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/*
* PARSEC - Culling Code
*
* $Author: uberlinuxguy $ - $Date: 2004/09/15 12:25:43 $
*
* Orginally written by:
* Copyright (c) Markus Hadwiger <msh@parsec.org> 1998
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
// C library
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
// compilation flags/debug support
#include "config.h"
#include "debug.h"
// general definitions
#include "general.h"
#include "objstruc.h"
// global externals
#include "globals.h"
// mathematics header
#include "utl_math.h"
// model header
#include "utl_model.h"
// local module header
#include "utl_cull.h"
// determine indexes of reject and accept points with respect to a plane ------
//
void CULL_ReAcIndexBox3( ReAcIndexBox3 *reac, Plane3 *plane )
{
ASSERT( reac != NULL );
ASSERT( plane != NULL );
//NOTE:
// reac->reject will be the point with the
// greatest signed distance to the plane.
// reac->accept will be the point with the
// least signed distance to the plane.
if ( GEOMV_NEGATIVE( plane->X ) ) {
reac->reject[ 0 ] = 0;
reac->accept[ 0 ] = 3;
} else {
reac->reject[ 0 ] = 3;
reac->accept[ 0 ] = 0;
}
if ( GEOMV_NEGATIVE( plane->Y ) ) {
reac->reject[ 1 ] = 1;
reac->accept[ 1 ] = 4;
} else {
reac->reject[ 1 ] = 4;
reac->accept[ 1 ] = 1;
}
if ( GEOMV_NEGATIVE( plane->Z ) ) {
reac->reject[ 2 ] = 2;
reac->accept[ 2 ] = 5;
} else {
reac->reject[ 2 ] = 5;
reac->accept[ 2 ] = 2;
}
}
// determine coordinates of reject and accept points with respect to a plane --
//
void CULL_ReAcPointBox3( ReAcPointBox3 *reac, CullBox3 *cullbox, Plane3 *plane )
{
ASSERT( reac != NULL );
ASSERT( cullbox != NULL );
ASSERT( plane != NULL );
//NOTE:
// reac->reject will be the point with the
// greatest signed distance to the plane.
// reac->accept will be the point with the
// least signed distance to the plane.
if ( GEOMV_NEGATIVE( plane->X ) ) {
reac->reject.X = cullbox->minmax[ 0 ];
reac->accept.X = cullbox->minmax[ 3 ];
} else {
reac->reject.X = cullbox->minmax[ 3 ];
reac->accept.X = cullbox->minmax[ 0 ];
}
if ( GEOMV_NEGATIVE( plane->Y ) ) {
reac->reject.Y = cullbox->minmax[ 1 ];
reac->accept.Y = cullbox->minmax[ 4 ];
} else {
reac->reject.Y = cullbox->minmax[ 4 ];
reac->accept.Y = cullbox->minmax[ 1 ];
}
if ( GEOMV_NEGATIVE( plane->Z ) ) {
reac->reject.Z = cullbox->minmax[ 2 ];
reac->accept.Z = cullbox->minmax[ 5 ];
} else {
reac->reject.Z = cullbox->minmax[ 5 ];
reac->accept.Z = cullbox->minmax[ 2 ];
}
}
// augment set of planes by reject/accept points for culling ------------------
//
void CULL_MakeVolumeCullVolume( Plane3 *volume, CullPlane3 *cullvolume, dword cullmask )
{
ASSERT( volume != NULL );
ASSERT( cullvolume != NULL );
for ( ; cullmask != 0x00; cullmask >>= 1, volume++, cullvolume++ ) {
if ( cullmask & 0x01 ) {
// copy plane
cullvolume->plane = *volume;
// calc reac indexes
CULL_ReAcIndexBox3( &cullvolume->reacx, &cullvolume->plane );
}
}
}
// cull an axial bounding box against a cull volume (set of cull planes) ------
//
int CULL_BoxAgainstCullVolume( CullBox3 *cullbox, CullPlane3 *volume, dword *cullmask )
{
//NOTE:
// this function returns:
// - TRUE if the box is trivial reject
// - FALSE if the box is not trivial reject
// - if ( *cullmask == 0x00 ) afterwards the box is trivial accept
// - if ( *cullmask != 0x00 ) afterwards the box needs to be clipped
ASSERT( cullbox != NULL );
ASSERT( volume != NULL );
ASSERT( cullmask != NULL );
dword curmask = *cullmask;
CullPlane3* cullplane = volume;
for ( int curplane = 0; curmask != 0x00; curmask >>= 1, curplane++ ) {
if ( curmask & 0x01 ) {
// one plane rejects: whole status is trivial reject
geomv_t dist = PLANEDIST_REJECTPOINT( cullplane, cullbox );
if ( GEOMV_NEGATIVE( dist ) ) {
return TRUE;
}
// mask plane if trivial accept
dist = PLANEDIST_ACCEPTPOINT( cullplane, cullbox );
if ( GEOMV_POSITIVE( dist ) ) {
*cullmask &= ~( 1 << curplane );
}
}
// sizeof( CullPlane3 ) is no power of two
cullplane = (CullPlane3 *)( (char *)cullplane + sizeof( cullplane[ 0 ] ) );
}
return FALSE;
}
// cull an axial bounding box against a volume (set of planes) ----------------
//
int CULL_BoxAgainstVolume( CullBox3 *cullbox, Plane3 *volume, dword *cullmask )
{
//NOTE:
// this function returns:
// - TRUE if the box is trivial reject
// - FALSE if the box is not trivial reject
// - if ( *cullmask == 0x00 ) afterwards the box is trivial accept
// - if ( *cullmask != 0x00 ) afterwards the box needs to be clipped
ASSERT( cullbox != NULL );
ASSERT( volume != NULL );
ASSERT( cullmask != NULL );
dword curmask = *cullmask;
for ( int curplane = 0; curmask != 0x00; curmask >>= 1, curplane++ ) {
if ( curmask & 0x01 ) {
Plane3 *plane = &volume[ curplane ];
// determine reject/accept points
ReAcPointBox3 reac;
CULL_ReAcPointBox3( &reac, cullbox, plane );
// one plane rejects: whole status is trivial reject
if ( PLANE_DOT( plane, &reac.reject ) <= PLANE_OFFSET( plane ) ) {
return TRUE;
}
// mask plane if trivial accept
if ( PLANE_DOT( plane, &reac.accept ) >= PLANE_OFFSET( plane ) ) {
*cullmask &= ~( 1 << curplane );
}
}
}
return FALSE;
}
// cull a bounding sphere against a volume (set of planes) --------------------
//
int CULL_SphereAgainstVolume( Sphere3 *sphere, Plane3 *volume, dword *cullmask )
{
//NOTE:
// this function returns:
// - TRUE if the sphere is trivial reject
// - FALSE if the sphere is not trivial reject
// - if ( *cullmask == 0x00 ) afterwards the sphere is trivial accept
// - if ( *cullmask != 0x00 ) afterwards the sphere needs to be clipped
ASSERT( sphere != NULL );
ASSERT( volume != NULL );
ASSERT( cullmask != NULL );
dword curmask = *cullmask;
for ( int curplane = 0; curmask != 0x00; curmask >>= 1, curplane++ ) {
if ( curmask & 0x01 ) {
Plane3 *plane = &volume[ curplane ];
geomv_t dist = PLANE_DOT( plane, sphere ) - PLANE_OFFSET( plane );
// one plane rejects: whole status is trivial reject
if ( dist < -sphere->R ) {
return TRUE;
}
// mask plane if trivial accept
if ( dist > sphere->R ) {
*cullmask &= ~( 1 << curplane );
}
}
}
return FALSE;
}
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