Raytracing Visualization

A real-time 2D ray casting visualization built with SDL2 that demonstrates light ray propagation and shadow casting.

Description

This application creates an interactive visualization where rays are cast from a light source (controllable circle) and interact with obstacles to create realistic shadow effects. The program uses mathematical ray-circle intersection algorithms to compute accurate light behavior.

Features

• Real-time Raytracing: 100 rays cast simultaneously from a light source
• Interactive Light Source: Mouse-controlled light positioning
• Shadow Casting: Realistic shadows created by circular obstacles
• Smooth Rendering: Uses Bresenham's line algorithm for efficient ray drawing
• Mathematical Precision: Accurate ray-geometry intersection calculations

Technologies

• SDL2: Graphics rendering and event handling
• C: Core implementation language
• Mathematical Libraries: math.h for trigonometric calculations

Architecture

The project is structured as a modular C application:

Core Components

• Ray Casting Engine: limits_to_ray.c/h - Handles ray-geometry intersections
• Line Drawing: line_drawing_alg.c/h - Implements Bresenham's algorithm
• Data Structures: structs.h - Defines Ray and Circle structures
• Main Loop: main.c - SDL2 event loop and rendering

Key Algorithms

• Ray-Circle Intersection: Quadratic equation solving for precise collision detection
• Ray-Screen Boundary: Parametric line intersection with screen edges
• Bresenham's Line Algorithm: Efficient pixel-perfect line rasterization

Build

Requirements

• SDL2: Graphics library
• GCC: C compiler with math library support
• Make: Build system (optional)

Compilation

gcc -o raytracing main.c limits_to_ray.c line_drawing_alg.c -lSDL2 -lm

Usage

1. Run the application:

   ./raytracing

2. Controls:

   • Mouse Movement: Move the light source (white circle)
   • Mouse Click + Drag: Continuous light source positioning
   • Close Window: Exit application

3. Visualization:

   • White circle: Light source (follows mouse)
   • White rays: Light beams cast from source
   • Large white circle: Obstacle casting shadows
   • Black areas: Shadow regions

Configuration

Key parameters in main.c:

#define RAYS_NUMBER 100    // Number of rays cast
#define WIDTH 1500         // Screen width
#define HEIGHT 600         // Screen height

Mathematical Foundation

The raytracing uses parametric ray equations:

• Ray: P(t) = Origin + t * Direction
• Circle intersection via discriminant: B² - 4AC
• Screen boundary intersection with parameter bounds checking