D3DRECTPATCH_INFO

Describes a rectangular high-order patch.

typedef struct _D3DRECTPATCH_INFO {
    UINT                StartVertexOffsetWidth;
    UINT                StartVertexOffsetHeight;
    UINT                Width;
    UINT                Height;
    UINT                Stride;
    D3DBASISTYPE        Basis;
    D3DORDERTYPE        Order;
} D3DRECTPATCH_INFO;

Members

StartVertexOffsetWidth

Starting vertex offset width, in number of vertices.

StartVertexOffsetHeight

Starting vertex offset height, in number of vertices.

Width

Width of each patch, in number of vertices.

Height

Height of each patch, in number of vertices.

Stride

The stride is a width of the imaginary 2-dimensional vertex array, which occupies the same space as the vertex buffer. See the diagram below for an example.

Basis

Member of the D3DBASISTYPE enumerated type, defining the basis type for the rectangular high-order patch.

Value	Order Supported	Width and Height
D3DBASIS_BEZIER	Linear, Cubic and Quintic	Width = Height = (DWORD)order + 1
D3DBASIS_BSPLINE	Linear, Cubic and Quintic	Width = Height > (DWORD)order
D3DBASIS_INTERPOLATE	Cubic	Width = Height > (DWORD)order

Order

Member of the D3DORDERTYPE enumerated type, defining the order type for the rectangular high-order patch.

Remarks

To render a stream of individual rectangular patches (non-mosaic), you should interpret your geometry as a long narrow (1 × N) rectangular patch. The D3DRECTPATCH_INFO structure for such a strip (cubic bézier) would be set up in the following manner.

D3DRECTPATCH_INFO RectInfo;

RectInfo.Width = 4;
RectInfo.Height= 4;
RectInfo.Stride= 4;
RectInfo.Basis =  D3DBASIS_BEZIER;
RectInfo.Order =  D3DORDER_CUBIC;
RectInfo.StartVertexOffsetWidth = 0;
RectInfo.StartVertexOffsetHeight = 4*i;  // The variable i is the index of the patch you want to render.

The following diagram identifies the parameters that specify a rectangle patch.

Each of the vertices in the vertex buffer is shown as a black dot. In this case, the vertex buffer has 20 vertices in it, 16 of which are in the rectangle patch. The stride is the number of vertices in the width of the vertex buffer, in this case 5. The "x" offset to the first vertex is called the StartIndexVertexWidth and is 1 in this case. The "y" offset to the first patch vertex is called the StartIndexVertexHeight and is 0 in this case.

Requirements

  Header: Declared in D3d8types.h.

See Also

IDirect3DDevice8::DrawRectPatch