gtkradiant/tools/quake2/q2map/trace.c
2012-03-17 15:01:54 -05:00

294 lines
6.3 KiB
C

/*
Copyright (C) 1999-2007 id Software, Inc. and contributors.
For a list of contributors, see the accompanying CONTRIBUTORS file.
This file is part of GtkRadiant.
GtkRadiant 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.
GtkRadiant 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 GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
// trace.c
/*
#include "cmdlib.h"
#include "mathlib.h"
#include "bspfile.h"
*/
#include "qrad.h"
#define ON_EPSILON 0.1
typedef struct tnode_s
{
int type;
vec3_t normal;
float dist;
int children[2];
int pad;
} tnode_t;
tnode_t *tnodes, *tnode_p;
/*
==============
MakeTnode
Converts the disk node structure into the efficient tracing structure
==============
*/
void MakeTnode( int nodenum ){
tnode_t *t;
dplane_t *plane;
int i;
dnode_t *node;
t = tnode_p++;
node = dnodes + nodenum;
plane = dplanes + node->planenum;
t->type = plane->type;
VectorCopy( plane->normal, t->normal );
t->dist = plane->dist;
for ( i = 0 ; i < 2 ; i++ )
{
if ( node->children[i] < 0 ) {
t->children[i] = ( dleafs[-node->children[i] - 1].contents & CONTENTS_SOLID ) | ( 1 << 31 );
}
else
{
t->children[i] = tnode_p - tnodes;
MakeTnode( node->children[i] );
}
}
}
/*
=============
MakeTnodes
Loads the node structure out of a .bsp file to be used for light occlusion
=============
*/
void MakeTnodes( dmodel_t *bm ){
// 32 byte align the structs
tnodes = malloc( ( numnodes + 1 ) * sizeof( tnode_t ) );
tnodes = (tnode_t *)( ( (int)tnodes + 31 ) & ~31 );
tnode_p = tnodes;
MakeTnode( 0 );
}
//==========================================================
int TestLine_r( int node, vec3_t start, vec3_t stop ){
tnode_t *tnode;
float front, back;
vec3_t mid;
float frac;
int side;
int r;
if ( node & ( 1 << 31 ) ) {
return node & ~( 1 << 31 ); // leaf node
}
tnode = &tnodes[node];
switch ( tnode->type )
{
case PLANE_X:
front = start[0] - tnode->dist;
back = stop[0] - tnode->dist;
break;
case PLANE_Y:
front = start[1] - tnode->dist;
back = stop[1] - tnode->dist;
break;
case PLANE_Z:
front = start[2] - tnode->dist;
back = stop[2] - tnode->dist;
break;
default:
front = ( start[0] * tnode->normal[0] + start[1] * tnode->normal[1] + start[2] * tnode->normal[2] ) - tnode->dist;
back = ( stop[0] * tnode->normal[0] + stop[1] * tnode->normal[1] + stop[2] * tnode->normal[2] ) - tnode->dist;
break;
}
if ( front >= -ON_EPSILON && back >= -ON_EPSILON ) {
return TestLine_r( tnode->children[0], start, stop );
}
if ( front < ON_EPSILON && back < ON_EPSILON ) {
return TestLine_r( tnode->children[1], start, stop );
}
side = front < 0;
frac = front / ( front - back );
mid[0] = start[0] + ( stop[0] - start[0] ) * frac;
mid[1] = start[1] + ( stop[1] - start[1] ) * frac;
mid[2] = start[2] + ( stop[2] - start[2] ) * frac;
r = TestLine_r( tnode->children[side], start, mid );
if ( r ) {
return r;
}
return TestLine_r( tnode->children[!side], mid, stop );
}
int TestLine( vec3_t start, vec3_t stop ){
return TestLine_r( 0, start, stop );
}
/*
==============================================================================
LINE TRACING
The major lighting operation is a point to point visibility test, performed
by recursive subdivision of the line by the BSP tree.
==============================================================================
*/
typedef struct
{
vec3_t backpt;
int side;
int node;
} tracestack_t;
/*
==============
TestLine
==============
*/
qboolean _TestLine( vec3_t start, vec3_t stop ){
int node;
float front, back;
tracestack_t *tstack_p;
int side;
float frontx,fronty, frontz, backx, backy, backz;
tracestack_t tracestack[64];
tnode_t *tnode;
frontx = start[0];
fronty = start[1];
frontz = start[2];
backx = stop[0];
backy = stop[1];
backz = stop[2];
tstack_p = tracestack;
node = 0;
while ( 1 )
{
if ( node == CONTENTS_SOLID ) {
#if 0
float d1, d2, d3;
d1 = backx - frontx;
d2 = backy - fronty;
d3 = backz - frontz;
if ( d1 * d1 + d2 * d2 + d3 * d3 > 1 )
#endif
return false; // DONE!
}
while ( node < 0 )
{
// pop up the stack for a back side
tstack_p--;
if ( tstack_p < tracestack ) {
return true;
}
node = tstack_p->node;
// set the hit point for this plane
frontx = backx;
fronty = backy;
frontz = backz;
// go down the back side
backx = tstack_p->backpt[0];
backy = tstack_p->backpt[1];
backz = tstack_p->backpt[2];
node = tnodes[tstack_p->node].children[!tstack_p->side];
}
tnode = &tnodes[node];
switch ( tnode->type )
{
case PLANE_X:
front = frontx - tnode->dist;
back = backx - tnode->dist;
break;
case PLANE_Y:
front = fronty - tnode->dist;
back = backy - tnode->dist;
break;
case PLANE_Z:
front = frontz - tnode->dist;
back = backz - tnode->dist;
break;
default:
front = ( frontx * tnode->normal[0] + fronty * tnode->normal[1] + frontz * tnode->normal[2] ) - tnode->dist;
back = ( backx * tnode->normal[0] + backy * tnode->normal[1] + backz * tnode->normal[2] ) - tnode->dist;
break;
}
if ( front > -ON_EPSILON && back > -ON_EPSILON ) {
// if (front > 0 && back > 0)
node = tnode->children[0];
continue;
}
if ( front < ON_EPSILON && back < ON_EPSILON ) {
// if (front <= 0 && back <= 0)
node = tnode->children[1];
continue;
}
side = front < 0;
front = front / ( front - back );
tstack_p->node = node;
tstack_p->side = side;
tstack_p->backpt[0] = backx;
tstack_p->backpt[1] = backy;
tstack_p->backpt[2] = backz;
tstack_p++;
backx = frontx + front * ( backx - frontx );
backy = fronty + front * ( backy - fronty );
backz = frontz + front * ( backz - frontz );
node = tnode->children[side];
}
}