nuclear@4: /*
nuclear@4: Cubemapper - a program for converting panoramic images into cubemaps
nuclear@4: Copyright (C) 2017  John Tsiombikas <nuclear@member.fsf.org>
nuclear@4: 
nuclear@4: This program is free software: you can redistribute it and/or modify
nuclear@4: it under the terms of the GNU General Public License as published by
nuclear@4: the Free Software Foundation, either version 3 of the License, or
nuclear@4: (at your option) any later version.
nuclear@4: 
nuclear@4: This program is distributed in the hope that it will be useful,
nuclear@4: but WITHOUT ANY WARRANTY; without even the implied warranty of
nuclear@4: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
nuclear@4: GNU General Public License for more details.
nuclear@4: 
nuclear@4: You should have received a copy of the GNU General Public License
nuclear@4: along with this program.  If not, see <http://www.gnu.org/licenses/>.
nuclear@4: */
nuclear@0: #include <assert.h>
nuclear@0: #include <float.h>
nuclear@0: #include <algorithm>
nuclear@0: #include "geom.h"
nuclear@0: 
nuclear@0: GeomObject::~GeomObject()
nuclear@0: {
nuclear@0: }
nuclear@0: 
nuclear@0: 
nuclear@0: Sphere::Sphere()
nuclear@0: {
nuclear@0: 	radius = 1.0;
nuclear@0: }
nuclear@0: 
nuclear@0: Sphere::Sphere(const Vec3 &cent, float radius)
nuclear@0: 	: center(cent)
nuclear@0: {
nuclear@0: 	this->radius = radius;
nuclear@0: }
nuclear@0: 
nuclear@0: void Sphere::set_union(const GeomObject *obj1, const GeomObject *obj2)
nuclear@0: {
nuclear@0: 	const Sphere *sph1 = dynamic_cast<const Sphere*>(obj1);
nuclear@0: 	const Sphere *sph2 = dynamic_cast<const Sphere*>(obj2);
nuclear@0: 
nuclear@0: 	if(!sph1 || !sph2) {
nuclear@0: 		fprintf(stderr, "Sphere::set_union: arguments must be spheres");
nuclear@0: 		return;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	float dist = length(sph1->center - sph2->center);
nuclear@0: 	float surf_dist = dist - (sph1->radius + sph2->radius);
nuclear@0: 	float d1 = sph1->radius + surf_dist / 2.0;
nuclear@0: 	float d2 = sph2->radius + surf_dist / 2.0;
nuclear@0: 	float t = d1 / (d1 + d2);
nuclear@0: 
nuclear@0: 	if(t < 0.0) t = 0.0;
nuclear@0: 	if(t > 1.0) t = 1.0;
nuclear@0: 
nuclear@0: 	center = sph1->center * t + sph2->center * (1.0 - t);
nuclear@0: 	radius = std::max(dist * t + sph2->radius, dist * (1.0f - t) + sph1->radius);
nuclear@0: }
nuclear@0: 
nuclear@0: void Sphere::set_intersection(const GeomObject *obj1, const GeomObject *obj2)
nuclear@0: {
nuclear@0: 	fprintf(stderr, "Sphere::intersection undefined\n");
nuclear@0: }
nuclear@0: 
nuclear@0: bool Sphere::intersect(const Ray &ray, HitPoint *hit) const
nuclear@0: {
nuclear@0: 	float a = dot(ray.dir, ray.dir);
nuclear@0: 	float b = 2.0 * ray.dir.x * (ray.origin.x - center.x) +
nuclear@0: 		2.0 * ray.dir.y * (ray.origin.y - center.y) +
nuclear@0: 		2.0 * ray.dir.z * (ray.origin.z - center.z);
nuclear@0: 	float c = dot(ray.origin, ray.origin) + dot(center, center) -
nuclear@0: 		2.0 * dot(ray.origin, center) - radius * radius;
nuclear@0: 
nuclear@0: 	float discr = b * b - 4.0 * a * c;
nuclear@0: 	if(discr < 1e-4) {
nuclear@0: 		return false;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	float sqrt_discr = sqrt(discr);
nuclear@0: 	float t0 = (-b + sqrt_discr) / (2.0 * a);
nuclear@0: 	float t1 = (-b - sqrt_discr) / (2.0 * a);
nuclear@0: 
nuclear@0: 	if(t0 < 1e-4)
nuclear@0: 		t0 = t1;
nuclear@0: 	if(t1 < 1e-4)
nuclear@0: 		t1 = t0;
nuclear@0: 
nuclear@0: 	float t = t0 < t1 ? t0 : t1;
nuclear@0: 	if(t < 1e-4) {
nuclear@0: 		return false;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	// fill the HitPoint structure
nuclear@0: 	if(hit) {
nuclear@0: 		hit->obj = this;
nuclear@0: 		hit->dist = t;
nuclear@0: 		hit->pos = ray.origin + ray.dir * t;
nuclear@0: 		hit->normal = (hit->pos - center) / radius;
nuclear@0: 	}
nuclear@0: 	return true;
nuclear@0: }
nuclear@0: 
nuclear@0: 
nuclear@0: AABox::AABox()
nuclear@0: {
nuclear@0: }
nuclear@0: 
nuclear@0: AABox::AABox(const Vec3 &vmin, const Vec3 &vmax)
nuclear@0: 	: min(vmin), max(vmax)
nuclear@0: {
nuclear@0: }
nuclear@0: 
nuclear@0: void AABox::set_union(const GeomObject *obj1, const GeomObject *obj2)
nuclear@0: {
nuclear@0: 	const AABox *box1 = dynamic_cast<const AABox*>(obj1);
nuclear@0: 	const AABox *box2 = dynamic_cast<const AABox*>(obj2);
nuclear@0: 
nuclear@0: 	if(!box1 || !box2) {
nuclear@0: 		fprintf(stderr, "AABox::set_union: arguments must be AABoxes too\n");
nuclear@0: 		return;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	min.x = std::min(box1->min.x, box2->min.x);
nuclear@0: 	min.y = std::min(box1->min.y, box2->min.y);
nuclear@0: 	min.z = std::min(box1->min.z, box2->min.z);
nuclear@0: 
nuclear@0: 	max.x = std::max(box1->max.x, box2->max.x);
nuclear@0: 	max.y = std::max(box1->max.y, box2->max.y);
nuclear@0: 	max.z = std::max(box1->max.z, box2->max.z);
nuclear@0: }
nuclear@0: 
nuclear@0: void AABox::set_intersection(const GeomObject *obj1, const GeomObject *obj2)
nuclear@0: {
nuclear@0: 	const AABox *box1 = dynamic_cast<const AABox*>(obj1);
nuclear@0: 	const AABox *box2 = dynamic_cast<const AABox*>(obj2);
nuclear@0: 
nuclear@0: 	if(!box1 || !box2) {
nuclear@0: 		fprintf(stderr, "AABox::set_intersection: arguments must be AABoxes too\n");
nuclear@0: 		return;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	for(int i=0; i<3; i++) {
nuclear@0: 		min[i] = std::max(box1->min[i], box2->min[i]);
nuclear@0: 		max[i] = std::min(box1->max[i], box2->max[i]);
nuclear@0: 
nuclear@0: 		if(max[i] < min[i]) {
nuclear@0: 			max[i] = min[i];
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: bool AABox::intersect(const Ray &ray, HitPoint *hit) const
nuclear@0: {
nuclear@0: 	Vec3 param[2] = {min, max};
nuclear@0: 	Vec3 inv_dir(1.0 / ray.dir.x, 1.0 / ray.dir.y, 1.0 / ray.dir.z);
nuclear@0: 	int sign[3] = {inv_dir.x < 0, inv_dir.y < 0, inv_dir.z < 0};
nuclear@0: 
nuclear@0: 	float tmin = (param[sign[0]].x - ray.origin.x) * inv_dir.x;
nuclear@0: 	float tmax = (param[1 - sign[0]].x - ray.origin.x) * inv_dir.x;
nuclear@0: 	float tymin = (param[sign[1]].y - ray.origin.y) * inv_dir.y;
nuclear@0: 	float tymax = (param[1 - sign[1]].y - ray.origin.y) * inv_dir.y;
nuclear@0: 
nuclear@0: 	if(tmin > tymax || tymin > tmax) {
nuclear@0: 		return false;
nuclear@0: 	}
nuclear@0: 	if(tymin > tmin) {
nuclear@0: 		tmin = tymin;
nuclear@0: 	}
nuclear@0: 	if(tymax < tmax) {
nuclear@0: 		tmax = tymax;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	float tzmin = (param[sign[2]].z - ray.origin.z) * inv_dir.z;
nuclear@0: 	float tzmax = (param[1 - sign[2]].z - ray.origin.z) * inv_dir.z;
nuclear@0: 
nuclear@0: 	if(tmin > tzmax || tzmin > tmax) {
nuclear@0: 		return false;
nuclear@0: 	}
nuclear@0: 	if(tzmin > tmin) {
nuclear@0: 		tmin = tzmin;
nuclear@0: 	}
nuclear@0: 	if(tzmax < tmax) {
nuclear@0: 		tmax = tzmax;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	float t = tmin < 1e-4 ? tmax : tmin;
nuclear@0: 	if(t >= 1e-4) {
nuclear@0: 
nuclear@0: 		if(hit) {
nuclear@0: 			hit->obj = this;
nuclear@0: 			hit->dist = t;
nuclear@0: 			hit->pos = ray.origin + ray.dir * t;
nuclear@0: 
nuclear@0: 			float min_dist = FLT_MAX;
nuclear@0: 			Vec3 offs = min + (max - min) / 2.0;
nuclear@0: 			Vec3 local_hit = hit->pos - offs;
nuclear@0: 
nuclear@0: 			static const Vec3 axis[] = {
nuclear@0: 				Vec3(1, 0, 0), Vec3(0, 1, 0), Vec3(0, 0, 1)
nuclear@0: 			};
nuclear@0: 			//int tcidx[][2] = {{2, 1}, {0, 2}, {0, 1}};
nuclear@0: 
nuclear@0: 			for(int i=0; i<3; i++) {
nuclear@0: 				float dist = fabs((max[i] - offs[i]) - fabs(local_hit[i]));
nuclear@0: 				if(dist < min_dist) {
nuclear@0: 					min_dist = dist;
nuclear@0: 					hit->normal = axis[i] * (local_hit[i] < 0.0 ? 1.0 : -1.0);
nuclear@0: 					//hit->texcoord = Vec2(hit->pos[tcidx[i][0]], hit->pos[tcidx[i][1]]);
nuclear@0: 				}
nuclear@0: 			}
nuclear@0: 		}
nuclear@0: 		return true;
nuclear@0: 	}
nuclear@0: 	return false;
nuclear@0: 
nuclear@0: }
nuclear@0: 
nuclear@0: Plane::Plane()
nuclear@0: 	: normal(0.0, 1.0, 0.0)
nuclear@0: {
nuclear@0: }
nuclear@0: 
nuclear@0: Plane::Plane(const Vec3 &p, const Vec3 &norm)
nuclear@0: 	: pt(p)
nuclear@0: {
nuclear@0: 	normal = normalize(norm);
nuclear@0: }
nuclear@0: 
nuclear@0: Plane::Plane(const Vec3 &p1, const Vec3 &p2, const Vec3 &p3)
nuclear@0: 	: pt(p1)
nuclear@0: {
nuclear@0: 	normal = normalize(cross(p2 - p1, p3 - p1));
nuclear@0: }
nuclear@0: 
nuclear@0: Plane::Plane(const Vec3 &normal, float dist)
nuclear@0: {
nuclear@0: 	this->normal = normalize(normal);
nuclear@0: 	pt = this->normal * dist;
nuclear@0: }
nuclear@0: 
nuclear@0: void Plane::set_union(const GeomObject *obj1, const GeomObject *obj2)
nuclear@0: {
nuclear@0: 	fprintf(stderr, "Plane::set_union undefined\n");
nuclear@0: }
nuclear@0: 
nuclear@0: void Plane::set_intersection(const GeomObject *obj1, const GeomObject *obj2)
nuclear@0: {
nuclear@0: 	fprintf(stderr, "Plane::set_intersection undefined\n");
nuclear@0: }
nuclear@0: 
nuclear@0: bool Plane::intersect(const Ray &ray, HitPoint *hit) const
nuclear@0: {
nuclear@0: 	float ndotdir = dot(normal, ray.dir);
nuclear@0: 	if(fabs(ndotdir) < 1e-4) {
nuclear@0: 		return false;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(hit) {
nuclear@0: 		Vec3 ptdir = pt - ray.origin;
nuclear@0: 		float t = dot(normal, ptdir) / ndotdir;
nuclear@0: 
nuclear@0: 		hit->pos = ray.origin + ray.dir * t;
nuclear@0: 		hit->normal = normal;
nuclear@0: 		hit->obj = this;
nuclear@0: 	}
nuclear@0: 	return true;
nuclear@0: }
nuclear@0: 
nuclear@0: float sphere_distance(const Vec3 &cent, float rad, const Vec3 &pt)
nuclear@0: {
nuclear@0: 	return length(pt - cent) - rad;
nuclear@0: }
nuclear@0: 
nuclear@0: // TODO version which takes both radii into account
nuclear@0: float capsule_distance(const Vec3 &a, float ra, const Vec3 &b, float rb, const Vec3 &pt)
nuclear@0: {
nuclear@0: 	Vec3 ab_dir = b - a;
nuclear@0: 	float ab_len_sq = length_sq(ab_dir);
nuclear@0: 
nuclear@0: 	if(fabs(ab_len_sq) < 1e-5) {
nuclear@0: 		// if a == b, the capsule is a sphere with radius the maximum of the capsule radii
nuclear@0: 		return sphere_distance(a, std::max(ra, rb), pt);
nuclear@0: 	}
nuclear@0: 	float ab_len = sqrt(ab_len_sq);
nuclear@0: 
nuclear@0: 	Vec3 ap_dir = pt - a;
nuclear@0: 
nuclear@0: 	float t = dot(ap_dir, ab_dir / ab_len) / ab_len;
nuclear@0: 	if(t < 0.0) {
nuclear@0: 		return sphere_distance(a, ra, pt);
nuclear@0: 	}
nuclear@0: 	if(t >= 1.0) {
nuclear@0: 		return sphere_distance(b, rb, pt);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	Vec3 pproj = a + ab_dir * t;
nuclear@0: 	return length(pproj - pt) - ra;
nuclear@0: }
nuclear@0: 
nuclear@0: #if 0
nuclear@0: float capsule_distance(const Vec3 &a, float ra, const Vec3 &b, float rb, const Vec3 &pt)
nuclear@0: {
nuclear@0: 	Vec3 ab_dir = b - a;
nuclear@0: 
nuclear@0: 	if(fabs(length_sq(ab_dir)) < 1e-5) {
nuclear@0: 		// if a == b, the capsule is a sphere with radius the maximum of the capsule radii
nuclear@0: 		return sphere_distance(a, std::max(ra, rb), pt);
nuclear@0: 	}
nuclear@0: 	float ab_len = length(ab_dir);
nuclear@0: 
nuclear@0: 	Vec3 ap_dir = pt - a;
nuclear@0: 	Vec3 rotaxis = normalize(cross(ab_dir, ap_dir));
nuclear@0: 
nuclear@0: 	Mat4 rmat;
nuclear@0: 	rmat.set_rotation(rotaxis, M_PI / 2.0);
nuclear@0: 	Vec3 right = rmat * ab_dir / ab_len;
nuclear@0: 
nuclear@0: 	// XXX I think this check is redundant, always false, due to the cross product order
nuclear@0: 	//assert(dot(right, ab_dir) >= 0.0);
nuclear@0: 	if(dot(right, ab_dir) < 0.0) {
nuclear@0: 		right = -right;
nuclear@0: 	}
nuclear@0: 	Vec3 aa = a + right * ra;
nuclear@0: 	Vec3 bb = b + right * rb;
nuclear@0: 
nuclear@0: 	// project pt to the line segment bb-aa, see if the projection lies within the interval [0, 1)
nuclear@0: 	Vec3 aabb_dir = bb - aa;
nuclear@0: 	float aabb_len = length(aabb_dir);
nuclear@0: 	Vec3 aap_dir = pt - aa;
nuclear@0: 
nuclear@0: 	float t = dot(aap_dir, aabb_dir / aabb_len) / aabb_len;
nuclear@0: 	if(t < 0.0) {
nuclear@0: 		return sphere_distance(a, ra, pt);
nuclear@0: 	}
nuclear@0: 	if(t >= 1.0) {
nuclear@0: 		return sphere_distance(b, rb, pt);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	Vec3 ppt = aa + aabb_dir * t;
nuclear@0: 	Vec3 norm = ppt - pt;
nuclear@0: 	float dist = length(norm);
nuclear@0: 
nuclear@0: 	if(dot(norm, right) < 0.0) {
nuclear@0: 		// inside the cone
nuclear@0: 		dist = -dist;
nuclear@0: 	}
nuclear@0: 	return dist;
nuclear@0: }
nuclear@0: #endif