我有一个名为Tool的精灵,它以一个表示为float的速度和一个表示为Vector2的方向移动。当我在屏幕上单击鼠标时,精灵会改变其方向并开始向鼠标点击移动。除此之外,我旋转精灵,使其朝向它前进的方向。但是,当我添加一个假定跟随精灵的摄像机以使精灵始终在屏幕上居中时,精灵不会沿给定方向移动并且旋转不再准确。这只发生在spriteBatch.Begin()中添加Camera.View时。我希望任何人都可以了解我在代码中遗漏的内容,我将非常感激。
这是我使用的相机类:
public class Camera
{
private const float zoomUpperLimit = 1.5f;
private const float zoomLowerLimit = 0.1f;
private float _zoom;
private Vector2 _pos;
private int ViewportWidth, ViewportHeight;
#region Properties
public float Zoom
{
get { return _zoom; }
set
{
_zoom = value;
if (_zoom < zoomLowerLimit)
_zoom = zoomLowerLimit;
if (_zoom > zoomUpperLimit)
_zoom = zoomUpperLimit;
}
}
public Rectangle Viewport
{
get
{
int width = (int)((ViewportWidth / _zoom));
int height = (int)((ViewportHeight / _zoom));
return new Rectangle((int)(_pos.X - width / 2), (int)(_pos.Y - height / 2), width, height);
}
}
public void Move(Vector2 amount)
{
_pos += amount;
}
public Vector2 Position
{
get { return _pos; }
set { _pos = value; }
}
public Matrix View
{
get
{
return Matrix.CreateTranslation(new Vector3(-_pos.X, -_pos.Y, 0)) *
Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) *
Matrix.CreateTranslation(new Vector3(ViewportWidth * 0.5f, ViewportHeight * 0.5f, 0));
}
}
#endregion
public Camera(Viewport viewport, float initialZoom)
{
_zoom = initialZoom;
_pos = Vector2.Zero;
ViewportWidth = viewport.Width;
ViewportHeight = viewport.Height;
}
}
这是我的更新和绘图方法:
protected override void Update (GameTime gameTime)
{
float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds;
TouchCollection touchCollection = TouchPanel.GetState ();
foreach (TouchLocation tl in touchCollection) {
if (tl.State == TouchLocationState.Pressed || tl.State == TouchLocationState.Moved) {
//direction the tool shall move towards
direction = touchCollection [0].Position - toolPos;
if (direction != Vector2.Zero) {
direction.Normalize ();
}
//change the direction the tool is moving and find the rotationangle the texture must rotate to point in given direction
toolPos += (direction * speed * elapsed);
RotationAngle = (float)Math.Atan2 (direction.Y, direction.X);
}
}
if (direction != Vector2.Zero) {
direction.Normalize ();
}
//move tool in given direction
toolPos += (direction * speed * elapsed);
//change cameracentre to the tools position
Camera.Position = toolPos;
base.Update (gameTime);
}
protected override void Draw (GameTime gameTime)
{
graphics.GraphicsDevice.Clear (Color.Blue);
spriteBatch.Begin (SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, Camera.View);
spriteBatch.Draw (tool, new Vector2 (toolPos.X, toolPos.Y), null, Color.White, RotationAngle, originOfToolTexture, 1, SpriteEffects.None, 1);
spriteBatch.End ();
base.Draw (gameTime);
}
答案 0 :(得分:1)
您需要将光标位置转换为世界位置:
Vector2 adjustedPosition = Vector2.Transform(touchCollection[0].Position, Matrix.Invert(camera.View));
然后你的方向是:
direction = adjustedPosition - toolPos;