Complex project using GLGraphics

Contributed Library Questions

ventai

Complex project using GLGraphics

in Contributed Library Questions • 2 years ago

Hi,

I'm working on a project at the moment that I want to eventually bounce to video.

The project is due to get a lot more complex quite quickly, with the following types of processes:-

- various animated primitive objects. Manipulated in real-time

- a particle system

- some general drawing / rendering to screen

- and some other stuff not thought of yet :)

There's due to be quite a lot happening on screen at the same time, so am planning on using the power of OPENGL at some point. Everything needs to happen in real-time for audio synchronisation purposes.

I have read the warnings about the direct manipulation of the OPENGL object in Processing, and also the suggestion of using an external IDE, and using JOGL directly.

I see the compromise in between as to use the GLGraphics lib, as this may be a good balance between safety, ease, and power.
EDIT: or would simply using the OPENGL renderer in size be sufficient?

Does anybody have any comments on the above? (I have not used this lib yet, and consider myself to be an intermediate user of Processing).

I'm also planning to do some ray tracing once I have the audio synced, and can then re-run while rendering out.

Any comments welcome. .

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Replies(7)

ventai

Re: Complex project using GLGraphics

2 years ago

Ok, if anybody has anything to add and help in this discussion, please do. .

In the meantime, due to spending far too much time looking into OPENGL / JOGL, GLGraphics, and all other related intricacies; I'm going to just use the OPENGL renderer in size(...) and relook at stuff if I run into any issues.

Cheers

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andres

Re: Complex project using GLGraphics

2 years ago

The OPENGL renderer is fine as long as the number of vertices in your scene is not very high. This renderer doesn't take full advantage of hardware acceleration, and it pushes vertex data to the video card using the OpenGL functions glBegin()/glEnd(), which are not very efficient.

If you need to handle large geometries in real-time and the OPENGL renderer becomes too slow, you could either use the GLGraphics library which encapsulates some more advanced OpenGL features like Vertex Buffer Objects and GLSL shaders, or program directly in OpenGL using the JOGL bindings. GLGraphics doesn't do anything you cannot implement yourself in pure OpenGL, so this might be the best option if you need the greatest flexibility.

ventai

Re: Complex project using GLGraphics

2 years ago

Thanks for the info andres. . though a little confusing, as I read the following quote which sounded like it was saying the opposite: -

"OpenGL (Open Graphics Library) is a cross-platform graphics interface for 3D and 2D graphics. This library allows Processing programs to utilize the speed of an OpenGL accelerated graphics card. This expands the potential for drawing more to the screen and creating larger windows."

From: http://www.processing.org/reference/libraries/opengl/

My only concern is that I have around 2 months to do this project, as well as a very large dissertation, and if I implement lots of stuff with 'traditional' P5 code, find out that it can't handle the complexity, then have to re-learn / re-write a large proportion of the classes / codebase, things could easily go wrong. I need to decide which is the best route at this juncture. . .

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andres

Re: Complex project using GLGraphics

2 years ago

Yes, this can be a little confusing, specially because a number of different elements have similar names. In principle, OpenGL is a cross-platform system interface that many applications use to access the drawing capabilities in the video card.

Within the context of Processing, OpenGL usually denotes a core library that provides a rendering engine called OPENGL... Now, Processing comes with several rendering engines: JAVA2D, P2D, P3D, OPENGL, etc, which you select with the size() function. Internally, the OPENGL rendering engine uses the OpenGL interface to talk to the video card and accelerate some drawing operations.

One source of confusion is that you can use the word OpenGL to refer either to the Processing library, its associated rendering engine, or the low-level system interface. Often, the context should be enough to clarify this potential confusion. To avoid confusion myself, I tend to call OPENGL, all uppercase, to both the Processing library and its accompanying rendering engine, and reserve OpenGL to talk specifically about the low-level interface.

The additional element you mention in your first post is JOGL, which is essentially the "glue" between the OPENGL library in Processing, and the low-level OpenGL interface. This glue, or binding as it is often called, is necessary because OPENGL and Processing are written in Java, while the OpenGL interface is written in C.

As you probably read somewhere else, when the selected rendering engine is OPENGL, then you can access the JOGL bindings from your sketch. This allows you to call OpenGL functions directly from your code.

Finally, the GLGraphics library is similar to OPENGL in the sense that it is a Processing library that also provides a rendering engine based on OpenGL. The GLGraphics rendering engine solves some limitations of the OPENGL engine, specially in terms of performance, and adds some additional functionality like shaders and offscreen rendering.

Anyways, I don't want to extend too much on this rant about GL-related terminology, and I hope that at least it clarifies things a bit. As for your more concrete question, I'd say that the GLGraphics library could be useful for your project, but it is probably a good idea if you first take a look at the examples that come with the library to get a feeling of what you can do with it. If you realize that is not enough for what you want to do, then using the JOGL bindings directly from your sketch could a better alternative.

ventai

Re: Complex project using GLGraphics

2 years ago

Thank you for a very thorough reply - I needed a clear explanation of the systems and how they interact.

I'm going to take a closer look at the GLGraphics library and do some testing. Hopefully it's syntactically similar to lower lever OpenGL, and will lend itself to a nice learning blend for further control later on.

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andres

Re: Complex project using GLGraphics

2 years ago

Actually, GLGraphics API tries to follow Processing's conventions rather than OpenGL's. But you can mix GLGraphics and JOGL calls without much trouble. Take a look at the models/GLIntegration example.

ventai

Re: Complex project using GLGraphics

2 years ago

Great - looks good. .

Thanks for your time andres - much appreciated

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