Draw
Draw 3d scene as 2d image with lighting and shadowing to assist the human observer in reconstructing the original 3d scene.
PhilipRBrenan@yahoo.com, 2004, Perl License
Synopsis
Example t/draw.t
#!perl -w
#______________________________________________________________________
# Test drawing.
# philiprbrenan@yahoo.com, 2004, Perl License
#______________________________________________________________________
use Math::Zap::Draw;
use Math::Zap::Cube unit=>'cu';
use Math::Zap::Triangle;
use Math::Zap::Vector;
use Test::Simple tests=>1;
#_ Draw _______________________________________________________________
# Draw this set of objects.
#______________________________________________________________________
$l =
draw
->from (vector( 10, 10, 10))
->to (vector( 0, 0, 0))
->horizon (vector( 1, 0.5, 0))
->light (vector( 20, 30, -20))
->object(triangle(vector( 0, 0, 0), vector( 8, 0, 0), vector( 0, 8, 0)), 'red')
->object(triangle(vector( 0, 0, 0), vector( 0, 0, 8), vector( 0, 8, 0)), 'green')
->object(triangle(vector( 0, 0, 0), vector(12, 0, 0), vector( 0, 0, 12)) - vector(2.5, 0, 2.5), 'blue')
->object(triangle(vector( 0, 0, 0), vector( 8, 0, 0), vector( 0, -8, 0)), 'pink')
->object(triangle(vector( 0, 0, 0), vector( 0, 0, 8), vector( 0, -8, 0)), 'orange')
->object(cu()*2+vector(3,5,1), 'lightblue')
->print;
$L = <<'END';
#!perl -w
use Math::Zap::Draw;
use Math::Zap::Triangle;
use Math::Zap::Vector;
draw
->from (vector(10, 10, 10))
->to (vector(0, 0, 0))
->horizon (vector(1, 0.5, 0))
->light (vector(20, 30, -20))
->object(triangle(vector(0, 0, 0), vector(8, 0, 0), vector(0, 8, 0)), 'red')
->object(triangle(vector(0, 0, 0), vector(0, 0, 8), vector(0, 8, 0)), 'green')
->object(triangle(vector(-2.5, 0, -2.5), vector(9.5, 0, -2.5), vector(-2.5, 0, 9.5)), 'blue')
->object(triangle(vector(0, 0, 0), vector(8, 0, 0), vector(0, -8, 0)), 'pink')
->object(triangle(vector(0, 0, 0), vector(0, 0, 8), vector(0, -8, 0)), 'orange')
->object(triangle(vector(3, 5, 1), vector(5, 5, 1), vector(3, 7, 1)), 'lightblue')
->object(triangle(vector(5, 7, 1), vector(5, 5, 1), vector(3, 7, 1)), 'lightblue')
->object(triangle(vector(3, 5, 3), vector(5, 5, 3), vector(3, 7, 3)), 'lightblue')
->object(triangle(vector(5, 7, 3), vector(5, 5, 3), vector(3, 7, 3)), 'lightblue')
->object(triangle(vector(3, 5, 1), vector(3, 7, 1), vector(3, 5, 3)), 'lightblue')
->object(triangle(vector(3, 7, 3), vector(3, 7, 1), vector(3, 5, 3)), 'lightblue')
->object(triangle(vector(5, 5, 1), vector(5, 7, 1), vector(5, 5, 3)), 'lightblue')
->object(triangle(vector(5, 7, 3), vector(5, 7, 1), vector(5, 5, 3)), 'lightblue')
->object(triangle(vector(3, 5, 1), vector(3, 5, 3), vector(5, 5, 1)), 'lightblue')
->object(triangle(vector(5, 5, 3), vector(3, 5, 3), vector(5, 5, 1)), 'lightblue')
->object(triangle(vector(3, 7, 1), vector(3, 7, 3), vector(5, 7, 1)), 'lightblue')
->object(triangle(vector(5, 7, 3), vector(3, 7, 3), vector(5, 7, 1)), 'lightblue')
->done;
END
ok($l eq $L);Description
This package supplies methods to draw a scene, containing three dimensional objects, as a two dimensional image, using lighting and shadowing to assist the human observer in reconstructing the original three dimensional scene.
There are many existing packages to perform this important task: this package Math::Zap::Is the only one to make the attempt in Pure Perl. Pending the $VERSION=1.07; power of Petaflop Parallel Perl (when we will be set free from C), this approach is slow. However, it is not so slow as to be completely useless for simple scenes as might be encountered inside, say for instance, beam lines used in high energy particle physics, the owners of which often have large Perl computers.
The key advantage of this package is that is open: you can manipulate both the objects to be drawn and the drawing itself all in Pure Perl.
Constructors
draw
Constructor
Methods
from
Set view point
to
Viewing this point
Horizon
Sets the direction of the horizon.
light
Light source position
withControls
Display a window allowing the user to set to,from,horizon,light
object
Draw this object
done
Draw the complete object list
Methods
Print the complete object list as a triangles in a reusable manner.
check
Check its a drawing
is
Test its a drawing
showFissionFragments
Show fission fragments: the objects to be drawn are triangulated where-ever they may intersect. It is useful to see these sub triangles when debugging. See also "fission".
Fission
Fission the triangles that intersect. See "showFissionFragments"
new
New drawing - not a constructor
newCanvas
Canvas for drawing
newControl
Controls for drawing
Configure
Configuration of canvas has been changed
drawing
New drawing of objects
shadows
Shadows from a point of illumination
zorder
Z-order: order the fission triangles from the back ground to the point of view:
Compare each triangle with every other, recording for each triangle which triangles are behind it.
Place all triangles with no triangles behind them with at the start of the order.
Reprocess the remainder until none left (success) or a cycle is detected (bad algorithm).
The two triangles to be compared are projected on to the background: if their projections have no points in common they are unordered, otherwise use the distance to each triangle from the view point towards the common point as a measure of which is first.
fission() guarantees that no two triangles intersect, this algorithm should correctly order each pair of triangles.
Exports
Export "draw"
Credits
Author
philiprbrenan@yahoo.com
Copyright
philiprbrenan@yahoo.com, 2004
License
Perl License.