50 |
|
return(dc); |
51 |
|
} |
52 |
|
|
53 |
+ |
#if 0 /* original version for reference */ |
54 |
|
|
55 |
|
void |
56 |
|
decodedir(FVECT dv, int32 dc) /* decode a normalized direction vector */ |
78 |
|
if (dc & FZNEG) dv[2] = -dv[2]; |
79 |
|
} |
80 |
|
|
81 |
+ |
#else |
82 |
|
|
83 |
+ |
void |
84 |
+ |
decodedir(FVECT dv, int32 dc) /* decode a normalized direction vector */ |
85 |
+ |
{ |
86 |
+ |
static const short itab[4][3] = { |
87 |
+ |
{1,0,2},{0,1,2},{1,2,0},{0,2,1} |
88 |
+ |
}; |
89 |
+ |
static const RREAL neg[2] = {1., -1.}; |
90 |
+ |
const int ndx = ((dc & F2Z) != 0)<<1 | ((dc & F1X) != 0); |
91 |
+ |
double d1, d2, der; |
92 |
+ |
|
93 |
+ |
if (!dc) { /* special code for zero normal */ |
94 |
+ |
dv[0] = dv[1] = dv[2] = 0.; |
95 |
+ |
return; |
96 |
+ |
} |
97 |
+ |
d1 = ((dc>>F1SFT & FMASK)+.5)*(1./DCSCALE); |
98 |
+ |
d2 = ((dc>>F2SFT & FMASK)+.5)*(1./DCSCALE); |
99 |
+ |
der = sqrt(1. - d1*d1 - d2*d2); |
100 |
+ |
dv[itab[ndx][0]] = d1; |
101 |
+ |
dv[itab[ndx][1]] = d2; |
102 |
+ |
dv[itab[ndx][2]] = der; |
103 |
+ |
dv[0] *= neg[(dc&FXNEG)!=0]; |
104 |
+ |
dv[1] *= neg[(dc&FYNEG)!=0]; |
105 |
+ |
dv[2] *= neg[(dc&FZNEG)!=0]; |
106 |
+ |
} |
107 |
+ |
|
108 |
+ |
#endif |
109 |
+ |
|
110 |
|
double |
111 |
|
dir2diff(int32 dc1, int32 dc2) /* approx. radians^2 between directions */ |
112 |
|
{ |
117 |
|
|
118 |
|
return(2. - 2.*DOT(v1,v2)); |
119 |
|
} |
91 |
– |
|
120 |
|
|
121 |
|
double |
122 |
|
fdir2diff(int32 dc1, FVECT v2) /* approx. radians^2 between directions */ |