I Built a 3D Game in Flutter — With No Game Engine

Everyone says the same thing: Flutter is for apps, not games. So I decided to find out where that's actually true — by building a 3D endless runner in Flutter. From scratch. No Unity, no Unreal, no game engine at all. Just Dart and Flutter's own rendering stack. It runs in your browser right now: ▶️ Play it live (desktop, keyboard controls — A / D to switch lanes, Space to jump). Here's how it works, and what building it taught me about how far Flutter can actually go. The stack: Flutter GPU + flutter_scene The whole thing sits on two pieces most Flutter developers have never touched: Flutter GPU — a low-level rendering API that talks almost directly to the GPU through Impeller (the engine that replaced Skia). This is what makes real-time 3D possible at all. flutter_scene — a higher-level 3D scene API on top of Flutter GPU. It gives you the building blocks a game needs: a scene graph of nodes , a perspective camera , meshes, and glTF model loading. You build a tree of nodes, point a camera at it, and render it every frame inside a normal Flutter widget. That last part still surprises me — the 3D world is just a CustomPaint -style surface living inside an otherwise ordinary Flutter app. Faking an infinite world with a handful of objects An "endless" runner obviously can't build an endless world — you'd run out of memory in seconds. The trick is object pooling : you keep a small pool of track segments and obstacles, and as they scroll past the camera behind the player, you recycle them back to the front with new positions. The player never actually moves forward. The world moves toward the player , and a fixed number of segments cycle forever. Same idea for obstacles and coins. It means the game runs at a constant, tiny memory footprint — which is exactly what keeps it smooth on weaker devices. The parts that were genuinely hard Collision that feels fair. Detecting a collision is easy. Making it feel right is not. Too strict and the player rages at hits that "clearly