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      1 /*
      2 Copyright (C) 1996-1997 Id Software, Inc.
      3 
      4 This program is free software; you can redistribute it and/or
      5 modify it under the terms of the GNU General Public License
      6 as published by the Free Software Foundation; either version 2
      7 of the License, or (at your option) any later version.
      8 
      9 This program is distributed in the hope that it will be useful,
     10 but WITHOUT ANY WARRANTY; without even the implied warranty of
     11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     12 
     13 See the GNU General Public License for more details.
     14 
     15 You should have received a copy of the GNU General Public License
     16 along with this program; if not, write to the Free Software
     17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
     18 
     19 */
     20 #include "quakedef.h"
     21 
     22 static	hull_t		box_hull;
     23 static	dclipnode_t	box_clipnodes[6];
     24 static	mplane_t	box_planes[6];
     25 
     26 extern	vec3_t player_mins;
     27 extern	vec3_t player_maxs;
     28 
     29 /*
     30 ===================
     31 PM_InitBoxHull
     32 
     33 Set up the planes and clipnodes so that the six floats of a bounding box
     34 can just be stored out and get a proper hull_t structure.
     35 ===================
     36 */
     37 void PM_InitBoxHull (void)
     38 {
     39 	int		i;
     40 	int		side;
     41 
     42 	box_hull.clipnodes = box_clipnodes;
     43 	box_hull.planes = box_planes;
     44 	box_hull.firstclipnode = 0;
     45 	box_hull.lastclipnode = 5;
     46 
     47 	for (i=0 ; i<6 ; i++)
     48 	{
     49 		box_clipnodes[i].planenum = i;
     50 
     51 		side = i&1;
     52 
     53 		box_clipnodes[i].children[side] = CONTENTS_EMPTY;
     54 		if (i != 5)
     55 			box_clipnodes[i].children[side^1] = i + 1;
     56 		else
     57 			box_clipnodes[i].children[side^1] = CONTENTS_SOLID;
     58 
     59 		box_planes[i].type = i>>1;
     60 		box_planes[i].normal[i>>1] = 1;
     61 	}
     62 
     63 }
     64 
     65 
     66 /*
     67 ===================
     68 PM_HullForBox
     69 
     70 To keep everything totally uniform, bounding boxes are turned into small
     71 BSP trees instead of being compared directly.
     72 ===================
     73 */
     74 hull_t	*PM_HullForBox (vec3_t mins, vec3_t maxs)
     75 {
     76 	box_planes[0].dist = maxs[0];
     77 	box_planes[1].dist = mins[0];
     78 	box_planes[2].dist = maxs[1];
     79 	box_planes[3].dist = mins[1];
     80 	box_planes[4].dist = maxs[2];
     81 	box_planes[5].dist = mins[2];
     82 
     83 	return &box_hull;
     84 }
     85 
     86 
     87 /*
     88 ==================
     89 PM_HullPointContents
     90 
     91 ==================
     92 */
     93 int PM_HullPointContents (hull_t *hull, int num, vec3_t p)
     94 {
     95 	float		d;
     96 	dclipnode_t	*node;
     97 	mplane_t	*plane;
     98 
     99 	while (num >= 0)
    100 	{
    101 		if (num < hull->firstclipnode || num > hull->lastclipnode)
    102 			Sys_Error ("PM_HullPointContents: bad node number");
    103 
    104 		node = hull->clipnodes + num;
    105 		plane = hull->planes + node->planenum;
    106 
    107 		if (plane->type < 3)
    108 			d = p[plane->type] - plane->dist;
    109 		else
    110 			d = DotProduct (plane->normal, p) - plane->dist;
    111 		if (d < 0)
    112 			num = node->children[1];
    113 		else
    114 			num = node->children[0];
    115 	}
    116 
    117 	return num;
    118 }
    119 
    120 /*
    121 ==================
    122 PM_PointContents
    123 
    124 ==================
    125 */
    126 int PM_PointContents (vec3_t p)
    127 {
    128 	float		d;
    129 	dclipnode_t	*node;
    130 	mplane_t	*plane;
    131 	hull_t		*hull;
    132 	int			num;
    133 
    134 	hull = &pmove.physents[0].model->hulls[0];
    135 
    136 	num = hull->firstclipnode;
    137 
    138 	while (num >= 0)
    139 	{
    140 		if (num < hull->firstclipnode || num > hull->lastclipnode)
    141 			Sys_Error ("PM_HullPointContents: bad node number");
    142 
    143 		node = hull->clipnodes + num;
    144 		plane = hull->planes + node->planenum;
    145 
    146 		if (plane->type < 3)
    147 			d = p[plane->type] - plane->dist;
    148 		else
    149 			d = DotProduct (plane->normal, p) - plane->dist;
    150 		if (d < 0)
    151 			num = node->children[1];
    152 		else
    153 			num = node->children[0];
    154 	}
    155 
    156 	return num;
    157 }
    158 
    159 /*
    160 ===============================================================================
    161 
    162 LINE TESTING IN HULLS
    163 
    164 ===============================================================================
    165 */
    166 
    167 // 1/32 epsilon to keep floating point happy
    168 #define	DIST_EPSILON	(0.03125)
    169 
    170 /*
    171 ==================
    172 PM_RecursiveHullCheck
    173 
    174 ==================
    175 */
    176 qboolean PM_RecursiveHullCheck (hull_t *hull, int num, float p1f, float p2f, vec3_t p1, vec3_t p2, pmtrace_t *trace)
    177 {
    178 	dclipnode_t	*node;
    179 	mplane_t	*plane;
    180 	float		t1, t2;
    181 	float		frac;
    182 	int			i;
    183 	vec3_t		mid;
    184 	int			side;
    185 	float		midf;
    186 
    187 // check for empty
    188 	if (num < 0)
    189 	{
    190 		if (num != CONTENTS_SOLID)
    191 		{
    192 			trace->allsolid = false;
    193 			if (num == CONTENTS_EMPTY)
    194 				trace->inopen = true;
    195 			else
    196 				trace->inwater = true;
    197 		}
    198 		else
    199 			trace->startsolid = true;
    200 		return true;		// empty
    201 	}
    202 
    203 	if (num < hull->firstclipnode || num > hull->lastclipnode)
    204 		Sys_Error ("PM_RecursiveHullCheck: bad node number");
    205 
    206 //
    207 // find the point distances
    208 //
    209 	node = hull->clipnodes + num;
    210 	plane = hull->planes + node->planenum;
    211 
    212 	if (plane->type < 3)
    213 	{
    214 		t1 = p1[plane->type] - plane->dist;
    215 		t2 = p2[plane->type] - plane->dist;
    216 	}
    217 	else
    218 	{
    219 		t1 = DotProduct (plane->normal, p1) - plane->dist;
    220 		t2 = DotProduct (plane->normal, p2) - plane->dist;
    221 	}
    222 
    223 #if 1
    224 	if (t1 >= 0 && t2 >= 0)
    225 		return PM_RecursiveHullCheck (hull, node->children[0], p1f, p2f, p1, p2, trace);
    226 	if (t1 < 0 && t2 < 0)
    227 		return PM_RecursiveHullCheck (hull, node->children[1], p1f, p2f, p1, p2, trace);
    228 #else
    229 	if ( (t1 >= DIST_EPSILON && t2 >= DIST_EPSILON) || (t2 > t1 && t1 >= 0) )
    230 		return PM_RecursiveHullCheck (hull, node->children[0], p1f, p2f, p1, p2, trace);
    231 	if ( (t1 <= -DIST_EPSILON && t2 <= -DIST_EPSILON) || (t2 < t1 && t1 <= 0) )
    232 		return PM_RecursiveHullCheck (hull, node->children[1], p1f, p2f, p1, p2, trace);
    233 #endif
    234 
    235 // put the crosspoint DIST_EPSILON pixels on the near side
    236 	if (t1 < 0)
    237 		frac = (t1 + DIST_EPSILON)/(t1-t2);
    238 	else
    239 		frac = (t1 - DIST_EPSILON)/(t1-t2);
    240 	if (frac < 0)
    241 		frac = 0;
    242 	if (frac > 1)
    243 		frac = 1;
    244 
    245 	midf = p1f + (p2f - p1f)*frac;
    246 	for (i=0 ; i<3 ; i++)
    247 		mid[i] = p1[i] + frac*(p2[i] - p1[i]);
    248 
    249 	side = (t1 < 0);
    250 
    251 // move up to the node
    252 	if (!PM_RecursiveHullCheck (hull, node->children[side], p1f, midf, p1, mid, trace) )
    253 		return false;
    254 
    255 #ifdef PARANOID
    256 	if (PM_HullPointContents (pm_hullmodel, mid, node->children[side])
    257 	== CONTENTS_SOLID)
    258 	{
    259 		Con_Printf ("mid PointInHullSolid\n");
    260 		return false;
    261 	}
    262 #endif
    263 
    264 	if (PM_HullPointContents (hull, node->children[side^1], mid)
    265 	!= CONTENTS_SOLID)
    266 // go past the node
    267 		return PM_RecursiveHullCheck (hull, node->children[side^1], midf, p2f, mid, p2, trace);
    268 
    269 	if (trace->allsolid)
    270 		return false;		// never got out of the solid area
    271 
    272 //==================
    273 // the other side of the node is solid, this is the impact point
    274 //==================
    275 	if (!side)
    276 	{
    277 		VectorCopy (plane->normal, trace->plane.normal);
    278 		trace->plane.dist = plane->dist;
    279 	}
    280 	else
    281 	{
    282 		VectorSubtract (vec3_origin, plane->normal, trace->plane.normal);
    283 		trace->plane.dist = -plane->dist;
    284 	}
    285 
    286 	while (PM_HullPointContents (hull, hull->firstclipnode, mid)
    287 	== CONTENTS_SOLID)
    288 	{ // shouldn't really happen, but does occasionally
    289 		frac -= 0.1;
    290 		if (frac < 0)
    291 		{
    292 			trace->fraction = midf;
    293 			VectorCopy (mid, trace->endpos);
    294 			Con_DPrintf ("backup past 0\n");
    295 			return false;
    296 		}
    297 		midf = p1f + (p2f - p1f)*frac;
    298 		for (i=0 ; i<3 ; i++)
    299 			mid[i] = p1[i] + frac*(p2[i] - p1[i]);
    300 	}
    301 
    302 	trace->fraction = midf;
    303 	VectorCopy (mid, trace->endpos);
    304 
    305 	return false;
    306 }
    307 
    308 
    309 /*
    310 ================
    311 PM_TestPlayerPosition
    312 
    313 Returns false if the given player position is not valid (in solid)
    314 ================
    315 */
    316 qboolean PM_TestPlayerPosition (vec3_t pos)
    317 {
    318 	int			i;
    319 	physent_t	*pe;
    320 	vec3_t		mins, maxs, test;
    321 	hull_t		*hull;
    322 
    323 	for (i=0 ; i< pmove.numphysent ; i++)
    324 	{
    325 		pe = &pmove.physents[i];
    326 	// get the clipping hull
    327 		if (pe->model)
    328 			hull = &pmove.physents[i].model->hulls[1];
    329 		else
    330 		{
    331 			VectorSubtract (pe->mins, player_maxs, mins);
    332 			VectorSubtract (pe->maxs, player_mins, maxs);
    333 			hull = PM_HullForBox (mins, maxs);
    334 		}
    335 
    336 		VectorSubtract (pos, pe->origin, test);
    337 
    338 		if (PM_HullPointContents (hull, hull->firstclipnode, test) == CONTENTS_SOLID)
    339 			return false;
    340 	}
    341 
    342 	return true;
    343 }
    344 
    345 /*
    346 ================
    347 PM_PlayerMove
    348 ================
    349 */
    350 pmtrace_t PM_PlayerMove (vec3_t start, vec3_t end)
    351 {
    352 	pmtrace_t		trace, total;
    353 	vec3_t		offset;
    354 	vec3_t		start_l, end_l;
    355 	hull_t		*hull;
    356 	int			i;
    357 	physent_t	*pe;
    358 	vec3_t		mins, maxs;
    359 
    360 // fill in a default trace
    361 	memset (&total, 0, sizeof(pmtrace_t));
    362 	total.fraction = 1;
    363 	total.ent = -1;
    364 	VectorCopy (end, total.endpos);
    365 
    366 	for (i=0 ; i< pmove.numphysent ; i++)
    367 	{
    368 		pe = &pmove.physents[i];
    369 	// get the clipping hull
    370 		if (pe->model)
    371 			hull = &pmove.physents[i].model->hulls[1];
    372 		else
    373 		{
    374 			VectorSubtract (pe->mins, player_maxs, mins);
    375 			VectorSubtract (pe->maxs, player_mins, maxs);
    376 			hull = PM_HullForBox (mins, maxs);
    377 		}
    378 
    379 	// PM_HullForEntity (ent, mins, maxs, offset);
    380 	VectorCopy (pe->origin, offset);
    381 
    382 		VectorSubtract (start, offset, start_l);
    383 		VectorSubtract (end, offset, end_l);
    384 
    385 	// fill in a default trace
    386 		memset (&trace, 0, sizeof(pmtrace_t));
    387 		trace.fraction = 1;
    388 		trace.allsolid = true;
    389 //		trace.startsolid = true;
    390 		VectorCopy (end, trace.endpos);
    391 
    392 	// trace a line through the apropriate clipping hull
    393 		PM_RecursiveHullCheck (hull, hull->firstclipnode, 0, 1, start_l, end_l, &trace);
    394 
    395 		if (trace.allsolid)
    396 			trace.startsolid = true;
    397 		if (trace.startsolid)
    398 			trace.fraction = 0;
    399 
    400 	// did we clip the move?
    401 		if (trace.fraction < total.fraction)
    402 		{
    403 			// fix trace up by the offset
    404 			VectorAdd (trace.endpos, offset, trace.endpos);
    405 			total = trace;
    406 			total.ent = i;
    407 		}
    408 
    409 	}
    410 
    411 	return total;
    412 }
    413 
    414 
    415