XYL_DISPLAY_OPENGL
Display 2D Points and Lines Using OpenGL

XYL_DISPLAY_OPENGL is a C++ program which reads XYL information defining points and lines in 2D, and draws a picture using OPENGL.

The point and line information is stored in a pair of files, called the XYL format. Essentially, the first file stores a list of point coordinates, and the second lists point indices to be connected in lines.

Usage:

xyl_display_opengl prefix

• prefix is the common prefix for the point and line data files.

Licensing:

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

Languages:

XYL_DISPLAY_OPENGL is available in a C++ version.

Related Data and Programs:

BOX_PLOT, a MATLAB program which can color in specified entries of a checkerboard, corresponding to pairs of integer data.

CAUSTIC_OPENGL, a C++ program which computes a caustic curve and displays it using OpenGL.

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

LIFE_OPENGL, a C++ program which plays John Conway's "Game of Life", using OpenGL to display the results.

LISSAJOUS_OPENGL, a C++ program which computes a Lissajous figure and displays it using OpenGL.

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

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

ROTATING_CUBE_DISPLAY_OPENGL, a C++ program which displays a rotating color cube in 3D, using OpenGL;

SCREENSHOT_OPENGL, a C++ program which shows how a program using the OpenGL graphics library can save a screenshot of the graphics being displayed.

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.

TABLE_DELAUNAY, a FORTRAN90 program which computes the Delaunay triangulation of a set of points.

TABLE_VORONOI, a C++ program which computes information about the Voronoi diagram of the points.

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

XYL, a data directory which contains some examples of the XYL format for 2D points and lines.

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

XYF_DISPLAY_OPENGL, a C++ program which reads XYF information defining points and faces in 2D, and displays an image using OpenGL.

XYL_DISPLAY, a MATLAB program which reads XYL information defining points and lines in 2D, and displays an image in a MATLAB graphics window.

Reference:

1. Edward Angel,
   Interactive Computer Graphics, a Top-Down Approach with OpenGL,
   Addison-Wesley, 2000,
   ISBN: 0-201-38597-X,
   LC: T385.A514.
2. Renate Kempf, Chris Frazier, editors,
   OpenGL Reference Manual,
   Fourth Edition,
   Addison-Wesley, 2004,
   ISBN: 032117383X,
   LC: T385.O642
3. Mason Woo, Jackie Neider, Tom Davis,
   OpenGL Programming Guide,
   Addison-Wesley, 1997,
   ISBN: 0-201-46138-2,
   LC: T385.N435
4. Richard Wright, Michael Sweet,
   OpenGL Superbible,
   Third Edition,
   Sams, 2004,
   ISBN: 0672326019,
   LC: T385.W73
5. http://www.opengl.org/
   The official OpenGL site.

Source Code:

• xyl_display_opengl.cpp, the source code.

Examples and Tests:

• house.xy, point coordinates.
• house.xyl, point indices to be connected as lines.
• house.png, a PNG image of the screen generated by Open GL.

List of Routines:

• MAIN is the main program for XYL_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.
• DTABLE_DATA_READ reads the data from a real TABLE file.
• DTABLE_HEADER_READ reads the header from a real TABLE file.
• MYINIT initializes OpenGL state variables dealing with viewing and attributes.
• R8_MAX returns the maximum of two R8.
• R82VEC_MAX returns the maximum value in a R82VEC.
• R82VEC_MIN returns the minimum value in a R82VEC.
• S_CAT concatenates two strings to make a third string.
• 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.
• TIMESTAMP prints the current YMDHMS date as a time stamp.
• TIMESTRING returns the current YMDHMS date as a string.
• XY_DATA_READ reads the data in an XY file.
• XY_HEADER_READ reads the header of an XY file.
• XYL_DATA_READ reads the data in an XYL file.
• XYL_HEADER_READ determines the number of line items in an XYL file.

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