126 lines
4.1 KiB
C++
126 lines
4.1 KiB
C++
#include <iostream>
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#include <limits>
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#include <glm/gtc/constants.hpp>
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#include "whitted_tracer.hpp"
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#include "area_light.hpp"
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using std::numeric_limits;
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using namespace glm;
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WhittedTracer::~WhittedTracer() { }
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vec3 WhittedTracer::trace_ray(Ray & r, Scene * s, unsigned int rec_level) const {
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float t, _t;
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Figure * _f;
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vec3 n, color, i_pos, ref, dir_diff_color, dir_spec_color;
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Ray mv_r, sr, rr;
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bool vis, is_area_light;
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float kr;
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AreaLight * al;
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t = numeric_limits<float>::max();
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_f = NULL;
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// Find the closest intersecting surface.
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for (size_t f = 0; f < s->m_figures.size(); f++) {
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if (s->m_figures[f]->intersect(r, _t) && _t < t) {
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t = _t;
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_f = s->m_figures[f];
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}
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}
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// If this ray intersects something:
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if (_f != NULL) {
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// Take the intersection point and the normal of the surface at that point.
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i_pos = r.m_origin + (t * r.m_direction);
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n = _f->normal_at_int(r, t);
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is_area_light = false;
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// Check if the object is an area light;
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for (size_t l = 0; l < s->m_lights.size(); l++) {
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if (s->m_lights[l]->light_type() == Light::AREA && static_cast<AreaLight *>(s->m_lights[l])->m_figure == _f)
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is_area_light = true;
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}
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// If the object is an area light, return it's emission value.
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if (is_area_light) {
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return clamp(_f->m_mat->m_emission, 0.0f, 1.0f);
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// Check if the material is not reflective/refractive.
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} else if (!_f->m_mat->m_refract) {
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// Calculate the direct lighting.
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for (size_t l = 0; l < s->m_lights.size(); l++) {
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// For every light source
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vis = true;
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if (s->m_lights[l]->light_type() == Light::INFINITESIMAL) {
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// Cast a shadow ray to determine visibility.
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sr = Ray(s->m_lights[l]->direction(i_pos), i_pos + n * BIAS);
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for (size_t f = 0; f < s->m_figures.size(); f++) {
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if (s->m_figures[f]->intersect(sr, _t) && _t < s->m_lights[l]->distance(i_pos)) {
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vis = false;
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break;
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}
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}
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} else if (s->m_lights[l]->light_type() == Light::AREA) {
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// Cast a shadow ray towards a sample point on the surface of the light source.
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al = static_cast<AreaLight *>(s->m_lights[l]);
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al->sample_at_surface();
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sr = Ray(al->direction(i_pos), i_pos + (n * BIAS));
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for (size_t f = 0; f < s->m_figures.size(); f++) {
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// Avoid self-intersection with the light source.
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if (al->m_figure != s->m_figures[f]) {
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if (s->m_figures[f]->intersect(sr, _t) && _t < al->distance(i_pos)) {
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vis = false;
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break;
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}
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}
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}
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}
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// Evaluate the shading model accounting for visibility.
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dir_diff_color += vis ? s->m_lights[l]->diffuse(n, r, i_pos, *_f->m_mat) : vec3(0.0f);
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dir_spec_color += vis ? s->m_lights[l]->specular(n, r, i_pos, *_f->m_mat) : vec3(0.0f);
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}
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color += (1.0f - _f->m_mat->m_rho) * ((dir_diff_color * (_f->m_mat->m_diffuse / pi<float>())) + (_f->m_mat->m_specular * dir_spec_color));
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// Determine the specular reflection color.
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if (_f->m_mat->m_rho > 0.0f && rec_level < m_max_depth) {
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rr = Ray(normalize(reflect(r.m_direction, n)), i_pos + n * BIAS);
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color += _f->m_mat->m_rho * trace_ray(rr, s, rec_level + 1);
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} else if (_f->m_mat->m_rho > 0.0f && rec_level >= m_max_depth)
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return vec3(0.0f);
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} else {
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// If the material has transmission enabled, calculate the Fresnel term.
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kr = fresnel(r.m_direction, n, r.m_ref_index, _f->m_mat->m_ref_index);
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// Determine the specular reflection color.
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if (kr > 0.0f && rec_level < m_max_depth) {
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rr = Ray(normalize(reflect(r.m_direction, n)), i_pos + n * BIAS);
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color += kr * trace_ray(rr, s, rec_level + 1);
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} else if (rec_level >= m_max_depth)
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return vec3(0.0f);
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// Determine the transmission color.
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if (_f->m_mat->m_refract && kr < 1.0f && rec_level < m_max_depth) {
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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);
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color += (1.0f - kr) * trace_ray(rr, s, rec_level + 1);
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} else if (rec_level >= m_max_depth)
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return vec3(0.0f);
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}
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// Return final color.
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return clamp(_f->m_mat->m_emission + color, 0.0f, 1.0f);
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} else
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return clamp(s->m_env->get_color(r), 0.0f, 1.0f);
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}
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