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diff --git a/src/cgame/cg_snapshot.c b/src/cgame/cg_snapshot.c
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+/*
+===========================================================================
+Copyright (C) 1999-2005 Id Software, Inc.
+Copyright (C) 2000-2009 Darklegion Development
+
+This file is part of Tremulous.
+
+Tremulous 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.
+
+Tremulous 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 Tremulous; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+===========================================================================
+*/
+
+// cg_snapshot.c -- things that happen on snapshot transition,
+// not necessarily every single rendered frame
+
+
+#include "cg_local.h"
+
+/*
+==================
+CG_ResetEntity
+==================
+*/
+static void CG_ResetEntity( centity_t *cent )
+{
+ // if the previous snapshot this entity was updated in is at least
+ // an event window back in time then we can reset the previous event
+ if( cent->snapShotTime < cg.time - EVENT_VALID_MSEC )
+ cent->previousEvent = 0;
+
+ cent->trailTime = cg.snap->serverTime;
+
+ VectorCopy( cent->currentState.origin, cent->lerpOrigin );
+ VectorCopy( cent->currentState.angles, cent->lerpAngles );
+
+ if( cent->currentState.eType == ET_PLAYER )
+ CG_ResetPlayerEntity( cent );
+}
+
+/*
+===============
+CG_TransitionEntity
+
+cent->nextState is moved to cent->currentState and events are fired
+===============
+*/
+static void CG_TransitionEntity( centity_t *cent )
+{
+ cent->currentState = cent->nextState;
+ cent->currentValid = qtrue;
+
+ // reset if the entity wasn't in the last frame or was teleported
+ if( !cent->interpolate )
+ CG_ResetEntity( cent );
+
+ // clear the next state. if will be set by the next CG_SetNextSnap
+ cent->interpolate = qfalse;
+
+ // check for events
+ CG_CheckEvents( cent );
+}
+
+
+/*
+==================
+CG_SetInitialSnapshot
+
+This will only happen on the very first snapshot, or
+on tourney restarts. All other times will use
+CG_TransitionSnapshot instead.
+
+FIXME: Also called by map_restart?
+==================
+*/
+void CG_SetInitialSnapshot( snapshot_t *snap )
+{
+ int i;
+ centity_t *cent;
+ entityState_t *state;
+
+ cg.snap = snap;
+
+ BG_PlayerStateToEntityState( &snap->ps, &cg_entities[ snap->ps.clientNum ].currentState, qfalse );
+
+ // sort out solid entities
+ CG_BuildSolidList( );
+
+ CG_ExecuteNewServerCommands( snap->serverCommandSequence );
+
+ // set our local weapon selection pointer to
+ // what the server has indicated the current weapon is
+ CG_Respawn( );
+
+ for( i = 0; i < cg.snap->numEntities; i++ )
+ {
+ state = &cg.snap->entities[ i ];
+ cent = &cg_entities[ state->number ];
+
+ memcpy( &cent->currentState, state, sizeof( entityState_t ) );
+ //cent->currentState = *state;
+ cent->interpolate = qfalse;
+ cent->currentValid = qtrue;
+
+ CG_ResetEntity( cent );
+
+ // check for events
+ CG_CheckEvents( cent );
+ }
+}
+
+
+/*
+===================
+CG_TransitionSnapshot
+
+The transition point from snap to nextSnap has passed
+===================
+*/
+static void CG_TransitionSnapshot( void )
+{
+ centity_t *cent;
+ snapshot_t *oldFrame;
+ int i;
+
+ if( !cg.snap )
+ CG_Error( "CG_TransitionSnapshot: NULL cg.snap" );
+
+ if( !cg.nextSnap )
+ CG_Error( "CG_TransitionSnapshot: NULL cg.nextSnap" );
+
+ // execute any server string commands before transitioning entities
+ CG_ExecuteNewServerCommands( cg.nextSnap->serverCommandSequence );
+
+ // clear the currentValid flag for all entities in the existing snapshot
+ for( i = 0; i < cg.snap->numEntities; i++ )
+ {
+ cent = &cg_entities[ cg.snap->entities[ i ].number ];
+ cent->currentValid = qfalse;
+ }
+
+ // move nextSnap to snap and do the transitions
+ oldFrame = cg.snap;
+ cg.snap = cg.nextSnap;
+
+ BG_PlayerStateToEntityState( &cg.snap->ps, &cg_entities[ cg.snap->ps.clientNum ].currentState, qfalse );
+ cg_entities[ cg.snap->ps.clientNum ].interpolate = qfalse;
+
+ for( i = 0; i < cg.snap->numEntities; i++ )
+ {
+ cent = &cg_entities[ cg.snap->entities[ i ].number ];
+ CG_TransitionEntity( cent );
+
+ // remember time of snapshot this entity was last updated in
+ cent->snapShotTime = cg.snap->serverTime;
+ }
+
+ cg.nextSnap = NULL;
+
+ // check for playerstate transition events
+ if( oldFrame )
+ {
+ playerState_t *ops, *ps;
+
+ ops = &oldFrame->ps;
+ ps = &cg.snap->ps;
+ // teleporting checks are irrespective of prediction
+ if( ( ps->eFlags ^ ops->eFlags ) & EF_TELEPORT_BIT )
+ cg.thisFrameTeleport = qtrue; // will be cleared by prediction code
+
+ // if we are not doing client side movement prediction for any
+ // reason, then the client events and view changes will be issued now
+ if( cg.demoPlayback || ( cg.snap->ps.pm_flags & PMF_FOLLOW ) ||
+ cg_nopredict.integer || cg_synchronousClients.integer )
+ CG_TransitionPlayerState( ps, ops );
+ }
+}
+
+
+/*
+===================
+CG_SetNextSnap
+
+A new snapshot has just been read in from the client system.
+===================
+*/
+static void CG_SetNextSnap( snapshot_t *snap )
+{
+ int num;
+ entityState_t *es;
+ centity_t *cent;
+
+ cg.nextSnap = snap;
+
+ BG_PlayerStateToEntityState( &snap->ps, &cg_entities[ snap->ps.clientNum ].nextState, qfalse );
+ cg_entities[ cg.snap->ps.clientNum ].interpolate = qtrue;
+
+ // check for extrapolation errors
+ for( num = 0 ; num < snap->numEntities ; num++ )
+ {
+ es = &snap->entities[ num ];
+ cent = &cg_entities[ es->number ];
+
+ memcpy( &cent->nextState, es, sizeof( entityState_t ) );
+ //cent->nextState = *es;
+
+ // if this frame is a teleport, or the entity wasn't in the
+ // previous frame, don't interpolate
+ if( !cent->currentValid || ( ( cent->currentState.eFlags ^ es->eFlags ) & EF_TELEPORT_BIT ) )
+ cent->interpolate = qfalse;
+ else
+ cent->interpolate = qtrue;
+ }
+
+ // if the next frame is a teleport for the playerstate, we
+ // can't interpolate during demos
+ if( cg.snap && ( ( snap->ps.eFlags ^ cg.snap->ps.eFlags ) & EF_TELEPORT_BIT ) )
+ cg.nextFrameTeleport = qtrue;
+ else
+ cg.nextFrameTeleport = qfalse;
+
+ // if changing follow mode, don't interpolate
+ if( cg.nextSnap->ps.clientNum != cg.snap->ps.clientNum )
+ cg.nextFrameTeleport = qtrue;
+
+ // if changing server restarts, don't interpolate
+ if( ( cg.nextSnap->snapFlags ^ cg.snap->snapFlags ) & SNAPFLAG_SERVERCOUNT )
+ cg.nextFrameTeleport = qtrue;
+
+ // sort out solid entities
+ CG_BuildSolidList( );
+}
+
+
+/*
+========================
+CG_ReadNextSnapshot
+
+This is the only place new snapshots are requested
+This may increment cgs.processedSnapshotNum multiple
+times if the client system fails to return a
+valid snapshot.
+========================
+*/
+static snapshot_t *CG_ReadNextSnapshot( void )
+{
+ qboolean r;
+ snapshot_t *dest;
+
+ if( cg.latestSnapshotNum > cgs.processedSnapshotNum + 1000 )
+ {
+ CG_Printf( "WARNING: CG_ReadNextSnapshot: way out of range, %i > %i\n",
+ cg.latestSnapshotNum, cgs.processedSnapshotNum );
+ }
+
+ while( cgs.processedSnapshotNum < cg.latestSnapshotNum )
+ {
+ // decide which of the two slots to load it into
+ if( cg.snap == &cg.activeSnapshots[ 0 ] )
+ dest = &cg.activeSnapshots[ 1 ];
+ else
+ dest = &cg.activeSnapshots[ 0 ];
+
+ // try to read the snapshot from the client system
+ cgs.processedSnapshotNum++;
+ r = trap_GetSnapshot( cgs.processedSnapshotNum, dest );
+
+ // FIXME: why would trap_GetSnapshot return a snapshot with the same server time
+ if( cg.snap && r && dest->serverTime == cg.snap->serverTime )
+ {
+ //continue;
+ }
+
+ // if it succeeded, return
+ if( r )
+ {
+ CG_AddLagometerSnapshotInfo( dest );
+ return dest;
+ }
+
+ // a GetSnapshot will return failure if the snapshot
+ // never arrived, or is so old that its entities
+ // have been shoved off the end of the circular
+ // buffer in the client system.
+
+ // record as a dropped packet
+ CG_AddLagometerSnapshotInfo( NULL );
+
+ // If there are additional snapshots, continue trying to
+ // read them.
+ }
+
+ // nothing left to read
+ return NULL;
+}
+
+
+/*
+============
+CG_ProcessSnapshots
+
+We are trying to set up a renderable view, so determine
+what the simulated time is, and try to get snapshots
+both before and after that time if available.
+
+If we don't have a valid cg.snap after exiting this function,
+then a 3D game view cannot be rendered. This should only happen
+right after the initial connection. After cg.snap has been valid
+once, it will never turn invalid.
+
+Even if cg.snap is valid, cg.nextSnap may not be, if the snapshot
+hasn't arrived yet (it becomes an extrapolating situation instead
+of an interpolating one)
+
+============
+*/
+void CG_ProcessSnapshots( void )
+{
+ snapshot_t *snap;
+ int n;
+
+ // see what the latest snapshot the client system has is
+ trap_GetCurrentSnapshotNumber( &n, &cg.latestSnapshotTime );
+
+ if( n != cg.latestSnapshotNum )
+ {
+ if( n < cg.latestSnapshotNum )
+ {
+ // this should never happen
+ CG_Error( "CG_ProcessSnapshots: n < cg.latestSnapshotNum" );
+ }
+
+ cg.latestSnapshotNum = n;
+ }
+
+ // If we have yet to receive a snapshot, check for it.
+ // Once we have gotten the first snapshot, cg.snap will
+ // always have valid data for the rest of the game
+ while( !cg.snap )
+ {
+ snap = CG_ReadNextSnapshot( );
+
+ if( !snap )
+ {
+ // we can't continue until we get a snapshot
+ return;
+ }
+
+ // set our weapon selection to what
+ // the playerstate is currently using
+ if( !( snap->snapFlags & SNAPFLAG_NOT_ACTIVE ) )
+ CG_SetInitialSnapshot( snap );
+ }
+
+ // loop until we either have a valid nextSnap with a serverTime
+ // greater than cg.time to interpolate towards, or we run
+ // out of available snapshots
+ do
+ {
+ // if we don't have a nextframe, try and read a new one in
+ if( !cg.nextSnap )
+ {
+ snap = CG_ReadNextSnapshot( );
+
+ // if we still don't have a nextframe, we will just have to
+ // extrapolate
+ if( !snap )
+ break;
+
+ CG_SetNextSnap( snap );
+
+ // if time went backwards, we have a level restart
+ if( cg.nextSnap->serverTime < cg.snap->serverTime )
+ CG_Error( "CG_ProcessSnapshots: Server time went backwards" );
+ }
+
+ // if our time is < nextFrame's, we have a nice interpolating state
+ if( cg.time >= cg.snap->serverTime && cg.time < cg.nextSnap->serverTime )
+ break;
+
+ // we have passed the transition from nextFrame to frame
+ CG_TransitionSnapshot( );
+ } while( 1 );
+
+ // assert our valid conditions upon exiting
+ if( cg.snap == NULL )
+ CG_Error( "CG_ProcessSnapshots: cg.snap == NULL" );
+
+ if( cg.time < cg.snap->serverTime )
+ {
+ // this can happen right after a vid_restart
+ cg.time = cg.snap->serverTime;
+ }
+
+ if( cg.nextSnap != NULL && cg.nextSnap->serverTime <= cg.time )
+ CG_Error( "CG_ProcessSnapshots: cg.nextSnap->serverTime <= cg.time" );
+}
+
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