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Fix flamers shooting into outer space due to unsigned underflow and f…
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…ix penetrating projectiles going 100 times too far.

Also, renamed the confusingly named partially-unsigned vectors {startX, startY, srcHeight} and {tarX, tarY, altChange - srcHeight} to signed vectors src and dst, respectively.
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@Cyp
Cyp committed Oct 23, 2010
1 parent 5c431a3 commit 1481ec6
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Showing 2 changed files with 36 additions and 55 deletions.
85 changes: 34 additions & 51 deletions src/projectile.c
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Expand Up @@ -379,10 +379,8 @@ int32_t projCalcIndirectVelocities(const int32_t dx, const int32_t dz, int32_t v
BOOL proj_SendProjectile(WEAPON *psWeap, BASE_OBJECT *psAttacker, int player, Vector3i target, BASE_OBJECT *psTarget, BOOL bVisible, int weapon_slot)
{
PROJECTILE *psProj = malloc(sizeof(PROJECTILE));
SDWORD tarHeight, srcHeight;
int32_t altChange, dx, dy, dz;
int32_t dx, dy, dz;
uint32_t dxy;
Vector3i muzzle;
WEAPON_STATS *psStats = &asWeaponStats[psWeap->nStat];

ASSERT_OR_RETURN( false, psWeap->nStat < numWeaponStats, "Invalid range referenced for numWeaponStats, %d > %d", psWeap->nStat, numWeaponStats);
Expand All @@ -394,33 +392,30 @@ BOOL proj_SendProjectile(WEAPON *psWeap, BASE_OBJECT *psAttacker, int player, Ve
{
// if there isn't an attacker just start at the target position
// NB this is for the script function to fire the las sats
muzzle = target;
psProj->src = target;
}
else if (psAttacker->type == OBJ_DROID && weapon_slot >= 0)
{
calcDroidMuzzleLocation( (DROID *) psAttacker, &muzzle, weapon_slot);
calcDroidMuzzleLocation((DROID *)psAttacker, &psProj->src, weapon_slot);
/*update attack runs for VTOL droid's each time a shot is fired*/
updateVtolAttackRun((DROID *)psAttacker, weapon_slot);
}
else if (psAttacker->type == OBJ_STRUCTURE && weapon_slot >= 0)
{
calcStructureMuzzleLocation( (STRUCTURE *) psAttacker, &muzzle, weapon_slot);
calcStructureMuzzleLocation((STRUCTURE *)psAttacker, &psProj->src, weapon_slot);
}
else // incase anything wants a projectile
{
muzzle = psAttacker->pos;
psProj->src = psAttacker->pos;
}

/* Initialise the structure */
psProj->id = ProjectileTrackerID |(gameTime2 >>4); // make unique id
psProj->type = OBJ_PROJECTILE;
psProj->psWStats = psStats;

psProj->pos = muzzle;
psProj->startX = muzzle.x;
psProj->startY = muzzle.y;
psProj->tarX = target.x;
psProj->tarY = target.y;
psProj->pos = psProj->src;
psProj->dst = target;

psProj->player = player;
psProj->bVisible = false;
Expand Down Expand Up @@ -468,23 +463,16 @@ BOOL proj_SendProjectile(WEAPON *psWeap, BASE_OBJECT *psAttacker, int player, Ve
{
scoreUpdateVar(WD_SHOTS_ON_TARGET);

tarHeight = psTarget->pos.z + gameRand(establishTargetHeight(psTarget));
psProj->dst.z = psTarget->pos.z + gameRand(establishTargetHeight(psTarget));
}
else
{
tarHeight = target.z;
scoreUpdateVar(WD_SHOTS_OFF_TARGET);
}

srcHeight = muzzle.z;
altChange = tarHeight - srcHeight;

psProj->srcHeight = srcHeight;
psProj->altChange = altChange;

dx = ((SDWORD)psProj->tarX) - muzzle.x;
dy = ((SDWORD)psProj->tarY) - muzzle.y;
dz = tarHeight - muzzle.z;
dx = psProj->dst.x - psProj->src.x;
dy = psProj->dst.y - psProj->src.y;
dz = psProj->dst.z - psProj->src.z;

/* roll never set */
psProj->rot.roll = 0;
Expand Down Expand Up @@ -685,7 +673,7 @@ static void proj_InFlightFunc(PROJECTILE *psProj, bool bIndirect)
/* we want a delay between Las-Sats firing and actually hitting in multiPlayer
magic number but that's how long the audio countdown message lasts! */
if (bMultiPlayer && psStats->weaponSubClass == WSC_LAS_SAT &&
timeSoFar < LAS_SAT_DELAY * GAME_TICKS_PER_SEC)
(unsigned)timeSoFar < LAS_SAT_DELAY * GAME_TICKS_PER_SEC)
{
return;
}
Expand Down Expand Up @@ -733,22 +721,22 @@ static void proj_InFlightFunc(PROJECTILE *psProj, bool bIndirect)
if (psStats->movementModel == MM_HOMINGDIRECT && psProj->psDest)
{
/* If it's homing and it has a target (not a miss)... */
move.x = psProj->psDest->pos.x - psProj->startX;
move.y = psProj->psDest->pos.y - psProj->startY;
move.z = psProj->psDest->pos.z + establishTargetHeight(psProj->psDest)/2 - psProj->srcHeight;
move.x = psProj->psDest->pos.x - psProj->src.x;
move.y = psProj->psDest->pos.y - psProj->src.y;
move.z = psProj->psDest->pos.z + establishTargetHeight(psProj->psDest)/2 - psProj->src.z;
}
else
{
move.x = psProj->tarX - psProj->startX;
move.y = psProj->tarY - psProj->startY;
move.x = psProj->dst.x - psProj->src.x;
move.y = psProj->dst.y - psProj->src.y;
// LASSAT doesn't have a z
if(psStats->weaponSubClass == WSC_LAS_SAT)
{
move.z = 0;
}
else if (!bIndirect)
{
move.z = psProj->altChange;
move.z = psProj->dst.z - psProj->src.z;
}
else
{
Expand All @@ -775,23 +763,23 @@ static void proj_InFlightFunc(PROJECTILE *psProj, bool bIndirect)
distancePercent = PERCENT(currentDistance, targetDistance);

/* Calculate next position */
nextPos.x = psProj->startX + move.x * currentDistance/targetDistance;
nextPos.y = psProj->startY + move.y * currentDistance/targetDistance;
nextPos.x = psProj->src.x + move.x * currentDistance/targetDistance;
nextPos.y = psProj->src.y + move.y * currentDistance/targetDistance;
if (!bIndirect)
{
nextPos.z = psProj->srcHeight + move.z * currentDistance/targetDistance;
nextPos.z = psProj->src.z + move.z * currentDistance/targetDistance;
}
else
{
nextPos.z = psProj->srcHeight + move.z;
nextPos.z = psProj->src.z + move.z;
}

/* impact if about to go off map else update coordinates */
if (!worldOnMap(nextPos.x, nextPos.y))
{
psProj->state = PROJ_IMPACT;
psProj->tarX = psProj->pos.x;
psProj->tarY = psProj->pos.y;
psProj->dst.x = psProj->pos.x;
psProj->dst.y = psProj->pos.y;
setProjectileDestination(psProj, NULL);
debug(LOG_NEVER, "**** projectile(%i) off map - removed ****\n", psProj->id);
return;
Expand Down Expand Up @@ -906,21 +894,16 @@ static void proj_InFlightFunc(PROJECTILE *psProj, bool bIndirect)
{
WEAPON asWeap;
// Determine position to fire a missile at
// (must be at least 0 because we don't use signed integers
// this shouldn't be larger than the height and width of the map either)
Vector3i newDest = {
psProj->startX + move.x * distanceExtensionFactor,
psProj->startY + move.y * distanceExtensionFactor,
psProj->srcHeight + move.z * distanceExtensionFactor
psProj->src.x + move.x * distanceExtensionFactor/100,
psProj->src.y + move.y * distanceExtensionFactor/100,
psProj->src.z + move.z * distanceExtensionFactor/100
};
memset(&asWeap, 0, sizeof(asWeap));
asWeap.nStat = psStats - asWeaponStats;

ASSERT(distanceExtensionFactor != 0, "Unitialized variable used! distanceExtensionFactor is not initialized.");

newDest.x = clip(newDest.x, 0, world_coord(mapWidth - 1));
newDest.y = clip(newDest.y, 0, world_coord(mapHeight - 1));

// Assume we damaged the chosen target
setProjectileDamaged(psProj, closestCollisionObject);

Expand Down Expand Up @@ -1230,7 +1213,7 @@ static void proj_ImpactFunc( PROJECTILE *psObj )
if ((((psStats->surfaceToAir & SHOOT_IN_AIR) && bTargetInAir) || ((psStats->surfaceToAir & SHOOT_ON_GROUND) && !bTargetInAir))
&& Vector3i_InSphere(psCurrD->pos, psObj->pos, psStats->radius))
{
int dice = gameRand(100);
unsigned dice = gameRand(100);
if (dice < weaponRadiusHit(psStats, psObj->player))
{
unsigned int damage = calcDamage(
Expand Down Expand Up @@ -1278,7 +1261,7 @@ static void proj_ImpactFunc( PROJECTILE *psObj )
// Check whether it is in hit radius
if (Vector3i_InCircle(psCurrS->pos, psObj->pos, psStats->radius))
{
int dice = gameRand(100);
unsigned dice = gameRand(100);
if (dice < weaponRadiusHit(psStats, psObj->player))
{
unsigned int damage = calcDamage(weaponRadDamage(psStats, psObj->player), psStats->weaponEffect, (BASE_OBJECT *)psCurrS);
Expand Down Expand Up @@ -1324,7 +1307,7 @@ static void proj_ImpactFunc( PROJECTILE *psObj )
// Check whether it is in hit radius
if (Vector3i_InCircle(psCurrF->pos, psObj->pos, psStats->radius))
{
int dice = gameRand(100);
unsigned dice = gameRand(100);
if (dice < weaponRadiusHit(psStats, psObj->player))
{
debug(LOG_NEVER, "Damage to object %d, player %d\n",
Expand Down Expand Up @@ -1534,7 +1517,7 @@ static void proj_checkBurnDamage( BASE_OBJECT *apsList, PROJECTILE *psProj)
/* Within the bounding box, now check the radius */
xDiff = psCurr->pos.x - psProj->pos.x;
yDiff = psCurr->pos.y - psProj->pos.y;
if (xDiff*xDiff + yDiff*yDiff <= radSquared)
if ((uint32_t)(xDiff*xDiff + yDiff*yDiff) <= radSquared)
{
/* The object is in the fire */
psCurr->inFire |= IN_FIRE;
Expand Down Expand Up @@ -1760,7 +1743,7 @@ static HIT_SIDE getHitSide(PROJECTILE *psObj, BASE_OBJECT *psTarget)
int impactAngle;

// If we hit the top of the droid
if (psObj->altChange > 300)
if (psObj->dst.z - psObj->src.z > 300)
{
return HIT_SIDE_TOP;
}
Expand All @@ -1772,8 +1755,8 @@ static HIT_SIDE getHitSide(PROJECTILE *psObj, BASE_OBJECT *psTarget)
// We hit an actual `side'
else
{
deltaX = psObj->startX - psTarget->pos.x;
deltaY = psObj->startY - psTarget->pos.y;
deltaX = psObj->src.x - psTarget->pos.x;
deltaY = psObj->src.y - psTarget->pos.y;

/*
* Work out the impact angle. It is easiest to understand if you
Expand Down
6 changes: 2 additions & 4 deletions src/projectiledef.h
View file
Expand Up @@ -52,11 +52,9 @@ typedef struct PROJECTILE
BASE_OBJECT ** psDamaged; ///< the targets that have already been dealt damage to (don't damage the same target twice)
unsigned psNumDamaged;

UDWORD startX, startY; ///< Where projectile started
UDWORD tarX, tarY; ///< The target coordinates
Vector3i src; ///< Where projectile started
Vector3i dst; ///< The target coordinates
SDWORD vXY, vZ; ///< axis velocities
UDWORD srcHeight; ///< Height of origin
SDWORD altChange; ///< Change in altitude
SPACETIME prevSpacetime; ///< Location of projectile in previous tick.
UDWORD expectedDamageCaused; ///< Expected damage that this projectile will cause to the target.
} PROJECTILE;
Expand Down

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