goat3d

annotate libs/vmath/vmath.inl @ 55:af1310ed212b

not done yet
author John Tsiombikas <nuclear@member.fsf.org>
date Sun, 19 Jan 2014 14:56:44 +0200
parents 4deb0b12fe14
children
rev   line source
nuclear@27 1 /*
nuclear@27 2 libvmath - a vector math library
nuclear@27 3 Copyright (C) 2004-2011 John Tsiombikas <nuclear@member.fsf.org>
nuclear@27 4
nuclear@27 5 This program is free software: you can redistribute it and/or modify
nuclear@27 6 it under the terms of the GNU Lesser General Public License as published
nuclear@27 7 by the Free Software Foundation, either version 3 of the License, or
nuclear@27 8 (at your option) any later version.
nuclear@27 9
nuclear@27 10 This program is distributed in the hope that it will be useful,
nuclear@27 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@27 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@27 13 GNU Lesser General Public License for more details.
nuclear@27 14
nuclear@27 15 You should have received a copy of the GNU Lesser General Public License
nuclear@27 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@27 17 */
nuclear@27 18
nuclear@27 19 #include <stdlib.h>
nuclear@27 20
nuclear@28 21 static VMATH_INLINE scalar_t smoothstep(float a, float b, float x)
nuclear@27 22 {
nuclear@27 23 if(x < a) return 0.0;
nuclear@27 24 if(x >= b) return 1.0;
nuclear@27 25
nuclear@27 26 x = (x - a) / (b - a);
nuclear@27 27 return x * x * (3.0 - 2.0 * x);
nuclear@27 28 }
nuclear@27 29
nuclear@27 30 /** Generates a random number in [0, range) */
nuclear@28 31 static VMATH_INLINE scalar_t frand(scalar_t range)
nuclear@27 32 {
nuclear@27 33 return range * (scalar_t)rand() / (scalar_t)RAND_MAX;
nuclear@27 34 }
nuclear@27 35
nuclear@27 36 /** Generates a random vector on the surface of a sphere */
nuclear@28 37 static VMATH_INLINE vec3_t sphrand(scalar_t rad)
nuclear@27 38 {
nuclear@27 39 scalar_t u = (scalar_t)rand() / RAND_MAX;
nuclear@27 40 scalar_t v = (scalar_t)rand() / RAND_MAX;
nuclear@27 41
nuclear@27 42 scalar_t theta = 2.0 * M_PI * u;
nuclear@27 43 scalar_t phi = acos(2.0 * v - 1.0);
nuclear@27 44
nuclear@27 45 vec3_t res;
nuclear@27 46 res.x = rad * cos(theta) * sin(phi);
nuclear@27 47 res.y = rad * sin(theta) * sin(phi);
nuclear@27 48 res.z = rad * cos(phi);
nuclear@27 49 return res;
nuclear@27 50 }
nuclear@27 51
nuclear@27 52 /** linear interpolation */
nuclear@28 53 static VMATH_INLINE scalar_t lerp(scalar_t a, scalar_t b, scalar_t t)
nuclear@27 54 {
nuclear@27 55 return a + (b - a) * t;
nuclear@27 56 }