A comprehensive collection of classic and advanced computer graphics algorithms implemented in C++ with OpenGL/GLUT. Perfect for learning graphics fundamentals, algorithm implementation, and 3D rendering concepts.
Understanding computer graphics is challenging without practical implementations. Students and developers often struggle with:
- ❌ Difficulty understanding graphics algorithms conceptually
- ❌ Lack of practical, production-quality code examples
- ❌ Missing step-by-step explanations of how algorithms work
- ❌ No reference implementations for learning projects
- ❌ Scattered resources across multiple platforms
This repository solves these problems by providing:
- ✅ 30+ complete, working implementations of classic graphics algorithms
- ✅ Well-documented C++ code with detailed comments
- ✅ Live, executable examples using OpenGL/GLUT
- ✅ Educational focus with algorithm explanations
- ✅ Organized practical exercises for structured learning
- 📍 DDA (Digital Differential Analyzer) - Simple line rendering
- 📍 Bresenham's Line Algorithm - Optimized integer-based line drawing
- 📍 Arithmetic Symbols & Operators - Composite figure drawing
- 🔵 Bresenham's Circle Algorithm - Efficient circle rendering
- 🔵 Parametric curves - Smooth curve generation
- 🏠 House Design - Complex 2D shape construction
- 🏠 Scan-Line Filling - Polygon fill algorithms
- 🏠 Letter Rendering - Character-based graphics
- 🎲 3D Cube Rendering - 3D geometry visualization
- 🎲 Rotation Transformations - X, Y, Z axis rotations
- 🎲 Transformation Matrices - 3D affine transformations
- 🎲 Depth Buffering - Proper 3D rendering pipeline
- ✂️ Cohen-Sutherland Line Clipping - Viewport clipping algorithms
- ✂️ Window-to-viewport transformation
Computer-Graphics/
│
├── PE/ # Practical Exercises Directory
│ ├── 30by30/ # 30 Fundamental Practicals
│ │ ├── DDA_ArithmeticOperators.cpp # DDA: Drawing operators using line algorithm
│ │ ├── DDA_Home.cpp # DDA: Complete house design
│ │ ├── practical_2.1_circle.cpp # Bresenham circle algorithm
│ │ ├── practical_2.2_line.cpp # Bresenham line algorithm
│ │ ├── practical_5_LineClipping.cpp # Cohen-Sutherland clipping
│ │ └── README.md # Practical set documentation
│ │
│ ├── CG_Practical/ # Advanced Computer Graphics Practicals
│ │ ├── DDA_Algo/ # DDA Algorithm Implementations
│ │ │ └── Arithmetic.cpp # DDA: Arithmetic operators
│ │ └── [Other algorithm folders]
│ │
│ └── CG_IMP/ # Graphics Implementation Reference
│ ├── CubeRY.txt # 3D Cube: Interactive rotation
│ ├── BresenLineY.txt # Bresenham line implementation
│ ├── 3d_Transformation_cube.txt # 3D transformation pipeline
│ └── ScanLine_W.txt # Scan-line fill: Letter W
│
├── README.md # This file (Project overview)
├── CONTRIBUTING.md # Contribution guidelines
├── LICENSE # MIT License
├── CODE_OF_CONDUCT.md # Community guidelines
└── .gitignore # Git ignore patterns
graph LR
A["Algorithm Selection<br/>DDA / Bresenham"] --> B["Input Coordinates<br/>x1,y1 → x2,y2"]
B --> C["Calculate Parameters<br/>dx, dy, steps"]
C --> D["Iterate & Calculate<br/>pixel positions"]
D --> E["Plot Pixels<br/>glVertex / glBegin"]
E --> F["Render to Buffer<br/>glFlush / swap"]
F --> G["Display Output<br/>OpenGL Window"]
graph LR
A["3D Model Data<br/>vertices"] --> B["Transformation<br/>Rotate/Scale/Translate"]
B --> C["View Matrix<br/>Camera positioning"]
C --> D["Projection<br/>Orthographic/Perspective"]
D --> E["Viewport Transform<br/>Screen coordinates"]
E --> F["Rasterization<br/>Depth testing"]
F --> G["Fragment Shading<br/>Colors & textures"]
G --> H["Display<br/>Final image"]
| Category | Technology | Purpose |
|---|---|---|
| Language | C++ (C++11/14) | Modern, efficient graphics implementation |
| Graphics API | OpenGL 2.x/3.x | Cross-platform rendering standard |
| Window Management | GLUT/FreeGLUT | Windowing and input handling |
| Math Operations | Standard Library | Vector/matrix calculations |
| Compilation | GCC/Clang/MSVC | Cross-platform support |
| Build System | Makefile / CMake (Optional) | Build automation |
Why These Technologies?
- C++: Industry-standard for graphics; excellent performance
- OpenGL: Universal graphics API; used in professional graphics
- GLUT: Lightweight; perfect for educational implementations
- Cross-platform: Code runs on Windows, Linux, macOS
# Using MinGW package manager
pacman -S mingw-w64-x86_64-freeglut mingw-w64-x86_64-gcc
# Or download GLUT from: https://www.opengl.org/resources/libraries/glut/sudo apt-get update
sudo apt-get install freeglut3-dev g++ build-essential# Using Homebrew
brew install freeglut glfw
# Or use system OpenGL framework# Compile a single file
g++ -o output_program DDA_Home.cpp -lGL -lGLU -lglut
# Run the program
./output_program# Create a Makefile in the project root
make build # Compile all programs
make run # Run a specific program
make clean # Remove compiled binariesmkdir build
cd build
cmake ..
make
./graphics_programCreate .env file (optional for configuration):
# Graphics Configuration
DISPLAY_WIDTH=500
DISPLAY_HEIGHT=500
WINDOW_TITLE="Computer Graphics"
BACKGROUND_COLOR_R=0.0
BACKGROUND_COLOR_G=0.0
BACKGROUND_COLOR_B=0.0// File: DDA_Home.cpp// Displays a house using DDA line drawing algorithm// Compile:
g++ -o house_demo DDA_Home.cpp -lGL -lGLU -lglut
// Run:
./house_demo
// Expected Output:// → OpenGL window with animated rotating house// File: practical_2.1_circle.cpp// Interactive circle drawing with Bresenham algorithm// Compile & Run:
g++ -o circle_demo practical_2.1_circle.cpp -lGL -lGLU -lglut
./circle_demo
// Input: Enter center coordinates and radius// Enter the center coordinates (xc yc) and radius (r): 250 250 100// File: CubeRY.txt// Interactive 3D cube with real-time rotation// Left Click → Rotate around X-axis// Middle Click → Rotate around Y-axis// Right Click → Rotate around Z-axis// File: practical_5_LineClipping.cpp// Cohen-Sutherland clipping algorithm visualization// Input:// p1: -50 -50 (start point)// p2: 50 50 (end point)// Clipping window: -100 to 100 (both axes)- Time Complexity: O(|max(dx, dy)|)
- Space Complexity: O(1)
- Precision: Floating-point calculations
- Use Case: General line drawing
Algorithm Steps:
- Calculate dx = x2 - x1, dy = y2 - y1
- Determine steps = max(|dx|, |dy|)
- Calculate x_increment = dx/steps, y_increment = dy/steps
- Iterate and plot pixels at calculated positions
- Time Complexity: O(|max(dx, dy)|)
- Space Complexity: O(1)
- Precision: Integer-only arithmetic (faster)
- Use Case: Optimized line rendering
Key Advantage: Uses only integer arithmetic, avoiding floating-point errors and improving performance.
- Time Complexity: O(radius)
- Space Complexity: O(1)
- Method: Midpoint circle algorithm
- Symmetry: Draws 8 octants simultaneously
- Time Complexity: O(number of lines)
- Space Complexity: O(1)
- Precision: Handles clipping window boundaries
- Use Case: Viewport clipping operations
// Step 1: Initialize OpenGL windowglClearColor(1.0, 1.0, 1.0, 1.0); // White backgroundglMatrixMode(GL_PROJECTION);
gluOrtho2D(0, 400, 0, 400);
// Step 2: Define line drawing functionvoiddrawline(int x1, int y1, int x2, int y2) {
// DDA algorithm implementation
}
// Step 3: Draw house componentsdrawline(100, 100, 200, 100); // Bottom sidedrawline(200, 100, 200, 200); // Right side// ... more lines// Mouse Click Handlers:
- Left Click → ax = 0; (X-axis rotation)
- Middle Click → ax = 1; (Y-axis rotation)
- Right Click → ax = 2; (Z-axis rotation)
// Rotation Update:glRotatef(angle[axis], axis_vector); // Apply rotationglutPostRedisplay(); // Refresh displayPE/
├── 30by30/ [30 Fundamental Practicals]
│ ├── DDA_ArithmeticOperators.cpp
│ ├── DDA_Home.cpp
│ ├── practical_2.1_circle.cpp
│ ├── practical_2.2_line.cpp
│ ├── practical_5_LineClipping.cpp
│ └── README.md
│
├── CG_Practical/ [Advanced Implementations]
│ ├── DDA_Algo/
│ │ └── Arithmetic.cpp
│ └── [Additional algorithm folders]
│
└── CG_IMP/ [Reference Implementations]
├── CubeRY.txt
├── BresenLineY.txt
├── 3d_Transformation_cube.txt
└── ScanLine_W.txt
- Run DDA line drawing example
- Run Bresenham circle algorithm
- Understand algorithm pseudocode
- Modify parameters and observe changes
- Study 3D transformation matrices
- Implement basic 3D cube rendering
- Learn viewport clipping algorithms
- Implement Cohen-Sutherland clipping
- Optimize algorithms for performance
- Implement scan-line polygon fill
- Study rasterization techniques
- Contribute improvements to codebase
- Implement modern graphics pipeline
- Add shaders (GLSL) to projects
- Optimize for large datasets
- Create tutorial documentation
| Algorithm | Time | Space | Precision | Speed |
|---|---|---|---|---|
| DDA Line | O(n) | O(1) | Float | Moderate |
| Bresenham Line | O(n) | O(1) | Integer | Fast ⚡ |
| Bresenham Circle | O(r) | O(1) | Integer | Fast ⚡ |
| Scan-line Fill | O(area) | O(height) | Integer | Moderate |
- Use Bresenham over DDA for production code
- Precompute transformation matrices
- Use double-buffering to prevent flicker
- Implement view frustum culling
- Cache vertex calculations
- Implement Gouraud and Phong shading
- Add texture mapping support
- Develop shadow rendering algorithms
- Create particle system effects
- Migrate to modern OpenGL (3.3+)
- Implement GLSL shader programs
- Add VAO/VBO buffer management
- Develop advanced lighting models
- Add CMake build system
- Create interactive tutorial GUI
- Implement benchmarking tools
- Add algorithm visualization tools
- Implement ray tracing
- Add volume rendering
- Develop 3D model loading (OBJ, FBX)
- Create game engine foundation
voiddrawline(int x1, int y1, int x2, int y2)
// Draws a line from (x1,y1) to (x2,y2) using DDA algorithm// Parameters: Starting and ending coordinatesvoiddrawCircle(int xc, int yc, int r)
// Draws a circle with center (xc,yc) and radius r// Uses 8-way symmetry for efficiencyvoidsetPixel(int x, int y)
// Sets a pixel at screen coordinates (x,y)// Uses OpenGL point renderingvoiddisplay()
// Main display callback// Clears buffer, applies transformations, renders geometryWe welcome contributions! Please see CONTRIBUTING.md for detailed guidelines.
- Fork the repository
- Create a feature branch (
git checkout -b feature/algorithm-name) - Implement your changes with clear comments
- Add documentation and test cases
- Submit a pull request
- 🐛 Bug fixes and optimizations
- 📚 Improved documentation and tutorials
- 🎨 Visual improvements and diagrams
- 🚀 New algorithm implementations
- 🧪 Test cases and benchmarks
This project is licensed under the MIT License - see LICENSE for details.
You are free to:
- ✅ Use this code for personal and commercial projects
- ✅ Modify and distribute the code
- ✅ Include in proprietary applications
You must:
- ✅ Include the original license and copyright notice
Developed by: Tushar Kaldate
Inspired by:
- Computer Graphics textbooks and research papers
- OpenGL and graphics programming communities
- Educational resources from universities worldwide
Contributing Community: Thanks to all contributors and users who help improve this project!
- OpenGL Tutorial - Modern OpenGL learning
- Computer Graphics: Principles and Practice - Textbook reference
- Bresenham's Algorithm - Wikipedia
- OpenGL Documentation - Official reference
- FreeGLUT - Cross-platform GLUT implementation
- GLFW - Modern window and input library
- GLM - Mathematics library for graphics
Have questions? Need help?
- 📝 Open an Issue: Create a GitHub Issue
- 💬 Start a Discussion: GitHub Discussions
- 📧 Email: Contact via GitHub profile
If you found this project helpful:
- ⭐ Star the repository - helps with discoverability
- 🔗 Share with others - spread the knowledge
- 📝 Write a review - help future learners
- 🤝 Contribute - improve the codebase
- Language: C++ (100%)
- Total Implementations: 30+
- Algorithm Coverage: Line, Circle, Clipping, Transformation, Fill
- Documentation: Comprehensive
Last Updated: January 2026 | Latest Commit: 24599cb
Made with ❤️ for computer graphics enthusiasts and students worldwide