C＃Sprite运动pos-x double

Question

Im working on a XNA project. I have drawn a background(skyline) and i want to move a cloud from left to right. This works whenever i use int, but the movement is too fast so i want to use a double. Is it possible to move the cloud on the x with a double?

public int GetRandomSpeedX() // Random speed pos-x
{            
        int speedX = r.Next(1, 100);
        return speedX;
}

protected override void Update(GameTime gameTime)
{
        if (cloudX <= 500)
        {
            cloudX += GetRandomSpeedX();
        }
        else
        {
            cloudX = 0;                
        }

        base.Update(gameTime);
}

If i use a double it says: cannot implicitly convert type double to int

and i cant change the cloudX to a double because the spriteBatch function wants int only!

any help?

Answer 1

My XNA might be a bit rusty, but you will need two variables for your Cloud, Position and Speed. You will change the Speed each update to increase the Position of the cloud.

Here is a basic implementation. You'll need to setup up the initial Position and Speed in your game initialization.

private float NextRandomFloat(double max, double min)
{
    var number = r.NextDouble() * (max - min) + min;

    return (float) number;
}

private Vector2 GetRandomSpeed(float dx, float dy)
{
    var speedX = NextRandomFloat(2.0, 0.5) * dx;
    var speedY = NextRandomFloat(2.0, 0.5) * dy;
    var vector = new Vector2(speedX, speedY);

    return vector;
}

private Vector2 cloudSpeed;
private Vector2 cloudPosition;

protected override void Update(GameTime gameTime)
{
        if (cloudPosition.X <= 500)
        {
            // Tinker with the dx to manage acceleration
            // Consider using MathHelper.Clamp for a maximum speed.
            cloudSpeed += GetRandomSpeed(1.0f, 0);
        }
        else
        {
            cloudSpeed.X = 0;
        }

        cloudPosition += cloudSpeed;

        base.Update(gameTime);
}

private void DrawCloud()
{
    spriteBatch.Draw(cloudTexture, cloudPosition, Color.White);
}