Code Review: IPlugVisage Example

This PR adds a new example demonstrating Visage UI integration with iPlug2. Overall, this is a valuable addition that shows alternative UI approaches. Here are my findings:

✅ Strengths

1. Good example structure - Follows iPlug2 conventions with clean separation of Plugin.h/cpp and config.h
2. Comprehensive project files - Includes all platform configurations (macOS, iOS, Windows, Web)
3. Proper licensing - Examples code includes MIT license headers from Visage
4. Documentation - Includes README and setup script

🔍 Code Quality Issues

Critical Issues

1. README description mismatch (README.md:2)

   • States "A basic volume control effect plug-in with IGraphics GUI"
   • Should be "...with Visage GUI" since this example specifically uses Visage, not IGraphics

2. Missing include guard/file (IPlugVisage.h:6)

   • References #include "showcase.h" but this file appears to be copied from Visage examples
   • Need to verify showcase.h/cpp are properly included in build targets

3. Lambda capture by reference in UI callback (IPlugVisage.cpp:38)

   • mEditor->onDraw() = [&](visage::Canvas& canvas) captures this by reference
   • If the lambda outlives the object, this creates dangling references
   • Consider explicit capture: [this] or ensure proper lifetime management

4. Unused ShaderCompiler (IPlugVisage.cpp:35-36)

   • compiler is created as local variable but goes out of scope immediately
   • Either remove it or make it a member if shader hot-reloading is needed

5. Hardcoded shader path (IPlugVisage.cpp:16)

   • return (folderPath / "visage/examples/shaders").string();
   • This assumes specific directory structure that may not exist in built plugins
   • Should handle missing directory gracefully or use bundled resources

Style & Convention Issues

6. Copyright year (config.h:9)

   • "Copyright 2020 Acme Inc" should probably be 2025 or current year

7. Config inconsistency (config.h:26, config/IPlugVisage-mac.xcconfig:26)

   • config.h sets NO_IGRAPHICS in preprocessor but PLUG_HAS_UI 1
   • This is intentional for Visage but could confuse developers copying this example
   • Add comment explaining this is specific to Visage UI

8. Unnecessary OnIdle override (IPlugVisage.cpp:25-27)

   • Empty implementation - can be removed unless planned for future use

9. Missing const correctness (IPlugVisage.cpp:60)

   • OnParentWindowResize(int width, int height) - parameters could be const

10. gitignore typo (.gitignore:23)

    • .DS_Stor* should be .DS_Store* (missing 'e')

⚠️ Potential Issues

11. Build dependency management

    • get_visage.sh clones Visage but project files reference hardcoded paths
    • No verification that Visage is built before building this example
    • Consider adding build instructions or CMakeLists.txt integration

12. ProcessBlock performance (IPlugVisage.cpp:78-88)

    • Nested loop could benefit from processing channels in outer loop for better cache locality
    • Current implementation is fine for simple gain but worth noting for educational purposes

13. Window lifecycle (IPlugVisage.cpp:69-76)

    • CloseWindow() calls mWindow.reset() but doesn't check if editor is still attached
    • Order of operations looks correct but could add null checks for safety

14. Missing error handling

    • OpenWindow doesn't handle allocation failures or Visage initialization errors
    • Should consider returning nullptr and checking in host if critical setup fails

📝 Documentation

15. Missing build instructions

    • README should mention:
      • Need to run get_visage.sh first
      • Visage build requirements (CMake, etc.)
      • Platform-specific setup steps

16. Example scope unclear

    • Is this meant to be a minimal example or showcase of Visage features?
    • The showcase frame suggests comprehensive demo, but README says "basic volume control"

🔒 Security & Performance

17. No security issues identified - Standard plugin code
18. Realtime-safe ProcessBlock - No allocations, locks, or file I/O ✓

🧪 Test Coverage

• No automated tests included (typical for examples)
• Manual testing instructions would be helpful

Recommendations

Must fix before merge:

• Fix README description
• Fix lambda capture or document lifetime guarantees
• Handle shader path more robustly
• Fix .gitignore typo

Should fix:

• Update copyright year
• Add build instructions to README
• Remove unused ShaderCompiler or make it functional
• Remove empty OnIdle() override
• Add comment explaining NO_IGRAPHICS usage

Nice to have:

• Add error handling in OpenWindow
• Improve ProcessBlock loop order for educational value
• Add CMake integration example

This is a solid example that will help users integrate Visage. With the critical fixes above, it will be ready to merge. Thanks for contributing this!