Skyrmion

A 2D Game Engine built in C++, very focused on tilemaps. Currently built on top of Raylib, with support for PC/Web/Android. (Can also be compiled with Sokol).

Many dependencies included as submodules, including: Dear ImGui, nlohmann json and libnoise.

Tilemaps

Load from txt files as ASCII art, each char representing a tile and it's properties, or randomly generate tiles and modify them during the game.

• Collision
• Transparency
• Animations
• Rotated and flipped textures
• Tiles with different properties sharing the same texture
• Invisible tiles
• Changing tiles during runtime
• Dynamic Lighting (emmision and shadow casting)
• Randomly rotating or choosing between multiple textures
• Perlin noise and related options provided by libnoise
• Choosing textures based on intersections between multiple tiles (Autotiling)
• Multiple layers rendering below and on top of other objects
• Using multiple layers to visually extend into other tiles
• Spawning objects at specific locations on startup
• Buffering to a render texture

Sources

• GridMaker.h
• TileMap.hpp
• LightMap.h

Nodes:

Everything visible in the game is a Node. Each node is attached to a specific layer in UpdateList, usually ordered and named by an enum, which decides render, collision, and update order.

• Vectors for Position, Origin, Size, and Scaling
• Textures are stored separatly and referenced with a global id
• Texture Rectangles allow for rendering sections of textures with transformations
• Support for animations, tilemaps, rotations
• Can replace texture with text rendering
• Can be hidden while still updating
• By default nodes are only rendered when on screen
• Layers can be paused while still being visible, or hidden without being paused
• Thread safe node deletion
• Nodes can be deleted on mass by layer
• Camera can be static or attached to any node
• Parent a node to any other node in a tree
• Uses centered position by default
• Set and get position relative to parent or globally
• Set position by screen coordinates
• Collision with tiles
• Collision with other nodes by layer
• Send signals to any nodes by layer
• Subscribe to input/window events by type (resizing, mouse, keyboard, etc)
• Thread safe deletion and render texture drawing

Updates are run at ~100 per second, with a time delta variable provided for consistency. Draw calls are done in a separate read-only thread.

Sources

• Node.h
• UpdateList.h

Backends

• Include core/backend/RaylibUpdateList.cpp to compile for Raylib
• Include core/backend/SokolUpdateList.cpp and SokolAudio.cpp to compile for Sokol
• Most functionality should be identical between them
• Originally built using SFML

DearImGui debug windows:

• FPS counters for draw thread and update thread, with both real times and theoretical unlimited times
• List of layers with names and flags
• Debug information and collision box for individual nodes
• Stream of latest events and inputs
• Modifyable perlin noise generator
• Color picker with list of loaded textures

Other tools:

• Json settings file with static/global reading and writing
• Json customizable controls supporting keyboard/mouse/gamepad buttons, joystick movement, and up to 3 binds for every action
• N dimensional directed edge-vertex graph
• Basic networking with a server to pass events between clients

Sources

• Settings.h
• Keylist.cpp
• VertexGraph.hpp
• nbnetServer.cpp

Example games:

• The engine was originally built with a group as the core systems of Temple-of-Pele, and later extracted into it's own project. As more game jam type projects were created with it I added more features
• Lighting was added with The Path Below : Source
• For GMTK 2022, Roll of the Dice, I created Rolling Labyrinth : Source
• For GMTK 2024 Built to Scale, I designed a side-scrolling physics engine (Soon to be moved into the engine proper) Climbing Blocks : Source