Triangular Grid of Points

**TRIANGLE_GRID**,
a C library which
generates a grid of points
within the interior of a triangle in 2D.

Starting with any 3 points A, B, and C that define a triangle, we can divide each side of the triangle into N subintervals, and create a triangular grid. This defines ((N+1)*(N+2))/2 points that lie on the intersections of grid lines. The arrangement is suggested by this diagram:

X 9 X 8 9 X 7 8 9 X 6 7 8 9 X 5 6 7 8 9 X 4 5 6 7 8 9 X 3 4 5 6 7 8 9 X 2 3 4 5 6 7 8 9 X 1 2 3 4 5 6 7 8 9 X 0 1 2 3 4 5 6 7 8 9 X

The library includes a routine which allows the user to pick an arbitrary triangle and an arbitrary number of subdivisions. It then returns the triangular gridpoints defined by that choice.

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

**TRIANGLE_GRID** is available in
a C version and
a C++ version and
a FORTRAN90 version and
a MATLAB version and
a Python version.

BALL_GRID, a C library which computes a grid of points over the interior of a ball in 3D.

CUBE_GRID, a C library which computes a grid of points over the interior of a cube in 3D.

DISK_GRID, a C library which computes a grid of points over the interior of a disk in 2D.

ELLIPSE_GRID, a C library which computes a grid of points over the interior of an ellipse in 2D.

ELLIPSOID_GRID, a C library which computes a grid of points over the interior of an ellipsoid in 3D.

HYPERCUBE_GRID, a C library which computes a grid of points over the interior of a hypercube in M dimensions.

LINE_GRID, a C library which computes a grid of points over the interior of a line segment in 1D.

POLYGON_GRID, a C library which generates a grid of points over the interior of a polygon in 2D.

PYRAMID_GRID, a C library which computes a grid of points over the interior of the unit pyramid in 3D;

SIMPLEX_GRID, a C library which generates a regular grid of points over the interior of an arbitrary simplex in M dimensions.

SPHERE_FIBONACCI_GRID, a C library which computes a grid of points using the Fibonacci spiral over the surface of a sphere in 3D.

SPHERE_GRID, a C library which provides a number of ways of generating grids of points, or of points and lines, or of points and lines and faces, on the surface of the unit sphere in 3D.

SPHERE_LLQ_GRID, a C library which uses longitudes and latitudes to create grids of points, lines, and quadrilaterals on the surface of the unit sphere in 3D.

SPHERE_LLT_GRID, a C library which uses longitudes and latitudes to create grids of points, lines, and triangles on the surface of the unit sphere in 3D.

SQUARE_GRID, a C library which computes a grid of points over the interior of a square in 2D.

TETRAHEDRON_GRID, a C library which computes a grid of points over the interior of a tetrahedron in 3D.

TRIANGLE_INTERPOLATE, a C library which shows how vertex data can be interpolated at any point in the interior of a triangle.

WEDGE_GRID, a C library which computes a grid of points over the interior of the unit wedge in 3D.

- triangle_grid.c, the source code.
- triangle_grid.sh, compiles the source code.
- triangle_grid.h, the include file.