Rendering Engine

A cross-platform 3D/2D rendering engine written in Rust using OpenGL / OpenGL ES through glow.

The goal of this project is to build a lightweight, modular, and flexible rendering library crate (rendering_engine) that runs seamlessly across desktop and mobile while utilizing modern rendering techniques (Multi-Draw Indirect, persistent mapped buffers, multi-threaded rendering, texture management, FBOs, compute shaders, and skybox passes).

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🌟 Features

• Modular Architecture (core, resources, render)

  • Clean separation between low-level memory/buffers, graphics resources, and rendering pipelines.

• Multi-Draw Indirect (MDI) & GPU Batching

  • Groups draw calls together to reduce CPU overhead.
  • Uses GPU-side instance data handling to avoid unnecessary CPU-to-GPU synchronization.

• Textures, Atlases & Texture Arrays

  • 2D textures, 2D texture arrays (GL_TEXTURE_2D_ARRAY), and UV atlas helpers (TextureAtlas).

• Offscreen Framebuffers & Render Targets

  • FBO abstractions (Framebuffer) with color attachments, depth textures, and depth renderbuffers.

• Compute Shader Pipelines

  • ComputeShader support for OpenGL ES 3.1+ / OpenGL 4.3+.

• Fullscreen Skybox Pass

  • Pre-pass skybox pipeline with LEQUAL depth testing and inverse view-projection uniform upload.

• Persistent Mapped Buffers

  • Uses persistent mapped SSBOs with multiple fenced regions (TRANSFORM_REGIONS) to safely update GPU data while avoiding CPU/GPU conflicts.

• Dedicated Render Thread & Lock-Free Triple Buffering

  • Game logic and rendering are separated into different threads via a lock-free TripleBuffer.

• Desktop and Android Support

  • Desktop support through winit / glutin.
  • Android support through android-native-activity and OpenGL ES.

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📁 Repository Structure

rendering-engine/
├── engine/                 # Core rendering engine crate (`rendering_engine`)
│   └── src/
│       ├── lib.rs
│       ├── core/           # Memory allocators, persistent buffers, math & triple buffer
│       ├── resources/      # Meshes, geometry pool, shaders, textures, materials, compute
│       └── render/         # Renderer facade, passes, MDI, framebuffers, skybox, scene graph
│
├── demo/                   # Example voxel 3D application
│   └── src/
│
├── docs/                   # Library documentation & guides
│   └── USAGE.md            # Simple, comprehensive library usage guide
│
└── shaders_gles/           # OpenGL / OpenGL ES shader sources

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📖 Documentation & Library Usage

For code examples on using rendering_engine as a library crate in your own projects, see Library Usage Guide.

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🚀 Getting Started

Building & Running Desktop Demo

To launch the desktop demo application:

cargo run --bin desktop

Controls (Demo)

• W / A / S / D: Move camera forward / left / backward / right.
• Mouse / Drag: Look around (yaw & pitch).
• Space / Left Ctrl: Fly up / down.

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📜 License

This project is open-source and available under the BSD-3-Clause License.