diff options
Diffstat (limited to '3dmath.c')
| -rw-r--r-- | 3dmath.c | 34 |
1 files changed, 20 insertions, 14 deletions
@@ -1,25 +1,25 @@ -#include <math.h> +#include "3dmath.h" -#define POW2(x) ((x) * (x)) +#include <math.h> float -dot(float x[3], float y[3]) { +dot(const float x[3], const float y[3]) { return x[0] * y[0] + x[1] * y[1] + x[2] * y[2]; } void normalize(float x[3]) { - float len; - int i; - - len = sqrt(dot(x, x)); + float len = 1.0f / sqrtf(dot(x, x)); - for(i = 0; i < 3; ++i) - x[i] /= len; + x[0] *= len; + x[1] *= len; + x[2] *= len; } float -sphere_intersect(float y[3], float r[3], float s[3], float d[3], float c[3], float R) { +sphere_intersect(float* restrict y, float* restrict r, + const float* restrict s, const float* restrict d, + const float* restrict c, float R, int invert) { int i; float D, n[3], t, v[3]; @@ -31,17 +31,23 @@ sphere_intersect(float y[3], float r[3], float s[3], float d[3], float c[3], flo if(D < 0) return -1; - t = -dot(v, d) - D; + if (invert) + t = -dot(v, d) + D; + else + t = -dot(v, d) - D; + + if (t <= 0) + return -1; for(i = 0; i < 3; ++i) { y[i] = s[i] + t * d[i]; n[i] = y[i] - c[i]; } - normalize(n); + float two_dot_nd_div_sq_n_mag = 2.0f * dot(n, d) / dot(n, n); - for(i = 0; i < 3; ++i) - r[i] = d[i] - 2 * dot(n, d) * n[i]; + for (i = 0; i < 3; ++i) + r[i] = d[i] - two_dot_nd_div_sq_n_mag * n[i]; return t; } |