diff options
Diffstat (limited to 'maths.c')
| -rw-r--r-- | maths.c | 28 |
1 files changed, 28 insertions, 0 deletions
@@ -73,6 +73,25 @@ int fpow(int a, int p) { return r; } +int fsqrt(int n) { + int lo, hi, mid, i, mm; + if (n <= 0) { return -1; } + lo = mini(1, n); + hi = maxi(1, n); + while ((100 << fbits * lo * lo) >> fbits * 2) + lo *= (10 << fbits) >> fbits; + while ((5 * hi * hi) >> fbits * 2 > n) + hi *= (1 << fbits) / 10; + for (i = 0; i < 100; i++) { + mid = ((lo + hi) * (1 << fbits)) / (2 << fbits); + mm = mid * mid >> fbits; + if (mm == n) return mid; + if (mm > n) hi = mid; + else lo = mid; + } + return mid; +} + int* mtx_iden(int* m) { register int o = f1; m[0] = o; @@ -254,6 +273,15 @@ int vec_dot(const int* a, const int* b, int d) { return r; } +int* vec_nrm(int* d, const int* a, int c) { + int l = vec_dot(a, a, c), i; + l = fsqrt(l); + for (i = 0; i < c; i++) { + d[i] = (a[i] << fbits) / l; + } + return d; +} + int* persp(int* v, int asp) { v[2] += !v[2]; v[0] = ((v[0] << fbits) / v[2]); |