedList <Shell>();
foreach (Shell shell in shells)
{
shell.Update(Elapsed);
heightMapInfo.GetHeightAndNormal(shell.position, out height, out temp);
if (shell.position.Y <= height)
{
delete.AddLast(shell);
}
}
foreach (Shell shell in delete)
{
shells.Remove(shell);
}
base.Update(gameTime);
}
/// <summary>
/// This function is called when the game is Updating in response to user input.
/// It'll move the tank around the heightmap, and update all of the tank's
/// necessary state.
/// </summary>
public void Update(float elapsed, float turnAmount, Vector3 movement, HeightMapInfo heightMapInfo, Vector2 turretVector)
{
facingDirection += turnAmount * TankTurnSpeed * elapsed;
// next, we'll create a rotation matrix from the direction the tank is
// facing, and use it to transform the vector.
Vector3 velocity = Vector3.Transform(movement, orientation);
velocity *= TankVelocity;
turretRotationValue = turretVector.X;
cannonRotationValue = turretVector.Y;
// Now we know how much the user wants to move. We'll construct a temporary
// vector, newPosition, which will represent where the user wants to go. If
// that value is on the heightmap, we'll allow the move.
Vector3 newPosition = position + velocity * elapsed;
if (heightMapInfo.IsOnHeightmap(newPosition))
{
// now that we know we're on the heightmap, we need to know the correct
// height and normal at this position.
heightMapInfo.GetHeightAndNormal(newPosition,
out newPosition.Y, out normal);
// As discussed in the doc, we'll use the normal of the heightmap
// and our desired forward direction to recalculate our orientation
// matrix. It's important to normalize, as well.
// now we need to roll the tank's wheels "forward." to do this, we'll
// calculate how far they have rolled, and from there calculate how much
// they must have rotated.
float distanceMoved = Vector3.Distance(position, newPosition);
float theta = distanceMoved / TankWheelRadius;
int rollDirection = movement.Z > 0 ? 1 : -1;
wheelRotationValue += theta * rollDirection;
// once we've finished all computations, we can set our position to the
// new position that we calculated.
position = newPosition;
}
orientation = Matrix.CreateRotationY(FacingDirection);
orientation.Up = normal;
orientation.Right = Vector3.Cross(orientation.Forward, orientation.Up);
orientation.Right = Vector3.Normalize(orientation.Right);
orientation.Forward = Vector3.Cross(orientation.Up, orientation.Right);
orientation.Forward = Vector3.Normalize(orientation.Forward);
}