JSFX tutorial for the total Newbie - guide

[Robert Randolph]

So I wrote a MIDI Note to CC plugin recently, and I thought I'd write a guide to how it's done.

I cover everything from basic MIDI concepts, to JSFX basics, to programming basics etc... I assume that the only thing you know is what Reaper is, how to create a text file and how to type.

There's no ads or anything on my site. So this is totally free unless you feel obliged to donate. (or become a patreon)

If you have any comments, questions or just want to berate me then I'm welcome to hear it. Thanks!

http://admiralbumblebee.com/music/20...m-scratch.html

p.s. I posted it here rather than the JSFX&ReaScript forum so that people _not_ generally interested in scripting already can see it.

EDIT - I don't even assume you know how to create a text file any more. The Tutorial is now 33% easier! (I'm sure that math works out)

[domzy]

cheers! i'll check it out.

[Melvin J.]

Dude, you are the shit! I'm definitely going to dive into this as I've been wondering for a while now on how to program a JS. Thanks!

[Justin]

Awesome, thank you! Reading now...

Some comments:

• you can create a new JSFX from the FX browser (avoiding having to use an external text editor).
  
• this was undocumented (oops, fixed), but rather than using

  ccValue = slider1;

  You can do:
  

  slider1:ccValue=0<0,127,1>CC to send

  (supported in REAPER 5.0+)
  
• You can also debug JSFX by using Ctrl/Cmd+K on a symbol to read its value (or if it points to memory, it will show you the value at that point in memory).
• JSFX can't actually be used to write video processors, but the language is the same for video processors (as well as EEL ReaScripts).
• I might ask you to ditch that askjf link if I get enough noise...

[Robert Randolph]

Originally Posted by Justin

Awesome, thank you! Reading now...

Some comments:

• you can create a new JSFX from the FX browser (avoiding having to use an external text editor).
  
• this was undocumented (oops, fixed), but rather than using

  ccValue = slider1;

  You can do:
  

  slider1:ccValue=0<0,127,1>CC to send

  (supported in REAPER 5.0+)
  
• You can also debug JSFX by using Ctrl/Cmd+K on a symbol to read its value (or if it points to memory, it will show you the value at that point in memory).
• JSFX can't actually be used to write video processors, but the language is the same for video processors (as well as EEL ReaScripts).
• I might ask you to ditch that askjf link if I get enough noise...

Awesome. I updated everything you listed and switched the askjf link.

Thank you very much for reading and the corrections! I feel annointed by the Holy Reaper Seer now.

[lolilol1975]

Originally Posted by Robert Randolph

So I wrote a MIDI Note to CC plugin recently, and I thought I'd write a guide to how it's done.

I cover everything from basic MIDI concepts, to JSFX basics, to programming basics etc... I assume that the only thing you know is what Reaper is, how to create a text file and how to type.

There's no ads or anything on my site. So this is totally free unless you feel obliged to donate. (or become a patreon)

If you have any comments, questions or just want to berate me then I'm welcome to hear it. Thanks!

http://admiralbumblebee.com/music/20...m-scratch.html

p.s. I posted it here rather than the JSFX&ReaScript forum so that people _not_ generally interested in scripting already can see it.

EDIT - I don't even assume you know how to create a text file any more. The Tutorial is now 33% easier! (I'm sure that math works out)

You rock, man ! Awesome blog btw.

[Tale]

Cool!

A very minor nitpick, but it might be worth mentioning anyway: You can also write hex numbers as e.g. 0x90 instead of $x90. This is more in line with other programming languages e.g. C/C++, JavaScript, etc. This does require REAPER v4.25+.

[X-Raym]

Very nice !

I hope it will help users to make their own modes :P

What's next step ?
Audio Processing ?
GFX ? :P

[Robert Randolph]

Originally Posted by Tale

Cool!

A very minor nitpick, but it might be worth mentioning anyway: You can also write hex numbers as e.g. 0x90 instead of $x90. This is more in line with other programming languages e.g. C/C++, JavaScript, etc. This does require REAPER v4.25+.

Thanks. I wasn't aware of that.

I picked up the $x notation (and most of the JSFX syntax) by reading through other scripts.

Unfortunately I don't think I can fully correct the $x usage, since there's so many screenshots that use the $x notation. I will update the post to mention it though.

[Tale]

Originally Posted by Robert Randolph

Unfortunately I don't think I can fully correct the $x usage, since there's so many screenshots that use the $x notation.

Of course! I guess in the end it's more of a personal preference anyway.

Originally Posted by Robert Randolph

I will update the post to mention it though.

Cool. Do note however that is should be 0x0F, not just x0F.

[martifingers]

As pretty much your target audience I think it was very generous of you to share your time and expertise. As to the content, the best compliment I can pay you would be to say you may be the Kenny of the JSFX world!

[pbattersby]

Originally Posted by Robert Randolph

So I wrote a MIDI Note to CC plugin recently, and I thought I'd write a guide to how it's done.

Well done. I imagine creating that tutorial was a lot of work. If/when I decide I want to write a plugin, I'll be back to work through the tutorial in detail.

Note, the link in this text near the top of the tutorial:

"This tutorial really isn’t for you, but maybe you can skip to results to see what happened."

... needs to target the anchor #result (singular) rather than the anchor #results (plural) which doesn't exist.

Despite having clicked that link, the tutorial is for me (even though I'm an experienced programmer), I was curious to skip to the end then come back or the beginning.

[pipelineaudio]

Thank you for this, this is awesome!

[Robert Randolph]

Originally Posted by pbattersby

Well done. I imagine creating that tutorial was a lot of work. If/when I decide I want to write a plugin, I'll be back to work through the tutorial in detail.

Note, the link in this text near the top of the tutorial:

"This tutorial really isn’t for you, but maybe you can skip to results to see what happened."

... needs to target the anchor #result (singular) rather than the anchor #results (plural) which doesn't exist.

Despite having clicked that link, the tutorial is for me (even though I'm an experienced programmer), I was curious to skip to the end then come back or the beginning.

Great catch on that anchor mistake.

I'm fixing it now!

[michaeltonight]

Whoa! Thank you so much for this! Exactly what I needed, exactly when I needed it!

[cyrilfb]

Thanks for this. The level of detail will help many of us.