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/*
* The 3D Studio File Format Library
* Copyright (C) 1996-2001 by J.E. Hoffmann <je-h@gmx.net>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This program 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: tcb.c,v 1.9 2001/07/07 19:05:30 jeh Exp $
*/
#define LIB3DS_EXPORT
#include <lib3ds/tcb.h>
#include <lib3ds/io.h>
#include <math.h>
/*!
* \defgroup tcb Tension/Continuity/Bias Splines
*
* \author J.E. Hoffmann <je-h@gmx.net>
*/
/*!
* \ingroup tcb
*/
void
lib3ds_tcb(Lib3dsTcb *p, Lib3dsTcb *pc, Lib3dsTcb *c, Lib3dsTcb *nc, Lib3dsTcb *n,
Lib3dsFloat *ksm, Lib3dsFloat *ksp, Lib3dsFloat *kdm, Lib3dsFloat *kdp)
{
Lib3dsFloat tm,cm,cp,bm,bp,tmcm,tmcp,cc;
Lib3dsFloat dt,fp,fn;
if (!pc) {
pc=c;
}
if (!nc) {
nc=c;
}
fp=fn=1.0f;
if (p&&n) {
dt=0.5f*(Lib3dsFloat)(pc->frame-p->frame+n->frame-nc->frame);
fp=((Lib3dsFloat)(pc->frame-p->frame))/dt;
fn=((Lib3dsFloat)(n->frame-nc->frame))/dt;
cc=(Lib3dsFloat)fabs(c->cont);
fp=fp+cc-cc*fp;
fn=fn+cc-cc*fn;
}
cm=1.0f-c->cont;
tm=0.5f*(1.0f-c->tens);
cp=2.0f-cm;
bm=1.0f-c->bias;
bp=2.0f-bm;
tmcm=tm*cm;
tmcp=tm*cp;
*ksm=tmcm*bp*fp;
*ksp=tmcp*bm*fp;
*kdm=tmcp*bp*fn;
*kdp=tmcm*bm*fn;
}
/*!
* \ingroup tcb
*/
Lib3dsBool
lib3ds_tcb_read(Lib3dsTcb *tcb, Lib3dsIo *io)
{
Lib3dsWord flags;
tcb->frame=lib3ds_io_read_intd(io);
tcb->flags=flags=lib3ds_io_read_word(io);
if (flags&LIB3DS_USE_TENSION) {
tcb->tens=lib3ds_io_read_float(io);
}
if (flags&LIB3DS_USE_CONTINUITY) {
tcb->cont=lib3ds_io_read_float(io);
}
if (flags&LIB3DS_USE_BIAS) {
tcb->bias=lib3ds_io_read_float(io);
}
if (flags&LIB3DS_USE_EASE_TO) {
tcb->ease_to=lib3ds_io_read_float(io);
}
if (flags&LIB3DS_USE_EASE_FROM) {
tcb->ease_from=lib3ds_io_read_float(io);
}
if (lib3ds_io_error(io)) {
return(LIB3DS_FALSE);
}
return(LIB3DS_TRUE);
}
/*!
* \ingroup tcb
*/
Lib3dsBool
lib3ds_tcb_write(Lib3dsTcb *tcb, Lib3dsIo *io)
{
lib3ds_io_write_intd(io, tcb->frame);
lib3ds_io_write_word(io, tcb->flags);
if (tcb->flags&LIB3DS_USE_TENSION) {
lib3ds_io_write_float(io, tcb->tens);
}
if (tcb->flags&LIB3DS_USE_CONTINUITY) {
lib3ds_io_write_float(io, tcb->cont);
}
if (tcb->flags&LIB3DS_USE_BIAS) {
lib3ds_io_write_float(io, tcb->bias);
}
if (tcb->flags&LIB3DS_USE_EASE_TO) {
lib3ds_io_write_float(io, tcb->ease_to);
}
if (tcb->flags&LIB3DS_USE_EASE_FROM) {
lib3ds_io_write_float(io, tcb->ease_from);
}
if (lib3ds_io_error(io)) {
return(LIB3DS_FALSE);
}
return(LIB3DS_TRUE);
}
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