Vuo Editor
I thought I'd share my current toolset for live visuals & performance as I found it tricky finding a complete workflow when I was starting out. For many years I used Quartz Composer to design and code my visuals. Quartz Composer is a free node based visual programming language that comes packaged with Xcode and is used by visual artists to create and manipulate real-time visuals. Sadly it hasn't been developed for years and as of macOS Catalina it's been deprecated by Apple. It's still an incredible tool but I'd advise against investing time in it if you're looking to learn a piece of software for live visuals creation.
In 2019 I starting the switch to Vuo, a similar environment and workflow to Quartz Composer which also integrates with VJ software like VMDX.
My introduction to creative coding and real-time visuals was actually Processing and later Hype, but I struggled to find a workflow for perfoming live and found this less suited to live performance due to it's lack of integration with tools like VDMX. This is also due to me feeling more comfortable with the node based approach to programming and a lack of knowledge of how to write "real" code.
Using Syphon you can send a Processing sketch into VDMX and it's definately something I want to come back to and continue to learn as I think there is a huge benefit to understanding how to write code.
Another one of my goals in 2020 is to explore Touchdesigner, Unity as well as Notch.
Lemur Controller
Controller
I use Lemur for iPad as a touch controller. Some people prefer the tangibility of a physical controller but I like the flexibility of building custom controllers depending on the project, and I find there are benefits to this approach as I can label and colour code things, have multiple pages etc.
I recommend watching this tutorial on MIDI controllers by Ali Demirel which demonstrates how he uses Lemur on an iPad along with his performance software 2V-P. I use (copied!) this exact setup for anything that involves live performances or controlling and manipulating visuals in real-time.
2V-P
Performance tools
My performance tools are either 2V-P or VDMX depending on the project. 2V-P uses a simple 2 channel structure, and is a lot easier to get started with. It’s very focused on encouraging you to design and create your own content. You can important QC compositions and movie files and use GLSL shaders in the ISF format. It's also only £25.99 on the app store.
VDMX
VDMX has a more complex interface and is very customisable but if you’re starting out it can be quite overwhelming. You can import QC and Vuo compositions, movie files and use GLSL shaders in the ISF format. I've currently configured the layout to match 2V-P with 2 channels, but you can have multiple channels and layers if you wish.
I personally feel that unless you have a clear artistic vision, you should exercise restraint when using multiple layers otherwise things can start looking pretty messy.
Finally, I use a iConnectMIDI2+ to create a cabled MIDI connection between my laptop and iPad and a Steinberg UR12 soundcard to control the volume of the incoming audio signal.