[Tioga-users] Tioga3d 0.0.1

[Edwin]

Most of the basic plotting functionality of my 3d project is finished, so  
I decided to share it in the hope of some feedback :) I attached the  
source code

====The Good====
The good is that the plotting functionality works. Show_plot_3d draws the  
axes, and you should be able to use most default methods by putting _3d  
behind them. This should work at least with all functions that expect xs  
and ys coordinates (show_polyline). Methods that expect dicts (like  
show_marker) should also be covered as long as they use the standard  
coord-notations (at, point, x, y, xs, ys). Other methods might need custom  
wrappers (like show_arrow) which aren't provided yet.

====The Bad====
I only concentrated on plotting, because I don't see a reason to use 3d  
otherwise. This means that I have only concentrated on the plotting  
functions and I can see no reason to support "figure only" things like  
append_arc_to_path. If you disagree please let me know

Testing has been very incomplete and there are probably quite a few  
functions that need customized wrappers, which I don't know about yet or  
have ignored for now (like show_arrow). If you find any "bugs" please let  
me know.

====The Ugly====
The way axes are handled is not nice and they don't look perfect yet. This  
is mostly because I have not yet taken the dive into writing c extensions.  
To be able to draw axes properly I would have to rewrite my show_axis  
function in c, so I can access the PlotAxis struct.
On the plus side I wrote a more versatile show_axis method (called  
show_axis_3d), which should also be usable for 2d axes. The method  
basically needs an origin ([x,y] for 2d and [x,y,z] for 3d), the minimum  
value of the axis, the maximum value, the direction the axis takes ([1,0]  
or [1,0,0] for in the x direction) and the direction of the ticks ([0,1]  
or [0,1,0] are ticks parellel to the y axis)

====Performance====
I haven't checked performance, but the easiest way to gain performance  
would be by implementing the transform_coord method in c. I used the  
gnuplot code as an example and we could just use their code almost  
directly, although I'm not sure if you can use gpl'ed code in lgpl  
projects (prob not)

====Example====
require 'tioga3d.rb'
class Test
   include Tioga
   include FigureConstants
   def initialize
     @figure_maker = FigureMaker.default
     #until the 3d code is part of the official tree you will need to  
initialize some constants separatedly
     t.initialize_3d
     t.save_dir = 'plots_out'
     #for linux users
     $open_command = 'xpdf'
     @cube = t.def_figure( "cube" ) { cube }
     @random = t.def_figure( "random" ) { random }
   end
   def t
     @figure_maker
   end
   def cube
     #t3d.view( 60,245 )
     xs = Dvector[-1,-1,1,1,-1,-1,1,1]
     ys = Dvector[-1,-1,-1,1,1,1,1,-1]
     zs = Dvector[-1,1,1,1,1,-1,-1,-1]
     t.show_plot_3d([xs.min-0.05, xs.max+0.05, ys.min-0.05, ys.max+0.05,  
zs.min, zs.max]) {
       t.append_points_to_path_3d(xs, ys, zs)
			t.append_point_to_path_3d(0,0,0)
       t.stroke
       t.show_polyline_3d([-1,1],[-1,1],[-1,1], Red)
     }
   end
   def random
     t.show_plot_3d() {
       100.times {
         x = rand
         y = rand
         z = rand
         t.show_marker_3d( 'marker' => Bullet, 'at' => [x, y, z], 'scale'  
=> 0.2 )
       }
       t.show_marker_3d( 'marker' => Bullet,
                       'xs' => [0,1,0],
                       'ys'=> [1,0,0],
                       'zs' => [0,0,1],
                       'color' => Red )
     }
   end
end

Test.new
====Future====
First thing I want to do is implement the drawing of a surface from data  
points. I have no experience with this type of thing, but google tells me  
I should use Delaunay triangulations, if anyone knows more, please let me  
know.

The easiest way to go about that is use the qhull library. This will also  
finally teach me how to extend ruby programs in c. If anyone has a good  
tutorial on that please let me know.

After that I'll probably want to fix/rewrite the axes (unless Bill or  
Vincent find time to do it ofcourse :) )
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