OpenGL 2D Blackhole Simulator v2
Build a 2D gravitational lensing simulator with OpenGL. Visualize light ray bending around a black hole using the Schwarzschild metric and numerical integration. (Updated version with geometric units and improved code organization)
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What You'll Build
An interactive 2D visualization showing light ray trajectories bending around a black hole. Watch as rays with different impact parameters either escape to infinity or spiral into the event horizon, demonstrating gravitational lensing in real-time.
Learning Objectives
- Set up OpenGL development environment
- Implement 2D rendering with OpenGL
- Understand the Schwarzschild metric
- Implement Runge-Kutta 4th order numerical integration
- Visualize gravitational lensing in 2D
What's New in This Version
- Geometric units (c=G=1) for cleaner equations, better numerical stability, and lower memory usage
- Symplectic integration (Velocity Verlet) for improved energy conservation
- Adaptive timestep for better performance far from the black hole
- Improved Windows support, validation checks, better code consistency between steps
Project Steps
OpenGL Setup - Part 1: CMake Configuration
Configure CMake to find and link OpenGL, GLFW, GLEW, and GLM libraries.
OpenGL Setup - Part 2: Window Creation
Create a GLFW window and initialize OpenGL context for 2D rendering.
OpenGL Setup - Part 3: Render Loop
Create the main render loop to keep the window responsive and ready for drawing.
2D Rendering - Part 1: Coordinate Systems
Set up a 2D coordinate system using orthographic projection to map world coordinates to screen pixels.
2D Rendering - Part 2: Filled Shapes
Learn to draw filled circles using trigonometry and GL_TRIANGLE_FAN for efficient rendering.
2D Rendering - Part 3: Outlines and Styling
Draw circle outlines with GL_LINE_LOOP and style shapes using colors and line widths.
2D Rendering - Part 4: Aspect Ratio Correction
Fix circle distortion by adjusting orthographic projection to match the window's aspect ratio.
Schwarzschild Physics - Part 1: Metric Basics
Implement the Schwarzschild metric and understand conserved quantities for light rays in curved spacetime.
Schwarzschild Physics - Part 2: RK4 Integration
Implement Runge-Kutta 4th order integration to trace light ray paths through curved spacetime.
Visualization - Part 1: Ray Paths
Draw light ray paths showing gravitational lensing using OpenGL lines.
Visualization - Part 2: Visual Enhancements
Add professional visual touches: background stars, photon sphere visualization, event horizon circle, and color-coded light rays.
Optimization - Part 1: Geometric Units
Convert from SI units to geometric units (c=G=1) for cleaner equations and better numerical stability.
Optimization - Part 2: Symplectic Integration
Replace RK4 with Velocity Verlet for better energy conservation and simpler code.
Optimization - Part 3: Adaptive Timestep
Implement adaptive timestep to improve performance far from the black hole while maintaining accuracy nearby.
Visualization - Part 3: Multiple Ray Scenarios
Implement three distinct ray scenarios (parallel, point source, and orbiting) with ~100 total rays to create a comprehensive, visually stunning gravitational lensing demonstration.
Project Organization
Refactor the single-file simulator into a well-organized multi-file C++ project with proper separation of concerns
Local Setup Required
This advanced project requires external libraries and will compile code that you download and run locally.
Want to Know More?
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See the final version of this project on GitHub. Please report any issues there.
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