Vinyl Audio Visualizer

An interactive 3D audio-reactive music visualizer built with Java, OpenGL (LWJGL 3), and TarsosDSP.

The application captures real-time audio streams (via your microphone or system loopback) and applies a Fast Fourier Transform (FFT) to deform the topography of a 3D polar circular grid resembling a classic vinyl record. In addition, it integrates with the Spotify Web API using the secure OAuth PKCE flow to dynamically pull currently playing track information and map the active song's album art directly onto the rotating vinyl's label.

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Features

• Interactive 3D Polar Topography: Vertices of a circular grid are displaced along the Y-axis using logarithmic frequency mappings, creating natural-looking acoustic ripples.
• Procedural OpenGL Shading: Custom vertex and fragment shaders render realistic vinyl grooves, edge reflections, center hole masking, and ambient breathing waves when silent.
• Logarithmic Amplitude Coloring: 4-stop color gradient (indigo ➔ magenta ➔ cyan ➔ white) mapped dynamically to the vertex height.
• Spotify Integration: Secure authentication callback server running on http://127.0.0.1:8888/callback. Pulls active track metadata and maps album art as a dynamic 2D OpenGL texture directly onto the center label.
• On-the-fly Input Selection: Cycle through available recording lines (Microphone, Stereo Mix, etc.) in real-time.

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Controls

Key / Input	Action
W / S / A / D	Move camera (Forward / Backward / Left / Right)
Mouse Left-Click + Drag	Rotate camera (Azimuth / Zenit)
Tab	Toggle Wireframe / Solid fill rendering
+ / - (or =)	Increase / Decrease audio gain (deformation height)
M	Cycle through available audio input devices (e.g. Stereo Mix, Mic)
O	Toggle Spotify Connection (triggers OAuth in your browser)
Escape	Close the application

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Prerequisites

• Java Development Kit (JDK): JDK 21 or later.
• Maven: To manage dependencies and build the project.
• Audio Source: Working system audio with recording capability.

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How to Enable System Loopback (Stereo Mix)

By default, Java's AudioSystem listens to your recording devices. To visualize music played on your computer (e.g., Spotify client, YouTube, media player) rather than room sound through your microphone, you must enable a loopback recording device.

Windows Setup (Stereo Mix)

1. Open Sound Settings: Right-click the Speaker/Volume icon in your taskbar and select Sounds (or navigate to Settings ➔ System ➔ Sound ➔ More sound settings).
2. Show Hidden Devices: Go to the Recording tab. Right-click on empty white space in the list and ensure both Show Disabled Devices and Show Disconnected Devices are checked.
3. Enable Stereo Mix: Look for Stereo Mix (sometimes called What U Hear or Wave Out Mix). Right-click it and choose Enable.
4. Set as Default: Right-click it again and choose Set as Default Device (or cycle to it inside the visualizer using the M key).
5. Microphone Privacy: Make sure Windows privacy settings permit apps to access your microphone.

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Spotify Integration Setup

To fetch live cover art and track metadata, you need to provide your own Spotify Developer credentials.

1. Log in to the Spotify Developer Dashboard.

2. Click Create App and fill in the details:

   • App Name: Vinyl Visualizer
   • Redirect URI: http://127.0.0.1:8888/callback (Must match exactly!)

3. Go to the settings of your newly created Spotify app and copy the Client ID.

4. In the root folder of this project (next to pom.xml), create a new file named spotify.properties.

5. Add your Client ID to the file using this exact key:

   spotify.client_id=YOUR_SPOTIFY_CLIENT_ID_HERE

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Building & Running

This project uses local custom-built LWJGL binaries supplied in the libs/ directory via Maven's system scope. By default, Maven's exec:java runtime classpath excludes system scoped dependencies, which can lead to a NoClassDefFoundError for classes like GLFWCursorPosCallbackI.

Pre-configured the exec-maven-plugin inside pom.xml to set the classpath scope to compile (which forces Maven to include local system-scope dependencies).

You can now build and run the application simply by executing:

mvn clean compile exec:java

Or open the project in your favorite Java IDE (IntelliJ IDEA, Eclipse, or VS Code) and run the Main class directly.

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Third-Party Libraries & Licensing

This project utilizes several external libraries that are included in this repo for convenience. Please note that:

• LWJGL 3 (Lightweight Java Game Library) is distributed under the BSD License.

• The following external libraries are used for academic/educational purposes:

  • transforms (by Jan Vaněk)
  • lwjgl-utils (by Bruno Ježek)

  These educational libraries are not part of my custom project source code. Any use, distribution, or modification of these libraries is governed strictly by their respective author's licenses and academic guidelines.

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Developed by Marek Fadrný | FIM UHK PGRF2 2025/26

While working on this project, coding assisting tools leveraging LLMs were used - namely GitHub Copilot and GitHub Copilot Chat