goat3d
annotate libs/vmath/vmath.inl @ 55:af1310ed212b
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| 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 } |