Color Perception Laboratory (Neon & Anti-Neon Demo)

Inspired by the Vsauce short on neon/brown color perception. Vsauce Neon/Brown

An interactive Color Perception Laboratory featuring real-time neon color simulation, classic color illusions with scientific explanations, and validation tools to prove that perception is relative. This implementation uses a highly optimized NumPy-based rendering engine for smooth interaction.

Feel free to use, modify, and distribute this code as you see fit. I will not be held responsible for any issues that may arise from using this code.

Core Features

Original Neon Demo

• Interactive UI using Dear PyGui
• Real-time sliders: Hue, Saturation, Brightness, Fluorescence
• Neon and Anti-Neon modes with pulsing/flicker shader effects
• Dual-color neon shader (core + halo) with adjustable parameters
• 13 Presets: Classic Neon, Synthwave Sunset, Matrix Green, Neon Brown, and more
• GPU acceleration via ModernGL (auto-fallback to high-performance CPU path)
• Demo mode with auto-cycling colors
• Keyboard shortcuts for quick control

High-Performance Rendering

• Vectorized Logic: All illusion modules are implemented using vectorized NumPy operations, eliminating Python loops and achieving up to 100x speedup.
• Dynamic Textures: Direct 1D array updates to Dear PyGui textures for low-latency visual feedback.
• Robust Fallback: Seamless transition between GPU (OpenGL) and CPU rendering paths.

Color Perception Modules

Module	Description
Neon Brown	Demonstrates how same RGB appears orange OR brown based on surround luminance.
Simultaneous Contrast	Identical gray patches appear different on high-contrast backgrounds.
Checker Shadow	Adelson's famous illusion - squares A and B are identical! Updated with realistic cylinder shadow.
Cornsweet Edge	15% contrast edge gradient makes identical regions look significantly different.
Neon Spreading	Ehrenstein radial lines with colored inducers create an illusory "neon" glow.
Chimerical Colors	Afterimage-induced "impossible" colors (Stygian Blue, Self-Luminous Red, etc.).
Lilac Chaser	Rotating gap in 12 magenta discs creates a green afterimage "pac-man".
Benham's Disk	Optimized 5Hz B/W rotation produces subjective (Fechner) colors.

Scientific & Validation Tools

• Pixel Proof Mode: Overlay squares to visually verify that illusory regions have identical RGB values.
• sRGB/Linear Color Management: Physically correct blending and inverse gamma operations.
• Eyedropper Tool: Real-time sampling of any pixel for HEX, sRGB, and linear values.
• Scientific Explanations: Detailed descriptions of the physiological mechanisms behind each effect.

Requirements

• Python 3.10+ (tested on 3.13)
• Required libraries: dearpygui, numpy, moderngl, pillow (see requirements.txt)

Installation

1. Create and activate a virtual environment (recommended):

python3 -m venv .venv
source .venv/bin/activate  # On Windows: .venv\Scripts\activate

2. Install dependencies:

python -m pip install -r requirements.txt

Usage

Run the main application:

python main.py

Keyboard Shortcuts

Key	Action
Space	Toggle Neon / Anti-Neon mode
R	Reset to defaults
Left / Right	Adjust hue (plus/minus 15 degrees)
Up / Down	Adjust brightness (plus/minus 10%)
D	Toggle Demo mode
1-9	Apply preset by number

Verification Tests

The project includes a comprehensive test suite for color correctness and performance:

python test_basic.py           # Core logic tests (9 passed)
python test_color_management.py # Scientific management tests (7 passed)

Project Structure

• main.py: Application entry point and UI orchestration.
• color_engine.py: State management, presets, and animation logic.
• color_management.py: Scientific color space conversions and appearance models.
• validation_tools.py: Pixel sampling and proof overlay logic.
• modules/: Individual illusion implementations (vectorized).
• shaders/: GLSL fragment shaders for advanced neon effects.

Safety Notices

[!] Some modules include safety warnings:

• Chimerical Colors: Extended viewing of saturated colors can cause visual fatigue.
• Benham's Disk / Motion Illusions: Rotating patterns may affect photosensitive viewers. Do not use if prone to seizures or severe motion sensitivity.

Scientific References

• Brown perception: Context-dependent color naming (PubMed)
• Simultaneous contrast: Pressbooks - Sensation and Perception
• Chimerical colors: PhilPapers - Chimerical Colors
• Neon spreading: Boston University - Filling-in Models
• Cornsweet Effect: Wolfram Research - Cornsweet Illusion

License

MIT License

Copyright (c) 2025 Jonathan Ray Reed