/* $Id: nurbssrf.c,v 1.1.1.1 1999/08/19 00:55:42 jtg Exp $ */

/*
 * Mesa 3-D graphics library
 * Version:  2.4
 * Copyright (C) 1995-1997  Brian Paul
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */


/*
 * $Log: nurbssrf.c,v $
 * Revision 1.1.1.1  1999/08/19 00:55:42  jtg
 * Imported sources
 *
 * Revision 1.7  1997/07/24 01:28:44  brianp
 * changed precompiled header symbol from PCH to PC_HEADER
 *
 * Revision 1.6  1997/06/23 00:22:07  brianp
 * include <string.h>
 *
 * Revision 1.5  1997/05/28 02:29:38  brianp
 * added support for precompiled headers (PCH), inserted APIENTRY keyword
 *
 * Revision 1.4  1997/05/27 03:20:35  brianp
 * minor clean-up
 *
 * Revision 1.3  1997/05/27 03:00:16  brianp
 * incorporated Bogdan's new NURBS code
 *
 * Revision 1.2  1996/09/27 23:13:02  brianp
 * added return 0 to get_surface_dim() to silence warning
 *
 * Revision 1.1  1996/09/27 01:19:39  brianp
 * Initial revision
 *
 */


/*
 * NURBS implementation written by Bogdan Sikorski (bogdan@cira.it)
 * See README2 for more info.
 */


#ifdef PC_HEADER
#include "all.h"
#else
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "gluP.h"
#include "nurbs.h"
#endif


static int
get_surface_dim(GLenum type)
{
	switch(type)
	{
		case GL_MAP2_VERTEX_3:			return 3;
		case GL_MAP2_VERTEX_4:			return 4;
		case GL_MAP2_INDEX:				return 1;
		case GL_MAP2_COLOR_4:			return 4;
		case GL_MAP2_NORMAL:			return 3;
		case GL_MAP2_TEXTURE_COORD_1:	return 1;
		case GL_MAP2_TEXTURE_COORD_2:	return 2;
		case GL_MAP2_TEXTURE_COORD_3:	return 3;
		case GL_MAP2_TEXTURE_COORD_4:	return 4;
                default:  abort();  /* TODO: is this OK? */
	}
        return 0; /*never get here*/
}

static GLenum
test_nurbs_surface(GLUnurbsObj *nobj, surface_attribs *attrib)
{
	GLenum err;
	GLint tmp_int;

	if(attrib->sorder < 0 || attrib->torder < 0)
	{
		call_user_error(nobj,GLU_INVALID_VALUE);
		return GLU_ERROR;
	}
	glGetIntegerv(GL_MAX_EVAL_ORDER,&tmp_int);
	if(attrib->sorder > tmp_int || attrib->sorder < 2)
	{
		call_user_error(nobj,GLU_NURBS_ERROR1);
		return GLU_ERROR;
	}
	if(attrib->torder > tmp_int || attrib->torder < 2)
	{
		call_user_error(nobj,GLU_NURBS_ERROR1);
		return GLU_ERROR;
	}
	if(attrib->sknot_count < attrib->sorder +2)
	{
		call_user_error(nobj,GLU_NURBS_ERROR2);
		return GLU_ERROR;
	}
	if(attrib->tknot_count < attrib->torder +2)
	{
		call_user_error(nobj,GLU_NURBS_ERROR2);
		return GLU_ERROR;
	}
	if(attrib->s_stride < 0 || attrib->t_stride < 0)
	{
		call_user_error(nobj,GLU_NURBS_ERROR34);
		return GLU_ERROR;
	}
	if(attrib->sknot==NULL || attrib->tknot==NULL || attrib->ctrlarray==NULL)
	{
		call_user_error(nobj,GLU_NURBS_ERROR36);
		return GLU_ERROR;
	}
	if((err=test_knot(attrib->tknot_count,attrib->tknot,attrib->torder))
		!=GLU_NO_ERROR)
	{
		call_user_error(nobj,err);
		return GLU_ERROR;
	}
	if((err=test_knot(attrib->sknot_count,attrib->sknot,attrib->sorder))
		!=GLU_NO_ERROR)
	{
		call_user_error(nobj,err);
		return GLU_ERROR;
	}
	return GLU_NO_ERROR;
}

static GLenum
test_nurbs_surfaces(GLUnurbsObj *nobj)
{
	/* test the geometric data */
	if(test_nurbs_surface(nobj,&(nobj->surface.geom))!=GLU_NO_ERROR)
		return GLU_ERROR;
	/* now test the attributive data */
	/* color */
	if(nobj->surface.color.type!=GLU_INVALID_ENUM)
		if(test_nurbs_surface(nobj,&(nobj->surface.color))!=GLU_NO_ERROR)
			return GLU_ERROR;
	/* normal */
	if(nobj->surface.normal.type!=GLU_INVALID_ENUM)
		if(test_nurbs_surface(nobj,&(nobj->surface.normal))!=GLU_NO_ERROR)
			return GLU_ERROR;
	/* texture */
	if(nobj->surface.texture.type!=GLU_INVALID_ENUM)
		if(test_nurbs_surface(nobj,&(nobj->surface.texture))!=GLU_NO_ERROR)
			return GLU_ERROR;
	return GLU_NO_ERROR;
}

static GLenum
convert_surf(knot_str_type *s_knot, knot_str_type *t_knot,
	surface_attribs *attrib, GLfloat **new_ctrl,
	GLint *s_n_ctrl, GLint *t_n_ctrl)
{
	GLfloat **tmp_ctrl;
	GLfloat *ctrl_offset;
	GLint tmp_n_control;
	GLint i,j,t_cnt,s_cnt;
	GLint tmp_stride;
	GLint dim;
	GLenum err;

	/* valid range is empty? */
	if((s_knot->unified_knot !=NULL && s_knot->unified_nknots==0) || 
		(t_knot->unified_knot !=NULL && t_knot->unified_nknots==0))
	{
		if(s_knot->unified_knot)
		{
			free(s_knot->unified_knot);
			s_knot->unified_knot=NULL;
		}
		if(t_knot->unified_knot)
		{
			free(t_knot->unified_knot);
			t_knot->unified_knot=NULL;
		}
		*s_n_ctrl=0;
		*t_n_ctrl=0;
		return GLU_NO_ERROR;
	}
	t_cnt=attrib->tknot_count-attrib->torder;
	s_cnt=attrib->sknot_count-attrib->sorder;
	if((tmp_ctrl=(GLfloat **)malloc(sizeof(GLfloat *)*t_cnt))==NULL)
		return GLU_OUT_OF_MEMORY;
	if((err=explode_knot(s_knot))!=GLU_NO_ERROR)
	{
		free(tmp_ctrl);
		if(s_knot->unified_knot)
		{
			free(s_knot->unified_knot);
			s_knot->unified_knot=NULL;
		}
		return err;
	}
	if(s_knot->unified_knot)
	{
		free(s_knot->unified_knot);
		s_knot->unified_knot=NULL;
	}
	if((err=calc_alphas(s_knot))!=GLU_NO_ERROR)
	{
		free(tmp_ctrl);
		free(s_knot->new_knot);
		return err;
	}
	free(s_knot->new_knot);
	ctrl_offset=attrib->ctrlarray;
	dim=attrib->dim;
	for(i=0;i<t_cnt;i++)
	{
		if((err=calc_new_ctrl_pts(ctrl_offset,attrib->s_stride,s_knot,
			dim,&(tmp_ctrl[i]),&tmp_n_control))!=GLU_NO_ERROR)
		{
			for(--i;i<=0;i--)
				free(tmp_ctrl[i]);
			free(tmp_ctrl);
			free(s_knot->alpha);
			return err;
		}
		ctrl_offset+=attrib->t_stride;
	}
	free(s_knot->alpha);
	tmp_stride=dim*tmp_n_control;
	if((*new_ctrl=(GLfloat *)malloc(sizeof(GLfloat)*tmp_stride*t_cnt))
		==NULL)
	{
		for(i=0;i<t_cnt;i++)
			free(tmp_ctrl[i]);
		free(tmp_ctrl);
		return GLU_OUT_OF_MEMORY;
	}
	for(i=0;i<tmp_n_control;i++)
		for(j=0;j<t_cnt;j++)
			MEMCPY(*new_ctrl+j*dim+i*dim*t_cnt,tmp_ctrl[j]+dim*i,
				sizeof(GLfloat)*dim);
	for(i=0;i<t_cnt;i++)
		free(tmp_ctrl[i]);
	free(tmp_ctrl);
	*s_n_ctrl=tmp_n_control;
	
	if((tmp_ctrl=(GLfloat **)malloc(sizeof(GLfloat *)*(*s_n_ctrl)))==NULL)
	{
		return GLU_OUT_OF_MEMORY;
	}
	if((err=explode_knot(t_knot))!=GLU_NO_ERROR)
	{
		free(tmp_ctrl);
		if(t_knot->unified_knot)
		{
			free(t_knot->unified_knot);
			t_knot->unified_knot=NULL;
		}
		return err;
	}
	if(t_knot->unified_knot)
	{
		free(t_knot->unified_knot);
		t_knot->unified_knot=NULL;
	}
	if((err=calc_alphas(t_knot))!=GLU_NO_ERROR)
	{
		free(tmp_ctrl);
		free(t_knot->new_knot);
		return err;
	}
	free(t_knot->new_knot);
	ctrl_offset=*new_ctrl;
	for(i=0;i<(*s_n_ctrl);i++)
	{
		if((err=calc_new_ctrl_pts(ctrl_offset,dim,t_knot,
			dim,&(tmp_ctrl[i]),&tmp_n_control))!=GLU_NO_ERROR)
		{
			for(--i;i<=0;i--)
				free(tmp_ctrl[i]);
			free(tmp_ctrl);
			free(t_knot->alpha);
			return err;
		}
		ctrl_offset+=dim*t_cnt;
	}
	free(t_knot->alpha);
	free(*new_ctrl);
	tmp_stride=dim*tmp_n_control;
	if((*new_ctrl=(GLfloat *)malloc(sizeof(GLfloat)*tmp_stride*(*s_n_ctrl)))
		==NULL)
	{
		for(i=0;i<(*s_n_ctrl);i++)
			free(tmp_ctrl[i]);
		free(tmp_ctrl);
		return GLU_OUT_OF_MEMORY;
	}
	for(i=0;i<(*s_n_ctrl);i++)
	{
		MEMCPY(*new_ctrl+i*tmp_stride,tmp_ctrl[i],sizeof(GLfloat)*tmp_stride);
		free(tmp_ctrl[i]);
	}
	free(tmp_ctrl);
	*t_n_ctrl=tmp_n_control;
	return GLU_NO_ERROR;
}

/* prepare the knot information structures */
static GLenum
fill_knot_structures(GLUnurbsObj *nobj,
	knot_str_type *geom_s_knot, knot_str_type *geom_t_knot,
	knot_str_type *color_s_knot, knot_str_type *color_t_knot,
	knot_str_type *normal_s_knot,  knot_str_type *normal_t_knot,
	knot_str_type *texture_s_knot, knot_str_type *texture_t_knot)
{
	GLint order;
	GLfloat *knot;
	GLint nknots;
	GLint t_min,t_max;

	geom_s_knot->unified_knot=NULL;
	knot=geom_s_knot->knot=nobj->surface.geom.sknot;
	nknots=geom_s_knot->nknots=nobj->surface.geom.sknot_count;
	order=geom_s_knot->order=nobj->surface.geom.sorder;
	geom_s_knot->delta_nknots=0;
	t_min=geom_s_knot->t_min=order-1;
	t_max=geom_s_knot->t_max=nknots-order;
	if(fabs(knot[t_min]-knot[t_max])<EPSILON)
	{
		call_user_error(nobj,GLU_NURBS_ERROR3);
		return GLU_ERROR;
	}
	if(fabs(knot[0]-knot[t_min])<EPSILON)
	{
		/* knot open at beggining */
		geom_s_knot->open_at_begin=GL_TRUE;
	}
	else
		geom_s_knot->open_at_begin=GL_FALSE;
	if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
	{
		/* knot open at end */
		geom_s_knot->open_at_end=GL_TRUE;
	}
	else
		geom_s_knot->open_at_end=GL_FALSE;
	geom_t_knot->unified_knot=NULL;
	knot=geom_t_knot->knot=nobj->surface.geom.tknot;
	nknots=geom_t_knot->nknots=nobj->surface.geom.tknot_count;
	order=geom_t_knot->order=nobj->surface.geom.torder;
	geom_t_knot->delta_nknots=0;
	t_min=geom_t_knot->t_min=order-1;
	t_max=geom_t_knot->t_max=nknots-order;
	if(fabs(knot[t_min]-knot[t_max])<EPSILON)
	{
		call_user_error(nobj,GLU_NURBS_ERROR3);
		return GLU_ERROR;
	}
	if(fabs(knot[0]-knot[t_min])<EPSILON)
	{
		/* knot open at beggining */
		geom_t_knot->open_at_begin=GL_TRUE;
	}
	else
		geom_t_knot->open_at_begin=GL_FALSE;
	if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
	{
		/* knot open at end */
		geom_t_knot->open_at_end=GL_TRUE;
	}
	else
		geom_t_knot->open_at_end=GL_FALSE;

	if(nobj->surface.color.type!=GLU_INVALID_ENUM)
	{
		color_s_knot->unified_knot=(GLfloat *)1;
		knot=color_s_knot->knot=nobj->surface.color.sknot;
		nknots=color_s_knot->nknots=nobj->surface.color.sknot_count;
		order=color_s_knot->order=nobj->surface.color.sorder;
		color_s_knot->delta_nknots=0;
		t_min=color_s_knot->t_min=order-1;
		t_max=color_s_knot->t_max=nknots-order;
		if(fabs(knot[t_min]-knot[t_max])<EPSILON)
		{
			call_user_error(nobj,GLU_NURBS_ERROR3);
			return GLU_ERROR;
		}
		if(fabs(knot[0]-knot[t_min])<EPSILON)
		{
			/* knot open at beggining */
			color_s_knot->open_at_begin=GL_TRUE;
		}
		else
			color_s_knot->open_at_begin=GL_FALSE;
		if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
		{
			/* knot open at end */
			color_s_knot->open_at_end=GL_TRUE;
		}
		else
			color_s_knot->open_at_end=GL_FALSE;
		color_t_knot->unified_knot=(GLfloat *)1;
		knot=color_t_knot->knot=nobj->surface.color.tknot;
		nknots=color_t_knot->nknots=nobj->surface.color.tknot_count;
		order=color_t_knot->order=nobj->surface.color.torder;
		color_t_knot->delta_nknots=0;
		t_min=color_t_knot->t_min=order-1;
		t_max=color_t_knot->t_max=nknots-order;
		if(fabs(knot[t_min]-knot[t_max])<EPSILON)
		{
			call_user_error(nobj,GLU_NURBS_ERROR3);
			return GLU_ERROR;
		}
		if(fabs(knot[0]-knot[t_min])<EPSILON)
		{
			/* knot open at beggining */
			color_t_knot->open_at_begin=GL_TRUE;
		}
		else
			color_t_knot->open_at_begin=GL_FALSE;
		if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
		{
			/* knot open at end */
			color_t_knot->open_at_end=GL_TRUE;
		}
		else
			color_t_knot->open_at_end=GL_FALSE;
	}
	else
	{
		color_s_knot->unified_knot=NULL;
		color_t_knot->unified_knot=NULL;
	}

	if(nobj->surface.normal.type!=GLU_INVALID_ENUM)
	{
		normal_s_knot->unified_knot=(GLfloat *)1;
		knot=normal_s_knot->knot=nobj->surface.normal.sknot;
		nknots=normal_s_knot->nknots=nobj->surface.normal.sknot_count;
		order=normal_s_knot->order=nobj->surface.normal.sorder;
		normal_s_knot->delta_nknots=0;
		t_min=normal_s_knot->t_min=order-1;
		t_max=normal_s_knot->t_max=nknots-order;
		if(fabs(knot[t_min]-knot[t_max])<EPSILON)
		{
			call_user_error(nobj,GLU_NURBS_ERROR3);
			return GLU_ERROR;
		}
		if(fabs(knot[0]-knot[t_min])<EPSILON)
		{
			/* knot open at beggining */
			normal_s_knot->open_at_begin=GL_TRUE;
		}
		else
			normal_s_knot->open_at_begin=GL_FALSE;
		if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
		{
			/* knot open at end */
			normal_s_knot->open_at_end=GL_TRUE;
		}
		else
			normal_s_knot->open_at_end=GL_FALSE;
		normal_t_knot->unified_knot=(GLfloat *)1;
		knot=normal_t_knot->knot=nobj->surface.normal.tknot;
		nknots=normal_t_knot->nknots=nobj->surface.normal.tknot_count;
		order=normal_t_knot->order=nobj->surface.normal.torder;
		normal_t_knot->delta_nknots=0;
		t_min=normal_t_knot->t_min=order-1;
		t_max=normal_t_knot->t_max=nknots-order;
		if(fabs(knot[t_min]-knot[t_max])<EPSILON)
		{
			call_user_error(nobj,GLU_NURBS_ERROR3);
			return GLU_ERROR;
		}
		if(fabs(knot[0]-knot[t_min])<EPSILON)
		{
			/* knot open at beggining */
			normal_t_knot->open_at_begin=GL_TRUE;
		}
		else
			normal_t_knot->open_at_begin=GL_FALSE;
		if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
		{
			/* knot open at end */
			normal_t_knot->open_at_end=GL_TRUE;
		}
		else
			normal_t_knot->open_at_end=GL_FALSE;
	}
	else
	{
		normal_s_knot->unified_knot=NULL;
		normal_t_knot->unified_knot=NULL;
	}

	if(nobj->surface.texture.type!=GLU_INVALID_ENUM)
	{
		texture_s_knot->unified_knot=(GLfloat *)1;
		knot=texture_s_knot->knot=nobj->surface.texture.sknot;
		nknots=texture_s_knot->nknots=nobj->surface.texture.sknot_count;
		order=texture_s_knot->order=nobj->surface.texture.sorder;
		texture_s_knot->delta_nknots=0;
		t_min=texture_s_knot->t_min=order-1;
		t_max=texture_s_knot->t_max=nknots-order;
		if(fabs(knot[t_min]-knot[t_max])<EPSILON)
		{
			call_user_error(nobj,GLU_NURBS_ERROR3);
			return GLU_ERROR;
		}
		if(fabs(knot[0]-knot[t_min])<EPSILON)
		{
			/* knot open at beggining */
			texture_s_knot->open_at_begin=GL_TRUE;
		}
		else
			texture_s_knot->open_at_begin=GL_FALSE;
		if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
		{
			/* knot open at end */
			texture_s_knot->open_at_end=GL_TRUE;
		}
		else
			texture_s_knot->open_at_end=GL_FALSE;
		texture_t_knot->unified_knot=(GLfloat *)1;
		knot=texture_t_knot->knot=nobj->surface.texture.tknot;
		nknots=texture_t_knot->nknots=nobj->surface.texture.tknot_count;
		order=texture_t_knot->order=nobj->surface.texture.torder;
		texture_t_knot->delta_nknots=0;
		t_min=texture_t_knot->t_min=order-1;
		t_max=texture_t_knot->t_max=nknots-order;
		if(fabs(knot[t_min]-knot[t_max])<EPSILON)
		{
			call_user_error(nobj,GLU_NURBS_ERROR3);
			return GLU_ERROR;
		}
		if(fabs(knot[0]-knot[t_min])<EPSILON)
		{
			/* knot open at beggining */
			texture_t_knot->open_at_begin=GL_TRUE;
		}
		else
			texture_t_knot->open_at_begin=GL_FALSE;
		if(fabs(knot[t_max]-knot[nknots-1])<EPSILON)
		{
			/* knot open at end */
			texture_t_knot->open_at_end=GL_TRUE;
		}
		else
			texture_t_knot->open_at_end=GL_FALSE;
	}
	else
	{
		texture_s_knot->unified_knot=NULL;
		texture_t_knot->unified_knot=NULL;
	}
	return GLU_NO_ERROR;
}

void
free_new_ctrl(new_ctrl_type *p)
{
	if(p->geom_ctrl)
		free(p->geom_ctrl);
	if(p->geom_offsets)
		free(p->geom_offsets);
	if(p->color_ctrl)
	{
		free(p->color_ctrl);
		if(p->color_offsets)
			free(p->color_offsets);
	}
	if(p->normal_ctrl)
	{
		free(p->normal_ctrl);
		if(p->normal_offsets)
			free(p->normal_offsets);
	}
	if(p->texture_ctrl)
	{
		free(p->texture_ctrl);
		if(p->texture_offsets)
			free(p->texture_offsets);
	}
}

/* convert surfaces - geometry and possible attribute ones into equivalent */
/* sequence of adjacent Bezier patches */
static GLenum
convert_surfs(GLUnurbsObj *nobj, new_ctrl_type *new_ctrl)
{
	knot_str_type	geom_s_knot,color_s_knot,normal_s_knot,texture_s_knot;
	knot_str_type	geom_t_knot,color_t_knot,normal_t_knot,texture_t_knot;
	GLenum			err;

	if((err=fill_knot_structures(nobj,&geom_s_knot,&geom_t_knot,
		&color_s_knot,&color_t_knot,&normal_s_knot,&normal_t_knot,
		&texture_s_knot,&texture_t_knot)) !=GLU_NO_ERROR)
	{
		return err;
	}
	/* unify knots - all knots should have the same working range */
	if((err=select_knot_working_range(nobj,&geom_s_knot,&color_s_knot,
		&normal_s_knot,&texture_s_knot)) !=GLU_NO_ERROR)
	{
		call_user_error(nobj,err);
		return err;
	}
	if((err=select_knot_working_range(nobj,&geom_t_knot,&color_t_knot,
		&normal_t_knot,&texture_t_knot)) !=GLU_NO_ERROR)
	{
		free_unified_knots(&geom_s_knot,&color_s_knot,&normal_s_knot,
			&texture_s_knot);
		call_user_error(nobj,err);
		return err;
	}

	/* convert the geometry surface */
	nobj->surface.geom.dim=get_surface_dim(nobj->surface.geom.type);
	if((err=convert_surf(&geom_s_knot,&geom_t_knot,&(nobj->surface.geom),
		&(new_ctrl->geom_ctrl),&(new_ctrl->geom_s_pt_cnt),
		&(new_ctrl->geom_t_pt_cnt)))!=GLU_NO_ERROR)
	{
		free_unified_knots(&geom_s_knot,&color_s_knot,&normal_s_knot,
			&texture_s_knot);
		free_unified_knots(&geom_t_knot,&color_t_knot,&normal_t_knot,
			&texture_t_knot);
		call_user_error(nobj,err);
		return err;
	}
	/* if additional attributive surfaces are given convert them as well */
	if(color_s_knot.unified_knot)
	{
		nobj->surface.color.dim=get_surface_dim(nobj->surface.color.type);
		if((err=convert_surf(&color_s_knot,&color_t_knot,&(nobj->surface.color),
			&(new_ctrl->color_ctrl),&(new_ctrl->color_s_pt_cnt),
			&(new_ctrl->color_t_pt_cnt)))!=GLU_NO_ERROR)
		{
			free_unified_knots(&color_s_knot,&color_s_knot,&normal_s_knot,
				&texture_s_knot);
			free_unified_knots(&color_t_knot,&color_t_knot,&normal_t_knot,
				&texture_t_knot);
			free_new_ctrl(new_ctrl);
			call_user_error(nobj,err);
			return err;
		}
	}
	if(normal_s_knot.unified_knot)
	{
		nobj->surface.normal.dim=get_surface_dim(nobj->surface.normal.type);
		if((err=convert_surf(&normal_s_knot,&normal_t_knot,
			&(nobj->surface.normal),
			&(new_ctrl->normal_ctrl),&(new_ctrl->normal_s_pt_cnt),
			&(new_ctrl->normal_t_pt_cnt)))!=GLU_NO_ERROR)
		{
			free_unified_knots(&normal_s_knot,&normal_s_knot,&normal_s_knot,
				&texture_s_knot);
			free_unified_knots(&normal_t_knot,&normal_t_knot,&normal_t_knot,
				&texture_t_knot);
			free_new_ctrl(new_ctrl);
			call_user_error(nobj,err);
			return err;
		}
	}
	if(texture_s_knot.unified_knot)
	{
		nobj->surface.texture.dim=get_surface_dim(nobj->surface.texture.type);
		if((err=convert_surf(&texture_s_knot,&texture_t_knot,
			&(nobj->surface.texture),
			&(new_ctrl->texture_ctrl),&(new_ctrl->texture_s_pt_cnt),
			&(new_ctrl->texture_t_pt_cnt)))!=GLU_NO_ERROR)
		{
			free_unified_knots(&texture_s_knot,&texture_s_knot,&texture_s_knot,
				&texture_s_knot);
			free_unified_knots(&texture_t_knot,&texture_t_knot,&texture_t_knot,
				&texture_t_knot);
			free_new_ctrl(new_ctrl);
			call_user_error(nobj,err);
			return err;
		}
	}
	return GLU_NO_ERROR;
}

/* tesselate the "boundary" Bezier edge strips */
void
tesselate_strip_t_line(GLint top_start,GLint top_end,GLint top_z,
	GLint bottom_start,GLint bottom_end,GLint bottom_z,GLint bottom_domain)
{
	GLint top_cnt,bottom_cnt,tri_cnt,k;
	GLint direction;

	top_cnt=top_end-top_start;
	direction= (top_cnt>=0 ? 1: -1);
	bottom_cnt=bottom_end-bottom_start;
	glBegin(GL_LINES);
	while(top_cnt)
	{
		if(bottom_cnt)
			tri_cnt=top_cnt/bottom_cnt;
		else
			tri_cnt=abs(top_cnt);
		for(k=0;k<=tri_cnt;k++ , top_start+=direction)
		{
			glEvalCoord2f((GLfloat)bottom_z/bottom_domain,
				(GLfloat)bottom_start/bottom_domain);
			glEvalPoint2(top_z,top_start);
		}
		if(bottom_cnt)
		{
			glEvalCoord2f((GLfloat)bottom_z/bottom_domain,
				(GLfloat)bottom_start/bottom_domain);
			bottom_start+=direction;
			top_start-=direction;
			glEvalCoord2f((GLfloat)bottom_z/bottom_domain,
				(GLfloat)bottom_start/bottom_domain);
			glEvalCoord2f((GLfloat)bottom_z/bottom_domain,
				(GLfloat)bottom_start/bottom_domain);
			glEvalPoint2(top_z,top_start);
		}
		top_cnt-=direction*tri_cnt;
		bottom_cnt-=direction;
	}
	glEnd();
}

void
tesselate_strip_t_fill(GLint top_start,GLint top_end,GLint top_z,
	GLint bottom_start,GLint bottom_end,GLint bottom_z,GLint bottom_domain)
{
	GLint top_cnt,bottom_cnt,tri_cnt,k;
	GLint direction;

	top_cnt=top_end-top_start;
	direction= (top_cnt>=0 ? 1: -1);
	bottom_cnt=bottom_end-bottom_start;
	while(top_cnt)
	{
		if(bottom_cnt)
			tri_cnt=top_cnt/bottom_cnt;
		else
			tri_cnt=abs(top_cnt);
		glBegin(GL_TRIANGLE_FAN);
		glEvalCoord2f((GLfloat)bottom_z/bottom_domain,
			(GLfloat)bottom_start/bottom_domain);
		for(k=0;k<=tri_cnt;k++ , top_start+=direction)
			glEvalPoint2(top_z,top_start);
		if(bottom_cnt)
		{
			bottom_start+=direction;
			top_start-=direction;
			glEvalCoord2f((GLfloat)bottom_z/bottom_domain,
				(GLfloat)bottom_start/bottom_domain);
		}
		glEnd();
		top_cnt-=direction*tri_cnt;
		bottom_cnt-=direction;
	}
}

void
tesselate_strip_t(GLenum display_mode, GLint top_start, GLint top_end, 
	GLint top_z, GLint bottom_start, GLint bottom_end, GLint bottom_z, 
	GLint bottom_domain)
{
	if(display_mode==GL_FILL)
		tesselate_strip_t_fill(top_start,top_end,top_z,bottom_start,
			bottom_end,bottom_z,bottom_domain);
	else
		tesselate_strip_t_line(top_start,top_end,top_z,bottom_start,
			bottom_end,bottom_z,bottom_domain);
}
	

void
tesselate_strip_s_fill(GLint top_start, GLint top_end, GLint top_z,
	GLint bottom_start, GLint bottom_end, GLint bottom_z, GLfloat bottom_domain)
{
	GLint top_cnt,bottom_cnt,tri_cnt,k;
	GLint direction;

	top_cnt=top_end-top_start;
	direction= (top_cnt>=0 ? 1: -1);
	bottom_cnt=bottom_end-bottom_start;
	while(top_cnt)
	{
		if(bottom_cnt)
			tri_cnt=top_cnt/bottom_cnt;
		else
			tri_cnt=abs(top_cnt);
		glBegin(GL_TRIANGLE_FAN);
		glEvalCoord2f((GLfloat)bottom_start/bottom_domain,
			(GLfloat)bottom_z/bottom_domain);
		for(k=0;k<=tri_cnt;k++ , top_start+=direction)
			glEvalPoint2(top_start,top_z);
		if(bottom_cnt)
		{
			bottom_start+=direction;
			top_start-=direction;
			glEvalCoord2f((GLfloat)bottom_start/bottom_domain,
				(GLfloat)bottom_z/bottom_domain);
		}
		glEnd();
		top_cnt-=direction*tri_cnt;
		bottom_cnt-=direction;
	}
}

void
tesselate_strip_s_line(GLint top_start, GLint top_end, GLint top_z,
	GLint bottom_start, GLint bottom_end, GLint bottom_z, GLfloat bottom_domain)
{
	GLint top_cnt,bottom_cnt,tri_cnt,k;
	GLint direction;

	top_cnt=top_end-top_start;
	direction= (top_cnt>=0 ? 1: -1);
	bottom_cnt=bottom_end-bottom_start;
	glBegin(GL_LINES);
	while(top_cnt)
	{
		if(bottom_cnt)
			tri_cnt=top_cnt/bottom_cnt;
		else
			tri_cnt=abs(top_cnt);
		for(k=0;k<=tri_cnt;k++ , top_start+=direction)
		{
			glEvalCoord2f((GLfloat)bottom_start/bottom_domain,
				(GLfloat)bottom_z/bottom_domain);
			glEvalPoint2(top_start,top_z);
		}
		if(bottom_cnt)
		{
			glEvalCoord2f((GLfloat)bottom_start/bottom_domain,
				(GLfloat)bottom_z/bottom_domain);
			bottom_start+=direction;
			top_start-=direction;
			glEvalCoord2f((GLfloat)bottom_start/bottom_domain,
				(GLfloat)bottom_z/bottom_domain);
			glEvalPoint2(top_start,top_z);
			glEvalCoord2f((GLfloat)bottom_start/bottom_domain,
				(GLfloat)bottom_z/bottom_domain);
		}
		top_cnt-=direction*tri_cnt;
		bottom_cnt-=direction;
	}
	glEnd();
}

void
tesselate_strip_s(GLenum display_mode, GLint top_start, GLint top_end,
	GLint top_z, GLint bottom_start, GLint bottom_end, GLint bottom_z,
	GLfloat bottom_domain)
{
	if(display_mode==GL_FILL)
		tesselate_strip_s_fill(top_start,top_end,top_z,bottom_start,
			bottom_end,bottom_z,bottom_domain);
	else
		tesselate_strip_s_line(top_start,top_end,top_z,bottom_start,
			bottom_end,bottom_z,bottom_domain);
}

void
tesselate_bottom_left_corner(GLenum display_mode, GLfloat s_1, GLfloat t_1)
{
	if(display_mode==GL_FILL)
	{
		glBegin(GL_TRIANGLE_FAN);
		glEvalPoint2(1,1);
		glEvalCoord2f(s_1,0.0);
		glEvalCoord2f(0.0,0.0);
		glEvalCoord2f(0.0,t_1);
	}
	else
	{
		glBegin(GL_LINES);
		glEvalCoord2f(0.0,0.0);
		glEvalCoord2f(0.0,t_1);
		glEvalCoord2f(0.0,0.0);
		glEvalPoint2(1,1);
		glEvalCoord2f(0.0,0.0);
		glEvalCoord2f(s_1,0.0);
	}
	glEnd();
}

void
tesselate_bottom_right_corner(GLenum display_mode, GLint v_top,GLint v_bottom,
	GLfloat s_1, GLfloat t_1)
{
	if(display_mode==GL_FILL)
	{
		glBegin(GL_TRIANGLE_FAN);
		glEvalPoint2(1,v_top);
		glEvalCoord2f(0.0,v_bottom*t_1);
		glEvalCoord2f(0.0,(v_bottom+1)*t_1);
		glEvalCoord2f(s_1,(v_bottom+1)*t_1);
	}
	else
	{
		glBegin(GL_LINES);
		glEvalCoord2f(0.0,(v_bottom+1)*t_1);
		glEvalPoint2(1,v_top);
		glEvalCoord2f(0.0,(v_bottom+1)*t_1);
		glEvalCoord2f(0.0,v_bottom*t_1);
		glEvalCoord2f(0.0,(v_bottom+1)*t_1);
		glEvalCoord2f(s_1,(v_bottom+1)*t_1);
	}
	glEnd();
}

void
tesselate_top_left_corner(GLenum display_mode, GLint u_right, GLint u_left,
	GLfloat s_1, GLfloat t_1)
{
	if(display_mode==GL_FILL)
	{
		glBegin(GL_TRIANGLE_FAN);
		glEvalPoint2(u_right,1);
		glEvalCoord2f((u_left+1)*s_1,t_1);
		glEvalCoord2f((u_left+1)*s_1,0.0);
		glEvalCoord2f(u_left*s_1,0.0);
	}
	else
	{
		glBegin(GL_LINES);
		glEvalCoord2f((u_left+1)*s_1,0.0);
		glEvalPoint2(u_right,1);
		glEvalCoord2f((u_left+1)*s_1,0.0);
		glEvalCoord2f(u_left*s_1,0.0);
		glEvalCoord2f((u_left+1)*s_1,0.0);
		glEvalCoord2f((u_left+1)*s_1,t_1);
	}
	glEnd();
}

void
tesselate_top_right_corner(GLenum display_mode, GLint u_left, GLint v_bottom,
	GLint u_right, GLint v_top, GLfloat s_1, GLfloat t_1)
{
	if(display_mode==GL_FILL)
	{
		glBegin(GL_TRIANGLE_FAN);
		glEvalPoint2(u_left,v_bottom);
		glEvalCoord2f((u_right-1)*s_1,v_top*t_1);
		glEvalCoord2f(u_right*s_1,v_top*t_1);
		glEvalCoord2f(u_right*s_1,(v_top-1)*t_1);
	}
	else
	{
		glBegin(GL_LINES);
		glEvalCoord2f(u_right*s_1,v_top*t_1);
		glEvalPoint2(u_left,v_bottom);
		glEvalCoord2f(u_right*s_1,v_top*t_1);
		glEvalCoord2f(u_right*s_1,(v_top-1)*t_1);
		glEvalCoord2f(u_right*s_1,v_top*t_1);
		glEvalCoord2f((u_right-1)*s_1,v_top*t_1);
	}
	glEnd();
}

/* do mesh mapping of Bezier */
static void
nurbs_map_bezier(GLenum display_mode,GLint *sfactors,GLint *tfactors,
	GLint s_bezier_cnt, GLint t_bezier_cnt, GLint s, GLint t)
{
	GLint		top,bottom,right,left;


	if(s==0)
	{
		top=*(tfactors+t*3);
		bottom=*(tfactors+t*3+1);
	}
	else
	if(s==s_bezier_cnt-1)
	{
		top=*(tfactors+t*3+2);
		bottom=*(tfactors+t*3);
	}
	else
	{
		top=bottom=*(tfactors+t*3);
	}
	if(t==0)
	{
		left=*(sfactors+s*3+1);
		right=*(sfactors+s*3);
	}
	else
	if(t==t_bezier_cnt-1)
	{
		left=*(sfactors+s*3);
		right=*(sfactors+s*3+2);
	}
	else
	{
		left=right=*(sfactors+s*3);
	}

	if(top>bottom)
	{
		if(left<right)
		{
			glMapGrid2f(right, 0.0, 1.0, top, 0.0, 1.0);
			glEvalMesh2(display_mode,1,right, 1, top);
			tesselate_strip_s(display_mode,1,right,1,1,left,0,(GLfloat)left);
			tesselate_bottom_left_corner(display_mode,(GLfloat)(1.0/left),
				(GLfloat)(1.0/bottom));
/*			tesselate_strip_t(display_mode,1,top,1,1,bottom,0,(GLfloat)bottom);*/
			tesselate_strip_t(display_mode,top,1,1,bottom,1,0,(GLfloat)bottom);
		}
		else
		if(left==right)
		{
			glMapGrid2f(right, 0.0, 1.0, top, 0.0, 1.0);
			glEvalMesh2(display_mode,1,right, 0, top);
/*			tesselate_strip_t(display_mode,0,top,1,0,bottom,0,(GLfloat)bottom);*/
			tesselate_strip_t(display_mode,top,0,1,bottom,0,0,(GLfloat)bottom);
		}
		else
		{
			glMapGrid2f(left, 0.0, 1.0, top, 0.0, 1.0);
			glEvalMesh2(display_mode,1,left, 0, top-1);
/*			tesselate_strip_t(display_mode,0,top-1,1,0,bottom-1,0,
				(GLfloat)bottom);*/
			tesselate_strip_t(display_mode,top-1,0,1,bottom-1,0,0,
				(GLfloat)bottom);
			tesselate_bottom_right_corner(display_mode,top-1,bottom-1,
				(GLfloat)(1.0/right),(GLfloat)(1.0/bottom));
/*			tesselate_strip_s(display_mode,1,left,top-1,1,right,right,
				(GLfloat)right);*/
			tesselate_strip_s(display_mode,left,1,top-1,right,1,right,
				(GLfloat)right);
		}
	}
	else
	if(top==bottom)
	{
		if(left<right)
		{
			glMapGrid2f(right, 0.0, 1.0, top, 0.0, 1.0);
			glEvalMesh2(display_mode,0,right, 1, top);
			tesselate_strip_s(display_mode,0,right,1,0,left,0,(GLfloat)left);
		}
		else
		if(left==right)
		{
			glMapGrid2f(right, 0.0, 1.0, top, 0.0, 1.0);
			glEvalMesh2(display_mode,0,right, 0, top);
		}
		else
		{
			glMapGrid2f(left, 0.0, 1.0, top, 0.0, 1.0);
			glEvalMesh2(display_mode,0,left, 0, top-1);
/*			tesselate_strip_s(display_mode,0,left,top-1,0,right,right,
				(GLfloat)right);*/
			tesselate_strip_s(display_mode,left,0,top-1,right,0,right,
				(GLfloat)right);
		}
	}
	else
	{
		if(left<right)
		{
			glMapGrid2f(right, 0.0, 1.0, bottom, 0.0, 1.0);
			glEvalMesh2(display_mode,0,right-1, 1, bottom);
			tesselate_strip_s(display_mode,0,right-1,1,0,left-1,0,
				(GLfloat)left);
			tesselate_top_left_corner(display_mode,right-1,left-1,
				(GLfloat)(1.0/left),(GLfloat)(1.0/top));
			tesselate_strip_t(display_mode,1,bottom,right-1,1,top,top,
				(GLfloat)top);
		}
		else
		if(left==right)
		{
			glMapGrid2f(right, 0.0, 1.0, bottom, 0.0, 1.0);
			glEvalMesh2(display_mode,0,right-1, 0, bottom);
			tesselate_strip_t(display_mode,0,bottom,right-1,0,top,top,
				(GLfloat)top);
		}
		else
		{
			glMapGrid2f(left, 0.0, 1.0, bottom, 0.0, 1.0);
			glEvalMesh2(display_mode,0,left-1, 0, bottom-1);
			tesselate_strip_t(display_mode,0,bottom-1,left-1,0,top-1,top,
				(GLfloat)top);
			tesselate_top_right_corner(display_mode,left-1,bottom-1,right,top,
				(GLfloat)(1.0/right),(GLfloat)(1.0/top));
/*			tesselate_strip_s(display_mode,0,left-1,bottom-1,0,right-1,right,
				(GLfloat)right);*/
			tesselate_strip_s(display_mode,left-1,0,bottom-1,right-1,0,right,
				(GLfloat)right);
		}
	}
}

/* draw NURBS surface in OUTLINE POLYGON mode */
static void
draw_polygon_mode( GLenum display_mode, GLUnurbsObj *nobj,
	new_ctrl_type *new_ctrl, GLint *sfactors, GLint *tfactors )
{
	GLsizei				offset;
	GLint				t_bezier_cnt,s_bezier_cnt;
	GLboolean			do_color,do_normal,do_texture;
	GLint				i,j;

	t_bezier_cnt=new_ctrl->t_bezier_cnt;
	s_bezier_cnt=new_ctrl->s_bezier_cnt;
	glEnable(nobj->surface.geom.type);
	if(new_ctrl->color_ctrl)
	{
		glEnable(nobj->surface.color.type);
		do_color=GL_TRUE;
	}
	else
		do_color=GL_FALSE;
	if(new_ctrl->normal_ctrl)
	{
		glEnable(nobj->surface.normal.type);
		do_normal=GL_TRUE;
	}
	else
		do_normal=GL_FALSE;
	if(new_ctrl->texture_ctrl)
	{
		glEnable(nobj->surface.texture.type);
		do_texture=GL_TRUE;
	}
	else
		do_texture=GL_FALSE;
	for(j=0; j<s_bezier_cnt; j++)
	{
		for(i=0; i<t_bezier_cnt; i++)
		{
			offset=j*t_bezier_cnt + i;
			if(fine_culling_test_3D(nobj,*(new_ctrl->geom_offsets + offset),
					nobj->surface.geom.sorder,nobj->surface.geom.torder,
					new_ctrl->geom_s_stride,new_ctrl->geom_t_stride,
					nobj->surface.geom.dim))
				continue;
			glMap2f(nobj->surface.geom.type,0.0,1.0,new_ctrl->geom_s_stride,
				nobj->surface.geom.sorder,0.0,1.0,new_ctrl->geom_t_stride,
				nobj->surface.geom.torder,*(new_ctrl->geom_offsets + offset));
			if(do_color)
			{
				glMap2f(nobj->surface.color.type,0.0,1.0,
					new_ctrl->color_s_stride,nobj->surface.color.sorder,
					0.0,1.0,new_ctrl->color_t_stride,nobj->surface.color.torder,
					*(new_ctrl->color_offsets + offset));
			}
			if(do_normal)
			{
				glMap2f(nobj->surface.normal.type,0.0,1.0,
					new_ctrl->normal_s_stride,nobj->surface.normal.sorder,
					0.0,1.0,new_ctrl->normal_t_stride,
					nobj->surface.normal.torder,
					*(new_ctrl->normal_offsets+offset));
			}
			if(do_texture)
			{
				glMap2f(nobj->surface.texture.type,0.0,1.0,
					new_ctrl->texture_s_stride,nobj->surface.texture.sorder,
					0.0,1.0,new_ctrl->texture_t_stride,
					nobj->surface.texture.torder,
					*(new_ctrl->texture_offsets+offset));
			}
/*			glMapGrid2f(sfactors[j*3+0],0.0,1.0,tfactors[i*3+0],0.0,1.0);
			glEvalMesh2(display_mode,0,sfactors[j*3+0],0,tfactors[i*3+0]);*/
			nurbs_map_bezier(display_mode,sfactors,tfactors,s_bezier_cnt,
				t_bezier_cnt,j,i);
		}
	}
}



/* draw NURBS surface in OUTLINE POLYGON mode */
#if 0
static void
draw_patch_mode( GLenum display_mode, GLUnurbsObj *nobj,
	new_ctrl_type *new_ctrl, GLint *sfactors, GLint *tfactors )
{
	GLsizei				offset;
	GLint				t_bezier_cnt,s_bezier_cnt;
	GLboolean			do_color,do_normal,do_texture;
	GLint				i,j;

	t_bezier_cnt=new_ctrl->t_bezier_cnt;
	s_bezier_cnt=new_ctrl->s_bezier_cnt;
	glEnable(nobj->surface.geom.type);
	if(new_ctrl->color_ctrl)
	{
		glEnable(nobj->surface.color.type);
		do_color=GL_TRUE;
	}
	else
		do_color=GL_FALSE;
	if(new_ctrl->normal_ctrl)
	{
		glEnable(nobj->surface.normal.type);
		do_normal=GL_TRUE;
	}
	else
		do_normal=GL_FALSE;
	if(new_ctrl->texture_ctrl)
	{
		glEnable(nobj->surface.texture.type);
		do_texture=GL_TRUE;
	}
	else
		do_texture=GL_FALSE;
	for(j=0; j<s_bezier_cnt; j++)
	{
		for(i=0; i<t_bezier_cnt; i++)
		{
			offset=j*t_bezier_cnt + i;
			if(fine_culling_test_3D(nobj,*(new_ctrl->geom_offsets + offset),
					nobj->surface.geom.sorder,nobj->surface.geom.torder,
					new_ctrl->geom_s_stride,new_ctrl->geom_t_stride,
					nobj->surface.geom.dim))
				continue;
			glMap2f(nobj->surface.geom.type,0.0,1.0,new_ctrl->geom_s_stride,
				nobj->surface.geom.sorder,0.0,1.0,new_ctrl->geom_t_stride,
				nobj->surface.geom.torder,*(new_ctrl->geom_offsets + offset));
			if(do_color)
			{
				glMap2f(nobj->surface.color.type,0.0,1.0,
					new_ctrl->color_s_stride,nobj->surface.color.sorder,
					0.0,1.0,new_ctrl->color_t_stride,nobj->surface.color.torder,
					*(new_ctrl->color_offsets + offset));
			}
			if(do_normal)
			{
				glMap2f(nobj->surface.normal.type,0.0,1.0,
					new_ctrl->normal_s_stride,nobj->surface.normal.sorder,
					0.0,1.0,new_ctrl->normal_t_stride,
					nobj->surface.normal.torder,
					*(new_ctrl->normal_offsets+offset));
			}
			if(do_texture)
			{
				glMap2f(nobj->surface.texture.type,0.0,1.0,
					new_ctrl->texture_s_stride,nobj->surface.texture.sorder,
					0.0,1.0,new_ctrl->texture_t_stride,
					nobj->surface.texture.torder,
					*(new_ctrl->texture_offsets+offset));
			}
			nurbs_map_bezier(display_mode,sfactors,tfactors,s_bezier_cnt,
				t_bezier_cnt,i,j);
/*			glMapGrid2f(sfactors[j],0.0,1.0,tfactors[i],0.0,1.0);
			glEvalMesh2(display_mode,0,sfactors[j],0,tfactors[i]);*/
		}
	}
}
#endif



void
init_new_ctrl(new_ctrl_type *p)
{
	p->geom_ctrl=p->color_ctrl=p->normal_ctrl=p->texture_ctrl=NULL;
	p->geom_offsets=p->color_offsets=p->normal_offsets=p->texture_offsets=NULL;
	p->s_bezier_cnt=p->t_bezier_cnt=0;
}

GLenum
augment_new_ctrl(GLUnurbsObj *nobj, new_ctrl_type *p)
{
	GLsizei offset_size;
	GLint	i,j;

	p->s_bezier_cnt=(p->geom_s_pt_cnt)/(nobj->surface.geom.sorder);
	p->t_bezier_cnt=(p->geom_t_pt_cnt)/(nobj->surface.geom.torder);
	offset_size=(p->s_bezier_cnt)*(p->t_bezier_cnt);
	p->geom_t_stride=nobj->surface.geom.dim;
	p->geom_s_stride=(p->geom_t_pt_cnt)*(nobj->surface.geom.dim);
	p->color_t_stride=nobj->surface.color.dim;
	p->color_s_stride=(p->color_t_pt_cnt)*(nobj->surface.color.dim);
	p->normal_t_stride=nobj->surface.normal.dim;
	p->normal_s_stride=(p->normal_t_pt_cnt)*(nobj->surface.normal.dim);
	p->texture_t_stride=nobj->surface.texture.dim;
	p->texture_s_stride=(p->texture_t_pt_cnt)*(nobj->surface.texture.dim);
	if((p->geom_offsets=(GLfloat **)malloc(sizeof(GLfloat *)*offset_size))==NULL)
	{
		call_user_error(nobj,GLU_OUT_OF_MEMORY);
		return GLU_ERROR;
	}
	if(p->color_ctrl)
		if((p->color_offsets=(GLfloat **)malloc(sizeof(GLfloat *)*offset_size))==NULL)
		{
			free_new_ctrl(p);
			call_user_error(nobj,GLU_OUT_OF_MEMORY);
			return GLU_ERROR;
		}
	if(p->normal_ctrl)
		if((p->normal_offsets=(GLfloat **)malloc(sizeof(GLfloat *)*offset_size))==NULL)
		{
			free_new_ctrl(p);
			call_user_error(nobj,GLU_OUT_OF_MEMORY);
			return GLU_ERROR;
		}
	if(p->texture_ctrl)
		if((p->texture_offsets=(GLfloat **)malloc(sizeof(GLfloat *)*offset_size))==NULL)
		{
			free_new_ctrl(p);
			call_user_error(nobj,GLU_OUT_OF_MEMORY);
			return GLU_ERROR;
		}
	for(i=0;i<p->s_bezier_cnt;i++)
		for(j=0;j<p->t_bezier_cnt;j++)
			*(p->geom_offsets + i*(p->t_bezier_cnt) + j) =
				p->geom_ctrl + i*(nobj->surface.geom.sorder)*
				(nobj->surface.geom.dim)*(p->geom_t_pt_cnt) +
				j*(nobj->surface.geom.dim)*(nobj->surface.geom.torder);
	if(p->color_ctrl)
		for(i=0;i<p->s_bezier_cnt;i++)
			for(j=0;j<p->t_bezier_cnt;j++)
				*(p->color_offsets + i*(p->t_bezier_cnt) + j) =
					p->color_ctrl + i*(nobj->surface.color.sorder)*
					(nobj->surface.color.dim)*(p->color_t_pt_cnt) +
					j*(nobj->surface.color.dim)*(nobj->surface.color.torder);
	if(p->normal_ctrl)
		for(i=0;i<p->s_bezier_cnt;i++)
			for(j=0;j<p->t_bezier_cnt;j++)
				*(p->normal_offsets + i*(p->t_bezier_cnt) + j) =
					p->normal_ctrl + i*(nobj->surface.normal.sorder)*
					(nobj->surface.normal.dim)*(p->normal_t_pt_cnt) +
					j*(nobj->surface.normal.dim)*(nobj->surface.normal.torder);
	if(p->texture_ctrl)
		for(i=0;i<p->s_bezier_cnt;i++)
			for(j=0;j<p->t_bezier_cnt;j++)
				*(p->texture_offsets + i*(p->t_bezier_cnt) + j) =
					p->texture_ctrl + i*(nobj->surface.texture.sorder)*
					(nobj->surface.texture.dim)*(p->texture_t_pt_cnt) +
					j*(nobj->surface.texture.dim)*(nobj->surface.texture.torder);
	return GLU_NO_ERROR;
}

/* main NURBS surface procedure */
void
do_nurbs_surface( GLUnurbsObj *nobj )
{
	GLint			*sfactors,*tfactors;
	new_ctrl_type	new_ctrl;

	/* test user supplied data */
	if(test_nurbs_surfaces(nobj)!=GLU_NO_ERROR)
		return;

	init_new_ctrl(&new_ctrl);

	if(convert_surfs(nobj,&new_ctrl)!=GLU_NO_ERROR)
		return;
	if(augment_new_ctrl(nobj,&new_ctrl)!=GLU_NO_ERROR)
		return;
	switch(nobj->sampling_method)
	{
		case GLU_PATH_LENGTH:
			if(glu_do_sampling_3D(nobj,&new_ctrl,&sfactors,&tfactors)!=
				GLU_NO_ERROR)
			{
				free_new_ctrl(&new_ctrl);
				return;
			}
			break;
		case GLU_DOMAIN_DISTANCE:
			if(glu_do_sampling_uv(nobj,&new_ctrl,&sfactors,&tfactors)!=
				GLU_NO_ERROR)
			{
				free_new_ctrl(&new_ctrl);
				return;
			}
			break;
		case GLU_PARAMETRIC_ERROR:
			if(glu_do_sampling_param_3D(nobj,&new_ctrl,&sfactors,&tfactors)!=
				GLU_NO_ERROR)
			{
				free_new_ctrl(&new_ctrl);
				return;
			}
			break;
		default:
			abort();
	}
	glFrontFace(GL_CW);
	switch(nobj->display_mode)
	{
		case GLU_FILL:
/*			if(polygon_trimming(nobj,&new_ctrl,sfactors,tfactors)==GLU_NO_ERROR)*/
				draw_polygon_mode(GL_FILL,nobj,&new_ctrl,sfactors,tfactors);
			break;
		case GLU_OUTLINE_POLYGON:
			/* TODO - missing trimming handeling */
/* just for now - no OUTLINE_PATCH mode 
			draw_patch_mode(GL_LINE,nobj,&new_ctrl,sfactors,tfactors);
			break; */
		case GLU_OUTLINE_PATCH:
/*			if(polygon_trimming(nobj,&new_ctrl,sfactors,tfactors)==GLU_NO_ERROR)*/
				draw_polygon_mode(GL_LINE,nobj,&new_ctrl,sfactors,tfactors);
			break;
		default:
			abort();  /* TODO: is this OK? */
	}
	free(sfactors);
	free(tfactors);
	free_new_ctrl(&new_ctrl);
}