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0x1337c0de / Toward a better DoRespawn
« on: March 22, 2020, 04:20:47 AM »
Every time I had to look at DoRespawn it always annoyed me to see these lines in it:
and
The crazy comma operators and the dangling semicolon always pressed my WFT button.
Since my age and health conditions make it dangerous for me to venture forth into the dirty world of Coronavirus infestations and since zombie-making infection carriers are indistinguishable from normal humans unless you have infrared vision to spot the fevers, I am confined to my home for the weekend, doing my part to flatten the curve and save the world. I was "essential personnel" Friday and I will be again Monday but once I solve one problem Monday I will be back to saving the world by not participating in it.
So I decided to focus on this one function in Q2 mods called DoRespawn. This is the "Think" function that gets triggered when it's time to respawn items like armor shards, armor jackets, weapons, health boxes and pills, megas, etc. Anything that gets picked up and needs to be respawned after a scheduled time period.
Modern C has different rules than it did back in the days of the creation of Q2 and Microsoft Visual C++ of 1997. Some idioms remain but the particular idiom used by Zoid just makes a code maintainer stop and say "Oh? Hmmmm." Modern C compilers are also better at optimizing code so it's not necessary to resort to idioms in an attempt to make the code faster. Succinct C is not necessarily efficient C.
So here's a fix for the most basic version of DoRespawn with the idiomatic syntax removed and some error checking and reporting in place and some coverage for cases of null pointer dereference. Some versions have more code in place to take various actions on respawn but my primary goal was to refactor the for loops into something more easily understood at a glance and to maintain.
QW
Code: [Select]
for (count = 0, ent = master; ent; ent = ent->chain, count++)
;
and
Code: [Select]
for (count = 0, ent = master; count < choice; ent = ent->chain, count++)
;
The crazy comma operators and the dangling semicolon always pressed my WFT button.
Since my age and health conditions make it dangerous for me to venture forth into the dirty world of Coronavirus infestations and since zombie-making infection carriers are indistinguishable from normal humans unless you have infrared vision to spot the fevers, I am confined to my home for the weekend, doing my part to flatten the curve and save the world. I was "essential personnel" Friday and I will be again Monday but once I solve one problem Monday I will be back to saving the world by not participating in it.
So I decided to focus on this one function in Q2 mods called DoRespawn. This is the "Think" function that gets triggered when it's time to respawn items like armor shards, armor jackets, weapons, health boxes and pills, megas, etc. Anything that gets picked up and needs to be respawned after a scheduled time period.
Modern C has different rules than it did back in the days of the creation of Q2 and Microsoft Visual C++ of 1997. Some idioms remain but the particular idiom used by Zoid just makes a code maintainer stop and say "Oh? Hmmmm." Modern C compilers are also better at optimizing code so it's not necessary to resort to idioms in an attempt to make the code faster. Succinct C is not necessarily efficient C.
So here's a fix for the most basic version of DoRespawn with the idiomatic syntax removed and some error checking and reporting in place and some coverage for cases of null pointer dereference. Some versions have more code in place to take various actions on respawn but my primary goal was to refactor the for loops into something more easily understood at a glance and to maintain.
Code: [Select]
void DoRespawn(edict_t* ent)
{
if (ent == NULL)
{
gi.dprintf("NULL ent passed to %s\n", __func__);
return;
}
if (ent->team)
{
edict_t* master;
unsigned count;
unsigned choice;
master = ent->teammaster;
if (master == NULL)
return;
count = 0;
for (ent = master; ent; ent = ent->chain)
count++;
assert(count != 0);
choice = rand() % count;
count = 0;
for (ent = master; count < choice; ent = ent->chain)
count++;
}
if (ent)
{
ent->svflags &= ~SVF_NOCLIENT;
ent->solid = SOLID_TRIGGER;
gi.linkentity(ent);
// send an effect
ent->s.event = EV_ITEM_RESPAWN;
}
}QW
