TakeV/dxx-rebirth
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Step powerup frame number carefully

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Avoid relying on integer underflow when checking for moving the current
frame number outside the range of frames.
This commit is contained in:
Kp 2012-12-02 06:57:22 +00:00
parent e4b091dd38
commit 3a8ca07132
1 changed files with 19 additions and 9 deletions
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28
similar/main/powerup.cpp
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@ -66,7 +66,8 @@ void do_powerup_frame(object *obj)
#if defined(DXX_BUILD_DESCENT_I)
fudge = 0;
#elif defined(DXX_BUILD_DESCENT_II)
fudge = (FrameTime * ((obj-Objects)&3)) >> 4;
long objnum = obj-Objects;
fudge = (FrameTime * (objnum&3)) >> 4;
#endif
vci->frametime -= FrameTime+fudge;
@ -74,14 +75,6 @@ void do_powerup_frame(object *obj)
while (vci->frametime < 0 ) {
vci->frametime += vc->frame_time;
#if defined(DXX_BUILD_DESCENT_II)
if ((obj-Objects)&1)
vci->framenum--;
else
#endif
vci->framenum++;
if (vci->framenum >= vc->num_frames)
vci->framenum=0;
@ -89,6 +82,23 @@ void do_powerup_frame(object *obj)
if (vci->framenum < 0)
vci->framenum = vc->num_frames-1;
#endif
#if defined(DXX_BUILD_DESCENT_II)
if (objnum&1)
{
if (vci->framenum)
vci->framenum--;
else
vci->framenum = vc->num_frames-1;
}
else
#endif
{
if (vci->framenum >= vc->num_frames-1)
vci->framenum=0;
else
vci->framenum++;
}
}
if (obj->lifeleft <= 0) {