commit 5ac7ac324198351603d07f8895a53ec906653ff7
Author: Simon Howard <fraggle@gmail.com>
AuthorDate: Fri Sep 14 22:20:08 2007 +0000
Commit: Simon Howard <fraggle@gmail.com>
CommitDate: Fri Sep 14 22:20:08 2007 +0000
Add P_SubstNullMobj, substitute NULL mobjs for a dummy mobj where
mo->target is not checked for NULL.
Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 971
---
src/p_enemy.c | 37 ++++++++++++++++++++++++++-----------
src/p_local.h | 1 +
src/p_mobj.c | 55 ++++++++++++++++++++++++++-----------------------------
3 files changed, 53 insertions(+), 40 deletions(-)
diff --git a/src/p_enemy.c b/src/p_enemy.c
index 0ed7f60f..16d2ff06 100644
--- a/src/p_enemy.c
+++ b/src/p_enemy.c
@@ -1258,14 +1258,17 @@ void A_FireCrackle (mobj_t* actor)
void A_Fire (mobj_t* actor)
{
mobj_t* dest;
+ mobj_t* target;
unsigned an;
dest = actor->tracer;
if (!dest)
return;
+
+ target = P_SubstNullMobj(actor->target);
// don't move it if the vile lost sight
- if (!P_CheckSight (actor->target, dest) )
+ if (!P_CheckSight (target, dest) )
return;
an = dest->angle >> ANGLETOFINESHIFT;
@@ -1359,14 +1362,17 @@ void A_FatRaise (mobj_t *actor)
void A_FatAttack1 (mobj_t* actor)
{
mobj_t* mo;
+ mobj_t* target;
int an;
-
+
A_FaceTarget (actor);
+
// Change direction to ...
actor->angle += FATSPREAD;
- P_SpawnMissile (actor, actor->target, MT_FATSHOT);
+ target = P_SubstNullMobj(actor->target);
+ P_SpawnMissile (actor, target, MT_FATSHOT);
- mo = P_SpawnMissile (actor, actor->target, MT_FATSHOT);
+ mo = P_SpawnMissile (actor, target, MT_FATSHOT);
mo->angle += FATSPREAD;
an = mo->angle >> ANGLETOFINESHIFT;
mo->momx = FixedMul (mo->info->speed, finecosine[an]);
@@ -1376,14 +1382,16 @@ void A_FatAttack1 (mobj_t* actor)
void A_FatAttack2 (mobj_t* actor)
{
mobj_t* mo;
+ mobj_t* target;
int an;
A_FaceTarget (actor);
// Now here choose opposite deviation.
actor->angle -= FATSPREAD;
- P_SpawnMissile (actor, actor->target, MT_FATSHOT);
+ target = P_SubstNullMobj(actor->target);
+ P_SpawnMissile (actor, target, MT_FATSHOT);
- mo = P_SpawnMissile (actor, actor->target, MT_FATSHOT);
+ mo = P_SpawnMissile (actor, target, MT_FATSHOT);
mo->angle -= FATSPREAD*2;
an = mo->angle >> ANGLETOFINESHIFT;
mo->momx = FixedMul (mo->info->speed, finecosine[an]);
@@ -1393,17 +1401,20 @@ void A_FatAttack2 (mobj_t* actor)
void A_FatAttack3 (mobj_t* actor)
{
mobj_t* mo;
+ mobj_t* target;
int an;
A_FaceTarget (actor);
+
+ target = P_SubstNullMobj(actor->target);
- mo = P_SpawnMissile (actor, actor->target, MT_FATSHOT);
+ mo = P_SpawnMissile (actor, target, MT_FATSHOT);
mo->angle -= FATSPREAD/2;
an = mo->angle >> ANGLETOFINESHIFT;
mo->momx = FixedMul (mo->info->speed, finecosine[an]);
mo->momy = FixedMul (mo->info->speed, finesine[an]);
- mo = P_SpawnMissile (actor, actor->target, MT_FATSHOT);
+ mo = P_SpawnMissile (actor, target, MT_FATSHOT);
mo->angle += FATSPREAD/2;
an = mo->angle >> ANGLETOFINESHIFT;
mo->momx = FixedMul (mo->info->speed, finecosine[an]);
@@ -1598,7 +1609,11 @@ void A_Fall (mobj_t *actor)
//
void A_Explode (mobj_t* thingy)
{
- P_RadiusAttack ( thingy, thingy->target, 128 );
+ mobj_t *target;
+
+ target = P_SubstNullMobj(thingy->target);
+
+ P_RadiusAttack(thingy, target, 128);
}
@@ -1823,7 +1838,7 @@ A_CloseShotgun2
mobj_t* braintargets[32];
int numbraintargets;
-int braintargeton;
+int braintargeton = 0;
void A_BrainAwake (mobj_t* mo)
{
@@ -1959,7 +1974,7 @@ void A_SpawnFly (mobj_t* mo)
if (--mo->reactiontime)
return; // still flying
- targ = mo->target;
+ targ = P_SubstNullMobj(mo->target);
// First spawn teleport fog.
fog = P_SpawnMobj (targ->x, targ->y, targ->z, MT_SPAWNFIRE);
diff --git a/src/p_local.h b/src/p_local.h
index d58a7708..2e602ad5 100644
--- a/src/p_local.h
+++ b/src/p_local.h
@@ -119,6 +119,7 @@ P_SpawnMobj
mobjtype_t type );
void P_RemoveMobj (mobj_t* th);
+mobj_t* P_SubstNullMobj (mobj_t* th);
boolean P_SetMobjState (mobj_t* mobj, statenum_t state);
void P_MobjThinker (mobj_t* mobj);
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 29dafdec..bb72166d 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -922,6 +922,28 @@ void P_CheckMissileSpawn (mobj_t* th)
P_ExplodeMissile (th);
}
+// Certain functions assume that a mobj_t pointer is non-NULL,
+// causing a crash in some situations where it is NULL. Vanilla
+// Doom did not crash because of the lack of proper memory
+// protection. This function substitutes NULL pointers for
+// pointers to a dummy mobj, to avoid a crash.
+
+mobj_t *P_SubstNullMobj(mobj_t *mobj)
+{
+ if (mobj == NULL)
+ {
+ static mobj_t dummy_mobj;
+
+ dummy_mobj.x = 0;
+ dummy_mobj.y = 0;
+ dummy_mobj.z = 0;
+ dummy_mobj.flags = 0;
+
+ mobj = &dummy_mobj;
+ }
+
+ return mobj;
+}
//
// P_SpawnMissile
@@ -935,31 +957,6 @@ P_SpawnMissile
mobj_t* th;
angle_t an;
int dist;
- fixed_t dest_x, dest_y, dest_z, dest_flags;
-
- // fraggle: This prevents against *crashes* when dest == NULL.
- // For example, when loading a game saved when a mancubus was
- // in the middle of firing, mancubus->target == NULL. SpawnMissile
- // then gets called with dest == NULL.
- //
- // However, this is not the *correct* behavior. At the moment,
- // the missile is aimed at 0,0,0. In reality, monsters seem to aim
- // somewhere else.
-
- if (dest)
- {
- dest_x = dest->x;
- dest_y = dest->y;
- dest_z = dest->z;
- dest_flags = dest->flags;
- }
- else
- {
- dest_x = 0;
- dest_y = 0;
- dest_z = 0;
- dest_flags = 0;
- }
th = P_SpawnMobj (source->x,
source->y,
@@ -969,10 +966,10 @@ P_SpawnMissile
S_StartSound (th, th->info->seesound);
th->target = source; // where it came from
- an = R_PointToAngle2 (source->x, source->y, dest_x, dest_y);
+ an = R_PointToAngle2 (source->x, source->y, dest->x, dest->y);
// fuzzy player
- if (dest_flags & MF_SHADOW)
+ if (dest->flags & MF_SHADOW)
an += (P_Random()-P_Random())<<20;
th->angle = an;
@@ -980,13 +977,13 @@ P_SpawnMissile
th->momx = FixedMul (th->info->speed, finecosine[an]);
th->momy = FixedMul (th->info->speed, finesine[an]);
- dist = P_AproxDistance (dest_x - source->x, dest_y - source->y);
+ dist = P_AproxDistance (dest->x - source->x, dest->y - source->y);
dist = dist / th->info->speed;
if (dist < 1)
dist = 1;
- th->momz = (dest_z - source->z) / dist;
+ th->momz = (dest->z - source->z) / dist;
P_CheckMissileSpawn (th);
return th;