🎮 RTT-Engine

A simple C++ game engine

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📖 Overview

Welcome to RTTEngine a simple approach at a 3D Game Engine with a strong focus on Learning the complex field of computer graphics, applications of Mathematics and software engineering princples & optimization techniques.

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⚡ Performance

Metric	Value
Frame Time	8ms (125 FPS)
Draw Calls	~50
Triangles	~50K
Bone Upload	0.007ms
Motion Search	0.02ms

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🏗️ Architecture

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🎮 Features

Core Systems

Motion Matching

• SAH-optimized KD-Tree (12 bins)
• 10,980 pose database
• 0.02ms search time
• Continuous pose searching

Bone Matrix Buffer

• Auto UBO/SSBO selection

World Rendering

• Frustum culling
• Distance LOD
• Instanced rendering
• Occlusion culling
• Texture atlasing

Memory Management

• Memory arenas (O(1) allocation)
• Object pools (O(1) alloc/free)
• Asset manager with reference counting

Foot IK System

• Dynamic terrain height tracking
• Enhanced foot planting detection
• Real-time floor height updates

Rendering

• OpenGL 3.3+ pipeline
• GPU skinning with bone buffer
• Batch rendering with instancing
• Multiple light types
• Normal mapping and PBR materials
• Skybox with cube mapping
• Atmospheric fog

World Streaming

• Procedural terrain (Perlin noise)
• Chunk-based LOD (4 levels)
• 800m × 800m explorable areas
• Height-based biomes
• Water system with waves
• Vegetation placement

Animation

• Skeletal animation with GPU skinning
• Animation blending and layering
• Root motion extraction
• Foot IK
• State machines
• Mixamo compatibility
• FBX import via Assimp

Physics

• Collision detection (boxes, spheres, capsules)
• Rigid body dynamics
• Continuous collision detection
• Raycasting
• Constraints (hinge, slider, springs)
• Character controller

Character Controller

• Third-person movement with root motion
• WASD locomotion
• Jump, Sprint, Crouch
• Smooth rotation
• Camera modes: Fixed, Orbit, Follow
• Smooth zoom (8-30m)

Debug Tools

• GPU Profiler (OpenGL timestamp queries)
• Foot IK Debug (Press G)
• Motion Matching Debug (Press H)
• Performance Stats (Press F1)

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📁 Project Structure

3D GAME ENGINE/
├── world/                      # Terrain, chunks, vegetation
├── animationSystem/            # Animation, bone buffer, foot IK
├── motionMatching/             # Motion matcher, KD-Tree, database
├── boneSystem/                 # Skeleton, bone naming
├── physicsSystem/              # Physics, rigid bodies, constraints
├── modelSystem/                # Model loading, meshes
├── playerSystem/               # Character controller
├── cameraSystem/               # Camera management
├── shaderSystem/               # Shaders, skybox
├── renderer/                   # Renderer, texture atlas, GPU profiler
├── lighting/                   # Light management
├── memory/                     # Arenas, asset manager
├── components/                 # ECS components
├── tests/                      # Unit tests (235 total)
├── assets/                     # FBX models, animations, skybox
├── include/                    # GLAD, GLM, KHR
├── Makefile                    # Build configuration
├── test.cpp                    # Main entry point
└── bin/                        # Executables

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🎮 Controls

Key	Action
W / S	Move forward / backward
A / D	Strafe left / right
SPACE	Jump
LEFT SHIFT	Sprint
LEFT CTRL	Crouch
C	Toggle camera mode
Mouse	Orbit camera
Scroll	Zoom (8-30m)
Q / E	Camera pivot
R	Reset camera
F	Toggle wireframe
B	Bone debug
G	Foot IK status
H	Motion matching debug
F1	GPU stats
ESC	Exit

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🛠️ Dependencies

Library	Installation (Ubuntu)
GLFW	sudo apt install libglfw3-dev
GLM	sudo apt install libglm-dev
Assimp	sudo apt install libassimp-dev
OpenAL	sudo apt install libopenal-dev
zlib	sudo apt install zlib1g-dev
Google Test	sudo apt install libgtest-dev

GLAD is included in include/.

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⚙️ Building

# Debug build
make

# Release build
make release

# Run tests
make test

# Run engine
./bin/run

Build Status

✅ Compilation: SUCCESS
✅ Tests: 230/235 PASSING (98%)

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🧪 Testing

Total Tests: 235
Passed: 230 (98%)
Disabled: 5 (2%)
Failed: 0 (0%)

Test Suites

Suite	Tests	Status
Animation	17	✅
Animation FSM	20	✅
Camera	77	✅
Character Controller	24	✅
Integration	19	✅
Math	19	✅
Memory Management	25	✅ 22 passing
Motion Matching	14	✅ 12 passing
Physics	13	✅
Terrain	7	✅

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📊 Metrics

Metric	Value
World Size	800m × 800m
Active Chunks	45-70
Total Vertices	~50K (with LOD)
Max Trees/Chunk	80
Frame Time	8ms (125 FPS)
Motion Search	0.02ms
Bone Upload	0.007ms

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✅ Implementation Status

Complete

• Procedural terrain generation
• Chunk streaming & LOD
• Frustum & occlusion culling
• Animated water system
• Vegetation instanced rendering
• Skeletal animation
• Motion matching system
• Bone matrix buffer (UBO/SSBO)
• Foot IK with terrain tracking
• Physics collision detection
• Rigid body dynamics
• Character controller
• Camera system
• Texture atlasing
• GPU profiling
• Memory arenas & pools
• Asset manager
• Unit tests (235 tests)
• NaN prevention

In Progress

• Grass instanced rendering
• Rock model rendering
• Texture splatting
• Water collision
• Shadows
• Full audio integration

Planned

• Infinite terrain streaming
• Day/night cycle
• Weather system
• Advanced lighting
• Particle system
• UI system
• Scripting support

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🔧 Configuration

Edit in test.cpp:

// Terrain
terrainConfig.chunkSize = 100.0f;
terrainConfig.viewDistance = 8;
terrainConfig.lodDistance = 50.0f;
terrainConfig.heightScale = 80.0f;

// Vegetation
vegConfig.treeDensity = 0.02f;
vegConfig.maxTreesPerChunk = 80;

// Camera
cameraDistance = 15.0f;
cameraHeight = 5.0f;
cameraZoomMin = 8.0f;
cameraZoomMax = 30.0f;
cameraFollowSmooth = 60.0f;

// Motion Matching
mmConfig.maxSearchResults = 10;
mmConfig.searchRadius = 2.0f;
mmConfig.blendDuration = 0.1f;

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🐛 Known Issues

Minor

• Grass instanced rendering not fully integrated
• Some FBX animations need retargeting
• Rock models need proper LOD

Workarounds

• Press G to check foot IK status
• Press H to check motion matching state
• Press F1 to profile performance

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🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Write tests for new features
4. Submit a pull request
5. Open issues for bugs or features

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📄 License

MIT License — See LICENSE file for details.

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🙏 Acknowledgments

Resource	Purpose
Mixamo	Character animations
Assimp	Model loading
GLFW	Windowing
OpenGL	Graphics API
GLM	Mathematics
Google Test	Unit testing
Papers & textbooks	techniques & experimentation

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📞 Support

Common Issues

Low FPS
Press F1 to see GPU stats, identify bottleneck

Character floating
Press G to check foot IK, verify floor height

NaN errors
Check character/terrain initialization order

Black screen
Check shader compilation, verify asset paths

Debug Workflow

1. Press F1 - Check GPU stats
2. Press G - Check foot IK
3. Press H - Check motion matching
4. Check console for errors
5. Run tests: make test

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(RTT-DEV)

Version 2.0 | C++17 | OpenGL 3.3+ | Linux

Last Updated: February 2026