Synopsis

PDX_MSGT gdx_EvalParmSplSurfDerivs(long option, T_GDX_SPLINE_SURF *gdx_spline_surf, int max_u_deriv, int max_v_deriv, double uval, double vval, double derivs[][GDX_MAX_DEG + 1][3])

Purpose

Evaluate a derivatives on a GDX parametric spline surface.

Description

Given the GDX parametric spline surface and a U and V parameter value evaluates derivatives on the surface at the given UV parameter value.

Input

option

GDX_UNNORM

Unnormalize the parameter values

GDX_FROMLEFT

Evaluate derivatives from the left

GDX_FROMLOW

Find the knot span from the low direction

gdx_spline_surf

The GDX parametric spline surface data structure

max_u_deriv

The maximium U deriviative desired

max_v_deriv

The maximium V deriviative desired

uval

U surface parmeter value

vval

V surface parmeter value

Output

derivs

The 3D mixed derivatives

Return

      GDX_NOERR
      GDX_PARMOUTOFRANGE
      Low level error return.
      .fi