Initial commit: InstaDrums VST3 drum sampler plugin

- 12-pad drum sampler with 4x3 grid (expandable by 4)
- Velocity layers with round-robin (Salamander-style filename parsing)
- Rhythm Engine-style GUI: pad grid (left), sample editor (right top),
  FX panel (right bottom), master panel (bottom)
- Waveform thumbnails on pads + large waveform in sample editor
- ADSR envelope, pitch, pan per pad
- Drag & drop sample/folder loading
- Kit save/load (.drumkit XML presets)
- Load Folder with smart name matching (kick, snare, hihat, etc.)
- Choke groups, one-shot/polyphonic mode
- Dark modern LookAndFeel with neon accent colors
- Built with JUCE framework, CMake, MSVC 2022

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Source/PadComponent.cpp

@@ -0,0 +1,166 @@
+#include "PadComponent.h"
+#include "LookAndFeel.h"
+
+PadComponent::PadComponent (DrumPad& pad, std::function<void(int, const juce::File&)> loadCallback, int padIndex)
+    : drumPad (pad), onLoadSample (std::move (loadCallback)), index (padIndex)
+{
+}
+
+void PadComponent::paint (juce::Graphics& g)
+{
+    auto bounds = getLocalBounds().toFloat().reduced (2.0f);
+    float cornerSize = 6.0f;
+
+    // Background
+    float alpha = isPressed ? 0.85f : (isDragOver ? 0.65f : (selected ? 0.55f : 0.3f));
+    g.setColour (drumPad.colour.withAlpha (alpha));
+    g.fillRoundedRectangle (bounds, cornerSize);
+
+    // Border — selected = bright accent, normal = pad colour
+    if (selected)
+    {
+        g.setColour (juce::Colour (0xff00aaff)); // blue selection
+        g.drawRoundedRectangle (bounds, cornerSize, 2.5f);
+    }
+    else
+    {
+        g.setColour (drumPad.colour.withAlpha (0.6f));
+        g.drawRoundedRectangle (bounds, cornerSize, 1.0f);
+    }
+
+    // Pad number (top-left, small)
+    g.setColour (InstaDrumsLookAndFeel::textSecondary);
+    g.setFont (juce::Font (juce::FontOptions (9.0f, juce::Font::bold)));
+    g.drawText (juce::String (index + 1), bounds.reduced (4, 3), juce::Justification::topLeft);
+
+    // Waveform thumbnail (center area)
+    if (drumPad.hasSample())
+    {
+        auto waveArea = bounds.reduced (4, 16);
+        drawWaveformThumbnail (g, waveArea);
+    }
+
+    // Pad name (bottom)
+    g.setColour (InstaDrumsLookAndFeel::textPrimary);
+    g.setFont (juce::Font (juce::FontOptions (10.0f, juce::Font::bold)));
+    g.drawText (drumPad.name, bounds.reduced (4, 2), juce::Justification::centredBottom);
+
+    // Playing flash
+    if (drumPad.isPlaying())
+    {
+        g.setColour (juce::Colours::white.withAlpha (0.12f));
+        g.fillRoundedRectangle (bounds, cornerSize);
+    }
+}
+
+void PadComponent::drawWaveformThumbnail (juce::Graphics& g, juce::Rectangle<float> area)
+{
+    auto& buf = drumPad.getSampleBuffer();
+    if (buf.getNumSamples() == 0) return;
+
+    const float* data = buf.getReadPointer (0);
+    const int numSamples = buf.getNumSamples();
+    const float w = area.getWidth();
+    const float h = area.getHeight();
+    const float midY = area.getCentreY();
+
+    juce::Path path;
+    int blockSize = std::max (1, numSamples / (int) w);
+
+    for (int x = 0; x < (int) w; ++x)
+    {
+        int si = (int) ((float) x / w * numSamples);
+        si = juce::jlimit (0, numSamples - 1, si);
+
+        float maxVal = 0.0f;
+        for (int j = 0; j < blockSize && (si + j) < numSamples; ++j)
+            maxVal = std::max (maxVal, std::abs (data[si + j]));
+
+        float topY = midY - maxVal * (h * 0.45f);
+        float botY = midY + maxVal * (h * 0.45f);
+
+        if (x == 0)
+            path.startNewSubPath (area.getX() + (float) x, topY);
+
+        path.lineTo (area.getX() + (float) x, topY);
+    }
+    // Mirror bottom
+    for (int x = (int) w - 1; x >= 0; --x)
+    {
+        int si = (int) ((float) x / w * numSamples);
+        si = juce::jlimit (0, numSamples - 1, si);
+        float maxVal = 0.0f;
+        for (int j = 0; j < blockSize && (si + j) < numSamples; ++j)
+            maxVal = std::max (maxVal, std::abs (data[si + j]));
+        float botY = midY + maxVal * (h * 0.45f);
+        path.lineTo (area.getX() + (float) x, botY);
+    }
+    path.closeSubPath();
+
+    // Greenish waveform tint
+    g.setColour (juce::Colour (0xff44cc88).withAlpha (0.4f));
+    g.fillPath (path);
+    g.setColour (juce::Colour (0xff44cc88).withAlpha (0.7f));
+    g.strokePath (path, juce::PathStrokeType (0.8f));
+}
+
+void PadComponent::resized() {}
+
+void PadComponent::mouseDown (const juce::MouseEvent& event)
+{
+    if (event.mods.isRightButtonDown())
+        return;
+
+    // Select this pad
+    if (onSelected)
+        onSelected (index);
+
+    isPressed = true;
+    drumPad.trigger (1.0f);
+    repaint();
+}
+
+void PadComponent::mouseUp (const juce::MouseEvent& event)
+{
+    if (event.mods.isRightButtonDown())
+        return;
+
+    isPressed = false;
+    if (! drumPad.oneShot)
+        drumPad.stop();
+    repaint();
+}
+
+bool PadComponent::isInterestedInFileDrag (const juce::StringArray& files)
+{
+    for (auto& f : files)
+    {
+        juce::File file (f);
+        if (file.isDirectory()) return true;
+        auto ext = file.getFileExtension().toLowerCase();
+        if (ext == ".wav" || ext == ".aiff" || ext == ".aif" || ext == ".flac"
+            || ext == ".ogg" || ext == ".mp3")
+            return true;
+    }
+    return false;
+}
+
+void PadComponent::filesDropped (const juce::StringArray& files, int, int)
+{
+    isDragOver = false;
+    if (! files.isEmpty() && onLoadSample)
+        onLoadSample (index, juce::File (files[0]));
+    repaint();
+}
+
+void PadComponent::fileDragEnter (const juce::StringArray&, int, int)
+{
+    isDragOver = true;
+    repaint();
+}
+
+void PadComponent::fileDragExit (const juce::StringArray&)
+{
+    isDragOver = false;
+    repaint();
+}