Creating iPlug2 Plugins

Learn how to create new iPlug2 audio plugins using the duplicate.py script

Overview

iPlug2 provides a Python script that duplicates example projects to create new plugins. This is the recommended way to start a new plugin project.

Prerequisites

• Python 2 or 3 installed
• iPlug2 repository cloned
• Python accessible from command line (Windows users need to add Python to PATH)

Using duplicate.py

The duplicate.py script is located in Examples/ and creates a new plugin by copying an existing example.

Basic Usage

cd /path/to/iPlug2/Examples
python duplicate.py [input_project] [output_project] [manufacturer]

1. Choose a Template
2. Select an example project as your starting point:
4. Run the Script
5. python duplicate.py IPlugEffect MyDelay MyCompany
   

6. This creates a new project:
8. Specify Output Path (Optional)
9. python duplicate.py IPlugEffect MyDelay MyCompany ~/Desktop/MyPlugins
   

10. Creates the project at ~/Desktop/MyPlugins/MyDelay/

Naming Rules:

• No spaces in project or manufacturer names
• Use CamelCase (e.g., MyAwesomePlugin)
• Avoid numbers, dots, or special characters at the start

What Gets Duplicated

The script performs these operations:

Files Copied

• Source code (.h, .cpp)
• Project files (.sln, .xcodeproj)
• Build configurations
• Resource files
• Scripts

Strings Replaced

• Project name
• CAPITALIZED names
• Manufacturer name
• iPlug2 root path (if needed)

Files Created

MyDelay/
├── MyDelay.h              # Plugin header
├── MyDelay.cpp            # Plugin implementation  
├── config.h               # Plugin configuration
├── config/                # Build configs (.xcconfig, .props)
├── projects/              # IDE projects
│   ├── MyDelay.sln       # Visual Studio
│   └── MyDelay.xcworkspace # Xcode
├── resources/            # Assets (fonts, images)
└── scripts/              # Build scripts

Configuration

After duplication, edit config.h to customize your plugin:

config.h

#define PLUG_NAME "MyDelay"
#define PLUG_MFR "MyCompany"
#define PLUG_VERSION_HEX 0x00010000
#define PLUG_VERSION_STR "1.0.0"
#define PLUG_UNIQUE_ID 'Xyz1'  // ⚠️ CHANGE THIS
#define PLUG_MFR_ID 'MyCP'      // ⚠️ CHANGE THIS

#define PLUG_CHANNEL_IO "2-2"   // Stereo in/out
#define PLUG_TYPE 0              // 0=Effect, 1=Instrument, 2=MIDI Effect
#define PLUG_DOES_MIDI_IN 0
#define PLUG_DOES_MIDI_OUT 0

Critical: Change PLUG_UNIQUE_ID and PLUG_MFR_ID immediately. The script assigns a random PLUG_UNIQUE_ID, but you should verify it’s unique and update PLUG_MFR_ID to your registered manufacturer code.

Plugin IDs

PLUG_UNIQUE_ID must be unique across all plugins. Use 4 alphanumeric characters (e.g., 'MdL1').

PLUG_MFR_ID identifies your company. Register a code or use your initials (e.g., 'ACME').

Project Structure

Main Files

Every iPlug2 plugin has three core files:

Header (.h)

MyDelay.h

#pragma once
#include "IPlug_include_in_plug_hdr.h"

const int kNumPresets = 1;

enum EParams
{
  kGain = 0,
  kNumParams
};

using namespace iplug;
using namespace igraphics;

class MyDelay final : public Plugin
{
public:
  MyDelay(const InstanceInfo& info);
  
#if IPLUG_DSP
  void ProcessBlock(sample** inputs, sample** outputs, int nFrames) override;
#endif
};

Source (.cpp)

MyDelay.cpp

#include "MyDelay.h"
#include "IPlug_include_in_plug_src.h"
#include "IControls.h"

MyDelay::MyDelay(const InstanceInfo& info)
: Plugin(info, MakeConfig(kNumParams, kNumPresets))
{
  GetParam(kGain)->InitDouble("Gain", 0., 0., 100.0, 0.01, "%");
  
#if IPLUG_EDITOR
  mMakeGraphicsFunc = [&]() {
    return MakeGraphics(*this, PLUG_WIDTH, PLUG_HEIGHT, PLUG_FPS, 
                        GetScaleForScreen(PLUG_WIDTH, PLUG_HEIGHT));
  };
  
  mLayoutFunc = [&](IGraphics* pGraphics) {
    pGraphics->AttachPanelBackground(COLOR_GRAY);
    const IRECT bounds = pGraphics->GetBounds();
    pGraphics->AttachControl(new IVKnobControl(bounds.GetCentredInside(100), kGain));
  };
#endif
}

#if IPLUG_DSP
void MyDelay::ProcessBlock(sample** inputs, sample** outputs, int nFrames)
{
  const double gain = GetParam(kGain)->Value() / 100.;
  const int nChans = NOutChansConnected();
  
  for (int s = 0; s < nFrames; s++) {
    for (int c = 0; c < nChans; c++) {
      outputs[c][s] = inputs[c][s] * gain;
    }
  }
}
#endif

Config (config.h)

config.h

#define PLUG_NAME "MyDelay"
#define PLUG_MFR "MyCompany"
#define PLUG_VERSION_HEX 0x00010000
#define PLUG_VERSION_STR "1.0.0"
#define PLUG_UNIQUE_ID 'MdL1'
#define PLUG_MFR_ID 'MyCo'

#define PLUG_CHANNEL_IO "2-2"
#define PLUG_TYPE 0
#define PLUG_HAS_UI 1
#define PLUG_WIDTH 600
#define PLUG_HEIGHT 600

Build System

iPlug2 supports multiple build systems:

Visual Studio

.sln files for Windows

AAX, VST3, CLAP, Standalone

Xcode

.xcworkspace for macOS/iOS

AU, VST3, CLAP, AAX, Standalone, AUv3

CMake

Cross-platform

All formats, Web Audio (WASM)

Next Steps

Audio Effects

Build audio processors with parameters and DSP

Instruments

Create MIDI synthesizers with polyphony

MIDI Effects

Process MIDI messages and generate notes

Parameters

Learn about parameter types and configuration

Troubleshooting

Error: input project doesn't exist

Check the spelling and case of the template name. Template must exist in the Examples/ directory.

ls Examples/
# Look for: IPlugEffect, IPlugInstrument, etc.

Error: output project already exists

The destination directory already exists. Choose a different name or delete the existing directory.

rm -rf MyDelay  # Delete existing project

Error: name has spaces

Project, manufacturer, and path names cannot contain spaces. Use CamelCase instead.

# ❌ Wrong
python duplicate.py IPlugEffect "My Delay" "My Company"

# ✅ Correct  
python duplicate.py IPlugEffect MyDelay MyCompany

Can't parse plugin config (REAPER extensions)

This is expected for REAPER extensions. They don’t use the standard plugin config format.