Step 1: Defining a Custom Vertex Type

The Vertices sample project renders a 2-D triangle by using three vertices. This introduces the concept of the vertex buffer, which is a Microsoft?Direct3D?object that is used to store and render vertices. Vertices can be defined in many ways by specifying a custom vertex structure and corresponding custom flexible vertex format (FVF). The format of the vertices in the Vertices sample project is shown in the following code fragment.

struct CUSTOMVERTEX
{
    FLOAT x, y, z, rhw; // The transformed position for the vertex.
    DWORD color;        // The vertex color.
};

The structure above specifies the format of the custom vertex type. The next step is to define the FVF that describes the contents of the vertices in the vertex buffer. The following code fragment defines a FVF that corresponds with the custom vertex type created above.

#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZRHW|D3DFVF_DIFFUSE)

D3DFVF describe what type of custom vertex is being used. The sample code above uses the D3DFVF_XYZRHW and D3DFVF_DIFFUSE flags, which tell the vertex buffer that the custom vertex type has a transformed point followed by a color component.

Now that the custom vector format and FVF are specified, the next step is to fill the vertex buffer with vertices, as described in Step 2: Setting Up the Vertex Buffer.

Note The vertices in the Vertices sample project are transformed. In other words, they are already in 2-D window coordinates. This means that the point (0,0) is at the top-left corner and the positive x-axis is right and the positive y-axis is down. These vertices are also lit, meaning that they are not using Direct3D lighting but are supplying their own color.