%% TEST04 tests HEX_GRID_ANGLE_SIZE.
%
%  Modified:
%
%    24 October 2006
%
%  Author:
%
%    John Burkardt
%
  clear

  dim_num = 2;

  box = [ ...
    10.0, 2.0;
    12.0, 2.5 ]';
  seed = 123456789;

  fprintf ( 1, '\n' );
  fprintf ( 1, 'TEST04\n' );
  fprintf ( 1, '  HEX_GRID_ANGLE_SIZE computes the number of\n' );
  fprintf ( 1, '  points in a hexagonal grid in the unit square,\n' );
  fprintf ( 1, '  with grid lines at a given angle ANGLE,\n' );
  fprintf ( 1, '  with a given spacing H between points on a grid line,\n' );
  fprintf ( 1, '  with the coordinates of the center at CENTER.\n' );
  fprintf ( 1, '\n' );
  fprintf ( 1, '        CENTER           ANGLE       H         N\n' );
  fprintf ( 1, '\n' );

  for i = 1 : 3

    [ t, seed ] = r8_uniform_01 ( seed );
    center(1) = box(1,1) + t * ( box(1,2) - box(1,1) );
    [ t, seed ] = r8_uniform_01 ( seed );
    center(2) = box(2,1) + t * ( box(2,2) - box(2,1) );

    angle = 45.0;
    h = 0.25;

    n = hex_grid_angle_size ( box, center, angle, h );

    fprintf ( 1, '  %8f  %8f  %8f  %10f  %6d\n', ...
      center(1:dim_num), angle, h, n );

  end

  fprintf ( 1, '\n' );

  for i = 1 : 3

    center(1:dim_num) = 0.5 * ( box(1:dim_num,1) +  box(1:dim_num,2) );
    angle = 45.0;
    h = 0.25 / i;

    n = hex_grid_angle_size ( box, center, angle, h );

    fprintf ( 1, '  %8f  %8f  %8f  %10f  %6d\n', ...
      center(1:dim_num), angle, h, n );

  end

  fprintf ( 1, '\n' );

  for i = 1 : 4

    center(1:dim_num) = 0.5 * ( box(1:dim_num,1) +  box(1:dim_num,2) );
    [ t, seed ] = r8_uniform_01 ( seed );
    angle = 180.0 * t;
    h = 0.25;

    n = hex_grid_angle_size ( box, center, angle, h );

    fprintf ( 1, '  %8f  %8f  %8f  %10f  %6d\n', ...
      center(1:dim_num), angle, h, n );

  end