1 files changed, 128 insertions, 0 deletions

diff --git a/src/tables.c b/src/tables.c
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+++ b/src/tables.c
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+/* Emacs style mode select   -*- C++ -*-
+ *-----------------------------------------------------------------------------
+ *
+ *
+ *  PrBoom: a Doom port merged with LxDoom and LSDLDoom
+ *  based on BOOM, a modified and improved DOOM engine
+ *  Copyright (C) 1999 by
+ *  id Software, Chi Hoang, Lee Killough, Jim Flynn, Rand Phares, Ty Halderman
+ *  Copyright (C) 1999-2000 by
+ *  Jess Haas, Nicolas Kalkhof, Colin Phipps, Florian Schulze
+ *  Copyright 2005, 2006 by
+ *  Florian Schulze, Colin Phipps, Neil Stevens, Andrey Budko
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ *  02111-1307, USA.
+ *
+ * DESCRIPTION:
+ *      Lookup tables.
+ *      Do not try to look them up :-).
+ *      In the order of appearance:
+ *
+ *      int finetangent[4096]   - Tangens LUT.
+ *       Should work with BAM fairly well (12 of 16bit,
+ *      effectively, by shifting).
+ *
+ *      int finesine[10240]             - Sine lookup.
+ *       Guess what, serves as cosine, too.
+ *       Remarkable thing is, how to use BAMs with this?
+ *
+ *      int tantoangle[2049]    - ArcTan LUT,
+ *        maps tan(angle) to angle fast. Gotta search.
+ *
+ *-----------------------------------------------------------------------------
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stddef.h>
+#include "w_wad.h"
+#include "tables.h"
+
+// killough 5/3/98: reformatted
+
+int SlopeDiv(unsigned num, unsigned den)
+{
+  unsigned ans;
+
+  if (den < 512)
+    return SLOPERANGE;
+  ans = (num<<3)/(den>>8);
+  return ans <= SLOPERANGE ? ans : SLOPERANGE;
+}
+
+fixed_t finetangent[4096];
+
+//const fixed_t *const finecosine = &finesine[FINEANGLES/4];
+
+fixed_t finesine[10240];
+
+angle_t tantoangle[2049];
+
+#include "m_swap.h"
+#include "lprintf.h"
+
+// R_LoadTrigTables
+// Load trig tables from a wad file lump
+// CPhipps 24/12/98 - fix endianness (!)
+//
+void R_LoadTrigTables(void)
+{
+  int lump;
+  {
+    lump = (W_CheckNumForName)("SINETABL",ns_prboom);
+    if (lump == -1) I_Error("Failed to locate trig tables");
+    if (W_LumpLength(lump) != sizeof(finesine))
+      I_Error("R_LoadTrigTables: Invalid SINETABL");
+    W_ReadLump(lump,(unsigned char*)finesine);
+  }
+  {
+    lump = (W_CheckNumForName)("TANGTABL",ns_prboom);
+    if (lump == -1) I_Error("Failed to locate trig tables");
+    if (W_LumpLength(lump) != sizeof(finetangent))
+      I_Error("R_LoadTrigTables: Invalid TANGTABL");
+    W_ReadLump(lump,(unsigned char*)finetangent);
+  }
+  {
+    lump = (W_CheckNumForName)("TANTOANG",ns_prboom);
+    if (lump == -1) I_Error("Failed to locate trig tables");
+    if (W_LumpLength(lump) != sizeof(tantoangle))
+      I_Error("R_LoadTrigTables: Invalid TANTOANG");
+    W_ReadLump(lump,(unsigned char*)tantoangle);
+  }
+  // Endianness correction - might still be non-portable, but is fast where possible
+  {
+    size_t n;
+    lprintf(LO_INFO, "Endianness...");
+
+    // This test doesn't assume the endianness of the tables, but deduces them from
+    // en entry. I hope this is portable.
+    if ((10 < finesine[1]) && (finesine[1] < 100)) {
+      lprintf(LO_INFO, "ok.");
+      return; // Endianness is correct
+    }
+
+    // Must correct endianness of every long loaded (!)
+#define CORRECT_TABLE_ENDIAN(tbl) \
+    for (n = 0; n<sizeof(tbl)/sizeof(tbl[0]); n++) tbl[n] = doom_swap_l(tbl[n])
+
+    CORRECT_TABLE_ENDIAN(finesine);
+    CORRECT_TABLE_ENDIAN(finetangent);
+    CORRECT_TABLE_ENDIAN(tantoangle);
+    lprintf(LO_INFO, "corrected.");
+  }
+}