我试图在 XNA 中绘制一个正方形,然后根据用户输入简单地用键盘移动它。不幸的是,我什至无法让正方形显示 - 我很肯定我在这里遗漏了一些东西,但我无法弄清楚它到底是什么。我计划创建一个可以在我的游戏中使用的原始形状的复杂层次结构。类的主要组件Shape
被初始化,派生类(在这种情况下Rect
)利用这些组件进一步使用,并配置它们。
我在这里做错了什么?
代码
形状.cs
public abstract class Shape
{
public Vector3 Center;
public Color[] Colors;
public bool SetColorsOnUpdate;
public virtual Rectangle BoundingBox { get; set; }
public float Radius { get { return mRadius; } }
protected VertexBuffer mVertexBuf;
protected IndexBuffer mIndexBuf;
protected float mRadius;
protected BasicEffect mShader;
public Shape(Vector3 center, Color[] colors, int numVertices, float radius)
{
Colors = colors;
Center = center;
mVertexBuf = new VertexBuffer(Graphics.MainDevice, typeof(VertexPositionColor), numVertices, BufferUsage.WriteOnly);
mIndexBuf = new IndexBuffer(Graphics.MainDevice, IndexElementSize.SixteenBits, numVertices, BufferUsage.WriteOnly);
SetColorsOnUpdate = true;
mShader = new BasicEffect(Graphics.MainDevice);
mRadius = radius;
}
public abstract void Update();
public abstract void Draw();
}
矩形文件
public class Rect : Shape
{
public override Rectangle BoundingBox
{
get
{
int x = (int)Center.X, y = (int)Center.Y;
int diameter = (int)mRadius * 2;
return new Rectangle(
x, y,
x + diameter,
y + diameter
);
}
}
const float TestRectZCoordinate = 0;
const int NumVertices = 4;
public Rect(Vector3 center, Color[] colors, float radius)
: base(center, colors, NumVertices, radius)
{
if (colors.Length < NumVertices)
throw new IndexOutOfRangeException(string.Format("Color array passed to Rect constructor MUST have an element index size of 4. Current length passed is {0}", colors.Length));
mShader.VertexColorEnabled = true;
mVertexBuf.SetData<VertexPositionColor>(
new VertexPositionColor[]
{
new VertexPositionColor(new Vector3(Center.X + mRadius, Center.Y + mRadius, TestRectZCoordinate), Colors[0]),
new VertexPositionColor(new Vector3(Center.X + mRadius, Center.Y - mRadius, TestRectZCoordinate), Colors[1]),
new VertexPositionColor(new Vector3(Center.X - mRadius, Center.Y - mRadius, TestRectZCoordinate), Colors[2]),
new VertexPositionColor(new Vector3(Center.X - mRadius, Center.Y + mRadius, TestRectZCoordinate), Colors[3])
}
);
mIndexBuf.SetData<short>(new short[] { 0, 1, 2, 3 });
}
public override void Update()
{
//TODO
}
public override void Draw()
{
mShader.World = Matrix.CreateWorld(Center, Vector3.Forward, Vector3.Up);
mShader.CurrentTechnique.Passes[0].Apply();
Graphics.MainDevice.SetVertexBuffer(mVertexBuf);
Graphics.MainDevice.Indices = mIndexBuf;
Graphics.MainDevice.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, NumVertices, 0, 1);
}
}
更新
这是最新的 Rect.Draw() 实现。
public override void Draw()
{
Viewport viewport = Graphics.MainDevice.Viewport;
mShader.World = Matrix.CreateWorld(Center, Vector3.Forward, Vector3.Up);
mShader.View = Matrix.CreateLookAt(new Vector3(viewport.Width / 2, viewport.Height / 2, -5f), Center, Vector3.Up);
mShader.CurrentTechnique.Passes[0].Apply();
Graphics.MainDevice.SetVertexBuffer(mVertexBuf);
Graphics.MainDevice.Indices = mIndexBuf;
Graphics.MainDevice.DrawIndexedPrimitives(PrimitiveType.LineStrip, 0, 0, NumVertices, 0, 2);
}