Untransformed and Unlit Vertices

Many applications use this vertex type, as it frees them from implementing their own transformation and lighting engines. However, because the system is making calculations for you, it requires that you provide a certain amount of information with each vertex.

• You are required to specify vertices in untransformed model coordinates. The system then applies world, view, and projection transformations to the model coordinates to position them in your scene and determine their final locations on the screen.
• You can include a vertex normal for more realistic lighting effects. Vertices lit by the system that don't include a vertex normal will use a dot product of 0 in all lighting calculations. These vertices are assumed to receive no incident light. The system uses the vertex normal, along with the current material, in its lighting calculations. For details, see Face and Vertex Normal Vectors, Lights and Materials.

When you define your own vertex format, remember which vertex components your application needs, and make sure they appear in the required order by declaring a properly ordered structure. The following code example declares a valid vertex format structure that includes a position, a vertex normal, a diffuse color, and two sets of texture coordinates.

'
' The vertex format description for this vertex would be:
' (D3DFVF_XYZ Or D3DFVF_NORMAL Or D3DFVF_DIFFUSE Or D3DFVF_TEX2)
'
Type UNLITVERTEX
    x As Single      ' Position
    y As Single
    z As Single
    nx As Single     ' Normal
    ny As Single
    nz As Single
    Diffuse As Long  ' diffuse color
    tu1 As Single    ' texture coordinates
    tv1 As Single
    tu2 As Single    ' texture coordinates
    tv2 As Single
End Type

The vertex description for the preceding structure is a combination of the D3DFVF_XYZ, D3DFVF_NORMAL, D3DFVF_DIFFUSE, and D3DFVF_TEX2 flexible vertex format flags.

For more information, see Vertex Formats.