TRI_SURFACE_DISPLAY_OPENGL
Display a 3D Triangulated Surface in MATLAB

TRI_SURFACE_DISPLAY_OPENGL is a C++ program which gets the names of the node and element files defining a 3D triangulated surface or "TRI_SURFACE", reads the information from the files, and displays the surface on the screen.

The surface is presented in rotation about the X axis. By clicking the mouse button, the axis of rotation will be advanced from X to Y to Z and back to X.

Usage:

tri_surface_display prefix

• prefix_nodes.txt contains the node coordinates;
• prefix_elements.txt contains indices of nodes that form the elements;

Licensing:

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

Languages:

TRI_SURFACE_DISPLAY_OPENGL is available in a C++ version.

Related Data and Programs:

FERN_OPENGL, a C++ program which uses OpenGL to display the Barnsley fractal fern.

OPENGL, C++ programs which illustrate the use of the OpenGL graphics library;

POLYGONAL_SURFACE_DISPLAY, a MATLAB program which displays a surface in 3D described as a set of polygons.

POLYGONAL_SURFACE_DISPLAY_OPENGL, a C++ program which displays a surface in 3D described as a set of polygons, using OpenGL.

SPHERE_XYZ_DISPLAY_OPENGL, a C++ program which reads XYZ information defining points in 3D, and displays a unit sphere and the points, using OpenGL.

TET_MESH_BOUNDARY, a FORTRAN90 program which returns the nodes and faces of the boundary of a tetrahedral mesh, which themselves form a 3D triangular mesh or "TRI_SURFACE".

TET_MESH_DISPLAY_OPENGL, a C++ program which reads files defining a tet mesh and displays an image using Open GL.

TRI_SURFACE, a data directory which contains examples of TRI_SURFACE files, a 3D surface described by a collection of triangles.

TRI_SURFACE_DISPLAY, a MATLAB program which displays the 3D graphics information in a TRI_SURFACE file;

TRIANGULATION_DISPLAY_OPENGL, a C++ program which reads files defining a triangulation and displays an image using Open GL.

TRIANGULATION_ORDER1_DISPLAY, a MATLAB program which reads files defining a piecewise constant triangulation of data, and displays a corresponding 3D surface.

XY_DISPLAY_OPENGL, a C++ program which reads an XY file of 2D point coordinates, and displays an image of those points using OpenGL.

XYL_DISPLAY_OPENGL, a C++ program which reads XYL information defining points and lines in 2D, and displays an image using OpenGL.

XYZ_DISPLAY_OPENGL, a C++ program which reads an XYZ file of 3D point coordinates, and displays an image of those points using OpenGL.

Reference:

1. Edward Angel,
   Interactive Computer Graphics, a Top-Down Approach with OpenGL,
   Addison-Wesley, 2000,
   ISBN: 0-201-38597-X,
   LC: T385.A514.

Source Code:

• tri_surface_display_opengl.cpp, the source code.
• tri_surface_display_opengl.sh, commands to compile the source code.

Examples and Tests:

SPHERE is a sphere, tiled with an 8 by 8 array of logically triangular patches.

• sphere_nodes.txt, the node file;
• sphere_elements.txt, the face file;
• sphere.png, a PNG image of the shape as displayed by TRI_SURFACE_DISPLAY.

List of Routines:

• MAIN is the main program for TRI_SURFACE_DISPLAY_OPENGL.
• CH_EQI is true if two characters are equal, disregarding case.
• CH_TO_DIGIT returns the integer value of a base 10 digit.
• DISPLAY generates the graphics output.
• FILE_COLUMN_COUNT counts the columns in the first line of a file.
• FILE_ROW_COUNT counts the number of row records in a file.
• I4_MAX returns the maximum of two I4's.
• I4_MIN returns the smaller of two I4's.
• I4MAT_DATA_READ reads data from an I4MAT file.
• I4MAT_HEADER_READ reads the header from an I4MAT file.
• I4MAT_TRANSPOSE_PRINT_SOME prints some of an I4MAT, transposed.
• MESH_BASE_ZERO ensures that the element definition is zero-based.
• MOUSE determines the response to mouse input.
• MYINIT initializes OpenGL state variables.
• MYRESHAPE determines the window mapping.
• NODE_NORMAL_SET computes node normal vectors.
• R8_MAX returns the maximum of two R8's.
• R83VEC_MAX returns the maximum value in an R83VEC.
• R83VEC_MIN returns the minimum value in an R83VEC.
• R8MAT_DATA_READ reads the data from an R8MAT file.
• R8MAT_HEADER_READ reads the header from an R8MAT file.
• R8MAT_TRANSPOSE_PRINT_SOME prints some of an R8MAT, transposed.
• S_LEN_TRIM returns the length of a string to the last nonblank.
• S_TO_I4 reads an I4 from a string.
• S_TO_I4VEC reads an I4VEC from a string.
• S_TO_R8 reads an R8 from a string.
• S_TO_R8VEC reads an R8VEC from a string.
• S_WORD_COUNT counts the number of "words" in a string.
• SPINSURFACE adjusts the angle of rotation and redisplays the picture.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the C++ source codes.