Make raindrops crawl down a window in jerks and merge when they meet

A rainy window is the classic quiet scene in a story game, and drops that slide down at a constant speed look like falling beads on a string. Real drops cling, then rush, then cling again, and big ones eat small ones. Here is how to get that behaviour with predictable results.

Why this works

A drop clings until it is heavy enough to break free, and heaviness grows with the surface it covers, not its width. That is why big drops run, small ones stay, and two that meet suddenly rush.

When not to use it

Don't use it for a heavy downpour seen from far away or for a fast scene, where single drops can't be followed. A scrolling texture or a simple wet-glass tint costs less and reads the same.

In the full entry

• What to build, step by step
• Starting values and the reason for each
• 3 common mistakes and the fix
• 46 lines of example code with 4 checks that pass
• How your AI shows you that it works

Say this to your AI

Use the Spielerando entry "Make raindrops crawl down a window in jerks and merge when they meet" (read_entry raindrops-stop-and-go-down-a-window) in my game. Build it step by step, and show me how you checked that it works.

Or skip this and connect the MCP: your AI then finds all of this by itself.Connect the MCP