[PD] GEM: is there a way to increase (perhaps hack) the limit on the number of GEM/OpenGL lights above 8

darren at webel.com.au darren at webel.com.au
Tue Dec 9 06:30:19 CET 2014

Claude Heiland-Allen wrote:
> You will need to write a shader to do your lighting. ..
> You won't be able to use the Gem objects for lighting once you use a
> shader, they work in a different way (only for fixed function
> pipeline, without shaders).  With shaders you need to send messages to
> the glsl_program object to set uniform variables.  This also means you
> have to do your own maths for the transformations, not using
> translate/rotate objects.
Thanks Claude for reply.

I just invested some time studying some shader tutorials and examples.
I can see how I could use them for a number for other related tasks.

But the inability to use translate/rotate objects with shaders is
probably a killer for my current simulation, as I am simulating LEDs
that have to be able to move, and that movement is relative
to (and bound to) other non-light objects in the scene.

I can see from some of the shader examples how one might be able
to simulate some glowing effects nicely, such as for the halo around
a street lamp, to evoke the impression of many lights in a row.

But I am not sure whether one could use shaders to create a really clear
light effect with clear shining of the light projected onto distant objects.

One of the main points of the demonstration is to show the result
of the projection of many (30) driven LEDs onto other surfaces.

The (transformable) [light]+[spot_light] work together nicely for this
for my LED simulation.


Webel IT Australia, "The Elements of the Web" 
Darren Kelly

More information about the Pd-list mailing list