Moving a camera in XNA, C#

Question

I am trying to make a scrolling level to a test game I am doing as a learning exercise. I have created a map containing lots of tiles which are drawn according to their position in an array. I basically want the camera to scroll down the level, but at the moment it just frantically shakes up and down a little bit.

I have a camera class which is just a blank static class containing a static vector2 for the camera location. It is just set as 50, 50 as all the tiles are 50 by 50.

Then in my maps update method I have the following:

public void Update(GameTime gameTime) {

Camera.Location.Y = MathHelper.Clamp(Camera.Location.Y + (float)speed, 0, (300 - 18) * 50)

}

The 300 and 18 are the total number of tiles and the number of tiles on screen (vertically).

I am completely lost so would appreciate any help or advice.

Answer 1

这是我在游戏中使用的一个简单的 2D 相机类。

public class Camera2D
{
    public Camera2D()
    {
        Zoom = 1;
        Position = Vector2.Zero;
        Rotation = 0;
        Origin = Vector2.Zero;
        Position = Vector2.Zero;
    }

    public float Zoom { get; set; }
    public Vector2 Position { get; set; }
    public float Rotation { get; set; }
    public Vector2 Origin { get; set; }

    public void Move(Vector2 direction)
    {
        Position += direction;
    }

    public Matrix GetTransform()
    {
        var translationMatrix = Matrix.CreateTranslation(new Vector3(Position.X, Position.Y, 0));
        var rotationMatrix = Matrix.CreateRotationZ(Rotation);
        var scaleMatrix = Matrix.CreateScale(new Vector3(Zoom, Zoom, 1));
        var originMatrix = Matrix.CreateTranslation(new Vector3(Origin.X, Origin.Y, 0));

        return translationMatrix * rotationMatrix * scaleMatrix * originMatrix;
    }
}

这个想法是当你像这样绘制你的精灵批次时，将它作为一个变换应用：

var screenScale = GetScreenScale();
var viewMatrix = Camera.GetTransform();

_spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.NonPremultiplied,
                           null, null, null, null, viewMatrix * Matrix.CreateScale(screenScale));

您可能还注意到屏幕比例尺的使用。虽然与相机没有直接关系，但它是一种确保您的屏幕缩放到所需分辨率的方法。通过这种方式，您可以独立于分辨率绘制场景并在最后对其进行缩放。以下是屏幕缩放方法供参考：

    public Vector3 GetScreenScale()
    {
        var scaleX = (float)_graphicsDevice.Viewport.Width / (float)_width;
        var scaleY = (float)_graphicsDevice.Viewport.Height / (float)_height;
        return new Vector3(scaleX, scaleY, 1.0f);
    }