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initial commit

author	John Tsiombikas <nuclear@member.fsf.org>
date	Thu, 27 Jul 2017 20:36:12 +0300
parents
children	2bfafdced01a

line source

1 #include <assert.h>

2 #include <float.h>

3 #include <algorithm>

4 #include "geom.h"

6 GeomObject::~GeomObject()

7 {

8 }

11 Sphere::Sphere()

12 {

13 radius = 1.0;

14 }

16 Sphere::Sphere(const Vec3 &cent, float radius)

17 : center(cent)

18 {

19 this->radius = radius;

20 }

22 void Sphere::set_union(const GeomObject *obj1, const GeomObject *obj2)

23 {

24 const Sphere *sph1 = dynamic_cast<const Sphere*>(obj1);

25 const Sphere *sph2 = dynamic_cast<const Sphere*>(obj2);

27 if(!sph1 || !sph2) {

28 fprintf(stderr, "Sphere::set_union: arguments must be spheres");

29 return;

30 }

32 float dist = length(sph1->center - sph2->center);

33 float surf_dist = dist - (sph1->radius + sph2->radius);

34 float d1 = sph1->radius + surf_dist / 2.0;

35 float d2 = sph2->radius + surf_dist / 2.0;

36 float t = d1 / (d1 + d2);

38 if(t < 0.0) t = 0.0;

39 if(t > 1.0) t = 1.0;

41 center = sph1->center * t + sph2->center * (1.0 - t);

42 radius = std::max(dist * t + sph2->radius, dist * (1.0f - t) + sph1->radius);

43 }

45 void Sphere::set_intersection(const GeomObject *obj1, const GeomObject *obj2)

46 {

47 fprintf(stderr, "Sphere::intersection undefined\n");

48 }

50 bool Sphere::intersect(const Ray &ray, HitPoint *hit) const

51 {

52 float a = dot(ray.dir, ray.dir);

53 float b = 2.0 * ray.dir.x * (ray.origin.x - center.x) +

54 2.0 * ray.dir.y * (ray.origin.y - center.y) +

55 2.0 * ray.dir.z * (ray.origin.z - center.z);

56 float c = dot(ray.origin, ray.origin) + dot(center, center) -

57 2.0 * dot(ray.origin, center) - radius * radius;

59 float discr = b * b - 4.0 * a * c;

60 if(discr < 1e-4) {

61 return false;

62 }

64 float sqrt_discr = sqrt(discr);

65 float t0 = (-b + sqrt_discr) / (2.0 * a);

66 float t1 = (-b - sqrt_discr) / (2.0 * a);

68 if(t0 < 1e-4)

69 t0 = t1;

70 if(t1 < 1e-4)

71 t1 = t0;

73 float t = t0 < t1 ? t0 : t1;

74 if(t < 1e-4) {

75 return false;

76 }

78 // fill the HitPoint structure

79 if(hit) {

80 hit->obj = this;

81 hit->dist = t;

82 hit->pos = ray.origin + ray.dir * t;

83 hit->normal = (hit->pos - center) / radius;

84 }

85 return true;

86 }

89 AABox::AABox()

90 {

91 }

93 AABox::AABox(const Vec3 &vmin, const Vec3 &vmax)

94 : min(vmin), max(vmax)

95 {

96 }

98 void AABox::set_union(const GeomObject *obj1, const GeomObject *obj2)

99 {

100 const AABox *box1 = dynamic_cast<const AABox*>(obj1);

101 const AABox *box2 = dynamic_cast<const AABox*>(obj2);

102

103 if(!box1 || !box2) {

104 fprintf(stderr, "AABox::set_union: arguments must be AABoxes too\n");

105 return;

106 }

107

108 min.x = std::min(box1->min.x, box2->min.x);

109 min.y = std::min(box1->min.y, box2->min.y);

110 min.z = std::min(box1->min.z, box2->min.z);

111

112 max.x = std::max(box1->max.x, box2->max.x);

113 max.y = std::max(box1->max.y, box2->max.y);

114 max.z = std::max(box1->max.z, box2->max.z);

115 }

116

117 void AABox::set_intersection(const GeomObject *obj1, const GeomObject *obj2)

118 {

119 const AABox *box1 = dynamic_cast<const AABox*>(obj1);

120 const AABox *box2 = dynamic_cast<const AABox*>(obj2);

121

122 if(!box1 || !box2) {

123 fprintf(stderr, "AABox::set_intersection: arguments must be AABoxes too\n");

124 return;

125 }

126

127 for(int i=0; i<3; i++) {

128 min[i] = std::max(box1->min[i], box2->min[i]);

129 max[i] = std::min(box1->max[i], box2->max[i]);

130

131 if(max[i] < min[i]) {

132 max[i] = min[i];

133 }

134 }

135 }

136

137 bool AABox::intersect(const Ray &ray, HitPoint *hit) const

138 {

139 Vec3 param[2] = {min, max};

140 Vec3 inv_dir(1.0 / ray.dir.x, 1.0 / ray.dir.y, 1.0 / ray.dir.z);

141 int sign[3] = {inv_dir.x < 0, inv_dir.y < 0, inv_dir.z < 0};

142

143 float tmin = (param[sign[0]].x - ray.origin.x) * inv_dir.x;

144 float tmax = (param[1 - sign[0]].x - ray.origin.x) * inv_dir.x;

145 float tymin = (param[sign[1]].y - ray.origin.y) * inv_dir.y;

146 float tymax = (param[1 - sign[1]].y - ray.origin.y) * inv_dir.y;

147

148 if(tmin > tymax || tymin > tmax) {

149 return false;

150 }

151 if(tymin > tmin) {

152 tmin = tymin;

153 }

154 if(tymax < tmax) {

155 tmax = tymax;

156 }

157

158 float tzmin = (param[sign[2]].z - ray.origin.z) * inv_dir.z;

159 float tzmax = (param[1 - sign[2]].z - ray.origin.z) * inv_dir.z;

160

161 if(tmin > tzmax || tzmin > tmax) {

162 return false;

163 }

164 if(tzmin > tmin) {

165 tmin = tzmin;

166 }

167 if(tzmax < tmax) {

168 tmax = tzmax;

169 }

170

171 float t = tmin < 1e-4 ? tmax : tmin;

172 if(t >= 1e-4) {

173

174 if(hit) {

175 hit->obj = this;

176 hit->dist = t;

177 hit->pos = ray.origin + ray.dir * t;

178

179 float min_dist = FLT_MAX;

180 Vec3 offs = min + (max - min) / 2.0;

181 Vec3 local_hit = hit->pos - offs;

182

183 static const Vec3 axis[] = {

184 Vec3(1, 0, 0), Vec3(0, 1, 0), Vec3(0, 0, 1)

185 };

186 //int tcidx[][2] = {{2, 1}, {0, 2}, {0, 1}};

187

188 for(int i=0; i<3; i++) {

189 float dist = fabs((max[i] - offs[i]) - fabs(local_hit[i]));

190 if(dist < min_dist) {

191 min_dist = dist;

192 hit->normal = axis[i] * (local_hit[i] < 0.0 ? 1.0 : -1.0);

193 //hit->texcoord = Vec2(hit->pos[tcidx[i][0]], hit->pos[tcidx[i][1]]);

194 }

195 }

196 }

197 return true;

198 }

199 return false;

200

201 }

202

203 Plane::Plane()

204 : normal(0.0, 1.0, 0.0)

205 {

206 }

207

208 Plane::Plane(const Vec3 &p, const Vec3 &norm)

209 : pt(p)

210 {

211 normal = normalize(norm);

212 }

213

214 Plane::Plane(const Vec3 &p1, const Vec3 &p2, const Vec3 &p3)

215 : pt(p1)

216 {

217 normal = normalize(cross(p2 - p1, p3 - p1));

218 }

219

220 Plane::Plane(const Vec3 &normal, float dist)

221 {

222 this->normal = normalize(normal);

223 pt = this->normal * dist;

224 }

225

226 void Plane::set_union(const GeomObject *obj1, const GeomObject *obj2)

227 {

228 fprintf(stderr, "Plane::set_union undefined\n");

229 }

230

231 void Plane::set_intersection(const GeomObject *obj1, const GeomObject *obj2)

232 {

233 fprintf(stderr, "Plane::set_intersection undefined\n");

234 }

235

236 bool Plane::intersect(const Ray &ray, HitPoint *hit) const

237 {

238 float ndotdir = dot(normal, ray.dir);

239 if(fabs(ndotdir) < 1e-4) {

240 return false;

241 }

242

243 if(hit) {

244 Vec3 ptdir = pt - ray.origin;

245 float t = dot(normal, ptdir) / ndotdir;

246

247 hit->pos = ray.origin + ray.dir * t;

248 hit->normal = normal;

249 hit->obj = this;

250 }

251 return true;

252 }

253

254 float sphere_distance(const Vec3 &cent, float rad, const Vec3 &pt)

255 {

256 return length(pt - cent) - rad;

257 }

258

259 // TODO version which takes both radii into account

260 float capsule_distance(const Vec3 &a, float ra, const Vec3 &b, float rb, const Vec3 &pt)

261 {

262 Vec3 ab_dir = b - a;

263 float ab_len_sq = length_sq(ab_dir);

264

265 if(fabs(ab_len_sq) < 1e-5) {

266 // if a == b, the capsule is a sphere with radius the maximum of the capsule radii

267 return sphere_distance(a, std::max(ra, rb), pt);

268 }

269 float ab_len = sqrt(ab_len_sq);

270

271 Vec3 ap_dir = pt - a;

272

273 float t = dot(ap_dir, ab_dir / ab_len) / ab_len;

274 if(t < 0.0) {

275 return sphere_distance(a, ra, pt);

276 }

277 if(t >= 1.0) {

278 return sphere_distance(b, rb, pt);

279 }

280

281 Vec3 pproj = a + ab_dir * t;

282 return length(pproj - pt) - ra;

283 }

284

285 #if 0

286 float capsule_distance(const Vec3 &a, float ra, const Vec3 &b, float rb, const Vec3 &pt)

287 {

288 Vec3 ab_dir = b - a;

289

290 if(fabs(length_sq(ab_dir)) < 1e-5) {

291 // if a == b, the capsule is a sphere with radius the maximum of the capsule radii

292 return sphere_distance(a, std::max(ra, rb), pt);

293 }

294 float ab_len = length(ab_dir);

295

296 Vec3 ap_dir = pt - a;

297 Vec3 rotaxis = normalize(cross(ab_dir, ap_dir));

298

299 Mat4 rmat;

300 rmat.set_rotation(rotaxis, M_PI / 2.0);

301 Vec3 right = rmat * ab_dir / ab_len;

302

303 // XXX I think this check is redundant, always false, due to the cross product order

304 //assert(dot(right, ab_dir) >= 0.0);

305 if(dot(right, ab_dir) < 0.0) {

306 right = -right;

307 }

308 Vec3 aa = a + right * ra;

309 Vec3 bb = b + right * rb;

310

311 // project pt to the line segment bb-aa, see if the projection lies within the interval [0, 1)

312 Vec3 aabb_dir = bb - aa;

313 float aabb_len = length(aabb_dir);

314 Vec3 aap_dir = pt - aa;

315

316 float t = dot(aap_dir, aabb_dir / aabb_len) / aabb_len;

317 if(t < 0.0) {

318 return sphere_distance(a, ra, pt);

319 }

320 if(t >= 1.0) {

321 return sphere_distance(b, rb, pt);

322 }

323

324 Vec3 ppt = aa + aabb_dir * t;

325 Vec3 norm = ppt - pt;

326 float dist = length(norm);

327

328 if(dot(norm, right) < 0.0) {

329 // inside the cone

330 dist = -dist;

331 }

332 return dist;

333 }

334 #endif