Gentle Lion Studios
Corundum Engine
A 2D game engine built from the ground up for classic RPGs.
C++23
Metal
GLFW
Dear ImGui
Apple Silicon
Gentle Lion Studios
A 2D game engine built from the ground up for classic RPGs.
The Project
Corundum Engine is a custom 2D game engine written in C++23, designed specifically for building classic role-playing games. It uses Metal for hardware-accelerated rendering and GLFW for windowing, with an initial focus on macOS and Apple Silicon. Every part of the engine — from the rendering pipeline to the RPG systems — is a work in progress.
The goal is a complete environment for developing story-driven 2D RPGs — engine, tools, and game, all built in-house.
What's Inside
Pack individual sprite images into one or more texture atlas PNGs, ready for use in the engine. Available as the open source Spritepacker CLI tool.
View on GitHub →Hardware-accelerated 2D sprite and tilemap rendering via Apple's Metal API, optimized for native Apple Silicon performance.
In DevelopmentNative integration with Azgaar's Fantasy World Generator. Import a world and automatically generate tilemaps — from continent down to regional detail.
In DevelopmentAn ImGui-based editor for creating and managing sprite sheets directly within the engine's toolset.
In DevelopmentVisual tilemap editor for constructing game worlds tile by tile, integrated tightly with the engine's rendering pipeline.
In DevelopmentRules systems, quest design, dialogue, combat, and character progression mechanics purpose-built for classic role-playing games.
In DevelopmentWhat's Next
Open source texture atlas CLI tool, available now on GitHub.
Metal-backed 2D renderer on macOS and Apple Silicon via GLFW.
ImGui-based sprite sheet editor, tilemap builder, texture atlas generator, and Azgaar's world importer.
Character stats, combat mechanics, dialogue trees, and quest tracking purpose-built for classic RPGs.
Expanding beyond macOS to additional platforms after the initial release.
A 2D CRPG built entirely on Corundum Engine.