TerminalGL: The High-Performance GPU Terminal

"Why render text when you can accelerate it?"

TerminalGL is a custom-built, hardware-accelerated terminal emulator written in C++ and OpenGL. It ditches legacy software rendering for raw GPU power, delivering silky smooth 120+ FPS, vibrant visuals, and a retro-futuristic aesthetic.

Powered by a custom Batch Rendering Engine and Dynamic Texture Atlasing, it handles thousands of characters with negligible CPU usage. It's not just a terminal; it's a graphical experience.

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Features

GPU-Accelerated Core

• Batch Rendering: Draws the entire screen in < 5 draw calls.
• Texture Atlas: Dynamic font packing on a 1024x1024 GPU texture.
• Zero Latency: Input processing happens at the speed of light (or roughly 16ms).

Visuals & Aesthetics

• Animated GIF Backgrounds: Support for dynamic, looping backgrounds (via stb_image).
• Retro-Modern Look: Gold text on Cyan cursors.
• Uncapped FPS: Push your GPU to the limit (Toggle VSync with F3).

Power User Tools

• Shell Integration: Seamless Zsh/Bash PTY spawning.
• Smart Zooming: Cmd + / Cmd - to scale text instantly.
• Clipboard Sync: Cmd+C / Cmd+V native system integration.
• Unicode Support: UTF-8 decoding for multilingual capability.

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⌨️ Controls

Shortcut	Action
Cmd + / Cmd -	Zoom In / Out
Cmd + V	Paste from Clipboard
Cmd + C	Copy Selection
Shift + PgUp/Dn	Scroll History
F3	Toggle VSync / FPS Cap
Mouse Drag	Select Text

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Building from Source

Dependencies

• CMake
• GLFW
• FreeType

MacOS (Homebrew)

brew install cmake glfw freetype

Build & Run

mkdir build
cd build
cmake ..
make
./terminal

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Technical Deep Dive

The Rendering Pipeline

Most terminals render text as individual bitmaps. TerminalGL approaches text like a game engine:

1. Glyph Loading: FreeType loads vector fonts.
2. Atlas Packing: Glyphs are packed into a single generic GL_RED texture on demand.
3. Vertex Buffering: Quads are generated for every character and stored in a dynamic VBO.
4. Batch Draw: glDrawArrays renders 10,000+ characters in a single GPU command.

Architecture

• Terminal.cpp: State machine handling ANSI escape codes and buffer management.
• Renderer.cpp: OpenGL abstraction layer for batching and shader control.
• PTYHandler.cpp: Low-level POSIX pseudo-terminal communication.

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Future Roadmap

• Shader Effects (Bloom, CRT Scanlines)
• Ligature Support
• Configuration File (json/toml)

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• standard C++17 and OpenGL 3.3.*