msg.c

quakeIII源码这个不用我多说吧

	}
	MSG_WriteBits( msg, 1, 1 );
	MSG_WriteBits( msg, newV ^ key, bits );
}

int	MSG_ReadDeltaKey( msg_t *msg, int key, int oldV, int bits ) {
	if ( MSG_ReadBits( msg, 1 ) ) {
		return MSG_ReadBits( msg, bits ) ^ (key & kbitmask[bits]);
	}
	return oldV;
}

void MSG_WriteDeltaKeyFloat( msg_t *msg, int key, float oldV, float newV ) {
	if ( oldV == newV ) {
		MSG_WriteBits( msg, 0, 1 );
		return;
	}
	MSG_WriteBits( msg, 1, 1 );
	MSG_WriteBits( msg, (*(int *)&newV) ^ key, 32 );
}

float MSG_ReadDeltaKeyFloat( msg_t *msg, int key, float oldV ) {
	if ( MSG_ReadBits( msg, 1 ) ) {
		float	newV;

		*(int *)&newV = MSG_ReadBits( msg, 32 ) ^ key;
		return newV;
	}
	return oldV;
}


/*
============================================================================

usercmd_t communication

============================================================================
*/

// ms is allways sent, the others are optional
#define	CM_ANGLE1 	(1<<0)
#define	CM_ANGLE2 	(1<<1)
#define	CM_ANGLE3 	(1<<2)
#define	CM_FORWARD	(1<<3)
#define	CM_SIDE		(1<<4)
#define	CM_UP		(1<<5)
#define	CM_BUTTONS	(1<<6)
#define CM_WEAPON	(1<<7)

/*
=====================
MSG_WriteDeltaUsercmd
=====================
*/
void MSG_WriteDeltaUsercmd( msg_t *msg, usercmd_t *from, usercmd_t *to ) {
	if ( to->serverTime - from->serverTime < 256 ) {
		MSG_WriteBits( msg, 1, 1 );
		MSG_WriteBits( msg, to->serverTime - from->serverTime, 8 );
	} else {
		MSG_WriteBits( msg, 0, 1 );
		MSG_WriteBits( msg, to->serverTime, 32 );
	}
	MSG_WriteDelta( msg, from->angles[0], to->angles[0], 16 );
	MSG_WriteDelta( msg, from->angles[1], to->angles[1], 16 );
	MSG_WriteDelta( msg, from->angles[2], to->angles[2], 16 );
	MSG_WriteDelta( msg, from->forwardmove, to->forwardmove, 8 );
	MSG_WriteDelta( msg, from->rightmove, to->rightmove, 8 );
	MSG_WriteDelta( msg, from->upmove, to->upmove, 8 );
	MSG_WriteDelta( msg, from->buttons, to->buttons, 16 );
	MSG_WriteDelta( msg, from->weapon, to->weapon, 8 );
}


/*
=====================
MSG_ReadDeltaUsercmd
=====================
*/
void MSG_ReadDeltaUsercmd( msg_t *msg, usercmd_t *from, usercmd_t *to ) {
	if ( MSG_ReadBits( msg, 1 ) ) {
		to->serverTime = from->serverTime + MSG_ReadBits( msg, 8 );
	} else {
		to->serverTime = MSG_ReadBits( msg, 32 );
	}
	to->angles[0] = MSG_ReadDelta( msg, from->angles[0], 16);
	to->angles[1] = MSG_ReadDelta( msg, from->angles[1], 16);
	to->angles[2] = MSG_ReadDelta( msg, from->angles[2], 16);
	to->forwardmove = MSG_ReadDelta( msg, from->forwardmove, 8);
	to->rightmove = MSG_ReadDelta( msg, from->rightmove, 8);
	to->upmove = MSG_ReadDelta( msg, from->upmove, 8);
	to->buttons = MSG_ReadDelta( msg, from->buttons, 16);
	to->weapon = MSG_ReadDelta( msg, from->weapon, 8);
}

/*
=====================
MSG_WriteDeltaUsercmd
=====================
*/
void MSG_WriteDeltaUsercmdKey( msg_t *msg, int key, usercmd_t *from, usercmd_t *to ) {
	if ( to->serverTime - from->serverTime < 256 ) {
		MSG_WriteBits( msg, 1, 1 );
		MSG_WriteBits( msg, to->serverTime - from->serverTime, 8 );
	} else {
		MSG_WriteBits( msg, 0, 1 );
		MSG_WriteBits( msg, to->serverTime, 32 );
	}
	if (from->angles[0] == to->angles[0] &&
		from->angles[1] == to->angles[1] &&
		from->angles[2] == to->angles[2] &&
		from->forwardmove == to->forwardmove &&
		from->rightmove == to->rightmove &&
		from->upmove == to->upmove &&
		from->buttons == to->buttons &&
		from->weapon == to->weapon) {
			MSG_WriteBits( msg, 0, 1 );				// no change
			oldsize += 7;
			return;
	}
	key ^= to->serverTime;
	MSG_WriteBits( msg, 1, 1 );
	MSG_WriteDeltaKey( msg, key, from->angles[0], to->angles[0], 16 );
	MSG_WriteDeltaKey( msg, key, from->angles[1], to->angles[1], 16 );
	MSG_WriteDeltaKey( msg, key, from->angles[2], to->angles[2], 16 );
	MSG_WriteDeltaKey( msg, key, from->forwardmove, to->forwardmove, 8 );
	MSG_WriteDeltaKey( msg, key, from->rightmove, to->rightmove, 8 );
	MSG_WriteDeltaKey( msg, key, from->upmove, to->upmove, 8 );
	MSG_WriteDeltaKey( msg, key, from->buttons, to->buttons, 16 );
	MSG_WriteDeltaKey( msg, key, from->weapon, to->weapon, 8 );
}


/*
=====================
MSG_ReadDeltaUsercmd
=====================
*/
void MSG_ReadDeltaUsercmdKey( msg_t *msg, int key, usercmd_t *from, usercmd_t *to ) {
	if ( MSG_ReadBits( msg, 1 ) ) {
		to->serverTime = from->serverTime + MSG_ReadBits( msg, 8 );
	} else {
		to->serverTime = MSG_ReadBits( msg, 32 );
	}
	if ( MSG_ReadBits( msg, 1 ) ) {
		key ^= to->serverTime;
		to->angles[0] = MSG_ReadDeltaKey( msg, key, from->angles[0], 16);
		to->angles[1] = MSG_ReadDeltaKey( msg, key, from->angles[1], 16);
		to->angles[2] = MSG_ReadDeltaKey( msg, key, from->angles[2], 16);
		to->forwardmove = MSG_ReadDeltaKey( msg, key, from->forwardmove, 8);
		to->rightmove = MSG_ReadDeltaKey( msg, key, from->rightmove, 8);
		to->upmove = MSG_ReadDeltaKey( msg, key, from->upmove, 8);
		to->buttons = MSG_ReadDeltaKey( msg, key, from->buttons, 16);
		to->weapon = MSG_ReadDeltaKey( msg, key, from->weapon, 8);
	} else {
		to->angles[0] = from->angles[0];
		to->angles[1] = from->angles[1];
		to->angles[2] = from->angles[2];
		to->forwardmove = from->forwardmove;
		to->rightmove = from->rightmove;
		to->upmove = from->upmove;
		to->buttons = from->buttons;
		to->weapon = from->weapon;
	}
}

/*
=============================================================================

entityState_t communication
  
=============================================================================
*/

/*
=================
MSG_ReportChangeVectors_f

Prints out a table from the current statistics for copying to code
=================
*/
void MSG_ReportChangeVectors_f( void ) {
	int i;
	for(i=0;i<256;i++) {
		if (pcount[i]) {
			Com_Printf("%d used %d\n", i, pcount[i]);
		}
	}
}

typedef struct {
	char	*name;
	int		offset;
	int		bits;		// 0 = float
} netField_t;

// using the stringizing operator to save typing...
#define	NETF(x) #x,(int)&((entityState_t*)0)->x

netField_t	entityStateFields[] = 
{
{ NETF(pos.trTime), 32 },
{ NETF(pos.trBase[0]), 0 },
{ NETF(pos.trBase[1]), 0 },
{ NETF(pos.trDelta[0]), 0 },
{ NETF(pos.trDelta[1]), 0 },
{ NETF(pos.trBase[2]), 0 },
{ NETF(apos.trBase[1]), 0 },
{ NETF(pos.trDelta[2]), 0 },
{ NETF(apos.trBase[0]), 0 },
{ NETF(event), 10 },
{ NETF(angles2[1]), 0 },
{ NETF(eType), 8 },
{ NETF(torsoAnim), 8 },
{ NETF(eventParm), 8 },
{ NETF(legsAnim), 8 },
{ NETF(groundEntityNum), GENTITYNUM_BITS },
{ NETF(pos.trType), 8 },
{ NETF(eFlags), 19 },
{ NETF(otherEntityNum), GENTITYNUM_BITS },
{ NETF(weapon), 8 },
{ NETF(clientNum), 8 },
{ NETF(angles[1]), 0 },
{ NETF(pos.trDuration), 32 },
{ NETF(apos.trType), 8 },
{ NETF(origin[0]), 0 },
{ NETF(origin[1]), 0 },
{ NETF(origin[2]), 0 },
{ NETF(solid), 24 },
{ NETF(powerups), 16 },
{ NETF(modelindex), 8 },
{ NETF(otherEntityNum2), GENTITYNUM_BITS },
{ NETF(loopSound), 8 },
{ NETF(generic1), 8 },
{ NETF(origin2[2]), 0 },
{ NETF(origin2[0]), 0 },
{ NETF(origin2[1]), 0 },
{ NETF(modelindex2), 8 },
{ NETF(angles[0]), 0 },
{ NETF(time), 32 },
{ NETF(apos.trTime), 32 },
{ NETF(apos.trDuration), 32 },
{ NETF(apos.trBase[2]), 0 },
{ NETF(apos.trDelta[0]), 0 },
{ NETF(apos.trDelta[1]), 0 },
{ NETF(apos.trDelta[2]), 0 },
{ NETF(time2), 32 },
{ NETF(angles[2]), 0 },
{ NETF(angles2[0]), 0 },
{ NETF(angles2[2]), 0 },
{ NETF(constantLight), 32 },
{ NETF(frame), 16 }
};


// if (int)f == f and (int)f + ( 1<<(FLOAT_INT_BITS-1) ) < ( 1 << FLOAT_INT_BITS )
// the float will be sent with FLOAT_INT_BITS, otherwise all 32 bits will be sent
#define	FLOAT_INT_BITS	13
#define	FLOAT_INT_BIAS	(1<<(FLOAT_INT_BITS-1))

/*
==================
MSG_WriteDeltaEntity

Writes part of a packetentities message, including the entity number.
Can delta from either a baseline or a previous packet_entity
If to is NULL, a remove entity update will be sent
If force is not set, then nothing at all will be generated if the entity is
identical, under the assumption that the in-order delta code will catch it.
==================
*/
void MSG_WriteDeltaEntity( msg_t *msg, struct entityState_s *from, struct entityState_s *to, 
						   qboolean force ) {
	int			i, lc;
	int			numFields;
	netField_t	*field;
	int			trunc;
	float		fullFloat;
	int			*fromF, *toF;

	numFields = sizeof(entityStateFields)/sizeof(entityStateFields[0]);

	// all fields should be 32 bits to avoid any compiler packing issues
	// the "number" field is not part of the field list
	// if this assert fails, someone added a field to the entityState_t
	// struct without updating the message fields
	assert( numFields + 1 == sizeof( *from )/4 );

	// a NULL to is a delta remove message
	if ( to == NULL ) {
		if ( from == NULL ) {
			return;
		}
		MSG_WriteBits( msg, from->number, GENTITYNUM_BITS );
		MSG_WriteBits( msg, 1, 1 );
		return;
	}

	if ( to->number < 0 || to->number >= MAX_GENTITIES ) {
		Com_Error (ERR_FATAL, "MSG_WriteDeltaEntity: Bad entity number: %i", to->number );
	}

	lc = 0;
	// build the change vector as bytes so it is endien independent
	for ( i = 0, field = entityStateFields ; i < numFields ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );
		if ( *fromF != *toF ) {
			lc = i+1;
		}
	}

	if ( lc == 0 ) {
		// nothing at all changed
		if ( !force ) {
			return;		// nothing at all
		}
		// write two bits for no change
		MSG_WriteBits( msg, to->number, GENTITYNUM_BITS );
		MSG_WriteBits( msg, 0, 1 );		// not removed
		MSG_WriteBits( msg, 0, 1 );		// no delta
		return;
	}

	MSG_WriteBits( msg, to->number, GENTITYNUM_BITS );
	MSG_WriteBits( msg, 0, 1 );			// not removed
	MSG_WriteBits( msg, 1, 1 );			// we have a delta

	MSG_WriteByte( msg, lc );	// # of changes

	oldsize += numFields;

	for ( i = 0, field = entityStateFields ; i < lc ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );

		if ( *fromF == *toF ) {
			MSG_WriteBits( msg, 0, 1 );	// no change
			continue;
		}

		MSG_WriteBits( msg, 1, 1 );	// changed

		if ( field->bits == 0 ) {
			// float
			fullFloat = *(float *)toF;
			trunc = (int)fullFloat;

			if (fullFloat == 0.0f) {
					MSG_WriteBits( msg, 0, 1 );
					oldsize += FLOAT_INT_BITS;
			} else {
				MSG_WriteBits( msg, 1, 1 );
				if ( trunc == fullFloat && trunc + FLOAT_INT_BIAS >= 0 && 
					trunc + FLOAT_INT_BIAS < ( 1 << FLOAT_INT_BITS ) ) {
					// send as small integer
					MSG_WriteBits( msg, 0, 1 );
					MSG_WriteBits( msg, trunc + FLOAT_INT_BIAS, FLOAT_INT_BITS );
				} else {
					// send as full floating point value
					MSG_WriteBits( msg, 1, 1 );
					MSG_WriteBits( msg, *toF, 32 );
				}
			}
		} else {
			if (*toF == 0) {
				MSG_WriteBits( msg, 0, 1 );
			} else {
				MSG_WriteBits( msg, 1, 1 );
				// integer
				MSG_WriteBits( msg, *toF, field->bits );
			}
		}
	}
}

/*
==================
MSG_ReadDeltaEntity

The entity number has already been read from the message, which
is how the from state is identified.

If the delta removes the entity, entityState_t->number will be set to MAX_GENTITIES-1

Can go from either a baseline or a previous packet_entity
==================
*/
extern	cvar_t	*cl_shownet;

void MSG_ReadDeltaEntity( msg_t *msg, entityState_t *from, entityState_t *to, 
						 int number) {
	int			i, lc;
	int			numFields;
	netField_t	*field;
	int			*fromF, *toF;
	int			print;
	int			trunc;
	int			startBit, endBit;

	if ( number < 0 || number >= MAX_GENTITIES) {
		Com_Error( ERR_DROP, "Bad delta entity number: %i", number );
	}

	if ( msg->bit == 0 ) {
		startBit = msg->readcount * 8 - GENTITYNUM_BITS;
	} else {
		startBit = ( msg->readcount - 1 ) * 8 + msg->bit - GENTITYNUM_BITS;
	}

	// check for a remove
	if ( MSG_ReadBits( msg, 1 ) == 1 ) {
		Com_Memset( to, 0, sizeof( *to ) );	
		to->number = MAX_GENTITIES - 1;
		if ( cl_shownet->integer >= 2 || cl_shownet->integer == -1 ) {
			Com_Printf( "%3i: #%-3i remove\n", msg->readcount, number );
		}
		return;
	}

	// check for no delta
	if ( MSG_ReadBits( msg, 1 ) == 0 ) {
		*to = *from;
		to->number = number;
		return;
	}

	numFields = sizeof(entityStateFields)/sizeof(entityStateFields[0]);
	lc = MSG_ReadByte(msg);

	// shownet 2/3 will interleave with other printed info, -1 will
	// just print the delta records`
	if ( cl_shownet->integer >= 2 || cl_shownet->integer == -1 ) {
		print = 1;
		Com_Printf( "%3i: #%-3i ", msg->readcount, to->number );
	} else {
		print = 0;
	}

	to->number = number;

	for ( i = 0, field = entityStateFields ; i < lc ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );

		if ( ! MSG_ReadBits( msg, 1 ) ) {
			// no change
			*toF = *fromF;
		} else {
			if ( field->bits == 0 ) {
				// float
				if ( MSG_ReadBits( msg, 1 ) == 0 ) {
						*(float *)toF = 0.0f; 
				} else {
					if ( MSG_ReadBits( msg, 1 ) == 0 ) {
						// integral float
						trunc = MSG_ReadBits( msg, FLOAT_INT_BITS );
						// bias to allow equal parts positive and negative
						trunc -= FLOAT_INT_BIAS;
						*(float *)toF = trunc; 
						if ( print ) {
							Com_Printf( "%s:%i ", field->name, trunc );
						}
					} else {
						// full floating point value
						*toF = MSG_ReadBits( msg, 32 );
						if ( print ) {
							Com_Printf( "%s:%f ", field->name, *(float *)toF );
						}
					}
				}
			} else {
				if ( MSG_ReadBits( msg, 1 ) == 0 ) {
					*toF = 0;
				} else {
					// integer
					*toF = MSG_ReadBits( msg, field->bits );
					if ( print ) {
						Com_Printf( "%s:%i ", field->name, *toF );
					}
				}
			}
//			pcount[i]++;
		}
	}
	for ( i = lc, field = &entityStateFields[lc] ; i < numFields ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );
		// no change
		*toF = *fromF;
	}

	if ( print ) {
		if ( msg->bit == 0 ) {
			endBit = msg->readcount * 8 - GENTITYNUM_BITS;
		} else {
			endBit = ( msg->readcount - 1 ) * 8 + msg->bit - GENTITYNUM_BITS;
		}
		Com_Printf( " (%i bits)\n", endBit - startBit  );
	}
}


/*
============================================================================

plyer_state_t communication

============================================================================
*/

// using the stringizing operator to save typing...
#define	PSF(x) #x,(int)&((playerState_t*)0)->x

netField_t	playerStateFields[] = 
{
{ PSF(commandTime), 32 },				
{ PSF(origin[0]), 0 },
{ PSF(origin[1]), 0 },
{ PSF(bobCycle), 8 },
{ PSF(velocity[0]), 0 },
{ PSF(velocity[1]), 0 },
{ PSF(viewangles[1]), 0 },
{ PSF(viewangles[0]), 0 },
{ PSF(weaponTime), -16 },
{ PSF(origin[2]), 0 },
{ PSF(velocity[2]), 0 },
{ PSF(legsTimer), 8 },
{ PSF(pm_time), -16 },
{ PSF(eventSequence), 16 },
{ PSF(torsoAnim), 8 },
{ PSF(movementDir), 4 },
{ PSF(events[0]), 8 },
{ PSF(legsAnim), 8 },
{ PSF(events[1]), 8 },
{ PSF(pm_flags), 16 },
{ PSF(groundEntityNum), GENTITYNUM_BITS },
{ PSF(weaponstate), 4 },
{ PSF(eFlags), 16 },
{ PSF(externalEvent), 10 },
{ PSF(gravity), 16 },
{ PSF(speed), 16 },
{ PSF(delta_angles[1]), 16 },
{ PSF(externalEventParm), 8 },
{ PSF(viewheight), -8 },
{ PSF(damageEvent), 8 },
{ PSF(damageYaw), 8 },
{ PSF(damagePitch), 8 },
{ PSF(damageCount), 8 },
{ PSF(generic1), 8 },
{ PSF(pm_type), 8 },					
{ PSF(delta_angles[0]), 16 },
{ PSF(delta_angles[2]), 16 },
{ PSF(torsoTimer), 12 },
{ PSF(eventParms[0]), 8 },
{ PSF(eventParms[1]), 8 },
{ PSF(clientNum), 8 },
{ PSF(weapon), 5 },
{ PSF(viewangles[2]), 0 },
{ PSF(grapplePoint[0]), 0 },
{ PSF(grapplePoint[1]), 0 },
{ PSF(grapplePoint[2]), 0 },
{ PSF(jumppad_ent), 10 },
{ PSF(loopSound), 16 }
};

/*
=============
MSG_WriteDeltaPlayerstate

=============
*/
void MSG_WriteDeltaPlayerstate( msg_t *msg, struct playerState_s *from, struct playerState_s *to ) {
	int				i;
	playerState_t	dummy;
	int				statsbits;
	int				persistantbits;
	int				ammobits;
	int				powerupbits;
	int				numFields;
	int				c;
	netField_t		*field;
	int				*fromF, *toF;
	float			fullFloat;
	int				trunc, lc;