Math 2D Functions

Header:

#include <UnigineMath2d.h>

This class represents a collection of two-dimensional math functions.

Notice

Math 2D functions are the members of the Unigine::Math namespace.

Methods:

Name	Description View: Sort by:
setPolygonToCCW	Sets the counter-clockwise orientation for the polygon.
triangulatePolygon	Performs triangulation by ear clipping algorithm (complexity: O(n^2)/O(n)).
resizePolygon	Returns a set of points representing a shrunk/enlarged polygon.
getPolygonArea	Returns the area of the given polygon in square units.
getPolygonAreaSigned	Returns the area of the given polygon in square units.
findIntersection	Finds the point of intersection between the two lines specified by the pairs of points p1 - p2 and p3 - p4 and sets the values of the last 5 arguments.
polygonIsOrientedClockwise	Returns a value indicating if a given polygon is oriented clockwise.
getTriangleArea	Returns the area of the given triangle in square units.
sign	Returns a value indicating to which part of the segment the point belongs.
pointTriangleInside	Returns a value indicating if a given point is inside the specified triangle.

Math Class

Members

int setPolygonToCCW ( Vector<vec2> & points ) #

Sets the counter-clockwise orientation for the polygon.

Arguments

Vector<vec2> & points - Vector containing all points of the polygon.

Return value

1 if the counter-clockwise orientation for the polygon is set successfully; otherwise, 0.

void triangulatePolygon ( const Vector<vec2> & points, Vector<unsigned short> & indices, int append_to_result ) #

Performs triangulation by ear clipping algorithm (complexity: O(n^2)/O(n)).

Arguments

const Vector<vec2> & points - Vector containing all points of the polygon.
Vector<unsigned short> & indices - Vector containing all points indices.
int append_to_result - Flag indicating if resulting points should be appended to the points of initial polygon - 0 (the default value), or replace them - 1.

void resizePolygon ( const Vector<vec2> & points, float offset, Vector<vec2> & result_points, int append_to_result ) #

Returns a set of points representing a shrunk/enlarged polygon. Supports concave polygons, CCW and CW orientations.

Arguments

const Vector<vec2> & points - Vector containing all points of the polygon.
float offset
Vector<vec2> & result_points - Vector containing all points of the shrunk/enlarged polygon.
int append_to_result - Flag indicating if resulting points should be appended to the points of initial polygon - 0 (the default value), or replace them - 1.

float getPolygonArea ( const Vector<vec2> & points ) #

Returns the area of the given polygon in square units.

Arguments

const Vector<vec2> & points - Vector containing all points of the polygon.

Return value

Polygon's area, in square units.

float getPolygonAreaSigned ( const Vector<vec2> & points ) #

Returns the area of the given polygon in square units.

Arguments

const Vector<vec2> & points - Vector containing all points of the polygon.

Return value

Polygon's area, in square units.

Notice

The value will be negative if the polygon is oriented clockwise.

void findIntersection ( const vec2 & p1, const vec2 & p2, const vec2 & p3, const vec2 & p4, int & lines_intersect, int & segments_intersect, vec2 & intersection, vec2 & close_p1, vec2 & close_p2 ) #

Finds the point of intersection between the two lines specified by the pairs of points p1 - p2 and p3 - p4 and sets the values of the last 5 arguments.

Arguments

const vec2 & p1 - Start point coordinates of the first line segment.
const vec2 & p2 - End point coordinates of the first line segment.
const vec2 & p3 - Start point coordinates of the second line segment.
const vec2 & p4 - End point coordinates of the second line segment.
int & lines_intersect - 1 if the lines to which the segments belong intersect; otherwise, 0.
int & segments_intersect - 1 if the lines to which the segments belong intersect; otherwise, 0.
vec2 & intersection - Coordinates of the point of intersection between the two line segments.
vec2 & close_p1 - Coordinates of the first of the two closest points belonging to the first segment.
vec2 & close_p2 - Coordinates of the second of the two closest points belonging to the second segment.

int polygonIsOrientedClockwise ( const Vector<vec2> & points ) #

Returns a value indicating if a given polygon is oriented clockwise.

Arguments

const Vector<vec2> & points - Vector containing all points of the polygon.

Return value

1 if a given polygon is oriented clockwise; otherwise, 0.

float getTriangleArea ( const vec2 & p1, const vec2 & p2, const vec2 & p3 ) #

Returns the area of the given triangle in square units.

Arguments

const vec2 & p1 - Coordinates of the first triangle vertex.
const vec2 & p2 - Coordinates of the second triangle vertex.
const vec2 & p3 - Coordinates of the third triangle vertex.

Return value

Triangle area, in square units.

Notice

The value will be negative if the polygon is oriented clockwise.

float sign ( const vec2 & point, const vec2 & segment_p1, const vec2 & segment_p2 ) #

Returns a value indicating to which part of the segment the point belongs.

Arguments

const vec2 & point - Coordinates of the point to be checked.
const vec2 & segment_p1 - Segment start point coordinates.
const vec2 & segment_p2 - Segment end point coordinates.

int pointTriangleInside ( const vec2 & point, const vec2 & v0, const vec2 & v1, const vec2 & v2 ) #

Returns a value indicating if a given point is inside the specified triangle.

Arguments

const vec2 & point - Coordinates of the point to be checked.
const vec2 & v0 - Coordinates of the first triangle vertex.
const vec2 & v1 - Coordinates of the second triangle vertex.
const vec2 & v2 - Coordinates of the third triangle vertex.

Return value

1 if a given point is inside the specified triangle; otherwise, 0.

Last update: 10.03.2022

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