IPlug2 cables thing - drag n drop example

IPlugEffect.cpp

#include "IPlugEffect.h"
#include "IPlug_include_in_plug_src.h"
#include "IControls.h"

struct Cable
{
  IVec2 pos1;
  IVec2 pos2;
  IColor color;
  
  Cable(float x, float y, const IColor& color)
  : pos1(x,y)
  , pos2(x+1,y+1)
  , color(color)
  {
  }
};

class CableControl : public IControl
{
private:
  WDL_PtrList<Cable> mCables;
  
public:
  CableControl(const IRECT& bounds)
  : IControl(bounds)
  {
    mIgnoreMouse = true;
  }
  
  ~CableControl()
  {
    mCables.Empty(true);
  }
  
  void Draw(IGraphics& g) override
  {
    for(int i=0;i<mCables.GetSize();i++)
    {
      DrawCable(g, mCables.Get(i));
    }
  }
  
  Cable* AddCable(float x, float y, const IColor& color)
  {
    Cable* pNewCable = mCables.Add(new Cable(x, y, color));
    SetDirty(false);
    return pNewCable;
  }
  
  void RemoveCable(Cable* pCable)
  {
    mCables.DeletePtr(pCable, true);
    SetDirty(false);
  }
      
private:
  void DrawCable(IGraphics& g, Cable* cable)
  {
    g.DrawLine(cable->color, cable->pos1.x, cable->pos1.y, cable->pos2.x, cable->pos2.y);
  }

};

class PlugControl : public IControl
{
public:
  PlugControl(const IRECT& bounds, CableControl* pCableControl)
  : IControl(bounds)
  , mCableControl(pCableControl)
  {}
  
  void Draw(IGraphics& g) override
  {
    g.FillEllipse(COLOR_RED, mRECT);
    
    if(mMouseIsOver || mAboutToConnect)
    {
      g.DrawEllipse(COLOR_BLACK, mRECT);
    }
  }
  
  void OnMouseDown(float x, float y, const IMouseMod& mod) override
  {
    mLastCable = mCableControl->AddCable(mRECT.MW(), mRECT.MH(), COLOR_RED);
  }

  void OnMouseUp(float x, float y, const IMouseMod& mod) override
  {
    bool valid = false;
    for(int i=0;i<4;i++)
    {
      PlugControl* pPlug = GetUI()->GetControlWithTag(i)->As<PlugControl>();
      if(pPlug!=this)
        valid |= pPlug->GetRECT().Contains(x, y);
    }
    
    if(!valid)
      mCableControl->RemoveCable(mLastCable);
    
    mLastCable = nullptr;
  }
  
  void OnMouseDrag(float x, float y, float dX, float dY, const IMouseMod& mod) override
  {
    if(mLastCable) {
      mLastCable->pos2 = {x, y};
      
      for(int i=0;i<4;i++)
      {
        PlugControl* pPlug = GetUI()->GetControlWithTag(i)->As<PlugControl>();
        pPlug->mAboutToConnect = pPlug->GetRECT().Contains(x, y);
      }

      mCableControl->SetDirty(false);
    }
  }

  bool mAboutToConnect = false;

private:
  Cable* mLastCable = nullptr;
  CableControl* mCableControl = nullptr;
};


IPlugEffect::IPlugEffect(const InstanceInfo& info)
: Plugin(info, MakeConfig(kNumParams, kNumPresets))
{
  GetParam(kGain)->InitDouble("Gain", 0., 0., 100.0, 0.01, "%");

#if IPLUG_EDITOR // http://bit.ly/2S64BDd
  mMakeGraphicsFunc = [&]() {
    return MakeGraphics(*this, PLUG_WIDTH, PLUG_HEIGHT, PLUG_FPS, GetScaleForScreen(PLUG_HEIGHT));
  };
  
  mLayoutFunc = [&](IGraphics* pGraphics) {
    pGraphics->AttachCornerResizer(EUIResizerMode::Scale, false);
    pGraphics->AttachPanelBackground(COLOR_GRAY);
    pGraphics->EnableMouseOver(true);
    pGraphics->LoadFont("Roboto-Regular", ROBOTO_FN);
    const IRECT b = pGraphics->GetBounds();
    CableControl* pCableControl = new CableControl(b);
    pGraphics->AttachControl(new PlugControl(b.GetGridCell(0,2,2).GetCentredInside(20,20), pCableControl), 0);
    pGraphics->AttachControl(new PlugControl(b.GetGridCell(1,2,2).GetCentredInside(20,20), pCableControl), 1);
    pGraphics->AttachControl(new PlugControl(b.GetGridCell(2,2,2).GetCentredInside(20,20), pCableControl), 2);
    pGraphics->AttachControl(new PlugControl(b.GetGridCell(3,2,2).GetCentredInside(20,20), pCableControl), 3);
    pGraphics->AttachControl(pCableControl);
  };
#endif
}

#if IPLUG_DSP
void IPlugEffect::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