marching_cubes.h

浏览该文件的文档.

#pragma once
#include "vde/core/point.h"
#include <vector>
#include <array>
#include <functional>
#include <cmath>
#include <algorithm>
 
namespace vde::mesh {
using core::Point2D;
using core::Point3D;
using core::Vector3D;
 
struct MCMesh {
    std::vector<Point3D> vertices;              
    std::vector<std::array<int, 3>> triangles;  
};
 
MCMesh marching_cubes(const std::function<double(double,double,double)>& f,
                      double iso_level,
                      const Point3D& bmin, const Point3D& bmax,
                      int resolution);
 
inline double sdf_sphere(double x, double y, double z, double cx, double cy, double cz, double r) {
    return std::sqrt((x-cx)*(x-cx) + (y-cy)*(y-cy) + (z-cz)*(z-cz)) - r;
}
 
inline double sdf_box(double x, double y, double z, double hx, double hy, double hz) {
    double dx = std::abs(x) - hx, dy = std::abs(y) - hy, dz = std::abs(z) - hz;
    return std::sqrt(std::max(dx,0.0)*std::max(dx,0.0)
                   + std::max(dy,0.0)*std::max(dy,0.0)
                   + std::max(dz,0.0)*std::max(dz,0.0))
         + std::min(std::max({dx,dy,dz}), 0.0);
}
 
namespace { inline double lerp_impl(double a, double b, double t) { return a + t * (b - a); } }
inline double sdf_smooth_union(double d1, double d2, double k) {
    double h = std::clamp(0.5 + 0.5*(d2-d1)/k, 0.0, 1.0);
    return lerp_impl(d2, d1, h) - k*h*(1.0-h);
}
 
inline double sdf_smooth_subtraction(double d1, double d2, double k) {
    double h = std::clamp(0.5 - 0.5*(d2+d1)/k, 0.0, 1.0);
    return lerp_impl(d2, -d1, h) + k*h*(1.0-h);
}
 
}  // namespace vde::mesh