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#include <imgen.h>
#include <cmath>
#include <thread>
#include <vector>
#include <algorithm>
int minkowski_metric(double p, int refX, int refY, int x, int y) {
return static_cast<int>(std::nearbyint(
std::pow(
std::pow(std::abs(refX - x), p) + std::pow(std::abs(refY - y), p),
1.0 / p
)
));
}
int manhattan_metric(int refX, int refY, int x, int y) {
return minkowski_metric(1, refX, refY, x, y);
}
int euclidean_metric(int refX, int refY, int x, int y) {
return minkowski_metric(2, refX, refY, x, y);
}
void generate_minkowski_voronoi(
const double lower,
const double upper,
const double epsilon
) {
constexpr std::array<imgen::colored_vector, 9> ref{
imgen::colored_vector{ 0, 0, imgen::red() },
imgen::colored_vector{ 240, 200, imgen::green() },
imgen::colored_vector{-100, 230, imgen::blue() },
imgen::colored_vector{ 120, -100, imgen::yellow() },
imgen::colored_vector{ -42, -200, imgen::cyan() },
imgen::colored_vector{ 120, 40, imgen::magenta()},
imgen::colored_vector{-150, 50, imgen::silver() },
imgen::colored_vector{ 60, -128, imgen::maroon() },
imgen::colored_vector{-240, -20, imgen::olive() }
};
for ( double p = lower; p < upper + epsilon; p = p + epsilon ) {
imgen::write_ppm(
"voronoi_" + std::to_string(p) + ".ppm",
512,
512,
[&ref, p](std::ptrdiff_t x, std::ptrdiff_t y) -> imgen::color {
std::array<int, 9> distances;
std::transform(
ref.begin(),
ref.end(),
distances.begin(),
[x, y, p](const imgen::colored_vector& pos) {
return minkowski_metric(p, std::get<0>(pos), std::get<1>(pos), x, y);
});
const auto& minimal_distance = std::min_element(
distances.begin(),
distances.end()
);
const imgen::colored_vector& nearest = ref[
std::distance(distances.begin(), minimal_distance)
];
if ( *minimal_distance <= 5 ) {
return imgen::black();
} else {
return std::get<2>(nearest);
}
}
);
}
}
void generate_parallel_minkowski_voronoi(
const unsigned int thread_count,
const double lower,
const double upper,
const double epsilon
) {
std::vector<std::thread> threads;
const double step = ( ( upper - lower ) / thread_count ) - epsilon;
double offset = lower;
threads.emplace_back([offset, step, epsilon]{
generate_minkowski_voronoi(
offset,
offset + step + epsilon,
epsilon
);
});
offset += step + epsilon + epsilon;
while ( threads.size() < thread_count ) {
threads.emplace_back([offset, step, epsilon]{
generate_minkowski_voronoi(
offset,
offset + step,
epsilon
);
});
offset += step + epsilon;
}
for ( auto& thread : threads ) {
thread.join();
}
}
int main(int, char*[]) {
generate_parallel_minkowski_voronoi(4, 1.0, 16.0, 0.05);
}
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