chatimgui — SA-MP ImGui Chat Replacement

A lightweight .asi plugin that replaces the default SA-MP chat box with a modern Dear ImGui overlay. Supports Thai (TIS-620) text with proper color rendering.

Features

• Modern chat UI — ImGui-based, transparent background, text outline for readability
• Thai text support — TIS-620 to UTF-8 conversion
• Color tags — {RRGGBB} inline color support from SA-MP
• Custom input box — T to open, Escape to close, sends commands via CInput::Send() and chat via CLocalPlayer::Chat()
• Fade animations — Configurable fade-in/out with hold duration
• Mouse wheel scroll — Scroll through chat history

Requirements

• Windows (x86/32-bit SA-MP client)
• CMake 3.20+
• Visual Studio 2022 (or any generator supporting C++20)
• DirectX 9 SDK (included in Windows SDK)

Project Structure

chatimgui/
├── source/
│   ├── dllmain.cpp    — DX9 Present/Reset hooks, MinHook setup, WndProc hook
│   ├── gui.cpp        — ImGui chat rendering, input box, fade system
│   ├── gui.h          — Chat manager class, color helpers, fade state machine
├── libs/
│   ├── imgui/         — Dear ImGui (submodule)
│   ├── minhook/       — MinHook (submodule)
│   ├── samp-api/      — SA-MP reverse-engineered API (submodule)
│   └── tis620.h       — Thai TIS-620 <-> UTF-8 conversion
├── CMakeLists.txt
└── README.md

Build

# Clone with submodules
git clone --recursive https://github.com/exsycore/chatimgui.git
cd chatimgui

# Configure (Visual Studio 2022, Win32)
cmake -B build -G "Visual Studio 17 2022" -A Win32

# Build Release
cmake --build build --config Release

The output is bin/Release/ImguiPlugin.asi.

Installation

1. Copy ImguiPlugin.asi to your GTA:SA / SA-MP directory (next to samp.exe)
2. Launch SA-MP — the default chat will be replaced automatically

How It Works

The plugin hooks three things:

1. IDirect3DDevice9::Present — Initializes ImGui and renders the chat overlay every frame
2. IDirect3DDevice9::Reset — Handles device lost/reset for ImGui
3. WndProc — Intercepts keyboard input (T to open chat, Escape to close, Up/Down for history)

It reads chat entries directly from SA-MP's CChat memory via the samp-api reverse-engineered structs, converts TIS-620 text to UTF-8, and renders them with ImGui.

Configuration

All settings are in source/gui.h:

Setting	Default	Description
fontSize	21	Chat font size
widthPct	55	Chat width as % of screen
heightPct	28	Chat height as % of screen
fade.holdSeconds	2.0	Seconds to show before fading
fade.fadeInSpeed	6.0	Fade-in speed (alpha/sec)
fade.fadeOutSpeed	2.0	Fade-out speed (alpha/sec)

Dependencies

Library	Purpose	Link
Dear ImGui	Immediate-mode GUI	Compiled in
MinHook	x86 function hooking	Static lib
samp-api	SA-MP memory structures	Static lib

License

MIT License. See LICENSE for details.