#optimization
7 postsMaking GPUI Fast: A Compositor Thread, an Overscroll Buffer, and Why Browsers Don't Re-Render on Scroll
How we're planning to pull a CoreAnimation-style compositor thread and a browser-inspired overscroll buffer into GPUI to move essentially all rendering work off the main thread — and why scrolling a massive list should cost near-zero CPU time.
Cascaded Shadow Maps: From Matrix Compute to PCSS Filtering
A complete walkthrough of Helio's shadow pipeline — GPU matrix generation for point/directional/spot lights, the 256-layer shadow atlas with GPU-driven dirty tracking, per-face frustum culling, and PCSS soft shadows with Vogel disk sampling.
Why Compute Shaders Beat CPU Loops: Helio's O(1) Frame Cost Philosophy
A deep technical walkthrough of Helio's GPU-driven architecture — why the CPU never iterates over objects, how every frame costs the same regardless of scene complexity, and what it took to make that work in practice.
Culling Done Right: Fixing What Everyone Gets Wrong About GPU Culling
A deep technical postmortem of Helio's culling system — the critical bugs that caused objects to vanish when they shouldn't and appear when they shouldn't, the fixes that brought everything inline with AAA standards, and what a 110% occlusion-culled stat taught us about atomic counter races.
Building an In-Engine GPU Profiler for Fun and Frame Time
A thorough technical walkthrough of how Helio's built-in profiler works — zero-instrumentation pass timing, GPU timestamp queries, resolve buffer mechanics, staging readback without stalling, and the live telemetry viewer that ties it all together.
Tiled Light Culling: From Linear Scan to Forward+
A technical walkthrough of Helio's tile-based light culling system — how we replaced a linear per-pixel light scan with a compute shader that assigns lights to 16x16 tiles, the tile frustum construction, the cache key that makes it free on static scenes, and what 1000+ dynamic lights look like in practice.
Corona: Building a GPU-Native Particle System
A full technical walkthrough of Corona — Helio's GPU-native particle system. How we went from invisible particles and flickering garbage to a million stable, depth-sorted, atlas-rendered particles using prefix sums, bitonic sort, and a lot of debugging.