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Gremlin rewrite for OpenGL ES and possible optimization

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21 Jun 2024 16:09 #303498 by alex_sar
Gremlin rewrite for OpenGL ES and possible optimization was created by alex_sar
Hi All,

I tried to rewrite Gremlin - make new widget based on existing code and contribute it. It made with using of recent OpenGL ES API (shaders/vertex buffers/etc.). The code is not ready to show yet, but I got all parts working and it is possible to make it handling bigger g-code files and do it fast enough. Currently big files simply excluded from preview. At first look, the problem is large Python trajectory arrays that filled one-by-one and then handled in Python again with lot of iterations. I rewrote it to use number of continous memory buffers (fixed size each) and it made a big change immediately. That is not the question, I hope I can show results soon. Just want to ask if anyone have interest in this new widget?

Another big deal is number of calls between C++ code and Python code. I did not measure it yet, but gcodemodule.cc does calls like this for any point in trajectory:
PyObject *result =
callmethod(callback, "straight_feed", "fffffffff", x, y, z, a, b, c, u, v, w); // gcodemodule.cc:340

When it repeated n*thousand times, it becomes a bottleneck for sure. My idea is to modify method
static PyObject *parse_file(PyObject *self, PyObject *args) {
and add an optional parameter for this to accept C method pointers for "straight_feed", "traverse", etc. So when this parameter passed, it will call C callbacks instead of python methods and do not do all this Python variable conversion back and forth.  Something like this
if (straight_feed_callback) {
  (*straight_feed_callback)(x, y, z, a, b, c, u, v, w);
} else {
  PyObject *result =
  callmethod(callback, "straight_feed", "fffffffff",
  x, y, z, a, b, c, u, v, w);
  if(result == NULL) interp_error ++;
  Py_XDECREF(result);
}
I believe this may be a huge performance win and I hope it does not violate any LinuxCNC development guidelines.
My question is to project maintainers. If I make this change and submit to Github to merge, will it be accepted? 
The following user(s) said Thank You: MennilTossFlykune, JT

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21 Jun 2024 16:26 #303499 by PCW
Replied by PCW on topic Gremlin rewrite for OpenGL ES and possible optimization
Not a developer but sounds great especially
for complex gcode or slower machines.

Probably best in a separate branch initially.
 

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21 Jun 2024 16:29 #303500 by tommylight
Replied by tommylight on topic Gremlin rewrite for OpenGL ES and possible optimization

If I make this change and submit to Github to merge, will it be accepted? 

If you do not try, you will never know.
:)

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21 Jun 2024 18:03 #303506 by alex_sar
Replied by alex_sar on topic Gremlin rewrite for OpenGL ES and possible optimization
got it :)
The following user(s) said Thank You: tommylight

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21 Jun 2024 22:03 #303516 by MennilTossFlykune
Replied by MennilTossFlykune on topic Gremlin rewrite for OpenGL ES and possible optimization
I am very interested in seeing it. Is it a drop-in replacement for glcanon.py?

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22 Jun 2024 07:49 #303537 by alex_sar
Replied by alex_sar on topic Gremlin rewrite for OpenGL ES and possible optimization
Yes, that is the goal.

One thing that is still 100% unclear for me is foam cutter visualization. There is some magic code in Gremlin for this. I never worked with such kind of machines. Is there any LinuxCNC documentation regarding foam cutter setup? Or may be one can explain in short?

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22 Jun 2024 08:01 - 22 Jun 2024 08:51 #303538 by Aciera
Replied by Aciera on topic Gremlin rewrite for OpenGL ES and possible optimization
Have a look at the foam simulation config 'configs/sim/axis/foam/axis_foam.ini'.

 

Basically it produces two separate previews, one for XY and one for UV

[edit]
Note that the Z,W height comes from the gcode lines (there are no actual Z or W axes)
(AXIS,XY_Z_POS,5)
(AXIS,UV_Z_POS,30)

[edit2]
The idea is that the two cones represent the end of a hot wire cutting through styrofoam
 
 
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Last edit: 22 Jun 2024 08:51 by Aciera.
The following user(s) said Thank You: alex_sar

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22 Jun 2024 09:03 #303543 by alex_sar
Replied by alex_sar on topic Gremlin rewrite for OpenGL ES and possible optimization
Thank you, that is clear now!

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