SlimDX Direct3D 11 索引问题

Question

我正在尝试使用 SlimDX 和 Direct3D11 绘制一个索引正方形。我已经成功地绘制了一个没有索引的正方形，但是当我切换到索引版本时，我只是得到一个空白屏幕。

我的输入布局设置为仅获取位置数据（我本质上是从 SlimDX 网站上的第三个教程扩展而来）并绘制三角形列表。

我的渲染循环代码如下（我使用教程中的triangle.fx像素和顶点着色器文件，它们采用顶点位置（在屏幕坐标中）并将它们涂成黄色，D3D是SlimDX.Direct3D11的简写）

//clear the render target
context.ClearRenderTargetView(renderTarget, new Color4(0.5f, 0.5f, 1.0f));
context.InputAssembler.SetVertexBuffers(0, new VertexBufferBinding(mesh.VertexBuffer,12, 0));
context.InputAssembler.SetIndexBuffer(mesh.IndexBuffer, Format.R16_UNorm, 0);
context.DrawIndexed(mesh.indices, 0, 0);
swapChain.Present(0, PresentFlags.None);

“网格”是一个保存顶点缓冲区、索引缓冲区和顶点计数的结构。数据填充在这里：

Vertex[] vertexes = new Vertex[4];
vertexes[0].Position = new Vector3(0, 0, 0.5f);
vertexes[1].Position = new Vector3(0, 0.5f, 0.5f);
vertexes[2].Position = new Vector3(0.5f, 0, 0.5f);
vertexes[3].Position = new Vector3(0.5f, 0.5f, 0.5f);

UInt16[] indexes = { 0, 1, 2, 1, 3, 2 };
DataStream vertices = new DataStream(12 * 4, true, true);
foreach (Vertex vertex in vertexes)
{
    vertices.Write(vertex.Position);
}
vertices.Position = 0;
DataStream indices = new DataStream(sizeof(int) * 6, true, true);
foreach (UInt16 index in indexes)
{
    indices.Write(index);
}
indices.Position = 0;
mesh = new Mesh();
D3D.Buffer vertexBuffer = new D3D.Buffer(device, vertices, 12 * 4, ResourceUsage.Default, BindFlags.VertexBuffer, CpuAccessFlags.None, ResourceOptionFlags.None, 0);
mesh.VertexBuffer = vertexBuffer;
mesh.IndexBuffer = new D3D.Buffer(device, indices, 2 * 6, ResourceUsage.Default, BindFlags.IndexBuffer, CpuAccessFlags.None, ResourceOptionFlags.None, 0);
mesh.vertices = vertexes.GetLength(0);
mesh.indices = indexes.Length;

所有这些都与我的无索引平方方法几乎相同（添加了索引缓冲区和索引，并删除了索引不需要的两个重复顶点），但是虽然无索引方法绘制了一个square，索引方法则不然。

我目前的理论是，这一行有问题：

mesh.IndexBuffer = new D3D.Buffer(device, indices, 2 * 6, ResourceUsage.Default, BindFlags.IndexBuffer, CpuAccessFlags.None, ResourceOptionFlags.None, 0);

或者这些行：

context.InputAssembler.SetIndexBuffer(mesh.IndexBuffer, Format.R16_UNorm, 0);
context.DrawIndexed(mesh.indices, 0, 0);

Answer 1

为什么在这个简单的例子中不使用顶点和索引缓冲区呢？

像这样（Directx9）：

VertexBuffer vb;
IndexBuffer ib;

vertices = new PositionColored[WIDTH * HEIGHT];
//vertex creation
vb = new VertexBuffer(device, HEIGHT * WIDTH * PositionColored.SizeInBytes, Usage.WriteOnly, PositionColored.Format, Pool.Default);
DataStream stream = vb.Lock(0, 0, LockFlags.None);
stream.WriteRange(vertices);
vb.Unlock();

indices = new short[(WIDTH - 1) * (HEIGHT - 1) * 6];
//indicies creation
ib = new IndexBuffer(device, sizeof(int) * (WIDTH - 1) * (HEIGHT - 1) * 6, Usage.WriteOnly, Pool.Default, false);
DataStream stream = ib.Lock(0, 0, LockFlags.None);
stream.WriteRange(indices);
ib.Unlock();

//Drawing
device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.DarkSlateBlue, 1.0f, 0);
device.BeginScene();
device.VertexFormat = PositionColored.Format;
device.SetStreamSource(0, vb, 0, PositionColored.SizeInBytes);
device.Indices = ib;
device.SetTransform(TransformState.World, Matrix.Translation(-HEIGHT / 2, -WIDTH / 2, 0) * Matrix.RotationZ(angle));
device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, WIDTH * HEIGHT, 0, indices.Length / 3);
device.EndScene();
device.Present();

我以另一种方式使用网格（再次使用directx9代码）：

        private void CreateMesh()
        {
            meshTerrain = new Mesh(device, (WIDTH - 1) * (HEIGHT - 1) * 2, WIDTH * HEIGHT, MeshFlags.Managed, PositionColored.Format);
            DataStream stream = meshTerrain.VertexBuffer.Lock(0, 0, LockFlags.None);
            stream.WriteRange(vertices);
            meshTerrain.VertexBuffer.Unlock();
            stream.Close();
            stream = meshTerrain.IndexBuffer.Lock(0, 0, LockFlags.None);
            stream.WriteRange(indices);
            meshTerrain.IndexBuffer.Unlock();
            stream.Close();

            meshTerrain.GenerateAdjacency(0.5f);
            meshTerrain.OptimizeInPlace(MeshOptimizeFlags.VertexCache);

            meshTerrain = meshTerrain.Clone(device, MeshFlags.Dynamic, PositionNormalColored.Format);
            meshTerrain.ComputeNormals();
        }


        //Drawing
        device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.DarkSlateBlue, 1.0f, 0);    
        device.BeginScene();
        device.VertexFormat = PositionColored.Format;
        device.SetTransform(TransformState.World, Matrix.Translation(-HEIGHT / 2, -WIDTH / 2, 0) * Matrix.RotationZ(angle));

        int numSubSets = meshTerrain.GetAttributeTable().Length;
        for (int i = 0; i < numSubSets; i++)
        {
            meshTerrain.DrawSubset(i);
        }
        device.EndScene();
        device.Present();