The Geometry module in Fossil Math provides essential tools for 2D and 3D geometric calculations. It includes distance computations, circle and triangle metrics, 2D transformations (translation, scaling, rotation), and 3D plane operations. The module is designed for scientific computation, graphics, physics simulations, and engineering applications. The C++ wrapper class offers a static-method interface, simplifying usage while keeping the underlying C API fully accessible.
Code reference for C and C++ APIs for the respective Fossil Logic library.
HEADER REFERENCE #
#ifndef FOSSIL_MATH_GEOM_H
#define FOSSIL_MATH_GEOM_H
#include "math.h"
#ifdef __cplusplus
extern "C"
{
#endif
// ======================================================
// Structures
// ======================================================
typedef struct {
double x;
double y;
} fossil_math_geom_point2d;
typedef struct {
double x;
double y;
double z;
} fossil_math_geom_point3d;
typedef struct {
fossil_math_geom_point2d center;
double radius;
} fossil_math_geom_circle;
typedef struct {
fossil_math_geom_point3d normal;
double d; // plane equation: normal·p + d = 0
} fossil_math_geom_plane;
// *****************************************************************************
// Function prototypes
// *****************************************************************************
/**
* ======================================================
* Distance calculations
* ======================================================
*/
/**
* @brief Calculates the Euclidean distance between two 2D points.
*
* @param a First 2D point.
* @param b Second 2D point.
* @return Distance between points a and b.
*/
double fossil_math_geom_distance2d(fossil_math_geom_point2d a,
fossil_math_geom_point2d b);
/**
* @brief Calculates the Euclidean distance between two 3D points.
*
* @param a First 3D point.
* @param b Second 3D point.
* @return Distance between points a and b.
*/
double fossil_math_geom_distance3d(fossil_math_geom_point3d a,
fossil_math_geom_point3d b);
/**
* ======================================================
* Circle geometry
* ======================================================
*/
/**
* @brief Calculates the area of a circle.
*
* @param c Circle structure.
* @return Area of the circle.
*/
double fossil_math_geom_circle_area(fossil_math_geom_circle c);
/**
* @brief Calculates the circumference of a circle.
*
* @param c Circle structure.
* @return Circumference of the circle.
*/
double fossil_math_geom_circle_circumference(fossil_math_geom_circle c);
/**
* @brief Checks if a 2D point lies inside or on the boundary of a circle.
*
* @param p 2D point.
* @param c Circle structure.
* @return 1 if the point is inside or on the circle, 0 otherwise.
*/
int fossil_math_geom_point_in_circle(fossil_math_geom_point2d p,
fossil_math_geom_circle c);
/**
* ======================================================
* Triangle geometry
* ======================================================
*/
/**
* @brief Calculates the area of a triangle given its three vertices.
*
* @param a First vertex of the triangle.
* @param b Second vertex of the triangle.
* @param c Third vertex of the triangle.
* @return Area of the triangle.
*/
double fossil_math_geom_triangle_area(fossil_math_geom_point2d a,
fossil_math_geom_point2d b,
fossil_math_geom_point2d c);
/**
* @brief Calculates the perimeter of a triangle given its three vertices.
*
* @param a First vertex of the triangle.
* @param b Second vertex of the triangle.
* @param c Third vertex of the triangle.
* @return Perimeter of the triangle.
*/
double fossil_math_geom_triangle_perimeter(fossil_math_geom_point2d a,
fossil_math_geom_point2d b,
fossil_math_geom_point2d c);
/**
* ======================================================
* Transformations (2D)
* ======================================================
*/
/**
* @brief Translates a 2D point by given offsets.
*
* @param p The point to translate.
* @param dx Offset along the x-axis.
* @param dy Offset along the y-axis.
* @return Translated 2D point.
*/
fossil_math_geom_point2d fossil_math_geom_translate2d(fossil_math_geom_point2d p, double dx, double dy);
/**
* @brief Scales a 2D point by given scale factors.
*
* @param p The point to scale.
* @param sx Scale factor along the x-axis.
* @param sy Scale factor along the y-axis.
* @return Scaled 2D point.
*/
fossil_math_geom_point2d fossil_math_geom_scale2d(fossil_math_geom_point2d p, double sx, double sy);
/**
* @brief Rotates a 2D point around the origin by a given angle (in radians).
*
* @param p The point to rotate.
* @param angle_rad Angle in radians.
* @return Rotated 2D point.
*/
fossil_math_geom_point2d fossil_math_geom_rotate2d(fossil_math_geom_point2d p, double angle_rad);
/**
* ======================================================
* Plane geometry (3D)
* ======================================================
*/
/**
* @brief Calculates the shortest distance from a 3D point to a plane.
*
* @param p The 3D point.
* @param plane The plane structure.
* @return Distance from the point to the plane.
*/
double fossil_math_geom_point_plane_distance(fossil_math_geom_point3d p,
fossil_math_geom_plane plane);
#ifdef __cplusplus
}
#include <stdexcept>
#include <vector>
#include <string>
namespace fossil {
namespace math {
/**
* @brief Geometry utility class providing static methods for common geometric operations.
*
* This class wraps the C geometry functions in a C++-friendly interface,
* allowing for easier use in C++ codebases. All methods are static and
* operate directly on the provided structures.
*/
class Geometry {
public:
/**
* @brief Calculates the Euclidean distance between two 2D points.
* @param a First 2D point.
* @param b Second 2D point.
* @return Distance between points a and b.
*/
static double distance_2d(const fossil_math_geom_point2d& a, const fossil_math_geom_point2d& b) {
return fossil_math_geom_distance2d(a, b);
}
/**
* @brief Calculates the Euclidean distance between two 3D points.
* @param a First 3D point.
* @param b Second 3D point.
* @return Distance between points a and b.
*/
static double distance_3d(const fossil_math_geom_point3d& a, const fossil_math_geom_point3d& b) {
return fossil_math_geom_distance3d(a, b);
}
/**
* @brief Calculates the area of a circle.
* @param c Circle structure.
* @return Area of the circle.
*/
static double circle_area(const fossil_math_geom_circle& c) {
return fossil_math_geom_circle_area(c);
}
/**
* @brief Calculates the circumference of a circle.
* @param c Circle structure.
* @return Circumference of the circle.
*/
static double circle_circumference(const fossil_math_geom_circle& c) {
return fossil_math_geom_circle_circumference(c);
}
/**
* @brief Checks if a 2D point lies inside or on the boundary of a circle.
* @param p 2D point.
* @param c Circle structure.
* @return true if the point is inside or on the circle, false otherwise.
*/
static bool point_in_circle(const fossil_math_geom_point2d& p, const fossil_math_geom_circle& c) {
return fossil_math_geom_point_in_circle(p, c) != 0;
}
/**
* @brief Calculates the area of a triangle given its three vertices.
* @param a First vertex of the triangle.
* @param b Second vertex of the triangle.
* @param c Third vertex of the triangle.
* @return Area of the triangle.
*/
static double triangle_area(const fossil_math_geom_point2d& a, const fossil_math_geom_point2d& b, const fossil_math_geom_point2d& c) {
return fossil_math_geom_triangle_area(a, b, c);
}
/**
* @brief Calculates the perimeter of a triangle given its three vertices.
* @param a First vertex of the triangle.
* @param b Second vertex of the triangle.
* @param c Third vertex of the triangle.
* @return Perimeter of the triangle.
*/
static double triangle_perimeter(const fossil_math_geom_point2d& a, const fossil_math_geom_point2d& b, const fossil_math_geom_point2d& c) {
return fossil_math_geom_triangle_perimeter(a, b, c);
}
/**
* @brief Translates a 2D point by given offsets.
* @param p The point to translate.
* @param dx Offset along the x-axis.
* @param dy Offset along the y-axis.
* @return Translated 2D point.
*/
static fossil_math_geom_point2d translate_2d(const fossil_math_geom_point2d& p, double dx, double dy) {
return fossil_math_geom_translate2d(p, dx, dy);
}
/**
* @brief Scales a 2D point by given scale factors.
* @param p The point to scale.
* @param sx Scale factor along the x-axis.
* @param sy Scale factor along the y-axis.
* @return Scaled 2D point.
*/
static fossil_math_geom_point2d scale_2d(const fossil_math_geom_point2d& p, double sx, double sy) {
return fossil_math_geom_scale2d(p, sx, sy);
}
/**
* @brief Rotates a 2D point around the origin by a given angle (in radians).
* @param p The point to rotate.
* @param angle_rad Angle in radians.
* @return Rotated 2D point.
*/
static fossil_math_geom_point2d rotate_2d(const fossil_math_geom_point2d& p, double angle_rad) {
return fossil_math_geom_rotate2d(p, angle_rad);
}
/**
* @brief Calculates the shortest distance from a 3D point to a plane.
* @param p The 3D point.
* @param plane The plane structure.
* @return Distance from the point to the plane.
*/
static double point_plane_distance(const fossil_math_geom_point3d& p, const fossil_math_geom_plane& plane) {
return fossil_math_geom_point_plane_distance(p, plane);
}
};
} // namespace math
} // namespace fossil
#endif
#endif /* FOSSIL_MATH_GEOM_H */SAMPLE CODE C #
#include <fossil/math/geom.h>
#include <stdio.h>
int main() {
fossil_math_geom_point2d p1 = {0.0, 0.0};
fossil_math_geom_point2d p2 = {3.0, 4.0};
double dist = fossil_math_geom_distance2d(p1, p2);
printf("Distance 2D: %f\n", dist);
fossil_math_geom_circle c = {{0.0, 0.0}, 5.0};
printf("Circle area: %f\n", fossil_math_geom_circle_area(c));
printf("Circle circumference: %f\n", fossil_math_geom_circle_circumference(c));
int inside = fossil_math_geom_point_in_circle(p2, c);
printf("Point inside circle: %s\n", inside ? "yes" : "no");
fossil_math_geom_point2d translated = fossil_math_geom_translate2d(p1, 2.0, 3.0);
printf("Translated point: (%f, %f)\n", translated.x, translated.y);
return 0;
}
SAMPLE CODE C++ #
#include <fossil/math/geom.h>
#include <iostream>
int main() {
using namespace fossil::math;
fossil_math_geom_point2d p1{0.0, 0.0};
fossil_math_geom_point2d p2{3.0, 4.0};
std::cout << "Distance 2D: " << Geometry::distance_2d(p1, p2) << "\n";
fossil_math_geom_circle c{{0.0, 0.0}, 5.0};
std::cout << "Circle area: " << Geometry::circle_area(c) << "\n";
std::cout << "Circle circumference: " << Geometry::circle_circumference(c) << "\n";
std::cout << "Point inside circle: "
<< (Geometry::point_in_circle(p2, c) ? "yes" : "no") << "\n";
auto translated = Geometry::translate_2d(p1, 2.0, 3.0);
std::cout << "Translated point: (" << translated.x << ", " << translated.y << ")\n";
fossil_math_geom_point3d pt3d{1.0, 2.0, 3.0};
fossil_math_geom_plane plane{{0.0, 0.0, 1.0}, -2.0};
std::cout << "Distance to plane: " << Geometry::point_plane_distance(pt3d, plane) << "\n";
return 0;
}
