Springs and curves
Learning paths through this topic
Let a list or map resist when dragged past its end, then spring back
Stopping dead at the edge feels broken and letting the content slide away freely loses it. A rubber-band feel needs a pull that gets harder the further you go and a return that does not bounce past. Here is the rule that gives it, and its reverse.
Close a circular iris on the hero and make sure no corner is left uncovered
A circle that shrinks around the hero or grows from them is a classic way to change scenes, but it often leaves the far corners showing at the start or end, especially when the hero is near an edge. Here is the size to start from and how to time it.
Zoom a scope in smoothly and keep mouse aiming feeling the same
When the view zooms in on a distant animal, the same mouse movement suddenly sweeps far too much picture, and a simple blend between the two view widths seems to speed up and slow down. Here is the right way to blend the zoom and scale the aim speed.
Speed up the clock when the player sleeps and land exactly on morning
Sleeping through the night should run the sky fast, then slow down gently at dawn, and the hunger and crops should age by exactly the skipped hours. Here is how to make the skip smooth, correct across midnight, and always ending on the exact wake-up time.
Move along a smooth curve through your waypoints without loops or kinks
Straight lines between waypoints look stiff, and the common way of rounding the corners can make little loops, overshoot past a point or form sharp tips where points are unevenly spaced. Here is a way that passes through every point and stays tidy.
Time floor spikes that rest, shake, snap up and sink, with a fair warning
Spike traps feel fair when the player can read their rhythm: a pause, a tell, a sudden strike and a slower retreat. The danger must match what the eye sees, and neighbouring traps should be out of step so a corridor makes a pattern. Here is a schedule that does all of this from one clock.
Let a turret or dial swing to its new angle with a spring, taking the short way
A springy dial or turret that has to cross from just below a full turn to just above it will often spin the long way round or snap by a whole turn. Here is how to give angles a springy feel that still takes the short path and keeps its swing.
Slow a spinning rune circle to a stop that lands on a tidy, matching pose
A magic circle that slows down and freezes at a random angle looks crooked, especially when its pattern repeats around it. Here is how to brake it with a steady, believable slowdown that finishes exactly on one of the neat angles, never going backwards.
Make a bouncy spring motion that never blows up on slow computers
Wobbling menus, hanging signs and bouncy cameras are often made with a simple spring that works at one frame rate and explodes into huge swings at another. Here is a version that behaves the same way at every speed and covers soft, bouncy and heavy settings.
Show the stamina wheel when it matters and fade it away after a calm moment
A stamina meter that is always on clutters the screen, and one that vanishes the instant it is full flickers when the player sprints in short bursts. Here is the rule for when it shows, how long it waits, and how quickly it fades in and out.
Know when a wobbling thing has stopped, and stop spending effort on it
Hundreds of springy objects on screen keep calculating forever for movements nobody can see anymore, and checking only whether it sits on its goal stops it too early, in the middle of a swing. Here is the right check and how to wake it again when something changes.
Make a pet or companion follow at a distance, without hugging or lagging behind
A companion stuck to your heels blocks the view and shakes when you stop, while one that ignores you gets lost in the wilderness. Here is a rule that lets it wander a little, speeds up with the distance, and appears next to you when it is hopelessly far.