100 lines
3.2 KiB
C++
100 lines
3.2 KiB
C++
#include <limits>
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#include <glm/gtc/constants.hpp>
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#include "path_tracer.hpp"
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using std::numeric_limits;
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using namespace glm;
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PathTracer::~PathTracer() { }
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vec3 PathTracer::trace_ray(Ray & r, vector<Figure *> & v_figures, vector<Light *> & v_lights, 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, sample, dir_diff_color, dir_spec_color, ind_color;
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Ray mv_r, sr, rr;
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bool vis;
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float kr, r1, r2;
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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 < v_figures.size(); f++) {
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if (v_figures[f]->intersect(r, _t) && _t < t) {
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t = _t;
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_f = v_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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// Check if the material is not reflective/refractive.
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if( !_f->m_mat.m_refract && _f->m_mat.m_rho == 0.0f) {
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// Calculate the direct lighting.
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for (size_t l = 0; l < v_lights.size(); l++) {
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// For every light source
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vis = true;
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// Cast a shadow ray to determine visibility.
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sr = Ray(v_lights[l]->direction(i_pos), i_pos + n * BIAS);
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for (size_t f = 0; f < v_figures.size(); f++) {
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if (v_figures[f]->intersect(sr, _t) && _t < v_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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// Evaluate the shading model accounting for visibility.
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dir_diff_color += (vis ? 1.0f : 0.0f) * v_lights[l]->diffuse(n, r, t, _f->m_mat);
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dir_spec_color += (vis ? 1.0f : 0.0f) * v_lights[l]->specular(n, r, t, _f->m_mat);
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}
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// If enabled, calculate indirect lighting contribution.
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if (indirect_l && rec_level < MAX_RECURSION) {
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r1 = random01();
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r2 = random01();
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sample = sample_hemisphere(r1, r2);
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rotate_sample(sample, n);
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rr = Ray(normalize(sample), i_pos + (sample * BIAS));
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ind_color += r1 * trace_ray(rr, v_figures, v_lights, rec_level + 1) / (1.0f / (2.0f * pi<float>()));
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}
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color += ((dir_diff_color + ind_color) * (_f->m_mat.m_diffuse / pi<float>())) + dir_spec_color;
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} else {
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// If the material has reflection/transmission enabled.
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// Calculate the Fresnel term if the surface is refracting.
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if (_f->m_mat.m_refract)
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kr = fresnel(r.m_direction, n, r.m_ref_index, _f->m_mat.m_ref_index);
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else
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kr = _f->m_mat.m_rho;
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// Determinte the specular reflection color.
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if (kr > 0.0f && rec_level < MAX_RECURSION) {
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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 * kr * trace_ray(rr, v_figures, v_lights, rec_level + 1);
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} else if (rec_level >= MAX_RECURSION)
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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 < MAX_RECURSION) {
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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 - _f->m_mat.m_rho) * (1.0f - kr) * trace_ray(rr, v_figures, v_lights, rec_level + 1);
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} else if (rec_level >= MAX_RECURSION)
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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(color, 0.0f, 1.0f);
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} else
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return vec3(BCKG_COLOR);
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}
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