Software rendering - no GPU, no packages

A real-time 3D engine that draws every pixel on the CPU.

FableEngine rasterizes a live game loop from scratch: a per-frame sun shadow map, a geometrically exact planar mirror, impulse rigid-body physics, and a Verlet rope - four cameras of one simulation, rendered at once. Every clip below is a screen capture of the running loop, with the measured frame rate burned into the HUD.

130fps steady, 4 views

120 Hzfixed physics

1,238triangles / frame

512²sun depth map

Pure C# on the .NET base library only. Target was 20 fps; it holds ~6.5x that on a 32-core desktop.

Live captures

Five systems, one loop

Four camera viewports of one scene rendered at once: first-person, third-person chase, top-down, and cinematic, with a live FPS HUD.

// 4-viewport composite

Four cameras, one simulation

First-person, chase, top-down, and cinematic rendered concurrently - one rasterizer and framebuffer per view, zero shared pixels.

Top-down view of the hall: columns cast long directional shadows across a checkerboard floor as the sun angle bites.

// sun shadow map

Shadows are missing light

A 512-square orthographic sun depth map; every shaded pixel tests its own world position with 2x2 PCF and slope bias. Never painted on.

Third-person chase: the hero stands before a wall mirror that reflects the checkerboard, columns, and his own body.

// planar mirror

A real reflection, by image method

The camera is reflected about the mirror plane and the world re-rendered through it - winding flipped, geometry behind the plane clipped. Exact for a flat mirror.

Cinematic wide angle: physics toys settle on the floor near a candle-lit table while a Verlet rope hangs between two posts.

// rigid bodies + Verlet rope

Impulse physics in SI units

Gravity 9.80665, mass from density x volume, restitution and Coulomb friction. Rubber out-bounces wood; gold hits hard. The rope is Verlet points with distance constraints.

// candle point light

A light that genuinely flickers

Warm directional sun plus cool sky ambient plus a candle whose intensity flickers on deterministic hash noise, with inverse-square falloff and Blinn-Phong specular.

The player's single full-size first-person viewport, filled by the mirror reflection at one metre.

// the play view

What the player sees

One full-size viewport, rendered band-parallel across cores. Walk the hall with WASD, turn with Q/E, cycle cameras with C - the mirror fills the frame at one metre.

The doctrine

Everything here is simulated, not faked

01A real game loop

A Stopwatch drives wall-clock dt into a fixed 120 Hz physics accumulator; rendering is decoupled and the frame rate is measured live. The sim advances on elapsed time, not a frame index - it is not a movie.

02Rasterized, not traced

A perspective-correct edge-function rasterizer with near-plane clipping, backface culling, and a 1/z depth buffer. Primary visibility is rasterized so the playable path stays fast; ray-style work is reserved for what needs it.

03Parallel across viewports

One rasterizer and framebuffer per viewport; the four views and each mirror pre-pass render concurrently with no locks and no shared mutable pixels. The shadow map builds once per frame and is read-only during the fan-out.

04Nothing but the base library

No GPU API, no game engine, no packages - vector math, the PNG and GIF encoders, and the terminal presenter come from a pure-C# standard library; the rasterizer, shadow map, mirror, and physics are written from scratch.

Measured this run

steady 130 fps · per-second range 65 to 166 fps · 2,806 physics steps in 24.0 s (120.0 Hz lockstep) · 1,238 triangles · up to 5 render passes per frame · 512-square shadow map · captured from the live loop, delays are the real wall-clock gaps.