A map of cafes that are in the sun
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I wanted to sit outside for coffee but there was no way to see which cafes are in the sun right now. So I built a map that shows which cafes, benches, and outdoor seats are in the sun vs. shade at any time of day.It ray-marches building shadows live in a WebGL shader over a MapLibre map. I also pre-index all places from OpenStreetMap into H3 hex cells and serve them as static JSON on Cloudflare R2, so the client just fetches the cells in view and no backend is needed.Feedback welcome, especially on shadow accuracy in your city. Currently only buildings and trees are taken into account when calculating the shadows but I'm planning to add terrain/mountain shadows as well.Try it: https://sunny.coffee
HN · launched Jul 16, 2026 · 8 upvotes (top 54%) · 1 view
Niche: specialized navigation and tracking apps · 203 launches, 35 in the last 7 days ▲ +84% · Explore this niche →
Category and tags
- Travel & hospitality
- Search & retrieval
- B2C
- Not AI
- Hobby / open-source project
Visit website ↗ Source listing ↗
More like this: all 203 launches in specialized navigation and tracking apps →
Could you build this?
Partial The map interface and POI data aggregation are straightforward, but live ray-marching 3D building shadows in a custom WebGL shader requires specialized graphics programming.
What it would actually take: Built with MapLibre GL JS, OpenStreetMap cafe data, solar position algorithms (like SunCalc), and 3D building elevation tiles. The hard component is writing and optimizing a custom WebGL fragment shader to perform live ray-marching against 3D extruded geometry to cast performant, real-time shadows.
Discussion
3 comments analyzed.
Concerns raised: Only works for flat areas, not slopes or multi-story buildings, Doesn't account for shadows from surrounding buildings
Feature requests: Integrate daily weather forecasts for cloud cover, Account for terrain slopes and building shadows in sun exposure prediction
Competitors
Other products that read as similar to this one : 189 launches clear the similarity bar, closest 8 shown.
Attention rank: #83 of 190 (itself plus its competitors, highest first, normalized so YC and Product Hunt are compared fairly).
Launched 255 days after the earliest competitor.
- ShadowFinder — Sun Position & Shadow · ph · 2026-09-23 · 2 upvotes · similarity 0.54
- I calculated sun/shade exposure for every seat at World Cup stadiums · hn · 2026-03-12 · 5 upvotes · similarity 0.53
- Warsaw in voxels · hn · 2026-11-02 · 325 upvotes · similarity 0.47
- Roam Community · ph · 2026-10-22 · 1 upvotes · similarity 0.46
- Asterfold: Sunset Planner · ph · 2026-11-08 · 1 upvotes · similarity 0.43
- Sun light and path calculation for photography · hn · 2026-07-05 · 7 upvotes · similarity 0.42
- Manolit∞ Aire · ph · 2026-10-02 · 1 upvotes · similarity 0.42
- random-city · github · 2026-09-09 · 13 upvotes · similarity 0.42
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