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rgareus — Fri, 10 May 2013 14:47:41 +0000

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openGL UIs for LV2 plugins

rgareus — Fri, 10 May 2013 08:47:14 +0000

Robin Gareus

linuxaudio.org, CiTu.fr

Linux Audio Conference 2013, Graz

Definitions

LV2 (LADSPA version 2) is an open standard for plugins (and hosts), targeted at audio processing.

openGL is a cross-language, multi-platform API for rendering 2D and 3D computer graphics.

Why LV2 GUIs

No custom UI is the preferred method
- Host generated UI (common look&feel, UI guidelines,..)

Why LV2 GUIs

No custom UI is the preferred method
- Host generated UI (common look&feel, UI guidelines,..)

but..

Why LV2 GUIs

No custom UI is the preferred method
- Host generated UI (common look&feel, UI guidelines,..)

but

Specialized plugins
- Important visual feedback
- Huge number of controls
- Dependencies between controls
- Custom widgets e.g. 3D panning

Why LV2 GUIs

No custom UI is the preferred method
- Host generated UI (common look&feel, UI guidelines,..)

but

Specialized plugins
- Important visual feedback
- Huge number of controls
- Dependencies between controls
- Custom widgets e.g. 3D panning
Corporate look&feel (VST anyone?!)

LV2 GUIs

openGL

LV2 GUIs

3D FPS..

LV2 GUIs

3D FPS..
Audio Effects!

LV2 GUIs

3D FPS..
Audio Effects!
WTF?!? :)

The toolkit + ABI issue 1

Simple setup - plugin inside host

The toolkit + ABI issue 2

Simple setup - plugin inside host

The toolkit + ABI issue 3

Simple setup - plugin inside host

The toolkit + ABI issue 4

Plugin and host use the same toolkit.
Toolkit is a shared lib
Identical version of library

The toolkit + ABI issue 5

Plugin and host use the same toolkit.
..but plugin & host were built with different versions
ABI (Application Binary Interface) does not match
→ conflicts of symbols
→ segfault..

The toolkit + ABI issue

Possible solutions to the API + ABI conflict:

Compile plugin and host with same version of the library

The toolkit + ABI issue

Possible solutions to the API + ABI conflict:

~~Compile plugin and host with same version of the library~~
Run plugin as separate process

The toolkit + ABI issue

Possible solutions to the API + ABI conflict:

~~Compile plugin and host with same version of the library~~
~~Run plugin as separate process~~
Use only libraries which are API and ABI compatible across versions

GUI Toolkits

gdk/gtk (non relocatable, problematic on win, hard on OSX)
Qt (huge framework, many edge-cases)
libx11/xcb (no windows, not on OSX by default)
libclxclient (no windows, not on OSX by default)
FLTK (different back-ends depending on OS,..)
openGL

GUI Toolkits

~~gdk/gtk (non relocatable, problematic on win, hard on OSX)~~
Qt (huge framework, many edge-cases)
libx11/xcb (no windows, not on OSX by default)
libclxclient (no windows, not on OSX by default)
FLTK (different back-ends depending on OS,..)
openGL

GUI Toolkits

~~gdk/gtk (non relocatable, problematic on win, hard on OSX)~~
~~Qt (huge framework, many edge-cases)~~
libx11/xcb (no windows, not on OSX by default)
libclxclient (no windows, not on OSX by default)
FLTK (different back-ends depending on OS,..)
openGL

GUI Toolkits

~~gdk/gtk (non relocatable, problematic on win, hard on OSX)~~
~~Qt (huge framework, many edge-cases)~~
~~libx11/xcb (no windows, not on OSX by default)~~
libclxclient (no windows, not on OSX by default)
FLTK (different back-ends depending on OS,..)
openGL

GUI Toolkits

~~gdk/gtk (non relocatable, problematic on win, hard on OSX)~~
~~Qt (huge framework, many edge-cases)~~
~~libx11/xcb (no windows, not on OSX by default)~~
~~libclxclient (no windows, not on OSX by default)~~
FLTK (different back-ends depending on OS,..)
openGL

GUI Toolkits

~~gdk/gtk (non relocatable, problematic on win, hard on OSX)~~
~~Qt (huge framework, many edge-cases)~~
~~libx11/xcb (no windows, not on OSX by default)~~
~~libclxclient (no windows, not on OSX by default)~~
~~FLTK (different back-ends depending on OS,..)~~
openGL

GUI Toolkits

gdk/gtk (non relocatable, problematic on win, hard on OSX)
Qt (huge framework, many edge-cases)
libx11/xcb (no windows, not on OSX by default)
libclxclient (no windows, not on OSX by default)
FLTK (different back-ends depending on OS,..)
openGL

There are no dedicated audio related widgets in either toolkit by default (with exception of libclxclient and some qt stuff*).

Pro/Cons of openGL

Problems:

No widgets at all.

Pro/Cons of openGL

Problems:

No widgets at all.
No default fonts.

Pro/Cons of openGL

Problems:

No widgets at all.
No default fonts.
No Desktop integration.

Pro/Cons of openGL

Advantages:

Cross-platform

Pro/Cons of openGL

Advantages:

Cross-platform
Minimal (no) library dependencies, API & ABI backwards compatible to ~1999.

Pro/Cons of openGL

Advantages:

Cross-platform
Minimal (no) library dependencies, API & ABI backwards compatible to ~1999.
Hardware accelerated.

Pro/Cons of openGL

Advantages:

Cross-platform
Minimal (no) library dependencies, API & ABI backwards compatible to ~1999.
Hardware accelerated.
3D (!)

Pro/Cons of openGL

Advantages:

Cross-platform
Minimal (no) library dependencies, API & ABI backwards compatible to ~1999.
Hardware accelerated.
3D (!)
UIs can be designed in e.g. blender.

State of the Art

August 2012: first LV2 + GL example plugin
March 2013: two real LV2 openGL plugins:
- setBfree – b_synth.lv2
- balance.lv2
Spring 2013: widget model from blender & implementation in C
- Dial aka rotary knob
- Switch / Toggle Button
- Radio Button / Push Button
- Level Meter
- Organ Drawbars
May 2013: started to break out openGL lv2 lib.
Last night: updates to libsuil to directly support openGL cross platform.