Desktop CRT Filter

A real-time CRT (Cathode Ray Tube) filter overlay application for Windows desktop. Apply authentic CRT effects like scanlines, phosphor bloom, screen curvature, and more to your entire desktop or specific applications.

✨ Features

• Real-time Filtering: Apply CRT effects directly to your desktop in real-time
• Adjustable Effects: Customize multiple CRT parameters for your preferred look
• Window Targeting: Target specific application windows or apply to entire desktop
• Monitoring: Built-in FPS tracking and performance graphs
• Always-on-top Control Panel: Convenient control window with pinned overlay

🛠️ Installation

Prerequisites:

• Windows 10/11
• .NET 10.0 Runtime or later
• OpenGL compatible graphics card

Download:

• Download the latest release from the Releases page
• Extract the files to your preferred location

Run:

• Execute DesktopCRTFilter.exe
• The control panel will appear as a small overlay window

🎮 How to Use

Start/Stop Filter:

• Click "Start" in the control panel to activate the filter
• Click "Stop" to deactivate

Target Selection:

• Click "Pick" to select a target window
• Move the cursor over the desired window and press Enter
• Click "Cancel pick" to exit picking mode

Filter Settings (Filter Tab):

• Scale: Adjust the overall scaling of the filter
• Scanline: Control scanline visibility and intensity
• CRT Mask: Add mask/slotmask patterns for authentic CRT look
• Arcade CRT: Special slotmask effect for arcade monitor appearance
• Chroma: Chromatic aberration/color separation effect
• Blur Horizontal/Vertical: Add horizontal/vertical blur
• Curve: Simulate CRT screen curvature
• Vignette: Darken screen edges for vintage look
• Jitter Speed/Strength: Add screen jitter/wobble effects
• Bloom: Light bloom/glow around bright areas
• Phosphor Decay: Simulate phosphor persistence
• Glow: Overall screen glow effect
• Line Glow Speed/Strength: Animated line glow effects

Crop Settings (Crop Tab):

• Adjust cropping on all four sides (Left, Top, Right, Bottom)
• Useful for removing borders or UI elements

Display Options:

• Lock: Lock current target window
• Stretch: Stretch filter to fill target area
• Fullscreen: Apply filter to full screen

⚙️ Technical Details

• Graphics Backend: OpenGL
• UI Framework: ImGui.NET and OpenTK
• Performance: Lightweight with minimal performance impact
• Window Capture: Uses Windows Desktop Duplication API
• Filter Rendering: Pixel shader-based real-time processing

📋 Important Requirement: Windowed Mode Only

⚠️ Critical Compatibility Note

Desktop CRT Filter only works with applications running in windowed mode or borderless windowed mode.

Why Windowed Mode?

The filter captures and processes individual application windows. Games running in exclusive fullscreen mode cannot be accessed by desktop capture APIs due to:

• DirectX/Vulkan Exclusive Control: Fullscreen applications take exclusive control of the display output
• Performance Optimization: Games bypass Windows Desktop Manager in fullscreen mode
• Security Restrictions: Some anti-cheat systems block external capture of fullscreen games

📊 Performance Tips

• Adjust Effects: Some effects (blur, glow) are more performance-intensive
• Target Smaller Windows: Filtering smaller windows uses fewer resources
• Use Lock: Lock target window to prevent re-targeting overhead

📝 Notes

• The control panel window is set to "Always on Top" and excluded from screen capture
• For best results, use with dark-themed applications or games

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.