Heretic: update P_GroupLines and (re-)create BLOCKMAP if necessary

src/heretic/CMakeLists.txt

@@ -21,6 +21,7 @@ add_library(heretic STATIC
             m_random.c          m_random.h
             mn_menu.c
                                 p_action.h
+            p_blockmap.c
             p_ceilng.c
             p_doors.c
             p_enemy.c

src/heretic/Makefile.am

@@ -32,6 +32,7 @@ in_lude.c                                            \
 m_random.c             m_random.h                    \
 mn_menu.c                                            \
                        p_action.h                    \
+p_blockmap.c                                         \
 p_ceilng.c                                           \
 p_doors.c                                            \
 p_enemy.c                                            \

src/heretic/doomdef.h

@@ -763,6 +763,9 @@ void P_Ticker(void);
 // can call G_PlayerExited
 // carries out all thinking of monsters and players
 
+// [crispy] (re-)create BLOCKMAP if necessary
+void P_CreateBlockMap(void);
+
 void P_SetupLevel(int episode, int map, int playermask, skill_t skill);
 // called by W_Ticker
 

src/heretic/p_blockmap.c

@@ -0,0 +1,194 @@
+//
+// Copyright(C) 1993-1996 Id Software, Inc.
+// Copyright(C) 1999 id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
+// Copyright(C) 2005-2014 Simon Howard
+// Copyright(C) 2017 Fabian Greffrath
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// DESCRIPTION:
+//	[crispy] Create Blockmap
+//
+
+#include <stdlib.h>
+#include "i_system.h"
+#include "p_local.h"
+#include "z_zone.h"
+
+// [crispy] taken from mbfsrc/P_SETUP.C:547-707, slightly adapted
+
+void P_CreateBlockMap(void)
+{
+  register int i;
+  fixed_t minx = INT_MAX, miny = INT_MAX, maxx = INT_MIN, maxy = INT_MIN;
+
+  // First find limits of map
+
+  for (i=0; i<numvertexes; i++)
+    {
+      if (vertexes[i].x >> FRACBITS < minx)
+	minx = vertexes[i].x >> FRACBITS;
+      else
+	if (vertexes[i].x >> FRACBITS > maxx)
+	  maxx = vertexes[i].x >> FRACBITS;
+      if (vertexes[i].y >> FRACBITS < miny)
+	miny = vertexes[i].y >> FRACBITS;
+      else
+	if (vertexes[i].y >> FRACBITS > maxy)
+	  maxy = vertexes[i].y >> FRACBITS;
+    }
+
+#if 0
+  // [crispy] doombsp/DRAWING.M:175-178
+  minx -= 8; miny -= 8;
+  maxx += 8; maxy += 8;
+#endif
+
+  // Save blockmap parameters
+
+  bmaporgx = minx << FRACBITS;
+  bmaporgy = miny << FRACBITS;
+  bmapwidth  = ((maxx-minx) >> MAPBTOFRAC) + 1;
+  bmapheight = ((maxy-miny) >> MAPBTOFRAC) + 1;
+
+  // Compute blockmap, which is stored as a 2d array of variable-sized lists.
+  //
+  // Pseudocode:
+  //
+  // For each linedef:
+  //
+  //   Map the starting and ending vertices to blocks.
+  //
+  //   Starting in the starting vertex's block, do:
+  //
+  //     Add linedef to current block's list, dynamically resizing it.
+  //
+  //     If current block is the same as the ending vertex's block, exit loop.
+  //
+  //     Move to an adjacent block by moving towards the ending block in
+  //     either the x or y direction, to the block which contains the linedef.
+
+  {
+    typedef struct { int n, nalloc, *list; } bmap_t;  // blocklist structure
+    unsigned tot = bmapwidth * bmapheight;            // size of blockmap
+    bmap_t *bmap = calloc(sizeof *bmap, tot);         // array of blocklists
+    int x, y, adx, ady, bend;
+
+    for (i=0; i < numlines; i++)
+      {
+	int dx, dy, diff, b;
+
+	// starting coordinates
+	x = (lines[i].v1->x >> FRACBITS) - minx;
+	y = (lines[i].v1->y >> FRACBITS) - miny;
+
+	// x-y deltas
+	adx = lines[i].dx >> FRACBITS, dx = adx < 0 ? -1 : 1;
+	ady = lines[i].dy >> FRACBITS, dy = ady < 0 ? -1 : 1;
+
+	// difference in preferring to move across y (>0) instead of x (<0)
+	diff = !adx ? 1 : !ady ? -1 :
+	  (((x >> MAPBTOFRAC) << MAPBTOFRAC) +
+	   (dx > 0 ? MAPBLOCKUNITS-1 : 0) - x) * (ady = abs(ady)) * dx -
+	  (((y >> MAPBTOFRAC) << MAPBTOFRAC) +
+	   (dy > 0 ? MAPBLOCKUNITS-1 : 0) - y) * (adx = abs(adx)) * dy;
+
+	// starting block, and pointer to its blocklist structure
+	b = (y >> MAPBTOFRAC)*bmapwidth + (x >> MAPBTOFRAC);
+
+	// ending block
+	bend = (((lines[i].v2->y >> FRACBITS) - miny) >> MAPBTOFRAC) *
+	    bmapwidth + (((lines[i].v2->x >> FRACBITS) - minx) >> MAPBTOFRAC);
+
+	// delta for pointer when moving across y
+	dy *= bmapwidth;
+
+	// deltas for diff inside the loop
+	adx <<= MAPBTOFRAC;
+	ady <<= MAPBTOFRAC;
+
+	// Now we simply iterate block-by-block until we reach the end block.
+	while ((unsigned) b < tot)    // failsafe -- should ALWAYS be true
+	  {
+	    // Increase size of allocated list if necessary
+	    if (bmap[b].n >= bmap[b].nalloc)
+	      bmap[b].list = I_Realloc(bmap[b].list,
+				     (bmap[b].nalloc = bmap[b].nalloc ?
+				      bmap[b].nalloc*2 : 8)*sizeof*bmap->list);
+
+	    // Add linedef to end of list
+	    bmap[b].list[bmap[b].n++] = i;
+
+	    // If we have reached the last block, exit
+	    if (b == bend)
+	      break;
+
+	    // Move in either the x or y direction to the next block
+	    if (diff < 0)
+	      diff += ady, b += dx;
+	    else
+	      diff -= adx, b += dy;
+	  }
+      }
+
+    // Compute the total size of the blockmap.
+    //
+    // Compression of empty blocks is performed by reserving two offset words
+    // at tot and tot+1.
+    //
+    // 4 words, unused if this routine is called, are reserved at the start.
+
+    {
+      int count = tot+6;  // we need at least 1 word per block, plus reserved's
+
+      for (i = 0; i < tot; i++)
+	if (bmap[i].n)
+	  count += bmap[i].n + 2; // 1 header word + 1 trailer word + blocklist
+
+      // Allocate blockmap lump with computed count
+      blockmaplump = Z_Malloc(sizeof(*blockmaplump) * count, PU_LEVEL, 0);
+    }
+
+    // Now compress the blockmap.
+    {
+      int ndx = tot += 4;         // Advance index to start of linedef lists
+      bmap_t *bp = bmap;          // Start of uncompressed blockmap
+
+      blockmaplump[ndx++] = 0;    // Store an empty blockmap list at start
+      blockmaplump[ndx++] = -1;   // (Used for compression)
+
+      for (i = 4; i < tot; i++, bp++)
+	if (bp->n)                                      // Non-empty blocklist
+	  {
+	    blockmaplump[blockmaplump[i] = ndx++] = 0;  // Store index & header
+	    do
+	      blockmaplump[ndx++] = bp->list[--bp->n];  // Copy linedef list
+	    while (bp->n);
+	    blockmaplump[ndx++] = -1;                   // Store trailer
+	    free(bp->list);                             // Free linedef list
+	  }
+	else            // Empty blocklist: point to reserved empty blocklist
+	  blockmaplump[i] = tot;
+
+      free(bmap);    // Free uncompressed blockmap
+    }
+  }
+
+  // [crispy] copied over from P_LoadBlockMap()
+  {
+    int count = sizeof(*blocklinks) * bmapwidth * bmapheight;
+    blocklinks = Z_Malloc(count, PU_LEVEL, 0);
+    memset(blocklinks, 0, count);
+    blockmap = blockmaplump+4;
+  }
+
+  printf("P_CreateBlockMap: BLOCKMAP recreated.\n");
+}

src/heretic/p_setup.c

@@ -1,4 +1,4 @@
 //
 // Copyright(C) 1993-1996 Id Software, Inc.
 // Copyright(C) 1993-2008 Raven Software
 // Copyright(C) 2005-2014 Simon Howard
@@ -515,15 +515,20 @@
 =================
 */
 
-void P_LoadBlockMap(int lump)
+boolean P_LoadBlockMap(int lump)
 {
     int i, count;
     int lumplen;
     short *wadblockmaplump;
 
-    lumplen = W_LumpLength(lump);
-
-    count = lumplen / 2; // [crispy] remove BLOCKMAP limit
+    // [crispy] (re-)create BLOCKMAP if necessary
+    if (M_CheckParm("-blockmap") ||
+        lump >= numlumps ||
+        (lumplen = W_LumpLength(lump)) < 8 ||
+        (count = lumplen / 2) >= 0x10000)
+    {
+        return false;
+    }
 
     // [crispy] remove BLOCKMAP limit
     wadblockmaplump = Z_Malloc(lumplen, PU_LEVEL, NULL);
@@ -556,6 +561,9 @@
     count = sizeof(*blocklinks) * bmapwidth * bmapheight;
     blocklinks = Z_Malloc(count, PU_LEVEL, 0);
     memset(blocklinks, 0, count);
+
+    // [crispy] (re-)create BLOCKMAP if necessary
+    return true;
 }
 
 
@@ -568,6 +576,8 @@
 =
 = Builds sector line lists and subsector sector numbers
 = Finds block bounding boxes for sectors
+= [crispy] updated old Doom 1.2 code with actual implementation of P_GroupLines
+= from Chocolate Doom for better handling and faster loading of complex levels
 =================
 */
 
@@ -606,23 +616,51 @@
 
 // build line tables for each sector    
     linebuffer = Z_Malloc(total * sizeof(line_t *), PU_LEVEL, 0);
+    for (i = 0; i < numsectors; ++i)
+    {
+        // Assign the line buffer for this sector
+        sectors[i].lines = linebuffer;
+        linebuffer += sectors[i].linecount;
+
+        // Reset linecount to zero so in the next stage we can count
+        // lines into the list.
+        sectors[i].linecount = 0;
+    }
+
+// [crispy] assign lines to sectors
+    for (i = 0; i < numlines; ++i)
+    { 
+        li = &lines[i];
+
+        if (li->frontsector != NULL)
+        {
+            sector = li->frontsector;
+
+            sector->lines[sector->linecount] = li;
+            ++sector->linecount;
+        }
+
+        if (li->backsector != NULL && li->frontsector != li->backsector)
+        {
+            sector = li->backsector;
+
+            sector->lines[sector->linecount] = li;
+            ++sector->linecount;
+        }
+    }
+
+// [crispy] generate bounding boxes for sectors
     sector = sectors;
     for (i = 0; i < numsectors; i++, sector++)
     {
         M_ClearBox(bbox);
-        sector->lines = linebuffer;
-        li = lines;
-        for (j = 0; j < numlines; j++, li++)
+        for (j = 0; j < sector->linecount; j++)
         {
-            if (li->frontsector == sector || li->backsector == sector)
-            {
-                *linebuffer++ = li;
+                li = sector->lines[j];
+
                 M_AddToBox(bbox, li->v1->x, li->v1->y);
                 M_AddToBox(bbox, li->v2->x, li->v2->y);
-            }
         }
-        if (linebuffer - sector->lines != sector->linecount)
-            I_Error("P_GroupLines: miscounted");
 
         // set the degenmobj_t to the middle of the bounding box
         sector->soundorg.x = (bbox[BOXRIGHT] + bbox[BOXLEFT]) / 2;
@@ -720,6 +758,7 @@
     char lumpname[9];
     int lumpnum;
     mobj_t *mobj;
+    boolean crispy_validblockmap;
     mapformat_t crispy_mapformat;
 
     totalkills = totalitems = totalsecret = 0;
@@ -763,13 +802,19 @@
     maplumpinfo = lumpinfo[lumpnum];
 
 // note: most of this ordering is important     
-    P_LoadBlockMap(lumpnum + ML_BLOCKMAP);
+    crispy_validblockmap = P_LoadBlockMap(lumpnum + ML_BLOCKMAP); // [crispy] (re-)create BLOCKMAP if necessary
     P_LoadVertexes(lumpnum + ML_VERTEXES);
     P_LoadSectors(lumpnum + ML_SECTORS);
     P_LoadSideDefs(lumpnum + ML_SIDEDEFS);
 
     P_LoadLineDefs(lumpnum + ML_LINEDEFS);
 
+    // [crispy] (re-)create BLOCKMAP if necessary
+    if (!crispy_validblockmap)
+    {
+        P_CreateBlockMap();
+    }
+
     if (crispy_mapformat & (MFMT_ZDBSPX | MFMT_ZDBSPZ))
     {
         P_LoadNodes_ZDBSP(lumpnum + ML_NODES, crispy_mapformat & MFMT_ZDBSPZ);