I think I have discovered how to make my approach
work with the subcomponent system based on openGL "display
lists." For me the breakthrough was understanding that with
the cover scripts provided by J via jzopengl.ijs , every
object must ultimately be embedded in a display list
**after** any coloring, rotations, and translations, etc.
Somehow I thought that the coloring, rotations, and
translations, etc. could be applied to the display list
after it was generated. What a mistake that was.
In the system I am designing for simulating
contra dancers, most features of the dancers remains
constant throughout a simulation, but often
their position and heading changes and periodically their
color changes to indicated the regrouping of foursomes and
(less often) the redirection of progress of couples reaching
the end of the contra line or set. So the building blocks
approach is appealing especially for the more static
features.
For anyone interested in the resulting code, I am
attaching a short test case script demonstrating a 3-layer
system with the following three layers.
display list (atoms) display lists
__________________________ __________________
3 LTurtle0 LTurtle1 <---These are in LISTS
2 Turtle0 Turtle1 <---These are in PARTS
1 Head0 Nose0 Head1 Nose1 <---These are in PARTS
Look in the verb "run" for the two command sequences
backetted by "glNewList LTurtleX , GL_COMPILE" ...
"glEndList ''" for the pieces I had to add.
(B=) <----------my "sig"
Brian Schott
Atlanta, GA, USA
schott DOT bee are eye eh en AT gee em ae eye el DOT com
http://schott.selfip.net/~brian/NB. turtlemove.ijs
NB. standalone version
require 'opengl'
coinsert 'jgl3 jzopengl '
turtle =: monad define
glPushMatrix ''
glPushAttrib GL_CURRENT_BIT
glEnable GL_NORMALIZE
glScale SCALE * SIZE
glClipPlane GL_CLIP_PLANE0, 0 0 1 0
glEnable GL_CLIP_PLANE0
gluSphere LQuad, 1 30 30
glCallList ".'LHead',":y.
glDisable GL_CLIP_PLANE0
glPopAttrib ''
glPopMatrix ''
)
turtlehead =: monad define
glPushMatrix ''
glTranslate 0 1 0
glColor HCOLOR
gluSphere LQuad, TURTLE_HEAD_RELATIVE , 30 30
glCallList ".'LNose',":y.
glPopMatrix ''
)
turtlenose =: monad define
glPushMatrix ''
glTranslate 0 0.25 0
glColor NCOLOR
gluSphere LQuad, TURTLE_HEAD_RELATIVE , 30 30
glPopMatrix ''
)
ROTturtle =: 30 0 0 1
TURTLE_HEAD_RELATIVE =: 0.3 NB. head size relative to body
PARTS =: i. 0
PARTSSTART =: 2000
run =: verb define
gldefault''
glinit''
stdlistlight''
LQuad =: gluNewQuadric''
gluQuadricDrawStyle LQuad,GLU_FILL
gluQuadricNormals LQuad,GLU_SMOOTH
genlist 'LTurtle0 LTurtle1'
genpartslist 'Turtle0 Turtle1 LHead0 LNose0 LHead1 LNose1'
HCOLOR =: 1 0 1 1
NCOLOR =: 0 1 0 1
turtlenose makelist LNose0 ''
turtlehead makelist LHead0 0
turtle makelist Turtle0 0
HCOLOR =: 0 1 0 1
NCOLOR =: 1 0 1 1
turtlenose makelist LNose1 ''
turtlehead makelist LHead1 1
turtle makelist Turtle1 1
glNewList LTurtle0 , GL_COMPILE
COLOR =: 0 0 1 1
POSITION =: _1 0 0
glPushMatrix ''
glColor COLOR
glTranslate POSITION
glCallList Turtle0
glPopMatrix ''
glEndList ''
glNewList LTurtle1 , GL_COMPILE
COLOR =: 1 0 0 1
POSITION =: 1 0 0
glPushMatrix ''
glColor COLOR
glTranslate POSITION
glCallList Turtle1
glPopMatrix ''
glEndList ''
stdpaintx ''
)
NB. patterned after genlist in jzopengl
genpartslist=: 3 : 0
bgn=. >:>./PARTS,PARTSSTART
if. 2 = 3!:0 y. do.
nms=. ;: y.
r=. bgn + i.#nms
(nms)=: r
else.
r=. bgn + i.y.
end.
PARTS=: PARTS,r
r
)
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