1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/geom.cc	Thu Jul 27 20:36:12 2017 +0300
     1.3 @@ -0,0 +1,334 @@
     1.4 +#include <assert.h>
     1.5 +#include <float.h>
     1.6 +#include <algorithm>
     1.7 +#include "geom.h"
     1.8 +
     1.9 +GeomObject::~GeomObject()
    1.10 +{
    1.11 +}
    1.12 +
    1.13 +
    1.14 +Sphere::Sphere()
    1.15 +{
    1.16 +	radius = 1.0;
    1.17 +}
    1.18 +
    1.19 +Sphere::Sphere(const Vec3 &cent, float radius)
    1.20 +	: center(cent)
    1.21 +{
    1.22 +	this->radius = radius;
    1.23 +}
    1.24 +
    1.25 +void Sphere::set_union(const GeomObject *obj1, const GeomObject *obj2)
    1.26 +{
    1.27 +	const Sphere *sph1 = dynamic_cast<const Sphere*>(obj1);
    1.28 +	const Sphere *sph2 = dynamic_cast<const Sphere*>(obj2);
    1.29 +
    1.30 +	if(!sph1 || !sph2) {
    1.31 +		fprintf(stderr, "Sphere::set_union: arguments must be spheres");
    1.32 +		return;
    1.33 +	}
    1.34 +
    1.35 +	float dist = length(sph1->center - sph2->center);
    1.36 +	float surf_dist = dist - (sph1->radius + sph2->radius);
    1.37 +	float d1 = sph1->radius + surf_dist / 2.0;
    1.38 +	float d2 = sph2->radius + surf_dist / 2.0;
    1.39 +	float t = d1 / (d1 + d2);
    1.40 +
    1.41 +	if(t < 0.0) t = 0.0;
    1.42 +	if(t > 1.0) t = 1.0;
    1.43 +
    1.44 +	center = sph1->center * t + sph2->center * (1.0 - t);
    1.45 +	radius = std::max(dist * t + sph2->radius, dist * (1.0f - t) + sph1->radius);
    1.46 +}
    1.47 +
    1.48 +void Sphere::set_intersection(const GeomObject *obj1, const GeomObject *obj2)
    1.49 +{
    1.50 +	fprintf(stderr, "Sphere::intersection undefined\n");
    1.51 +}
    1.52 +
    1.53 +bool Sphere::intersect(const Ray &ray, HitPoint *hit) const
    1.54 +{
    1.55 +	float a = dot(ray.dir, ray.dir);
    1.56 +	float b = 2.0 * ray.dir.x * (ray.origin.x - center.x) +
    1.57 +		2.0 * ray.dir.y * (ray.origin.y - center.y) +
    1.58 +		2.0 * ray.dir.z * (ray.origin.z - center.z);
    1.59 +	float c = dot(ray.origin, ray.origin) + dot(center, center) -
    1.60 +		2.0 * dot(ray.origin, center) - radius * radius;
    1.61 +
    1.62 +	float discr = b * b - 4.0 * a * c;
    1.63 +	if(discr < 1e-4) {
    1.64 +		return false;
    1.65 +	}
    1.66 +
    1.67 +	float sqrt_discr = sqrt(discr);
    1.68 +	float t0 = (-b + sqrt_discr) / (2.0 * a);
    1.69 +	float t1 = (-b - sqrt_discr) / (2.0 * a);
    1.70 +
    1.71 +	if(t0 < 1e-4)
    1.72 +		t0 = t1;
    1.73 +	if(t1 < 1e-4)
    1.74 +		t1 = t0;
    1.75 +
    1.76 +	float t = t0 < t1 ? t0 : t1;
    1.77 +	if(t < 1e-4) {
    1.78 +		return false;
    1.79 +	}
    1.80 +
    1.81 +	// fill the HitPoint structure
    1.82 +	if(hit) {
    1.83 +		hit->obj = this;
    1.84 +		hit->dist = t;
    1.85 +		hit->pos = ray.origin + ray.dir * t;
    1.86 +		hit->normal = (hit->pos - center) / radius;
    1.87 +	}
    1.88 +	return true;
    1.89 +}
    1.90 +
    1.91 +
    1.92 +AABox::AABox()
    1.93 +{
    1.94 +}
    1.95 +
    1.96 +AABox::AABox(const Vec3 &vmin, const Vec3 &vmax)
    1.97 +	: min(vmin), max(vmax)
    1.98 +{
    1.99 +}
   1.100 +
   1.101 +void AABox::set_union(const GeomObject *obj1, const GeomObject *obj2)
   1.102 +{
   1.103 +	const AABox *box1 = dynamic_cast<const AABox*>(obj1);
   1.104 +	const AABox *box2 = dynamic_cast<const AABox*>(obj2);
   1.105 +
   1.106 +	if(!box1 || !box2) {
   1.107 +		fprintf(stderr, "AABox::set_union: arguments must be AABoxes too\n");
   1.108 +		return;
   1.109 +	}
   1.110 +
   1.111 +	min.x = std::min(box1->min.x, box2->min.x);
   1.112 +	min.y = std::min(box1->min.y, box2->min.y);
   1.113 +	min.z = std::min(box1->min.z, box2->min.z);
   1.114 +
   1.115 +	max.x = std::max(box1->max.x, box2->max.x);
   1.116 +	max.y = std::max(box1->max.y, box2->max.y);
   1.117 +	max.z = std::max(box1->max.z, box2->max.z);
   1.118 +}
   1.119 +
   1.120 +void AABox::set_intersection(const GeomObject *obj1, const GeomObject *obj2)
   1.121 +{
   1.122 +	const AABox *box1 = dynamic_cast<const AABox*>(obj1);
   1.123 +	const AABox *box2 = dynamic_cast<const AABox*>(obj2);
   1.124 +
   1.125 +	if(!box1 || !box2) {
   1.126 +		fprintf(stderr, "AABox::set_intersection: arguments must be AABoxes too\n");
   1.127 +		return;
   1.128 +	}
   1.129 +
   1.130 +	for(int i=0; i<3; i++) {
   1.131 +		min[i] = std::max(box1->min[i], box2->min[i]);
   1.132 +		max[i] = std::min(box1->max[i], box2->max[i]);
   1.133 +
   1.134 +		if(max[i] < min[i]) {
   1.135 +			max[i] = min[i];
   1.136 +		}
   1.137 +	}
   1.138 +}
   1.139 +
   1.140 +bool AABox::intersect(const Ray &ray, HitPoint *hit) const
   1.141 +{
   1.142 +	Vec3 param[2] = {min, max};
   1.143 +	Vec3 inv_dir(1.0 / ray.dir.x, 1.0 / ray.dir.y, 1.0 / ray.dir.z);
   1.144 +	int sign[3] = {inv_dir.x < 0, inv_dir.y < 0, inv_dir.z < 0};
   1.145 +
   1.146 +	float tmin = (param[sign[0]].x - ray.origin.x) * inv_dir.x;
   1.147 +	float tmax = (param[1 - sign[0]].x - ray.origin.x) * inv_dir.x;
   1.148 +	float tymin = (param[sign[1]].y - ray.origin.y) * inv_dir.y;
   1.149 +	float tymax = (param[1 - sign[1]].y - ray.origin.y) * inv_dir.y;
   1.150 +
   1.151 +	if(tmin > tymax || tymin > tmax) {
   1.152 +		return false;
   1.153 +	}
   1.154 +	if(tymin > tmin) {
   1.155 +		tmin = tymin;
   1.156 +	}
   1.157 +	if(tymax < tmax) {
   1.158 +		tmax = tymax;
   1.159 +	}
   1.160 +
   1.161 +	float tzmin = (param[sign[2]].z - ray.origin.z) * inv_dir.z;
   1.162 +	float tzmax = (param[1 - sign[2]].z - ray.origin.z) * inv_dir.z;
   1.163 +
   1.164 +	if(tmin > tzmax || tzmin > tmax) {
   1.165 +		return false;
   1.166 +	}
   1.167 +	if(tzmin > tmin) {
   1.168 +		tmin = tzmin;
   1.169 +	}
   1.170 +	if(tzmax < tmax) {
   1.171 +		tmax = tzmax;
   1.172 +	}
   1.173 +
   1.174 +	float t = tmin < 1e-4 ? tmax : tmin;
   1.175 +	if(t >= 1e-4) {
   1.176 +
   1.177 +		if(hit) {
   1.178 +			hit->obj = this;
   1.179 +			hit->dist = t;
   1.180 +			hit->pos = ray.origin + ray.dir * t;
   1.181 +
   1.182 +			float min_dist = FLT_MAX;
   1.183 +			Vec3 offs = min + (max - min) / 2.0;
   1.184 +			Vec3 local_hit = hit->pos - offs;
   1.185 +
   1.186 +			static const Vec3 axis[] = {
   1.187 +				Vec3(1, 0, 0), Vec3(0, 1, 0), Vec3(0, 0, 1)
   1.188 +			};
   1.189 +			//int tcidx[][2] = {{2, 1}, {0, 2}, {0, 1}};
   1.190 +
   1.191 +			for(int i=0; i<3; i++) {
   1.192 +				float dist = fabs((max[i] - offs[i]) - fabs(local_hit[i]));
   1.193 +				if(dist < min_dist) {
   1.194 +					min_dist = dist;
   1.195 +					hit->normal = axis[i] * (local_hit[i] < 0.0 ? 1.0 : -1.0);
   1.196 +					//hit->texcoord = Vec2(hit->pos[tcidx[i][0]], hit->pos[tcidx[i][1]]);
   1.197 +				}
   1.198 +			}
   1.199 +		}
   1.200 +		return true;
   1.201 +	}
   1.202 +	return false;
   1.203 +
   1.204 +}
   1.205 +
   1.206 +Plane::Plane()
   1.207 +	: normal(0.0, 1.0, 0.0)
   1.208 +{
   1.209 +}
   1.210 +
   1.211 +Plane::Plane(const Vec3 &p, const Vec3 &norm)
   1.212 +	: pt(p)
   1.213 +{
   1.214 +	normal = normalize(norm);
   1.215 +}
   1.216 +
   1.217 +Plane::Plane(const Vec3 &p1, const Vec3 &p2, const Vec3 &p3)
   1.218 +	: pt(p1)
   1.219 +{
   1.220 +	normal = normalize(cross(p2 - p1, p3 - p1));
   1.221 +}
   1.222 +
   1.223 +Plane::Plane(const Vec3 &normal, float dist)
   1.224 +{
   1.225 +	this->normal = normalize(normal);
   1.226 +	pt = this->normal * dist;
   1.227 +}
   1.228 +
   1.229 +void Plane::set_union(const GeomObject *obj1, const GeomObject *obj2)
   1.230 +{
   1.231 +	fprintf(stderr, "Plane::set_union undefined\n");
   1.232 +}
   1.233 +
   1.234 +void Plane::set_intersection(const GeomObject *obj1, const GeomObject *obj2)
   1.235 +{
   1.236 +	fprintf(stderr, "Plane::set_intersection undefined\n");
   1.237 +}
   1.238 +
   1.239 +bool Plane::intersect(const Ray &ray, HitPoint *hit) const
   1.240 +{
   1.241 +	float ndotdir = dot(normal, ray.dir);
   1.242 +	if(fabs(ndotdir) < 1e-4) {
   1.243 +		return false;
   1.244 +	}
   1.245 +
   1.246 +	if(hit) {
   1.247 +		Vec3 ptdir = pt - ray.origin;
   1.248 +		float t = dot(normal, ptdir) / ndotdir;
   1.249 +
   1.250 +		hit->pos = ray.origin + ray.dir * t;
   1.251 +		hit->normal = normal;
   1.252 +		hit->obj = this;
   1.253 +	}
   1.254 +	return true;
   1.255 +}
   1.256 +
   1.257 +float sphere_distance(const Vec3 &cent, float rad, const Vec3 &pt)
   1.258 +{
   1.259 +	return length(pt - cent) - rad;
   1.260 +}
   1.261 +
   1.262 +// TODO version which takes both radii into account
   1.263 +float capsule_distance(const Vec3 &a, float ra, const Vec3 &b, float rb, const Vec3 &pt)
   1.264 +{
   1.265 +	Vec3 ab_dir = b - a;
   1.266 +	float ab_len_sq = length_sq(ab_dir);
   1.267 +
   1.268 +	if(fabs(ab_len_sq) < 1e-5) {
   1.269 +		// if a == b, the capsule is a sphere with radius the maximum of the capsule radii
   1.270 +		return sphere_distance(a, std::max(ra, rb), pt);
   1.271 +	}
   1.272 +	float ab_len = sqrt(ab_len_sq);
   1.273 +
   1.274 +	Vec3 ap_dir = pt - a;
   1.275 +
   1.276 +	float t = dot(ap_dir, ab_dir / ab_len) / ab_len;
   1.277 +	if(t < 0.0) {
   1.278 +		return sphere_distance(a, ra, pt);
   1.279 +	}
   1.280 +	if(t >= 1.0) {
   1.281 +		return sphere_distance(b, rb, pt);
   1.282 +	}
   1.283 +
   1.284 +	Vec3 pproj = a + ab_dir * t;
   1.285 +	return length(pproj - pt) - ra;
   1.286 +}
   1.287 +
   1.288 +#if 0
   1.289 +float capsule_distance(const Vec3 &a, float ra, const Vec3 &b, float rb, const Vec3 &pt)
   1.290 +{
   1.291 +	Vec3 ab_dir = b - a;
   1.292 +
   1.293 +	if(fabs(length_sq(ab_dir)) < 1e-5) {
   1.294 +		// if a == b, the capsule is a sphere with radius the maximum of the capsule radii
   1.295 +		return sphere_distance(a, std::max(ra, rb), pt);
   1.296 +	}
   1.297 +	float ab_len = length(ab_dir);
   1.298 +
   1.299 +	Vec3 ap_dir = pt - a;
   1.300 +	Vec3 rotaxis = normalize(cross(ab_dir, ap_dir));
   1.301 +
   1.302 +	Mat4 rmat;
   1.303 +	rmat.set_rotation(rotaxis, M_PI / 2.0);
   1.304 +	Vec3 right = rmat * ab_dir / ab_len;
   1.305 +
   1.306 +	// XXX I think this check is redundant, always false, due to the cross product order
   1.307 +	//assert(dot(right, ab_dir) >= 0.0);
   1.308 +	if(dot(right, ab_dir) < 0.0) {
   1.309 +		right = -right;
   1.310 +	}
   1.311 +	Vec3 aa = a + right * ra;
   1.312 +	Vec3 bb = b + right * rb;
   1.313 +
   1.314 +	// project pt to the line segment bb-aa, see if the projection lies within the interval [0, 1)
   1.315 +	Vec3 aabb_dir = bb - aa;
   1.316 +	float aabb_len = length(aabb_dir);
   1.317 +	Vec3 aap_dir = pt - aa;
   1.318 +
   1.319 +	float t = dot(aap_dir, aabb_dir / aabb_len) / aabb_len;
   1.320 +	if(t < 0.0) {
   1.321 +		return sphere_distance(a, ra, pt);
   1.322 +	}
   1.323 +	if(t >= 1.0) {
   1.324 +		return sphere_distance(b, rb, pt);
   1.325 +	}
   1.326 +
   1.327 +	Vec3 ppt = aa + aabb_dir * t;
   1.328 +	Vec3 norm = ppt - pt;
   1.329 +	float dist = length(norm);
   1.330 +
   1.331 +	if(dot(norm, right) < 0.0) {
   1.332 +		// inside the cone
   1.333 +		dist = -dist;
   1.334 +	}
   1.335 +	return dist;
   1.336 +}
   1.337 +#endif