NGLFeatherGen

A Qt-based application that demonstrates procedural feather generation using the NGL graphics library. Feathers are created from Bezier curves for the rachis, outlines and barbs then rendered in an OpenGL scene.

Build

1. Install dependencies:

   • CMake >= 3.12
   • NGL library https://github.com/NCCA/NGL.git
   • Qt5 or Qt6 (Widgets and OpenGLWidgets)
   • GoogleTest for optional unit tests

2. Configure and build:

   mkdir build
   cd build
   cmake -G -Ninja ..
   ninja
   

Usage

Run the generated Feather executable. The UI provides tabs to tweak rachis, outline, barb, and full-feather parameters. Press Render to regenerate the feather with the current settings.

Note: Render output depends on current tab i.e. Only show rachis when pressing render under Rachis tab.

Diagram

classDiagram
   class BezierCurve {
      +addPoint(ngl::Vec3 point) void
      +setLOD(unsigned int lod) void
      +getPointOnCurve(ngl::Real t) ngl::Vec3
      +getSamplePoints() std::vector<ngl::Vec3>
      +draw() void
      +drawControlPoints() void
      +createVAO() void
      -m_controlPoints std::vector<ngl::Vec3>
      -m_samplePoints std::vector<ngl::Vec3>
      -m_lod unsigned int
      -m_vao GLuint
}

    class Feather {
        +GenerateRachis() void
        +generateOutlines() void
        +generateTemplateBarbs() void
        +generateAllBarbs() void
        +setSampleNum(int num) void
        +setF0(ngl::Real f0) void
        +setFn(ngl::Real fn) void
        +setNumBarbs(unsigned int num) void
        +setBarbLOD(unsigned int lod) void
        +setOutlineMappingRange(ngl::Real start, ngl::Real end) void
        +drawRachis() void
        +drawOutlines() void
        +drawAllBarbs() void
        +drawFullFeather() void
        -m_rachis std::unique_ptr<BezierCurve>
        -m_leftOutline std::unique_ptr<BezierCurve>
        -m_rightOutline std::unique_ptr<BezierCurve>
        -m_leftBarb std::unique_ptr<BezierCurve>
        -m_rightBarb std::unique_ptr<BezierCurve>
        -m_leftBarbs std::vector<std::unique_ptr<BezierCurve>>
        -m_rightBarbs std::vector<std::unique_ptr<BezierCurve>>
        -m_sample unsigned int
        -m_F0 ngl::Real
        -m_Fn ngl::Real
        -m_numBarbs unsigned int
        -m_leftBarbOutlineFactor ngl::Real
        -m_rightBarbOutlineFactor ngl::Real
        -m_outlineMappingStart ngl::Real
        -m_outlineMappingEnd ngl::Real
        -ensureRachisExists() void
    }

    Feather "1" *-- "*" BezierCurve : Composition
    Feather "1" o-- "1" BezierCurve : Rachis
    Feather "1" o-- "1" BezierCurve : LeftOutline
    Feather "1" o-- "1" BezierCurve : RightOutline
    Feather "1" o-- "1" BezierCurve : LeftBarbTemplate
    Feather "1" o-- "1" BezierCurve : RightBarbTemplate
    Feather "1" *-- "*" BezierCurve : LeftBarbs
    Feather "1" *-- "*" BezierCurve : RightBarbs

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