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annotate libs/vmath/geom.c @ 51:fa5c52ea9d59

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author John Tsiombikas <nuclear@member.fsf.org>
date Fri, 17 Jan 2014 18:16:09 +0200
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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
nuclear@27 20 #include <math.h>
nuclear@27 21 #include "geom.h"
nuclear@27 22 #include "vector.h"
nuclear@27 23
nuclear@27 24 plane_t plane_cons(scalar_t nx, scalar_t ny, scalar_t nz, scalar_t d)
nuclear@27 25 {
nuclear@27 26 plane_t p;
nuclear@27 27 p.norm.x = nx;
nuclear@27 28 p.norm.y = ny;
nuclear@27 29 p.norm.z = nz;
nuclear@27 30 p.d = d;
nuclear@27 31 return p;
nuclear@27 32 }
nuclear@27 33
nuclear@27 34 plane_t plane_poly(vec3_t v0, vec3_t v1, vec3_t v2)
nuclear@27 35 {
nuclear@27 36 vec3_t a, b, norm;
nuclear@27 37
nuclear@27 38 a = v3_sub(v1, v0);
nuclear@27 39 b = v3_sub(v2, v0);
nuclear@27 40 norm = v3_cross(a, b);
nuclear@27 41 norm = v3_normalize(norm);
nuclear@27 42
nuclear@27 43 return plane_ptnorm(v0, norm);
nuclear@27 44 }
nuclear@27 45
nuclear@27 46 plane_t plane_ptnorm(vec3_t pt, vec3_t normal)
nuclear@27 47 {
nuclear@27 48 plane_t plane;
nuclear@27 49
nuclear@27 50 plane.norm = normal;
nuclear@27 51 plane.d = v3_dot(pt, normal);
nuclear@27 52
nuclear@27 53 return plane;
nuclear@27 54 }
nuclear@27 55
nuclear@27 56 plane_t plane_invert(plane_t p)
nuclear@27 57 {
nuclear@27 58 p.norm = v3_neg(p.norm);
nuclear@27 59 p.d = -p.d;
nuclear@27 60 return p;
nuclear@27 61 }
nuclear@27 62
nuclear@27 63 scalar_t plane_signed_dist(plane_t plane, vec3_t pt)
nuclear@27 64 {
nuclear@27 65 vec3_t pp = plane_point(plane);
nuclear@27 66 vec3_t pptopt = v3_sub(pt, pp);
nuclear@27 67 return v3_dot(pptopt, plane.norm);
nuclear@27 68 }
nuclear@27 69
nuclear@27 70 scalar_t plane_dist(plane_t plane, vec3_t pt)
nuclear@27 71 {
nuclear@27 72 return fabs(plane_signed_dist(plane, pt));
nuclear@27 73 }
nuclear@27 74
nuclear@27 75 vec3_t plane_point(plane_t plane)
nuclear@27 76 {
nuclear@27 77 return v3_scale(plane.norm, plane.d);
nuclear@27 78 }
nuclear@27 79
nuclear@27 80 int plane_ray_intersect(ray_t ray, plane_t plane, scalar_t *pos)
nuclear@27 81 {
nuclear@27 82 vec3_t pt, orig_to_pt;
nuclear@27 83 scalar_t ndotdir;
nuclear@27 84
nuclear@27 85 pt = plane_point(plane);
nuclear@27 86 ndotdir = v3_dot(plane.norm, ray.dir);
nuclear@27 87
nuclear@27 88 if(fabs(ndotdir) < 1e-7) {
nuclear@27 89 return 0;
nuclear@27 90 }
nuclear@27 91
nuclear@27 92 if(pos) {
nuclear@27 93 orig_to_pt = v3_sub(pt, ray.origin);
nuclear@27 94 *pos = v3_dot(plane.norm, orig_to_pt) / ndotdir;
nuclear@27 95 }
nuclear@27 96 return 1;
nuclear@27 97 }
nuclear@27 98
nuclear@27 99 sphere_t sphere_cons(scalar_t x, scalar_t y, scalar_t z, scalar_t rad)
nuclear@27 100 {
nuclear@27 101 sphere_t sph;
nuclear@27 102 sph.pos.x = x;
nuclear@27 103 sph.pos.y = y;
nuclear@27 104 sph.pos.z = z;
nuclear@27 105 sph.rad = rad;
nuclear@27 106 return sph;
nuclear@27 107 }
nuclear@27 108
nuclear@27 109 int sphere_ray_intersect(ray_t ray, sphere_t sph, scalar_t *pos)
nuclear@27 110 {
nuclear@27 111 scalar_t a, b, c, d, sqrt_d, t1, t2, t;
nuclear@27 112
nuclear@27 113 a = v3_dot(ray.dir, ray.dir);
nuclear@27 114 b = 2.0 * ray.dir.x * (ray.origin.x - sph.pos.x) +
nuclear@27 115 2.0 * ray.dir.y * (ray.origin.y - sph.pos.y) +
nuclear@27 116 2.0 * ray.dir.z * (ray.origin.z - sph.pos.z);
nuclear@27 117 c = v3_dot(sph.pos, sph.pos) + v3_dot(ray.origin, ray.origin) +
nuclear@27 118 2.0 * v3_dot(v3_neg(sph.pos), ray.origin) - sph.rad * sph.rad;
nuclear@27 119
nuclear@27 120 d = b * b - 4.0 * a * c;
nuclear@27 121 if(d < 0.0) {
nuclear@27 122 return 0;
nuclear@27 123 }
nuclear@27 124
nuclear@27 125 sqrt_d = sqrt(d);
nuclear@27 126 t1 = (-b + sqrt_d) / (2.0 * a);
nuclear@27 127 t2 = (-b - sqrt_d) / (2.0 * a);
nuclear@27 128
nuclear@27 129 if(t1 < 1e-7 || t1 > 1.0) {
nuclear@27 130 t1 = t2;
nuclear@27 131 }
nuclear@27 132 if(t2 < 1e-7 || t2 > 1.0) {
nuclear@27 133 t2 = t1;
nuclear@27 134 }
nuclear@27 135 t = t1 < t2 ? t1 : t2;
nuclear@27 136
nuclear@27 137 if(t < 1e-7 || t > 1.0) {
nuclear@27 138 return 0;
nuclear@27 139 }
nuclear@27 140
nuclear@27 141 if(pos) {
nuclear@27 142 *pos = t;
nuclear@27 143 }
nuclear@27 144 return 1;
nuclear@27 145 }
nuclear@27 146
nuclear@27 147 int sphere_sphere_intersect(sphere_t sph1, sphere_t sph2, scalar_t *pos, scalar_t *rad)
nuclear@27 148 {
nuclear@27 149 return -1;
nuclear@27 150 }