112 lines
2.9 KiB
C++
112 lines
2.9 KiB
C++
#pragma once
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#include <cstddef>
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#include <vector>
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#include "random_sampler_wrapper.hpp"
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#include "math/vec2.h"
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#include "math/vec3fa.h"
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class MLTRandomSampler : public embree::RandomSamplerWrapper {
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private:
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size_t index;
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std::vector<float> data;
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std::vector<float> new_data;
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std::vector<size_t> last_changed;
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size_t time;
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size_t last_large_step;
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float small_step_size;
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float large_step_probability;
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bool large_step;
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float normalize(float x) {
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if (x < 0.0) {
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return x + 1.0;
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} else if (x >= 1.0) {
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return x - 1.0;
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}
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return x;
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}
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public:
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MLTRandomSampler() {
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}
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MLTRandomSampler(float small_step_size, float large_step_probability)
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: index(0), data({}), last_changed({}), time(0), last_large_step(0),
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small_step_size(small_step_size),
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large_step_probability(large_step_probability) {}
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void init(int id) override { RandomSampler_init(sampler, id); }
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void accept() {
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time++;
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for (size_t i = 0; i < new_data.size(); i++) {
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if (i >= data.size()) {
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data.push_back(new_data[i]);
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last_changed.push_back(time);
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} else {
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data.at(i) = new_data.at(i);
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last_changed.at(i) = time;
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}
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}
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if (large_step)
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last_large_step = time;
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}
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void new_ray(bool l) {
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index = 0;
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new_data.clear();
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large_step = l;
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}
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bool is_large_step() { return large_step; }
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float get1D() override {
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float result;
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if (is_large_step()) {
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float r = RandomSampler_get1D(sampler);
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new_data.push_back(r);
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result = r;
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} else {
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if (index >= data.size()) {
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float r = RandomSampler_get1D(sampler);
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data.push_back(r);
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last_changed.push_back(time);
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new_data.push_back(r);
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result = r;
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}
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// printf("%d, %d\n", index, last_large_step);
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if (last_changed.at(index) < last_large_step) {
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float r = RandomSampler_get1D(sampler);
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data.at(index) = r;
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last_changed.at(index) = time;
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new_data.push_back(r);
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result = r;
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} else {
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size_t steps = time - last_changed.at(index);
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float d = data.at(index);
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for (size_t i = 0; i < steps; i++) {
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float r = RandomSampler_get1D(sampler);
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float o = r * small_step_size - (small_step_size / 2.0);
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d = normalize(d + o);
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}
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data.at(index) = d;
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last_changed.at(index) = time;
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float r = RandomSampler_get1D(sampler);
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float o = r * small_step_size - (small_step_size / 2.0);
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d = normalize(d + o);
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new_data.push_back(d);
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// printf("%zu, %zu, %f, %f\n", index, steps, data.at(index), d);
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result = d;
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}
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}
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// printf("%zu, %f\n", index, result);
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index++;
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return result;
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}
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embree::Vec2f get2D() override { return embree::Vec2f(get1D(), get1D()); }
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embree::Vec3fa get3D() override { return embree::Vec3fa(get1D(), get1D(), get1D()); }
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};
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