ref: 84cdb4e2e9e1712fc913c05c38f3cf94ca100e5d
dir: /code/game/bg_slidemove.c/
/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
This file is part of Quake III Arena source code.
Quake III Arena source code 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.
Quake III Arena source code 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 Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
===========================================================================
*/
//
// bg_slidemove.c -- part of bg_pmove functionality
#include "q_shared.h"
#include "bg_public.h"
#include "bg_local.h"
/*
input: origin, velocity, bounds, groundPlane, trace function
output: origin, velocity, impacts, stairup boolean
*/
/*
==================
PM_SlideMove
Returns qtrue if the velocity was clipped in some way
==================
*/
#define MAX_CLIP_PLANES 5
qboolean PM_SlideMove( qboolean gravity ) {
int bumpcount, numbumps;
vec3_t dir;
float d;
int numplanes;
vec3_t planes[MAX_CLIP_PLANES];
vec3_t primal_velocity;
vec3_t clipVelocity;
int i, j, k;
trace_t trace;
vec3_t end;
float time_left;
float into;
vec3_t endVelocity;
vec3_t endClipVelocity;
numbumps = 4;
VectorCopy (pm->ps->velocity, primal_velocity);
if ( gravity ) {
VectorCopy( pm->ps->velocity, endVelocity );
endVelocity[2] -= pm->ps->gravity * pml.frametime;
pm->ps->velocity[2] = ( pm->ps->velocity[2] + endVelocity[2] ) * 0.5;
primal_velocity[2] = endVelocity[2];
if ( pml.groundPlane ) {
// slide along the ground plane
PM_ClipVelocity (pm->ps->velocity, pml.groundTrace.plane.normal,
pm->ps->velocity, OVERCLIP );
}
}
time_left = pml.frametime;
// never turn against the ground plane
if ( pml.groundPlane ) {
numplanes = 1;
VectorCopy( pml.groundTrace.plane.normal, planes[0] );
} else {
numplanes = 0;
}
// never turn against original velocity
VectorNormalize2( pm->ps->velocity, planes[numplanes] );
numplanes++;
for ( bumpcount=0 ; bumpcount < numbumps ; bumpcount++ ) {
// calculate position we are trying to move to
VectorMA( pm->ps->origin, time_left, pm->ps->velocity, end );
// see if we can make it there
pm->trace ( &trace, pm->ps->origin, pm->mins, pm->maxs, end, pm->ps->clientNum, pm->tracemask);
if (trace.allsolid) {
// entity is completely trapped in another solid
pm->ps->velocity[2] = 0; // don't build up falling damage, but allow sideways acceleration
return qtrue;
}
if (trace.fraction > 0) {
// actually covered some distance
VectorCopy (trace.endpos, pm->ps->origin);
}
if (trace.fraction == 1) {
break; // moved the entire distance
}
// save entity for contact
PM_AddTouchEnt( trace.entityNum );
time_left -= time_left * trace.fraction;
if (numplanes >= MAX_CLIP_PLANES) {
// this shouldn't really happen
VectorClear( pm->ps->velocity );
return qtrue;
}
//
// if this is the same plane we hit before, nudge velocity
// out along it, which fixes some epsilon issues with
// non-axial planes
//
for ( i = 0 ; i < numplanes ; i++ ) {
if ( DotProduct( trace.plane.normal, planes[i] ) > 0.99 ) {
VectorAdd( trace.plane.normal, pm->ps->velocity, pm->ps->velocity );
break;
}
}
if ( i < numplanes ) {
continue;
}
VectorCopy (trace.plane.normal, planes[numplanes]);
numplanes++;
//
// modify velocity so it parallels all of the clip planes
//
// find a plane that it enters
for ( i = 0 ; i < numplanes ; i++ ) {
into = DotProduct( pm->ps->velocity, planes[i] );
if ( into >= 0.1 ) {
continue; // move doesn't interact with the plane
}
// see how hard we are hitting things
if ( -into > pml.impactSpeed ) {
pml.impactSpeed = -into;
}
// slide along the plane
PM_ClipVelocity (pm->ps->velocity, planes[i], clipVelocity, OVERCLIP );
// slide along the plane
PM_ClipVelocity (endVelocity, planes[i], endClipVelocity, OVERCLIP );
// see if there is a second plane that the new move enters
for ( j = 0 ; j < numplanes ; j++ ) {
if ( j == i ) {
continue;
}
if ( DotProduct( clipVelocity, planes[j] ) >= 0.1 ) {
continue; // move doesn't interact with the plane
}
// try clipping the move to the plane
PM_ClipVelocity( clipVelocity, planes[j], clipVelocity, OVERCLIP );
PM_ClipVelocity( endClipVelocity, planes[j], endClipVelocity, OVERCLIP );
// see if it goes back into the first clip plane
if ( DotProduct( clipVelocity, planes[i] ) >= 0 ) {
continue;
}
// slide the original velocity along the crease
CrossProduct (planes[i], planes[j], dir);
VectorNormalize( dir );
d = DotProduct( dir, pm->ps->velocity );
VectorScale( dir, d, clipVelocity );
CrossProduct (planes[i], planes[j], dir);
VectorNormalize( dir );
d = DotProduct( dir, endVelocity );
VectorScale( dir, d, endClipVelocity );
// see if there is a third plane the the new move enters
for ( k = 0 ; k < numplanes ; k++ ) {
if ( k == i || k == j ) {
continue;
}
if ( DotProduct( clipVelocity, planes[k] ) >= 0.1 ) {
continue; // move doesn't interact with the plane
}
// stop dead at a tripple plane interaction
VectorClear( pm->ps->velocity );
return qtrue;
}
}
// if we have fixed all interactions, try another move
VectorCopy( clipVelocity, pm->ps->velocity );
VectorCopy( endClipVelocity, endVelocity );
break;
}
}
if ( gravity ) {
VectorCopy( endVelocity, pm->ps->velocity );
}
// don't change velocity if in a timer (FIXME: is this correct?)
if ( pm->ps->pm_time ) {
VectorCopy( primal_velocity, pm->ps->velocity );
}
return ( bumpcount != 0 );
}
/*
==================
PM_StepSlideMove
==================
*/
void PM_StepSlideMove( qboolean gravity ) {
vec3_t start_o, start_v;
vec3_t down_o, down_v;
trace_t trace;
// float down_dist, up_dist;
// vec3_t delta, delta2;
vec3_t up, down;
float stepSize;
VectorCopy (pm->ps->origin, start_o);
VectorCopy (pm->ps->velocity, start_v);
if ( PM_SlideMove( gravity ) == 0 ) {
return; // we got exactly where we wanted to go first try
}
VectorCopy(start_o, down);
down[2] -= STEPSIZE;
pm->trace (&trace, start_o, pm->mins, pm->maxs, down, pm->ps->clientNum, pm->tracemask);
VectorSet(up, 0, 0, 1);
// never step up when you still have up velocity
if ( pm->ps->velocity[2] > 0 && (trace.fraction == 1.0 ||
DotProduct(trace.plane.normal, up) < 0.7)) {
return;
}
VectorCopy (pm->ps->origin, down_o);
VectorCopy (pm->ps->velocity, down_v);
VectorCopy (start_o, up);
up[2] += STEPSIZE;
// test the player position if they were a stepheight higher
pm->trace (&trace, start_o, pm->mins, pm->maxs, up, pm->ps->clientNum, pm->tracemask);
if ( trace.allsolid ) {
if ( pm->debugLevel ) {
Com_Printf("%i:bend can't step\n", c_pmove);
}
return; // can't step up
}
stepSize = trace.endpos[2] - start_o[2];
// try slidemove from this position
VectorCopy (trace.endpos, pm->ps->origin);
VectorCopy (start_v, pm->ps->velocity);
PM_SlideMove( gravity );
// push down the final amount
VectorCopy (pm->ps->origin, down);
down[2] -= stepSize;
pm->trace (&trace, pm->ps->origin, pm->mins, pm->maxs, down, pm->ps->clientNum, pm->tracemask);
if ( !trace.allsolid ) {
VectorCopy (trace.endpos, pm->ps->origin);
}
if ( trace.fraction < 1.0 ) {
PM_ClipVelocity( pm->ps->velocity, trace.plane.normal, pm->ps->velocity, OVERCLIP );
}
#if 0
// if the down trace can trace back to the original position directly, don't step
pm->trace( &trace, pm->ps->origin, pm->mins, pm->maxs, start_o, pm->ps->clientNum, pm->tracemask);
if ( trace.fraction == 1.0 ) {
// use the original move
VectorCopy (down_o, pm->ps->origin);
VectorCopy (down_v, pm->ps->velocity);
if ( pm->debugLevel ) {
Com_Printf("%i:bend\n", c_pmove);
}
} else
#endif
{
// use the step move
float delta;
delta = pm->ps->origin[2] - start_o[2];
if ( delta > 2 ) {
if ( delta < 7 ) {
PM_AddEvent( EV_STEP_4 );
} else if ( delta < 11 ) {
PM_AddEvent( EV_STEP_8 );
} else if ( delta < 15 ) {
PM_AddEvent( EV_STEP_12 );
} else {
PM_AddEvent( EV_STEP_16 );
}
}
if ( pm->debugLevel ) {
Com_Printf("%i:stepped\n", c_pmove);
}
}
}