Issues implementing a simple waterfall in Java3D

Question

I am currently implementing a waterfall display using Java3D. I have some questions about design, and also one about performance difficulties.
The overall design structure is as follows:
* The display is made up of a 2 dimensional grid, with each cell representing a data point viewed as a different color. Specifically I am testing with 360 points per line, with 60 lines. That's a lot of snow. ;)
* At each iteration the display must add a newline to the top, shift everything down by one line, and end by dropping the bottom line (in no particular order). This gives a nice animation affect.
* I am representing each line by a BranchGroup containing a Shape3D constructed with a QuadArray. Each quad within the array represents a cell. So each line contains 4*360=1440 points.
* At each iteration I generate a new object containing the above. The coordinates of each point are set to sit one line above the previous line. This BranchGroup (which contains the Shape3D of quads) is added to the scene. The last line in the display is told to detach itself from the scene.
* I am then moving the viewer up by the distance of one line. I am doing this by setting the viewingplatform's viewplatformtransform.
So, some questions:
* Is this design hopelessly convoluted for Java3D?
* Does the fact that I'm dealing with 4 * 360 * 60 = 86,400 points mean that my performance is going to be awful no matter what?
* Does it make sense to use more individual Shape3D objects, or use other primatives (or even utility shapes like cubes)?
* Should I move the points instead of the viewer?
* Can anyone offer an alternative to drawing tens of thousands of little points into a 3D environment?
As far as my performance question, I have the above working, but I'm experiencing bad screen flicker. Remember that I am adding a new Shape3D to the top, dropping one from the bottom, and moving the viewer. Is there a better way of doing this, something I should add, particular flags I should set, anything? Performance isn't completely awful, but it isn't really acceptable --the flickering is very hard on the eyes.
Thanks for any help you can send my way!

Answer 1

I am currently implementing a waterfall display using
Java3D. I have some questions about design, and also
one about performance difficulties.Hey there, I'm new to the Java 3D scene, but I'll see what I can do with my limited knowledge and good old plane sense. ;o)
The overall design structure is as follows:
* The display is made up of a 2 dimensional grid, with
each cell representing a data point viewed as a
different color. Specifically I am testing with 360
points per line, with 60 lines. That's a lot of snow.
* At each iteration the display must add a newline to
the top, shift everything down by one line, and end by
dropping the bottom line (in no particular order).
This gives a nice animation affect.
* I am representing each line by a BranchGroup
containing a Shape3D constructed with a QuadArray.
Each quad within the array represents a cell. So each
line contains 4*360=1440 points.
* At each iteration I generate a new object containing
the above. The coordinates of each point are set to
sit one line above the previous line. This BranchGroup
(which contains the Shape3D of quads) is added to the
scene. The last line in the display is told to detach
itself from the scene.
* I am then moving the viewer up by the distance of
one line. I am doing this by setting the
viewingplatform's viewplatformtransform.
So, some questions:
* Is this design hopelessly convoluted for Java3D?
* Does the fact that I'm dealing with 4 * 360 * 60 =
86,400 points mean that my performance is going to be
awful no matter what?Well, graphically, it may not be that bad (where it in another language). But I think the real lagging is caused by the way Java 3D represents the scene, in a scene graph. So, you're asking the renderer to travel through a an object tree (branchgroup) containing 86 400 idiviudal objects to be treated seperatly... We all know that Java is a RAM and CPU monster and I think doing this may be the drop that overflows the glass (your system anyway)...
* Does it make sense to use more individual Shape3D
objects, or use other primatives (or even utility
shapes like cubes)?
* Should I move the points instead of the viewer?You're already moving the points down each time (as mentionned before). So, I dunno, maybe just moving the viewer and deleting the last line and adding the top line (the rest staying put) would be faster... I still find there's lots of objects to treat there...
* Can anyone offer an alternative to drawing tens of
thousands of little points into a 3D environment? Sounds like you want a 2D looking foutain. Why not just create a big board and add an animated texture to it? I can see the performance increasing by 50 gazillion just by doing this. ;o)
As far as my performance question, I have the above
working, but I'm experiencing bad screen flicker.
Remember that I am adding a new Shape3D to the top,
dropping one from the bottom, and moving the viewer.
Is there a better way of doing this, something I
should add, particular flags I should set, anything?
Performance isn't completely awful, but it isn't
really acceptable --the flickering is very hard on the
eyes.
Thanks for any help you can send my way!I hope this helps! Happy coding!