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annotate libs/vmath/geom.c @ 0:b2f14e535253

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 01 Feb 2014 19:58:19 +0200
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nuclear@0 1 /*
nuclear@0 2 libvmath - a vector math library
nuclear@0 3 Copyright (C) 2004-2011 John Tsiombikas <nuclear@member.fsf.org>
nuclear@0 4
nuclear@0 5 This program is free software: you can redistribute it and/or modify
nuclear@0 6 it under the terms of the GNU Lesser General Public License as published
nuclear@0 7 by the Free Software Foundation, either version 3 of the License, or
nuclear@0 8 (at your option) any later version.
nuclear@0 9
nuclear@0 10 This program is distributed in the hope that it will be useful,
nuclear@0 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@0 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
nuclear@0 13 GNU Lesser General Public License for more details.
nuclear@0 14
nuclear@0 15 You should have received a copy of the GNU Lesser General Public License
nuclear@0 16 along with this program. If not, see <http://www.gnu.org/licenses/>.
nuclear@0 17 */
nuclear@0 18
nuclear@0 19
nuclear@0 20 #include <math.h>
nuclear@0 21 #include "geom.h"
nuclear@0 22 #include "vector.h"
nuclear@0 23
nuclear@0 24 plane_t plane_cons(scalar_t nx, scalar_t ny, scalar_t nz, scalar_t d)
nuclear@0 25 {
nuclear@0 26 plane_t p;
nuclear@0 27 p.norm.x = nx;
nuclear@0 28 p.norm.y = ny;
nuclear@0 29 p.norm.z = nz;
nuclear@0 30 p.d = d;
nuclear@0 31 return p;
nuclear@0 32 }
nuclear@0 33
nuclear@0 34 plane_t plane_poly(vec3_t v0, vec3_t v1, vec3_t v2)
nuclear@0 35 {
nuclear@0 36 vec3_t a, b, norm;
nuclear@0 37
nuclear@0 38 a = v3_sub(v1, v0);
nuclear@0 39 b = v3_sub(v2, v0);
nuclear@0 40 norm = v3_cross(a, b);
nuclear@0 41 norm = v3_normalize(norm);
nuclear@0 42
nuclear@0 43 return plane_ptnorm(v0, norm);
nuclear@0 44 }
nuclear@0 45
nuclear@0 46 plane_t plane_ptnorm(vec3_t pt, vec3_t normal)
nuclear@0 47 {
nuclear@0 48 plane_t plane;
nuclear@0 49
nuclear@0 50 plane.norm = normal;
nuclear@0 51 plane.d = v3_dot(pt, normal);
nuclear@0 52
nuclear@0 53 return plane;
nuclear@0 54 }
nuclear@0 55
nuclear@0 56 plane_t plane_invert(plane_t p)
nuclear@0 57 {
nuclear@0 58 p.norm = v3_neg(p.norm);
nuclear@0 59 p.d = -p.d;
nuclear@0 60 return p;
nuclear@0 61 }
nuclear@0 62
nuclear@0 63 scalar_t plane_signed_dist(plane_t plane, vec3_t pt)
nuclear@0 64 {
nuclear@0 65 vec3_t pp = plane_point(plane);
nuclear@0 66 vec3_t pptopt = v3_sub(pt, pp);
nuclear@0 67 return v3_dot(pptopt, plane.norm);
nuclear@0 68 }
nuclear@0 69
nuclear@0 70 scalar_t plane_dist(plane_t plane, vec3_t pt)
nuclear@0 71 {
nuclear@0 72 return fabs(plane_signed_dist(plane, pt));
nuclear@0 73 }
nuclear@0 74
nuclear@0 75 vec3_t plane_point(plane_t plane)
nuclear@0 76 {
nuclear@0 77 return v3_scale(plane.norm, plane.d);
nuclear@0 78 }
nuclear@0 79
nuclear@0 80 int plane_ray_intersect(ray_t ray, plane_t plane, scalar_t *pos)
nuclear@0 81 {
nuclear@0 82 vec3_t pt, orig_to_pt;
nuclear@0 83 scalar_t ndotdir;
nuclear@0 84
nuclear@0 85 pt = plane_point(plane);
nuclear@0 86 ndotdir = v3_dot(plane.norm, ray.dir);
nuclear@0 87
nuclear@0 88 if(fabs(ndotdir) < 1e-7) {
nuclear@0 89 return 0;
nuclear@0 90 }
nuclear@0 91
nuclear@0 92 if(pos) {
nuclear@0 93 orig_to_pt = v3_sub(pt, ray.origin);
nuclear@0 94 *pos = v3_dot(plane.norm, orig_to_pt) / ndotdir;
nuclear@0 95 }
nuclear@0 96 return 1;
nuclear@0 97 }
nuclear@0 98
nuclear@0 99 sphere_t sphere_cons(scalar_t x, scalar_t y, scalar_t z, scalar_t rad)
nuclear@0 100 {
nuclear@0 101 sphere_t sph;
nuclear@0 102 sph.pos.x = x;
nuclear@0 103 sph.pos.y = y;
nuclear@0 104 sph.pos.z = z;
nuclear@0 105 sph.rad = rad;
nuclear@0 106 return sph;
nuclear@0 107 }
nuclear@0 108
nuclear@0 109 int sphere_ray_intersect(ray_t ray, sphere_t sph, scalar_t *pos)
nuclear@0 110 {
nuclear@0 111 scalar_t a, b, c, d, sqrt_d, t1, t2, t;
nuclear@0 112
nuclear@0 113 a = v3_dot(ray.dir, ray.dir);
nuclear@0 114 b = 2.0 * ray.dir.x * (ray.origin.x - sph.pos.x) +
nuclear@0 115 2.0 * ray.dir.y * (ray.origin.y - sph.pos.y) +
nuclear@0 116 2.0 * ray.dir.z * (ray.origin.z - sph.pos.z);
nuclear@0 117 c = v3_dot(sph.pos, sph.pos) + v3_dot(ray.origin, ray.origin) +
nuclear@0 118 2.0 * v3_dot(v3_neg(sph.pos), ray.origin) - sph.rad * sph.rad;
nuclear@0 119
nuclear@0 120 d = b * b - 4.0 * a * c;
nuclear@0 121 if(d < 0.0) {
nuclear@0 122 return 0;
nuclear@0 123 }
nuclear@0 124
nuclear@0 125 sqrt_d = sqrt(d);
nuclear@0 126 t1 = (-b + sqrt_d) / (2.0 * a);
nuclear@0 127 t2 = (-b - sqrt_d) / (2.0 * a);
nuclear@0 128
nuclear@0 129 if(t1 < 1e-7 || t1 > 1.0) {
nuclear@0 130 t1 = t2;
nuclear@0 131 }
nuclear@0 132 if(t2 < 1e-7 || t2 > 1.0) {
nuclear@0 133 t2 = t1;
nuclear@0 134 }
nuclear@0 135 t = t1 < t2 ? t1 : t2;
nuclear@0 136
nuclear@0 137 if(t < 1e-7 || t > 1.0) {
nuclear@0 138 return 0;
nuclear@0 139 }
nuclear@0 140
nuclear@0 141 if(pos) {
nuclear@0 142 *pos = t;
nuclear@0 143 }
nuclear@0 144 return 1;
nuclear@0 145 }
nuclear@0 146
nuclear@0 147 int sphere_sphere_intersect(sphere_t sph1, sphere_t sph2, scalar_t *pos, scalar_t *rad)
nuclear@0 148 {
nuclear@0 149 return -1;
nuclear@0 150 }