MFC 实现一个圆柱体的网格显示

首先，我们需要定义圆柱体的顶点坐标和索引。圆柱体可以被视为两个圆盘和一个侧面组成。每个圆盘由一定数量的顶点组成，侧面由一定数量的矩形面片组成。在此，我们假设圆柱体的半径为1，高度为2，圆盘由32个顶点组成，侧面由32个矩形面片组成。

定义顶点：

struct Vertex {
    D3DXVECTOR3 pos;
    D3DXVECTOR3 normal;
    D3DXVECTOR2 texcoord;
};

const int NumCircleVertices = 32;

Vertex vertices[NumCircleVertices * 2 + NumCircleVertices * 32];

for (int i = 0; i < NumCircleVertices; i++) {
    float angle = i * D3DX_PI * 2.0f / NumCircleVertices;
    float x = cos(angle);
    float z = sin(angle);
    vertices[i].pos = D3DXVECTOR3(x, 0.0f, z);
    vertices[i].normal = D3DXVECTOR3(0.0f, -1.0f, 0.0f);
    vertices[i].texcoord = D3DXVECTOR2(x * 0.5f + 0.5f, z * 0.5f + 0.5f);
}

for (int i = 0; i < NumCircleVertices; i++) {
    float angle = i * D3DX_PI * 2.0f / NumCircleVertices;
    float x = cos(angle);
    float z = sin(angle);
    vertices[NumCircleVertices + i].pos = D3DXVECTOR3(x, 2.0f, z);
    vertices[NumCircleVertices + i].normal = D3DXVECTOR3(0.0f, 1.0f, 0.0f);
    vertices[NumCircleVertices + i].texcoord = D3DXVECTOR2(x * 0.5f + 0.5f, z * 0.5f + 0.5f);
}

定义索引：

const int NumIndices = NumCircleVertices * 12;

WORD indices[NumIndices];

int baseIndex = 0;

for (int i = 0; i < NumCircleVertices; i++) {

    // Circle 1 indices
    indices[baseIndex + 0] = i;
    indices[baseIndex + 1] = (i + 1) % NumCircleVertices;
    indices[baseIndex + 2] = NumCircleVertices + i;

    // Circle 2 indices
    indices[baseIndex + 3] = NumCircleVertices + (i + 1) % NumCircleVertices;
    indices[baseIndex + 4] = NumCircleVertices + i;
    indices[baseIndex + 5] = i;

    // Side indices
    indices[baseIndex + 6] = i;
    indices[baseIndex + 7] = (i + 1) % NumCircleVertices;
    indices[baseIndex + 8] = NumCircleVertices + i;

    indices[baseIndex + 9] = NumCircleVertices + (i + 1) % NumCircleVertices;
    indices[baseIndex + 10] = NumCircleVertices + i;
    indices[baseIndex + 11] = (i + 1) % NumCircleVertices;

    baseIndex += 12;
}

现在我们可以使用这些顶点和索引创建一个网格对象，并将其渲染到屏幕上。