48 lines
1.5 KiB
C++
48 lines
1.5 KiB
C++
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#pragma once
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#include "vde/core/point.h"
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#include <vector>
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#include <array>
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#include <functional>
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namespace vde::mesh {
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struct MCMesh {
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std::vector<Point3D> vertices;
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std::vector<std::array<int, 3>> triangles;
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};
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/// Marching Cubes for scalar field f(x,y,z)
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/// Extracts isosurface at value = iso_level within the bounding box
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MCMesh marching_cubes(const std::function<double(double,double,double)>& f,
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double iso_level,
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const Point3D& bmin, const Point3D& bmax,
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int resolution);
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/// SDF sphere
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inline double sdf_sphere(double x, double y, double z, double cx, double cy, double cz, double r) {
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return std::sqrt((x-cx)*(x-cx) + (y-cy)*(y-cy) + (z-cz)*(z-cz)) - r;
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}
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/// SDF box
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inline double sdf_box(double x, double y, double z, double hx, double hy, double hz) {
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double dx = std::abs(x) - hx, dy = std::abs(y) - hy, dz = std::abs(z) - hz;
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return std::sqrt(std::max(dx,0.0)*std::max(dx,0.0)
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+ std::max(dy,0.0)*std::max(dy,0.0)
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+ std::max(dz,0.0)*std::max(dz,0.0))
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+ std::min(std::max({dx,dy,dz}), 0.0);
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}
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/// SDF smooth union
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inline double sdf_smooth_union(double d1, double d2, double k) {
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double h = std::clamp(0.5 + 0.5*(d2-d1)/k, 0.0, 1.0);
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return std::lerp(d2, d1, h) - k*h*(1.0-h);
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}
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/// SDF smooth subtraction
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inline double sdf_smooth_subtraction(double d1, double d2, double k) {
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double h = std::clamp(0.5 - 0.5*(d2+d1)/k, 0.0, 1.0);
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return std::lerp(d2, -d1, h) + k*h*(1.0-h);
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}
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} // namespace vde::mesh
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