[k82a]

Looks great, congrats. Dragging a very zoomed out view back and forth is also quite mesmerizing e.g. https://shademap.app/#39.70557,-113.85396,4.52593z,164148075...

How do the calculations go so smoothly? I mean for each pixel that is potentially in the shade there can be a many 'upstream' pixels in the direction that the light is coming from that could cause it to be shady if there was something high there. Doing that calculation for each pixel seems very intensive, or is it achieved in some other way?

[tppiotrowski]

You're spot on. One optimization is that once you are above the highest pixel of the map, you can assume you won't hit anything else. Another is calculating if the Earth's curvature will move pixels out of your way before you hit them.