ref: a46588d36c95922d3b42c08c4ccec54b32b94b1c
parent: b2d085aea4e0a5986a9347fce6bd8be6d141cb59
author: Simon Howard <fraggle@gmail.com>
date: Sat Jan 7 14:11:54 EST 2006
Import the spechit overrun code from prboom-plus. Thanks to Andrey Budko for his investigation into this behavior. Subversion-branch: /trunk/chocolate-doom Subversion-revision: 260
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,8 @@
any sample rate now play, but only sounds with valid headers.
This is the *real* way Vanilla Doom behaves. Thanks to myk for
pointing out the incorrect behavior.
+ Imported the spechit overrun emulation code from prboom-plus. Thanks to
+ Andrey Budko for this.
0.1.2 (2005-10-29):
--- a/src/p_map.c
+++ b/src/p_map.c
@@ -1,10 +1,10 @@
// Emacs style mode select -*- C++ -*-
//-----------------------------------------------------------------------------
//
-// $Id: p_map.c 212 2005-10-17 22:07:26Z fraggle $
+// $Id: p_map.c 260 2006-01-07 19:11:54Z fraggle $
//
// Copyright(C) 1993-1996 Id Software, Inc.
-// Copyright(C) 2005 Simon Howard
+// Copyright(C) 2005 Simon Howard, Andrey Budko
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
@@ -22,6 +22,10 @@
// 02111-1307, USA.
//
// $Log$
+// Revision 1.4 2006/01/07 19:11:54 fraggle
+// Import the spechit overrun code from prboom-plus. Thanks to Andrey Budko
+// for his investigation into this behavior.
+//
// Revision 1.3 2005/10/17 22:07:26 fraggle
// Fix "Monsters Infight"
//
@@ -39,7 +43,7 @@
//-----------------------------------------------------------------------------
static const char
-rcsid[] = "$Id: p_map.c 212 2005-10-17 22:07:26Z fraggle $";
+rcsid[] = "$Id: p_map.c 260 2006-01-07 19:11:54Z fraggle $";
#include <stdlib.h>
@@ -82,8 +86,18 @@
// keep track of special lines as they are hit,
// but don't process them until the move is proven valid
-#define MAXSPECIALCROSS 8
+// fraggle: I have increased the size of this buffer. In the original Doom,
+// overrunning past this limit caused other bits of memory to be overwritten,
+// affecting demo playback. However, in doing so, the limit was still
+// exceeded. So we have to support more than 8 specials.
+//
+// We keep the original limit, to detect what variables in memory were
+// overwritten (see SpechitOverrun())
+
+#define MAXSPECIALCROSS 20
+#define MAXSPECIALCROSS_ORIGINAL 8
+
line_t* spechit[MAXSPECIALCROSS];
int numspechit;
@@ -199,6 +213,7 @@
// MOVEMENT ITERATOR FUNCTIONS
//
+static void SpechitOverrun(line_t *ld);
//
// PIT_CheckLine
@@ -257,7 +272,14 @@
// if contacted a special line, add it to the list
if (ld->special)
{- spechit[numspechit] = ld;
+ // fraggle: spechits overrun emulation code from prboom-plus
+ if (numspechit >= MAXSPECIALCROSS_ORIGINAL)
+ {+ SpechitOverrun(ld);
+ }
+
+ spechit[numspechit] = ld;
+
numspechit++;
}
@@ -1357,5 +1379,55 @@
return nofit;
+}
+
+// Code to emulate the behavior of Vanilla Doom when encountering an overrun
+// of the spechit array. This is by Andrey Budko (e6y) and comes from his
+// PrBoom plus port. A big thanks to Andrey for this.
+
+static void SpechitOverrun(line_t *ld)
+{+ int addr = 0x01C09C98 + (ld - lines) * 0x3E;
+
+ printf("Emulating spechit overrun, numspechit=%i\n", numspechit);+
+ switch(numspechit)
+ {+ case 9:
+ case 10:
+ case 11:
+ case 12:
+ tmbbox[numspechit-9] = addr;
+ break;
+ case 13:
+ crushchange = addr;
+ break;
+ case 14:
+ nofit = addr;
+ break;
+ case 15:
+ bombsource = (mobj_t*)addr;
+ break;
+ case 16:
+ bombdamage = addr;
+ break;
+ case 17:
+ bombspot = (mobj_t*)addr;
+ break;
+ case 18:
+ usething = (mobj_t*)addr;
+ break;
+ case 19:
+ attackrange = addr;
+ break;
+ case 20:
+ la_damage = addr;
+ break;
+ default:
+ fprintf(stderr, "SpechitOverrun: Warning: unable to emulate"
+ "an overrun where numspechit=%i\n",
+ numspechit);
+ break;
+ }
}