diff options
Diffstat (limited to 'src/doom/p_spec.c')
| -rw-r--r-- | src/doom/p_spec.c | 150 |
1 files changed, 138 insertions, 12 deletions
diff --git a/src/doom/p_spec.c b/src/doom/p_spec.c index 27042b5d..37beb850 100644 --- a/src/doom/p_spec.c +++ b/src/doom/p_spec.c @@ -38,6 +38,7 @@ #include "i_system.h" #include "z_zone.h" #include "m_argv.h" +#include "m_misc.h" #include "m_random.h" #include "w_wad.h" @@ -1169,10 +1170,94 @@ void P_UpdateSpecials (void) memset(&buttonlist[i],0,sizeof(button_t)); } } - } +// +// Donut overrun emulation +// +// Derived from the code from PrBoom+. Thanks go to Andrey Budko (entryway) +// as usual :-) +// + +#define DONUT_FLOORHEIGHT_DEFAULT 0x00000000 +#define DONUT_FLOORPIC_DEFAULT 0x16 + +static void DonutOverrun(fixed_t *s3_floorheight, short *s3_floorpic, + line_t *line, sector_t *pillar_sector) +{ + static int first = 1; + static int tmp_s3_floorheight; + static int tmp_s3_floorpic; + + extern int numflats; + + if (first) + { + int p; + + // This is the first time we have had an overrun. + first = 0; + + // Default values + tmp_s3_floorheight = DONUT_FLOORHEIGHT_DEFAULT; + tmp_s3_floorpic = DONUT_FLOORPIC_DEFAULT; + + //! + // @category compat + // @arg <x> <y> + // + // Use the specified magic values when emulating behavior caused + // by memory overruns from improperly constructed donuts. + // In Vanilla Doom this can differ depending on the operating + // system. The default (if this option is not specified) is to + // emulate the behavior when running under Windows 98. + + p = M_CheckParm("-donut"); + + if (p > 0 && p < myargc - 2) + { + // Dump of needed memory: (fixed_t)0000:0000 and (short)0000:0008 + // + // C:\>debug + // -d 0:0 + // + // DOS 6.22: + // 0000:0000 (57 92 19 00) F4 06 70 00-(16 00) + // DOS 7.1: + // 0000:0000 (9E 0F C9 00) 65 04 70 00-(16 00) + // Win98: + // 0000:0000 (00 00 00 00) 65 04 70 00-(16 00) + // DOSBox under XP: + // 0000:0000 (00 00 00 F1) ?? ?? ?? 00-(07 00) + + M_StrToInt(myargv[p + 1], &tmp_s3_floorheight); + M_StrToInt(myargv[p + 2], &tmp_s3_floorpic); + + if (tmp_s3_floorpic >= numflats) + { + fprintf(stderr, + "DonutOverrun: The second parameter for \"-donut\" " + "switch should be greater than 0 and less than number " + "of flats (%d). Using default value (%d) instead. \n", + numflats, DONUT_FLOORPIC_DEFAULT); + tmp_s3_floorpic = DONUT_FLOORPIC_DEFAULT; + } + } + } + + /* + fprintf(stderr, + "Linedef: %d; Sector: %d; " + "New floor height: %d; New floor pic: %d\n", + line->iLineID, pillar_sector->iSectorID, + tmp_s3_floorheight >> 16, tmp_s3_floorpic); + */ + + *s3_floorheight = (fixed_t) tmp_s3_floorheight; + *s3_floorpic = (short) tmp_s3_floorpic; +} + // // Special Stuff that can not be categorized @@ -1186,26 +1271,67 @@ int EV_DoDonut(line_t* line) int rtn; int i; floormove_t* floor; - + fixed_t s3_floorheight; + short s3_floorpic; + secnum = -1; rtn = 0; while ((secnum = P_FindSectorFromLineTag(line,secnum)) >= 0) { s1 = §ors[secnum]; - + // ALREADY MOVING? IF SO, KEEP GOING... if (s1->specialdata) continue; - + rtn = 1; s2 = getNextSector(s1->lines[0],s1); - for (i = 0;i < s2->linecount;i++) + + // Vanilla Doom does not check if the linedef is one sided. The + // game does not crash, but reads invalid memory and causes the + // sector floor to move "down" to some unknown height. + // DOSbox prints a warning about an invalid memory access. + // + // I'm not sure exactly what invalid memory is being read. This + // isn't something that should be done, anyway. + // Just print a warning and return. + + if (s2 == NULL) + { + fprintf(stderr, + "EV_DoDonut: linedef had no second sidedef! " + "Unexpected behavior may occur in Vanilla Doom. \n"); + break; + } + + for (i = 0; i < s2->linecount; i++) { - if ((!s2->lines[i]->flags & ML_TWOSIDED) || - (s2->lines[i]->backsector == s1)) - continue; s3 = s2->lines[i]->backsector; - + + if (s3 == s1) + continue; + + if (s3 == NULL) + { + // e6y + // s3 is NULL, so + // s3->floorheight is an int at 0000:0000 + // s3->floorpic is a short at 0000:0008 + // Trying to emulate + + fprintf(stderr, + "EV_DoDonut: WARNING: emulating buffer overrun due to " + "NULL back sector. " + "Unexpected behavior may occur in Vanilla Doom.\n"); + + DonutOverrun(&s3_floorheight, &s3_floorpic, line, s1); + } + else + { + s3_floorheight = s3->floorheight; + s3_floorpic = s3->floorpic; + } + // Spawn rising slime floor = Z_Malloc (sizeof(*floor), PU_LEVSPEC, 0); P_AddThinker (&floor->thinker); @@ -1216,9 +1342,9 @@ int EV_DoDonut(line_t* line) floor->direction = 1; floor->sector = s2; floor->speed = FLOORSPEED / 2; - floor->texture = s3->floorpic; + floor->texture = s3_floorpic; floor->newspecial = 0; - floor->floordestheight = s3->floorheight; + floor->floordestheight = s3_floorheight; // Spawn lowering donut-hole floor = Z_Malloc (sizeof(*floor), PU_LEVSPEC, 0); @@ -1230,7 +1356,7 @@ int EV_DoDonut(line_t* line) floor->direction = -1; floor->sector = s1; floor->speed = FLOORSPEED / 2; - floor->floordestheight = s3->floorheight; + floor->floordestheight = s3_floorheight; break; } } |