308 lines
10 KiB
C++
308 lines
10 KiB
C++
#include <iostream>
|
|
#include <iomanip>
|
|
#include <limits>
|
|
#include <vector>
|
|
|
|
#include <glm/gtc/constants.hpp>
|
|
|
|
#include "photon_tracer.hpp"
|
|
#include "sampling.hpp"
|
|
#include "area_light.hpp"
|
|
|
|
using std::cout;
|
|
using std::endl;
|
|
using std::setw;
|
|
using std::vector;
|
|
using std::numeric_limits;
|
|
using namespace glm;
|
|
|
|
#define ANSI_BOLD_YELLOW "\x1b[1;33m"
|
|
#define ANSI_RESET_STYLE "\x1b[m"
|
|
|
|
PhotonTracer::~PhotonTracer() { }
|
|
|
|
vec3 PhotonTracer::trace_ray(Ray & r, Scene * s, unsigned int rec_level) const {
|
|
float t, _t, radius, red, green, blue, kr;
|
|
Figure * _f;
|
|
vec3 n, color, i_pos, ref, dir_diff_color, dir_spec_color, p_contrib;
|
|
Ray mv_r, sr, rr;
|
|
bool vis, is_area_light;
|
|
AreaLight * al;
|
|
Vec3 mn, mx;
|
|
vector<Photon> photons;
|
|
|
|
t = numeric_limits<float>::max();
|
|
_f = NULL;
|
|
|
|
// Find the closest intersecting surface.
|
|
for (size_t f = 0; f < s->m_figures.size(); f++) {
|
|
if (s->m_figures[f]->intersect(r, _t) && _t < t) {
|
|
t = _t;
|
|
_f = s->m_figures[f];
|
|
}
|
|
}
|
|
|
|
// If this ray intersects something:
|
|
if (_f != NULL) {
|
|
// Take the intersection point and the normal of the surface at that point.
|
|
i_pos = r.m_origin + (t * r.m_direction);
|
|
n = _f->normal_at_int(r, t);
|
|
|
|
is_area_light = false;
|
|
// Check if the object is an area light;
|
|
for (size_t l = 0; l < s->m_lights.size(); l++) {
|
|
if (s->m_lights[l]->light_type() == Light::AREA && static_cast<AreaLight *>(s->m_lights[l])->m_figure == _f)
|
|
is_area_light = true;
|
|
}
|
|
|
|
// If the object is an area light, return it's emission value.
|
|
if (is_area_light) {
|
|
return _f->m_mat->m_emission;
|
|
|
|
// Check if the material is not reflective/refractive.
|
|
} else if (!_f->m_mat->m_refract) {
|
|
|
|
// Calculate the direct lighting.
|
|
for (size_t l = 0; l < s->m_lights.size(); l++) {
|
|
// For every light source
|
|
vis = true;
|
|
|
|
if (s->m_lights[l]->light_type() == Light::INFINITESIMAL) {
|
|
// Cast a shadow ray to determine visibility.
|
|
sr = Ray(s->m_lights[l]->direction(i_pos), i_pos + n * BIAS);
|
|
for (size_t f = 0; f < s->m_figures.size(); f++) {
|
|
if (s->m_figures[f]->intersect(sr, _t) && _t < s->m_lights[l]->distance(i_pos)) {
|
|
vis = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
} else if (s->m_lights[l]->light_type() == Light::AREA) {
|
|
// Cast a shadow ray towards a sample point on the surface of the light source.
|
|
al = static_cast<AreaLight *>(s->m_lights[l]);
|
|
al->sample_at_surface();
|
|
sr = Ray(al->direction(i_pos), i_pos + (n * BIAS));
|
|
|
|
for (size_t f = 0; f < s->m_figures.size(); f++) {
|
|
// Avoid self-intersection with the light source.
|
|
if (al->m_figure != s->m_figures[f]) {
|
|
if (s->m_figures[f]->intersect(sr, _t) && _t < al->distance(i_pos)) {
|
|
vis = false;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Evaluate the shading model accounting for visibility.
|
|
dir_diff_color += vis ? s->m_lights[l]->diffuse(n, r, i_pos, *_f->m_mat) : vec3(0.0f);
|
|
dir_spec_color += vis ? s->m_lights[l]->specular(n, r, i_pos, *_f->m_mat) : vec3(0.0f);
|
|
}
|
|
|
|
// TODO: Change photon map search method for hemisphere search.
|
|
radius = m_h_radius;
|
|
mn = Vec3(i_pos.x - radius, i_pos.y - radius, i_pos.z - radius);
|
|
mx = Vec3(i_pos.x + radius, i_pos.y + radius, i_pos.z + radius);
|
|
|
|
while((photons = m_photon_map.findInRange(mn, mx)).size() == 0 && radius < 5.0) {
|
|
radius *= 2;
|
|
mn = Vec3(i_pos.x - radius, i_pos.y - radius, i_pos.z - radius);
|
|
mx = Vec3(i_pos.x + radius, i_pos.y + radius, i_pos.z + radius);
|
|
}
|
|
|
|
for (vector<Photon>::iterator it = photons.begin(); it != photons.end(); it++) {
|
|
(*it).getColor(red, green, blue);
|
|
p_contrib += vec3(red, green, blue);
|
|
}
|
|
p_contrib /= pi<float>() * (radius * radius);
|
|
|
|
color += (1.0f - _f->m_mat->m_rho) * (((dir_diff_color + p_contrib) * (_f->m_mat->m_diffuse / pi<float>())) +
|
|
(_f->m_mat->m_specular * dir_spec_color));
|
|
|
|
// Determine the specular reflection color.
|
|
if (_f->m_mat->m_rho > 0.0f && rec_level < m_max_depth) {
|
|
rr = Ray(normalize(reflect(r.m_direction, n)), i_pos + n * BIAS);
|
|
color += _f->m_mat->m_rho * trace_ray(rr, s, rec_level + 1);
|
|
} else if (_f->m_mat->m_rho > 0.0f && rec_level >= m_max_depth)
|
|
return vec3(0.0f);
|
|
|
|
} else {
|
|
// If the material has transmission enabled, calculate the Fresnel term.
|
|
kr = fresnel(r.m_direction, n, r.m_ref_index, _f->m_mat->m_ref_index);
|
|
|
|
// Determine the specular reflection color.
|
|
if (kr > 0.0f && rec_level < m_max_depth) {
|
|
rr = Ray(normalize(reflect(r.m_direction, n)), i_pos + n * BIAS);
|
|
color += kr * trace_ray(rr, s, rec_level + 1);
|
|
} else if (rec_level >= m_max_depth)
|
|
return vec3(0.0f);
|
|
|
|
// Determine the transmission color.
|
|
if (_f->m_mat->m_refract && kr < 1.0f && rec_level < m_max_depth) {
|
|
rr = Ray(normalize(refract(r.m_direction, n, r.m_ref_index / _f->m_mat->m_ref_index)), i_pos - n * BIAS, _f->m_mat->m_ref_index);
|
|
color += (1.0f - kr) * trace_ray(rr, s, rec_level + 1);
|
|
} else if (rec_level >= m_max_depth)
|
|
return vec3(0.0f);
|
|
|
|
}
|
|
|
|
// Return final color.
|
|
return _f->m_mat->m_emission + color;
|
|
|
|
} else
|
|
return s->m_env->get_color(r);
|
|
}
|
|
|
|
void PhotonTracer::build_photon_map(Scene * s, const size_t n_photons_per_ligth, const bool specular) {
|
|
Light * l;
|
|
AreaLight * al;
|
|
vec3 l_sample, s_normal, h_sample, power;
|
|
Vec3 ls, dir;
|
|
float r1, r2;
|
|
Photon ph;
|
|
size_t total = 0, current = 0;
|
|
|
|
for (vector<Light *>::iterator it = s->m_lights.begin(); it != s->m_lights.end(); it++) {
|
|
total += (*it)->light_type() == Light::AREA ? 1 : 0;
|
|
}
|
|
total *= n_photons_per_ligth;
|
|
|
|
cout << "Tracing a total of " << ANSI_BOLD_YELLOW << total << ANSI_RESET_STYLE << " primary photons:" << endl;
|
|
|
|
for (vector<Light *>::iterator it = s->m_lights.begin(); it != s->m_lights.end(); it++) {
|
|
l = *it;
|
|
|
|
/* Only area lights supported right now. */
|
|
if (l->light_type() != Light::AREA)
|
|
continue;
|
|
|
|
al = static_cast<AreaLight *>(l);
|
|
|
|
#pragma omp parallel for schedule(dynamic, 1) private(l_sample, s_normal, h_sample, r1, r2) shared(current)
|
|
for (size_t p = 0; p < n_photons_per_ligth; p++) {
|
|
if (!specular) {
|
|
l_sample = al->sample_at_surface();
|
|
s_normal = al->normal_at_last_sample();
|
|
|
|
r1 = random01();
|
|
r2 = random01();
|
|
h_sample = normalize(sample_hemisphere(r1, r2));
|
|
rotate_sample(h_sample, s_normal);
|
|
ls = Vec3(l_sample.x, l_sample.y, l_sample.z);
|
|
dir = Vec3(h_sample.x, h_sample.y, h_sample.z);
|
|
power = (al->m_figure->m_mat->m_emission / static_cast<float>(n_photons_per_ligth)) / (al->m_figure->pdf());
|
|
ph = Photon(ls, dir, power.r, power.g, power.b, 1.0f);
|
|
|
|
} else {
|
|
// TODO: Generate photon from light source in direction of specular reflective objects.
|
|
}
|
|
|
|
#pragma omp critical
|
|
{
|
|
m_photon_map.addPhoton(ph);
|
|
}
|
|
|
|
trace_photon(ph, s, 0);
|
|
|
|
#pragma omp atomic
|
|
current++;
|
|
}
|
|
|
|
cout << "\r" << setw(3) << static_cast<size_t>((static_cast<double>(current) / static_cast<double>(total)) * 100.0) << "% done.";
|
|
}
|
|
cout << endl;
|
|
|
|
cout << "Building photon map Kd-tree." << endl;
|
|
m_photon_map.buildKdTree();
|
|
}
|
|
|
|
void PhotonTracer::trace_photon(Photon & ph, Scene * s, const unsigned int rec_level) {
|
|
Photon photon;
|
|
float t, _t, red, green, blue;
|
|
Figure * _f;
|
|
vec3 n, color, i_pos, sample, ph_dir, ph_pos;
|
|
Vec3 p_pos, p_dir;
|
|
Ray r;
|
|
float kr, r1, r2;
|
|
|
|
t = numeric_limits<float>::max();
|
|
_f = NULL;
|
|
|
|
// Find the closest intersecting surface.
|
|
r = Ray(ph.direction.x, ph.direction.y, ph.direction.z, ph.position.x, ph.position.y, ph.position.z);
|
|
for (size_t f = 0; f < s->m_figures.size(); f++) {
|
|
if (s->m_figures[f]->intersect(r, _t) && _t < t) {
|
|
t = _t;
|
|
_f = s->m_figures[f];
|
|
}
|
|
}
|
|
|
|
// If this ray intersects something:
|
|
if (_f != NULL) {
|
|
// Take the intersection point and the normal of the surface at that point.
|
|
i_pos = r.m_origin + (t * r.m_direction);
|
|
n = _f->normal_at_int(r, t);
|
|
|
|
// Store the diffuse photon and trace.
|
|
if (!_f->m_mat->m_refract && rec_level < m_max_depth){
|
|
if (rec_level < m_max_depth) {
|
|
r1 = random01();
|
|
r2 = random01();
|
|
sample = sample_hemisphere(r1, r2);
|
|
rotate_sample(sample, n);
|
|
normalize(sample);
|
|
} else
|
|
sample = vec3(0.0f);
|
|
|
|
ph.getColor(red, green, blue);
|
|
color = (1.0f - _f->m_mat->m_rho) * (vec3(red, green, blue) * (_f->m_mat->m_diffuse / pi<float>()));
|
|
p_pos = Vec3(i_pos.x, i_pos.y, i_pos.z);
|
|
p_dir = Vec3(sample.x, sample.y, sample.z);
|
|
photon = Photon(p_pos, p_dir, color.r, color.g, color.b, ph.ref_index);
|
|
#pragma omp critical
|
|
{
|
|
m_photon_map.addPhoton(photon);
|
|
}
|
|
|
|
trace_photon(photon, s, rec_level + 1);
|
|
}
|
|
|
|
// Trace the reflected photon.
|
|
if (!_f->m_mat->m_refract && _f->m_mat->m_rho > 0.0f && rec_level < m_max_depth) {
|
|
color = (_f->m_mat->m_rho) * vec3(red, green, blue);
|
|
i_pos += n * BIAS;
|
|
p_pos = Vec3(i_pos.x, i_pos.y, i_pos.z);
|
|
ph_dir = normalize(reflect(vec3(ph.direction.x, ph.direction.y, ph.direction.z), n));
|
|
p_dir = Vec3(ph_dir.x, ph_dir.y, ph_dir.z);
|
|
photon = Photon(p_pos, p_dir, color.r, color.g, color.b, ph.ref_index);
|
|
trace_photon(photon, s, rec_level + 1);
|
|
|
|
} else if (_f->m_mat->m_refract && rec_level >= m_max_depth) {
|
|
// If the material has transmission enabled, calculate the Fresnel term.
|
|
kr = fresnel(r.m_direction, n, r.m_ref_index, _f->m_mat->m_ref_index);
|
|
|
|
// Trace the reflected photon.
|
|
if (kr > 0.0f && rec_level < m_max_depth) {
|
|
color = kr * vec3(red, green, blue);
|
|
i_pos += n * BIAS;
|
|
p_pos = Vec3(i_pos.x, i_pos.y, i_pos.z);
|
|
ph_dir = normalize(reflect(vec3(ph.direction.x, ph.direction.y, ph.direction.z), n));
|
|
p_dir = Vec3(ph_dir.x, ph_dir.y, ph_dir.z);
|
|
photon = Photon(p_pos, p_dir, color.r, color.g, color.b, ph.ref_index);
|
|
trace_photon(photon, s, rec_level + 1);
|
|
}
|
|
|
|
// Trace the transmitted photon.
|
|
if (_f->m_mat->m_refract && kr < 1.0f && rec_level < m_max_depth) {
|
|
color = (1.0f - kr) * vec3(red, green, blue);
|
|
i_pos -= n * (2 * BIAS);
|
|
p_pos = Vec3(i_pos.x, i_pos.y, i_pos.z);
|
|
ph_dir = normalize(refract(vec3(ph.direction.x, ph.direction.y, ph.direction.z), n, ph.ref_index / _f->m_mat->m_ref_index));
|
|
p_dir = Vec3(ph_dir.x, ph_dir.y, ph_dir.z);
|
|
photon = Photon(p_pos, p_dir, color.r, color.g, color.b, _f->m_mat->m_ref_index);
|
|
trace_photon(photon, s, rec_level + 1);
|
|
}
|
|
}
|
|
}
|
|
}
|