3D Graphics Engine (Built from Scratch in C++)

About the Project

This is a 3D graphics engine built entirely from scratch in C++ without using external graphics libraries (like OpenGL or DirectX).
The goal of this project is to learn 3D computer graphics through practical application by implementing everything from rendering pipelines to lighting models manually.

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Features

✅ Wireframe Rendering → Real-time rendering of wireframe models with smooth performance.
✅ Flat Shading → Per-triangle lighting calculations with efficient shading.
✅ Gouraud Shading → Per-vertex lighting with color interpolation across triangles for smoother shading.
✅ Phong Shading → Per-vertex lighting with color interpolation across triangles for smoother shading + Specular Refletion.
✅ Multiple Light Source → Multiple Light Source Support, each light can be anywhere, any colored, any intensity.
✅ Deapth Buffer/ Z-Buffer → Accurate hidden surface removal using depth comparisons, ensuring correct visibility of objects.
✅ OBJ File Support → Load and render external .obj 3D models.
✅ Frustum Culling → Optimized rendering by culling triangles outside the camera’s frustum.
✅ Gamma Correction & Color Saturation → Improved color accuracy and visual quality.
✅ Efficient CPU Rendering → Entire rendering pipeline runs on the CPU, with smart optimizations for better performance.

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Performance Highlights

• Efficient Rendering: Renders .obj models with thousands of triangles at 100+ FPS even on a low-spec machine.
• Optimized Culling & Lighting: FPS boost achieved through culling and optimized shading.
• Scalable Performance: On higher-end CPUs, it will perform significantly faster due to better processing capabilities.

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Screenshots

Wireframe Model

Flat Shaded Model

Gouraud Shaded Model

Phong Shaded Model

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How It Works

1. Vertex Transformation:
   • Transforms model vertices using translation, rotation, and scaling matrices.
2. Backface Culling:
   • Removes triangles facing away from the camera to reduce unnecessary rendering.
3. Lighting & Shading:
   • Implements Additive and Multiplicative lighting models with adjustable light intensity and position.
4. Frustum Culling:
   • Eliminates triangles outside the screen frustum to boost performance.
5. Color Correction:
   • Applies gamma correction, exposure, and saturation for better visuals.

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Installation

1. Clone the repository:

   git clone https://github.com/Anubhav-Mondal/Graphics-Engine.git
   cd 3d-graphics-engine 

   clone the project then go to the project folder.

2. Make /build folder:

      mkdir build
      cd build

3. Build the Project:

      cmake ..
      cmake --build . --config Release

4. Run the Project:

   ./Release/engine.exe

   The executable will be in /build/Release.

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Explaination of Commands

• cmake .. → Generates the build configuration files using the parent directory's CMakeLists.txt.
• cmake --build . --config Release → Compiles the project in Release mode with full optimizations.
• ./Release/engine.exe → Runs the compiled executable.

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Requirements

• CMake 3.10 or higher
• Visual Studio 2022 with the Desktop development with C++ workload (provides MSVC compiler)

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Custom Model

1. Place Your Model:

• Add your custom 3D model (.obj file) to the models/ folder.

2. Include the Model in Your Code:

• Open main.cpp and add the following line anywhere before the main() function:

  Model modelDetail("../models/YourModelName.obj", baseColor, offset);

• Replace the parameters with your desired values:

  • YourModelName.obj: The name of your model file.

  • baseColor: The base color of the model, using Color(r, g, b) format.

  • Example:

    Color(255, 255, 255)  // White  
    Color(255, 0, 0)      // Red

  • offset: The distance from the camera. You’ll need to tweak this value to avoid performance issues.

    • Guidelines for offset:

      • If all vertices are within the range [-1, 1], use an offset of around 50.0f.

      • If the range is larger, increase the offset (e.g., 1000.0f, 2000.0f, etc.) for proper rendering.

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Controls

Current Controls:

• 0 → Wireframe (WF)
• 1 → Flat Shading (FS)
• 2 → Gouraud Shading (GS)
• 3 → Phong Shading (Specular + Gouraud)

← (Left Arrow): Switch to the previous rendering mode (cyclic).

Example: GS → FS → WF → Phong ...

→ (Right Arrow): Switch to the next rendering mode (cyclic).

Example: WF → FS → GS → Phong → WF ...

↑ (Up Arrow): Decrease the model offset (model moves closer to the camera).

↓ (Down Arrow): Increase the model offset (model moves further from the camera).

Left Click + Drag Horizontally : Rotate model around Y-axis.

Left Click + Drag Vertically : Rotate model around X-axis.

Left Click + Drag Diagonally : Adds slight Z-axis rotation.

R: Reset all rotations to default position.

esc: Exit the application.

⚠️ More controls coming soon!

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Author

• Name: Anubhav Mondal
• Github: https://github.com/Anubhav-Mondal