Question

我正在尝试制作一个垂直和水平方向跟随我的播放器的2D相机。相机仅在水平方向上跟随我的播放器。我被告知在我的ScrollCamera()方法中更新Y部分以及X部分，但我无法弄清楚如何做到这一点（最终导致一团糟）。

下面是代码：

private void ScrollCamera(Viewport viewport)
        {
#if ZUNE
const float ViewMargin = 0.45f;
#else
            const float ViewMargin = 0.5f;
#endif

            // Calculate the edges of the screen.
            float marginWidth = viewport.Width * ViewMargin;
            float marginLeft = cameraPosition + marginWidth;
            float marginRight = cameraPosition + viewport.Width - marginWidth;



            // Calculate how far to scroll when the player is near the edges of the screen.
            float cameraMovement = 0.0f;
            if (Player.Position.X < marginLeft)
                cameraMovement = Player.Position.X - marginLeft;
            else if (Player.Position.X > marginRight)
                cameraMovement = Player.Position.X - marginRight;

            // Update the camera position, but prevent scrolling off the ends of the level.
            float maxCameraPositionWidth = Tile.Width * Width - viewport.Width;
            cameraPosition = MathHelper.Clamp(cameraPosition + cameraMovement, 0.0f, maxCameraPositionWidth);


        }

这是我的关卡类中的draw方法：

public void Draw(GameTime gameTime, SpriteBatch spriteBatch)
        {
            spriteBatch.Begin();
            for (int i = 0; i <= EntityLayer; ++i)
                layers[i].Draw(spriteBatch, cameraPosition);
            spriteBatch.End();

            ScrollCamera(spriteBatch.GraphicsDevice.Viewport);
            Matrix cameraTransform = Matrix.CreateTranslation(-cameraPosition, 0.0f, 0.0f);
            spriteBatch.Begin(SpriteSortMode.Immediate, BlendState.AlphaBlend, SamplerState.LinearClamp, DepthStencilState.Default,
                RasterizerState.CullCounterClockwise, null, cameraTransform);

            DrawTiles(spriteBatch);

            Player.Draw(gameTime, spriteBatch);

            foreach (Enemy enemy in enemies)
                enemy.Draw(gameTime, spriteBatch);

            spriteBatch.End();

            spriteBatch.Begin();
            for (int i = EntityLayer + 1; i < layers.Length; ++i)
                layers[i].Draw(spriteBatch, cameraPosition);
            spriteBatch.End();
        }

我是Xna和C＃的新手，我这样做只是为了好玩，但如果有人能告诉我该怎么做的话会很棒：）

我试过了：

private void ScrollCamera(Viewport viewport)
        {
#if ZUNE
const float ViewMargin = 0.45f;
#else
            const float ViewMargin = 0.5f;
            const float ViewHeight = 0.3f;
#endif

            // Calculate the edges of the screen.
            float marginHeight = viewport.Height * ViewHeight;
            float marginTop = cameraPosition + marginHeight;
            float marginBottom = cameraPosition + marginHeight;

            float marginWidth = viewport.Width * ViewMargin;
            float marginLeft = cameraPosition + marginWidth;
            float marginRight = cameraPosition + viewport.Width - marginWidth;


            // Calculate how far to scroll when the player is near the edges of the screen.
            float cameraMovement = 0.0f;
            if (Player.Position.X < marginLeft)
                cameraMovement = Player.Position.X - marginLeft;
            else if (Player.Position.X > marginRight)
                cameraMovement = Player.Position.X - marginRight;

            if (Player.Position.Y < marginTop)
                cameraMovement = Player.Position.Y - marginTop;
            else if (Player.Position.Y > marginBottom)
                cameraMovement = Player.Position.X - marginBottom;



            // Update the camera position, but prevent scrolling off the ends of the level.
            float maxCameraPositionWidth = Tile.Width * Width - viewport.Width;
            cameraPosition = MathHelper.Clamp(cameraPosition + cameraMovement, 0.0f, maxCameraPositionWidth);

        }

这根本不对。

Answer 1

从您提供的代码中我得出结论'cameraPosition'是一个浮点数，您只能跟踪X位置。我建议使用Vector2。这在技术上是两个浮在一个;一个用于X位置，一个用于Y.如果执行此操作，则必须重复计算Y值。如果您不想使用Vector2，则可以为Y位置创建第二个变量。

我无法看到你对cameraPosition做了什么，所以我无法帮助你处理Y部分。

修改您所做的绘图功能不正确，因为相机位置只有一个变量。 X位置需要一个变量，Y位置需要一个变量。如上所述，在XNA中执行此操作的典型方法是通过Vector2结构。如果您不熟悉结构（或类），我建议尽快阅读它，因为它们在面向对象编程中非常重要。 Microsoft Office2文档的链接：http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.vector2.aspx

您基本上要做的是先进行计算。

float cameraMovement = 0.0f; if (Player.Position.X < marginLeft) cameraMovement = Player.Position.X - marginLeft; else if (Player.Position.X > marginRight) cameraMovement = Player.Position.X - marginRight; // Update the camera position, but prevent scrolling off the ends of the level. float maxCameraPositionWidth = Tile.Width * Width - viewport.Width; cameraPosition = MathHelper.Clamp(cameraPosition + cameraMovement, 0.0f, maxCameraPositionWidth);

这是相机X位置的计算。使用Vector2的代码是：

// Declare a Vector2 cameraPosition where you are now declaring a float cameraPosition right now. Vector2 cameraMovement = new Vector2(0,0); if (Player.Position.X < marginLeft) cameraMovement.X = Player.Position.X - marginLeft; else if (Player.Position.X > marginRight) cameraMovement.X = Player.Position.X - marginRight; float maxCameraPositionWidth = Tile.Width * Width - viewport.Width; cameraPosition.X = MathHelper.Clamp(cameraPosition.X + cameraMovement.X, 0.0f, maxCameraPositionWidth);

您必须对cameraMovement.Y和cameraPosition.Y进行类似的计算。

当你拥有这些时，你在绘制功能中唯一需要改变的是Y平移。目前你有：

Matrix cameraTransform = Matrix.CreateTranslation(-cameraPosition, 0.0f, 0.0f);

如您所见，您只是在X轴上进行翻译。添加Y轴后，它看起来像这样：

Matrix cameraTransform = Matrix.CreateTranslation(-cameraPosition.X, -cameraPosition.Y, 0.0f);

我希望你现在明白这一点。祝你好运！

更新Y位置以及2D摄像机的X位置

1 个答案: