tcdirect.cpp

一个三维打斗游戏

// (C) Copyright 1996 by Anthony J. Carin.  All Rights Reserved.

#include <stdafx.h>
#include "tcdirect.h"
#include <math.h>


direction& direction::operator *(float r)
{
    static direction ret;
    ret.m_val = (short) (recalc() * r);
    return ret;
}

char operator<(direction& a, direction& b)
{
   short r = (short)((a.recalc()+TC_PI2)-(b.recalc()+TC_PI2));
   if (abs(r) > TC_PI)
   {
      if (r < 0)
         r = (a+(direction) TC_PI2)-b;
      else
         r = a-(b+(direction) TC_PI2);
   }
   if (r > 0)
      return FALSE;
   return TRUE;
}

const float ISTEP     = .01f;
const int     CSCTBLSIZ = 314;
const int     INTV      = 163;
const float   TCPI      = 3.14f;

static float searchcsc(float);
static float getangle(float x,float y);

static const short csctbl[] =
{32760, 16239, 8118, 5411, 4057, 3245, 2703, 2316, 2025, 1799, 1618, 
1470, 1346, 1242, 1152, 1074, 1006, 945, 892, 844, 801, 761, 726, 
693, 663, 635, 610, 586, 564, 544, 524, 506, 489, 473, 458, 444, 431, 
418, 406, 394, 383, 373, 363, 353, 344, 336, 327, 319, 311, 304, 297, 
290, 283, 276, 270, 264, 258, 253, 247, 242, 237, 232, 227, 222, 217, 
213, 208, 204, 200, 196, 192, 188, 184, 181, 177, 173, 170, 167, 163, 
160, 157, 154, 151, 148, 145, 142, 139, 136, 133, 131, 128, 125, 123, 
120, 118, 115, 113, 110, 108, 106, 103, 101, 99, 97, 94, 92, 90, 88, 
86, 84, 82, 80, 78, 76, 74, 72, 70, 68, 66, 64, 62, 60, 58, 56, 55, 
53, 51, 49, 47, 46, 44, 42, 40, 39, 37, 35, 34, 32, 30, 28, 27, 25, 
23, 22, 20, 18, 17, 15, 13, 12, 10, 9, 7, 5, 4, 2, 0, 0, -2, -4, -5, 
-7, -9, -10, -12, -13, -15, -17, -18, -20, -22, -23, -25, -27, -28, 
-30, -32, -34, -35, -37, -39, -40, -42, -44, -46, -47, -49, -51, -53, 
-55, -56, -58, -60, -62, -64, -66, -68, -70, -72, -74, -76, -78, -80, 
-82, -84, -86, -88, -90, -92, -94, -97, -99, -101, -103, -106, -108, 
-110, -113, -115, -118, -120, -123, -125, -128, -131, -133, -136, 
-139, -142, -145, -148, -151, -154, -157, -160, -163, -167, -170, 
-173, -177, -181, -184, -188, -192, -196, -200, -204, -208, -213, 
-217, -222, -227, -232, -237, -242, -247, -253, -258, -264, -270, 
-276, -283, -290, -297, -304, -311, -319, -327, -336, -344, -353, 
-363, -373, -383, -394, -406, -418, -431, -444, -458, -473, -489, 
-506, -524, -544, -564, -586, -610, -635, -663, -693, -726, -761, 
-801, -844, -892, -945, -1006, -1074, -1152, -1242, -1346, -1470, 
-1618, -1799, -2025, -2316, -2703, -3245, -4057, -5411, -8118, -16239, 
-32760};


direction& getdirection(float ox,float oy,float px,float py)
{
    static direction r;
    r = (short)(getangle(px-ox,py-oy)*100.0f);
    return r;
}

static float getangle(float x,float y)
{
    if (x == 0) {
        if (y > 0)
            return 0.0f;
        else
            return TCPI;
    }
    float i = (searchcsc((float)y/(float)x)*TCPI)/CSCTBLSIZ;
    if (x < 0)
        i += TCPI;
    return i;
}

static float searchcsc(float x)
{
    short
        e = CSCTBLSIZ,
        b = 0,
        i = (CSCTBLSIZ/2);
    long
        k = (long) (x*INTV);

    while ((e - b) > 2) {
        if (k == (long) csctbl[i])
            break;
        if (k < (long) csctbl[i]) {
            b = i;
            i = (short)((short)i + (short) (((e - b) / 2) + 1));
        }
        else {
            e = i;
            i = (short)((short)i - (short) (((e - b) / 2) + 1));
        }
    }
    return (float) i;
}

void createtrigtable(float *sintable, float *costable)
{
    for (int i = 0; i < TC_PI2; i++)
    {
        sintable[i] = (float) sin((6.28*(double)i)/(double)TC_PI2);
        costable[i] = (float) cos((6.28*(double)i)/(double)TC_PI2);
    }
}