1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/vmath/vmath.inl	Sun Nov 09 13:03:36 2014 +0200
     1.3 @@ -0,0 +1,56 @@
     1.4 +/*
     1.5 +libvmath - a vector math library
     1.6 +Copyright (C) 2004-2011 John Tsiombikas <nuclear@member.fsf.org>
     1.7 +
     1.8 +This program is free software: you can redistribute it and/or modify
     1.9 +it under the terms of the GNU Lesser General Public License as published
    1.10 +by the Free Software Foundation, either version 3 of the License, or
    1.11 +(at your option) any later version.
    1.12 +
    1.13 +This program is distributed in the hope that it will be useful,
    1.14 +but WITHOUT ANY WARRANTY; without even the implied warranty of
    1.15 +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    1.16 +GNU Lesser General Public License for more details.
    1.17 +
    1.18 +You should have received a copy of the GNU Lesser General Public License
    1.19 +along with this program.  If not, see <http://www.gnu.org/licenses/>.
    1.20 +*/
    1.21 +
    1.22 +#include <stdlib.h>
    1.23 +
    1.24 +static inline scalar_t smoothstep(float a, float b, float x)
    1.25 +{
    1.26 +	if(x < a) return 0.0;
    1.27 +	if(x >= b) return 1.0;
    1.28 +
    1.29 +	x = (x - a) / (b - a);
    1.30 +	return x * x * (3.0 - 2.0 * x);
    1.31 +}
    1.32 +
    1.33 +/** Generates a random number in [0, range) */
    1.34 +static inline scalar_t frand(scalar_t range)
    1.35 +{
    1.36 +	return range * (scalar_t)rand() / (scalar_t)RAND_MAX;
    1.37 +}
    1.38 +
    1.39 +/** Generates a random vector on the surface of a sphere */
    1.40 +static inline vec3_t sphrand(scalar_t rad)
    1.41 +{
    1.42 +	scalar_t u = (scalar_t)rand() / RAND_MAX;
    1.43 +	scalar_t v = (scalar_t)rand() / RAND_MAX;
    1.44 +
    1.45 +	scalar_t theta = 2.0 * M_PI * u;
    1.46 +	scalar_t phi = acos(2.0 * v - 1.0);
    1.47 +
    1.48 +	vec3_t res;
    1.49 +	res.x = rad * cos(theta) * sin(phi);
    1.50 +	res.y = rad * sin(theta) * sin(phi);
    1.51 +	res.z = rad * cos(phi);
    1.52 +	return res;
    1.53 +}
    1.54 +
    1.55 +/** linear interpolation */
    1.56 +static inline scalar_t lerp(scalar_t a, scalar_t b, scalar_t t)
    1.57 +{
    1.58 +	return a + (b - a) * t;
    1.59 +}