NAME

M_Triangle — Agar-Math triangle structure

SYNOPSIS

#include <agar/core.h>
#include <agar/gui.h>
#include <agar/math/m.h>

DESCRIPTION

The M_Triangle2 structure describes a triangle in R^2 in terms of three lines:

typedef struct m_triangle2 {
	M_Line2 a, b, c;
} M_Triangle2;

Similarly, M_Triangle3 describes a triangle in R^3:

typedef struct m_triangle3 {
	M_Line3 a, b, c;
} M_Triangle3;

INITIALIZATION

M_Triangle2
M_TriangleFromLines2(M_Line2 L1, M_Line2 L2, M_Line2 L3);

M_Triangle3
M_TriangleFromLines3(M_Line3 L1, M_Line3 L2, M_Line3 L3);

M_Triangle2
M_TriangleFromPts2(M_Vector2 a, M_Vector2 b, M_Vector2 c);

M_Triangle3
M_TriangleFromPts3(M_Vector3 a, M_Vector3 b, M_Vector3 c);

M_Triangle2
M_TriangleRead2(AG_DataSource *ds);

M_Triangle3
M_TriangleRead3(AG_DataSource *ds);

void
M_TriangleWrite2(AG_DataSource *ds, M_Triangle2 *T);

void
M_TriangleWrite3(AG_DataSource *ds, M_Triangle3 *T);

M_Triangle2
M_TRIANGLE2_INITIALIZER(M_Vector2 a, M_Vector2 b, M_Vector2 c);

M_Triangle3
M_TRIANGLE3_INITIALIZER(M_Vector3 a, M_Vector3 b, M_Vector3 c);

The functions M_TriangleFromLines2() and M_TriangleFromLines3() return an M_Triangle2 or M_Triangle3 describing a triangle in terms of three lines L1, L2 and L3. The three lines must be non-colinear and their endpoints must coincide.

M_TriangleFromPts2() and M_TriangleFromPts3() return a triangle in terms of three (non-colinear) points a, b, c.

The M_TriangleRead[23]() and M_TriangleWrite[23]() functions read or write a triangle structure from/to an AG_DataSource(3).

The macros M_TRIANGLE2_INITIALIZER() and M_TRIANGLE3_INITIALIZER() expand to static initializers for M_Triangle2 and M_Triangle3, respectively.

COMPUTATIONS

int
M_PointInTriangle2(M_Triangle2 T, M_Vector2 p);

The M_PointInTriangle2() routine tests (using barycentric coordinates) whether point p lies within the triangle T and returns 1 if it does, otherwise 0.

SEE ALSO

AG_DataSource(3), AG_Intro(3), M_Circle(3), M_Geometry(3), M_Plane(3), M_Polygon(3), M_Rectangle(3), M_Sphere(3), M_Triangle(3), M_Vector(3)

HISTORY

The M_Triangle structure first appeared in Agar 1.3.4.