Direct3D 9学习笔记(3)基本顶点绘制

 

一.顶点缓存和索引缓存概念

二.顶点缓存

HRESULT CreateVertexBuffer(
    [in]           UINT Length,
    [in]           DWORD Usage,
    [in]           DWORD FVF,
    [in]           D3DPOOL Pool,
    [out, retval]  IDirect3DVertexBuffer9 **ppVertexBuffer,
    [in]           HANDLE *pSharedHandle
    );

http://msdn.microsoft.com/en-us/library/windows/desktop/bb174364(v=vs.85).aspx

如下顶点数据结构

struct Vertex
{
    Vertex(){}

    Vertex(float x, float y, float z)
    {
        _x = x;     _y = y;  _z = z;
    }

    float _x, _y, _z;

    static const DWORD FVF;
};

然后创建一个顶点缓存

    Device->CreateVertexBuffer(
        3 * sizeof(Vertex), // size in bytes
        D3DUSAGE_WRITEONLY, // flags
        Vertex::FVF,        // vertex format
        D3DPOOL_MANAGED,    // managed memory pool
        &Triangle,          // return create vertex buffer
        0);                 // not used - set to 0

三.向顶点缓存写数据

http://msdn.microsoft.com/en-us/library/windows/desktop/bb205915(v=vs.85).aspx

//
// Fill the buffers with the triangle data.
//

Vertex* vertices;
Triangle->Lock(0, 0, (void**)&vertices, 0);

vertices[0] = Vertex(-1.0f, 0.0f, 2.0f);
vertices[1] = Vertex( 0.0f, 1.0f, 2.0f);
vertices[2] = Vertex( 1.0f, 0.0f, 2.0f);

Triangle->Unlock();

四.获取顶点坐标信息

/* Vertex Buffer Description */
typedef struct _D3DVERTEXBUFFER_DESC
{
    D3DFORMAT           Format;
    D3DRESOURCETYPE     Type;
    DWORD               Usage;
    D3DPOOL             Pool;
    UINT                Size;

    DWORD               FVF;

} D3DVERTEXBUFFER_DESC;

D3DVERTEXBUFFER_DESC desc={};
Triangle->GetDesc(&desc);

五.设置绘制状态

使用IDirect3DDevice9接口的SetRenderState方法设置

Device->SetRenderState(D3DRS_FILLMODE, D3DFILL_WIREFRAME);

 

比如顶点的绘制方法可以是点或填充,上面D3DFILL_WIREFRAME是以连接点来绘制

六.