sdf.hpp

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/*
 * Copyright (C) 2023  Christopher J. Howard
 *
 * This file is part of Antkeeper source code.
 *
 * Antkeeper source code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Antkeeper source code is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Antkeeper source code.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#ifndef ANTKEEPER_GEOM_SDF_HPP
#define ANTKEEPER_GEOM_SDF_HPP
 
#include <engine/math/vector.hpp>
#include <algorithm>
 
namespace geom {
 
namespace sdf {
 
inline math::fvec3 translate(const math::fvec3& sample, const math::fvec3& offset)
{
    return sample - offset;
}
 
inline float sphere(const math::fvec3& p, float r)
{
    return math::length(p) - r;
}
 
inline float cylinder(const math::fvec3& p, float r, float h)
{
    float dx = std::abs(math::length(math::swizzle<0, 2>(p))) - r;
    float dy = std::abs(p[1]) - h;
    return std::min<float>(std::max<float>(dx, dy), 0.0f) + math::length(math::fvec2{std::max<float>(dx, 0.0f), std::max<float>(dy, 0.0f)});
}
 
inline float op_union(float a, float b)
{
    return std::min<float>(a, b);
}
 
inline float op_difference(float a, float b)
{
    return std::max<float>(-a, b);
}
 
inline float op_intersection(float a, float b)
{
    return std::max<float>(a, b);
}
 
inline float op_round(float d, float r)
{
    return d - r;
}
 
} // namespace sdf
} // namespace geom
 
#endif // ANTKEEPER_GEOM_SDF_HPP