[chaoscope] Re: New preview comment and bugs

  • From: Chaoscope <chaoscope@xxxxxxxxxxxxxx>
  • To: chaoscope@xxxxxxxxxxxxx
  • Date: Sat, 04 Sep 2004 17:37:57 +0100

Hi François, hello all,

- Solid mode:
It's the first time I can see this, wonderful! Exactlty what I hoped from you Nicolas :-) This time you can tell it's a real preview in solid mode! No transparency nor gamma settings but a preview with an astounding accuracy, except for lights (1 suspect one more in preview but maybe is it the lack of shadows) Of course I understand, shadows are very time consuming. Moving the mouse is like watching a cartoon.

The Solid preview is a very crude simulation of the software (Chaoscope's own) rendering. There are no lights at all, although the colors are based on the lights setup.
It'd be possible to display something closer to software render using OpenGL, including shadows, but that would involve using pixel shaders and I've got no idea how fast and compatible (from one card manufacturer to another) it would be.


I had a bug when hight zooming with your first exe but I can't reproduce it with the new one. Good no? ;-)

You're probably mentioning the "near clipping" bug. Scaling an attractor up would bring it too close to the near clipping plane, so it would eventually disappear, the far side being lost into the fog. Scaling is now apply to the projection instead, so you can zoom in as much as you want. :-)


- Colored modes: Beautiful too but here there is a problem. It can be very beautiful but I don't have the same colors I have with rendering (?). Colors are differents. Like if the gradient's arithmetic would'nt be the same in both cases. Just try any kind with the standard gradients: youl'll see the first calculations but if you click to see the enhanced preview, you won't see anything or something very dark. Try to render the picture... surprise, it appears. Easy to see this strange behavior: just change the black angle gradient by a red one for instance, press F3, see, and click on view, you'll see what I mean. It's not the same color scheme...

Could you provide a couple of screenshots to illustrate this problem? It could have something to do with the fact that OpenGL preview brightness isn't normalized like it is for the software render. The overall brightness of an attractor can differ significantly from the preview to the render.


263524 Ko for a huge zoom, more than 90 ;-). Depends of parameters in options file. Even returning to a 'normal' view by a new F3, the memory consumption stays hight. To free the memory I need to launch an other rendering mode. Sometimes a peak at more than 400 Mo. Launching an other rendering mode reallocates the minimum required memory.

I let the C++ Builder and STL deal with memory allocation. The preview vertex buffer is stored in a STL vector container, which may allocate more memory than needed (to limit redundant memory allocation calls) and keep the amount of allocated RAM high in case more is requested. It's up to you to decide how much RAM you're ready to allot to Chaoscope by setting the "max_iter" value. Each vertex takes 12 bytes, plus 3 bytes in Light/Plasma mode.


For a normal usage, it could be useful to have a sign somewhere showing the machine is in calculations instead watching the task manager ;-) I know it's a test release... I appreciate the iteration correction on zoom feature, great! Fast and efficient!

I've asked you to keep an eye on the Task Manager so that you know what is going on. It's intended to be transparent to the user, no need for them to worry about what the program is up to.


Bug when passing from light to plasma: violation access in module atioglxx.dll (read of adress 000000) and an other with "external exception EEFFACE"

Not all the memory allocations are checked (boo me!) so this is what probably happened there, not enough memory.


All these values can vary a little bit, around 100 Ko more or less. Don't know why.

It's absolutely normal, C++ Builder has its own memory allocation system, partly to avoid memory fragmentation, and it's not absolutely constant.


Thanks for your detailed test report!

Nicolas Desprez
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