prj/tech/libsrc/r3d/clipclip.c

   1 // $Header: x:/prj/tech/libsrc/r3d/RCS/clipclip.c 1.9 1996/10/29 12:44:47 KEVIN Exp $
   2
   3 // clipping is:
   4 //    off the right is  y < -x
   5 //    off the left is   y > x
   6 //    off the top is    z > x
   7 //    off the bottom is z < -x
   8
   9 //  clipspace clipping
  10
  11 #include <r3ds.h>
  12 #include <clip_.h>
  13 #include <clipcon_.h>
  14 #include <clipoff.h>
  15 #include <_test.h>
  16
  17 void r3_clipspace_code_points(int n, r3s_point *src)
  18 {
  19    uchar *cur, *last;
  20    mxs_real nearxxx = r3d_near_plane;
  21
  22    TEST_IN_BLOCK("r3_clipspace_code_points");
  23
  24    cur = (uchar *)src;
  25    last = cur + n * r3d_glob.cur_stride;
  26
  27    while (cur < last) {
  28       r3s_point *p = (r3s_point *)cur;
  29       int code = 0;
  30       mxs_real z = p->p.z;
  31
  32       cur += r3d_glob.cur_stride;
  33
  34       if (p->p.x > z) code = R3C_OFF_RIGHT; else code = R3C_NONE;
  35       if (p->p.x < -z) code |= R3C_OFF_LEFT;
  36
  37       if (p->p.y < -z) code |= R3C_OFF_TOP;
  38       if (p->p.y > z) code |= R3C_OFF_BOTTOM;
  39
  40       if (z < nearxxx) code |= R3C_BEHIND;
  41
  42       p->ccodes = code;
  43    }
  44
  45    if (r3d_num_planes)
  46       r3_std_code_points(n, src);
  47 }