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RayTracing.cpp
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RayTracing.cpp
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#include "Utils.h"
#include "RayTracing.h"
#define PPE_GAMMA 0.5f
#define RT_MAX_DEPTH 50
#define RT_MIN_INTERSECTION_T 0.001f
void
compute_ray_tracing(int width, int height, int samples, Camera *camera, Object *list, Image2D *image)
{
std::cout << "\nRay Tracing Progress" << std::endl;
#ifdef EXECUTION_TIME_COMPUTATION
auto start = high_resolution_clock::now();
#endif
Vec3 **_colors = new Vec3 *[width];
for (int i = 0; i < width; ++i) {
_colors[i] = new Vec3[height];
}
float _progress_i = 0.0f;
float _progress_total = static_cast<float>(width*height);
#ifdef _OPENMP
#ifdef _WIN32
#pragma omp parallel for
#else
#pragma omp parallel for collapse(2)
#endif
#endif
// For each pixel (in parallel)
for (int j = height - 1; j >= 0; --j) {
for (int i = 0; i < width; ++i) {
_colors[i][j] = Vec3(0.0f, 0.0f, 0.0f);
for (int s = 0; s < samples; ++s) {
// Compute pixel sample coords - UV
float _u = static_cast<float>(i + RANDOM_GEN()) / static_cast<float>(width);
float _v = static_cast<float>(j + RANDOM_GEN()) / static_cast<float>(height);
// Compute ray that pass through each pixel
Ray _ray = camera->GetRay(_u, _v);
// Compute pixel sample color
_colors[i][j] += compute_sample_color(_ray, list, 0);
}
// Compute sample-averaged pixel color
_colors[i][j] /= static_cast<float>(samples);
// Gamma Correction
_colors[i][j] = compute_gamma_corrected_color(_colors[i][j], PPE_GAMMA);
printProgress(++_progress_i / _progress_total);
}
}
#ifdef EXECUTION_TIME_COMPUTATION
auto stop = high_resolution_clock::now();
auto duration = duration_cast<milliseconds>(stop - start);
std::cout << "\nImage was successfully generated in " << duration.count() << " ms" << std::endl;
#endif
image->WritePixel2File(_colors);
for (int i = 0; i < width; ++i) {
safe_array_delete(_colors[i]);
}
safe_array_delete(_colors);
}
Vec3
compute_gamma_corrected_color(const Vec3& color, float gamma)
{
return Vec3(powf(color[0], gamma), powf(color[1], gamma), powf(color[2], gamma));
}
Vec3
compute_background_color(const Ray& ray)
{
// Background color
const Vec3 _a(0.0f,0.0f,0.0f);
const Vec3 _b(0.15f,0.15f,0.15f);
const Vec3 _unit_dir = unit_vector(ray.GetDirection());
const float _t = 0.5f * (_unit_dir.y() + 1.0f); // [-1,1] -> [0,1]
return lerp(_a, _b, _t);
}
Vec3
compute_sample_color(const Ray& ray, Object *list, int depth)
{
hit_record_t _hit_record;
if(list->Intersect(ray, RT_MIN_INTERSECTION_T, std::numeric_limits<float>::max(), _hit_record)) {
Ray _scattered;
Vec3 _attenuation;
Vec3 _emitted = _hit_record.m_material->Emitted(_hit_record.m_point, _hit_record.m_u, _hit_record.m_v);
if (depth < RT_MAX_DEPTH && _hit_record.m_material->Scatter(ray, _hit_record, _attenuation, _scattered)) {
return _emitted + _attenuation * compute_sample_color(_scattered, list, depth+1);
}
else {
return _emitted;
}
}
return compute_background_color(ray);
}