# Seeded scenes

> The engine behind every post’s picture, to play with: live scenes, a timing sheet and the post with the code. https://www.luannzin.com/projects/seeded-scenes

Nobody drew the picture on top of my posts. I wanted each one to have its own, but I didn’t want to make covers and keep them up to date. So every post gets a number, its seed, and this engine grows a scene from it: the place, the time of day, what’s standing there, down to the shape of the clouds. Type any number or word in the field, or let the die pick one.

When the seed changes, the old scene doesn’t just cut to the new one. It melts into it while the die tumbles to the face the new seed picks, and the sheet under the scene runs both: replay them, slow them to a tenth or step through a frame at a time. The scene reacts to you too. Move your pointer over it and a small light follows, or tap the sky for a shooting star.

## Same seed, same scene

Six seeds and the scenes they grow. Hover one to make it move. Reload the page and you get the same six, down to where every star sits, because a seed always makes the same choices in the same order. Type one of these numbers in the field up top and that scene shows up there too.

## The place comes first

There are nine places, eleven times of day and eleven landmarks, but a seed doesn’t pick them separately. The place goes first, because it decides the rest: the times it can be drawn at and what can stand in it. That’s why a street is never drawn at sunset, and nothing under the sea gets snow. Pick a place and the page goes looking for a seed that lands there.

| Place | Drawn at | What stands in it |
| --- | --- | --- |
| Coast | Night, twilight, dusk, dawn, aurora, storm | A lighthouse or a cabin |
| Fjord | Night, twilight, dawn, aurora, alpenglow, storm | A cabin or a sailboat |
| Lake | Night, twilight, dusk, dawn, aurora, alpenglow, lanterns | A sailboat or a cabin |
| Valley | Night, twilight, dusk, dawn, aurora, alpenglow, storm, lanterns | A windmill or a cabin |
| Dunes | Night, twilight, dusk, dawn, storm | Only the sky |
| Garden | Plum dusk, dusk, twilight, night, dawn, lanterns | A pagoda or a torii, under a cherry tree |
| River | Dusk, dawn, twilight, night, lanterns | A temple over steps down to the water |
| City | Rain, night, twilight, storm | Someone under an umbrella, or a vending machine |
| Reef | Deep water | A wreck, or a manta ray |

## One dot per cell

Every frame is a grid of cells, one every three pixels or so, and each cell becomes a single dot: one of three sizes, or none at all, like a printed halftone. The brighter the cell, the bigger its dot. When a cell falls between two sizes, a four-by-four pattern decides which one it gets, so a smooth gradient turns into an even texture instead of hard bands. At three pixels you barely notice any of it. Make the dots bigger and it’s all you see.

## The whole story

I left the code out of this page. The post has all of it: the tiny random number generator behind every choice, how a frame gets shaded, the water that reflects whatever is above it, the street drawn in one-point perspective, and how the dots get to the GPU. [Art from a seed](https://www.luannzin.com/writing/art-from-a-seed.md)