Tangents

QuickDraw 3D defines the TQ3Tangent2D and TQ3Tangent3D data structures to represent two- and three-dimensional parametric surface tangents. A surface tangent indicates the directions of changing u, v, and w parameters on a surface.

typedef struct TQ3Tangent2D {
    TQ3Vector3D                         uTangent;
    TQ3Vector3D                         vTangent;
} TQ3Tangent2D;
typedef struct TQ3Tangent3D {
    TQ3Vector3D                         uTangent;
    TQ3Vector3D                         vTangent;
    TQ3Vector3D                         wTangent;
} TQ3Tangent3D;


uTangent

The tangent in the u direction.

vTangent

The tangent in the v direction.

wTangent

The tangent in the w direction.

---

© 1997 Apple Computer, Inc.

Previous | QD3D Book | Overview | Chapter Contents | Next |