TRIANGLE_INTERPOLATE is a FORTRAN90 library which demonstrates some simple techniques for interpolating data on a triangle.
In the most common case, the value of a quantity is known at the vertices of a triangle, and a reasonable interpolated value is desired at some point p in the interior of that triangle. This can be done by linear interpolation.
The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.
TRIANGLE_INTERPOLATE is available in a FORTRAN90 version and a MATLAB version and a Python version.
FEM_BASIS, a FORTRAN90 library which can define basis functions for the finite element method (FEM) for any degree in an M-dimensional simplex (1D interval, 2D triangle, 3D tetrahedron, and higher dimensional generalizations.)
GEOMETRY, a FORTRAN90 library which performs geometric calculations in 2, 3 and N dimensional space.
TOMS886, a FORTRAN90 library which defines the Padua points for interpolation in a 2D region, including the rectangle, triangle, and ellipse, by Marco Caliari, Stefano de Marchi, Marco Vianello. This is a version of ACM TOMS algorithm 886.
TRIANGLE_ANALYZE, a FORTRAN90 program which reads a triangle defined in a file, and uses the triangle_properties() library to compute angles, area, centroid, circumcircle, edge lengths, incircle, orientation, orthocenter, and quality.
TRIANGLE_FEKETE_RULE, a FORTRAN90 library which defines Fekete rules for quadrature or interpolation over the interior of a triangle in 2D.
TRIANGLE_GRID, a FORTRAN90 library which computes a grid of points over the interior of a triangle in 2D.
TRIANGLE_HISTOGRAM, a FORTRAN90 program which computes histograms of data on the unit triangle in 2D.
TRIANGLE_PROPERTIES, a FORTRAN90 library which can compute properties, including angles, area, centroid, circumcircle, edge lengths, incircle, orientation, orthocenter, and quality, of a triangle in 2D.
You can go up one level to the FORTRAN90 source codes.