Nature and effects
Learning paths through this topic
Blend the look of the seasons smoothly, also from December back to January
A game that follows the calendar can change its trees, grass and sky with the seasons. Switching on a date looks abrupt, and a blend that stops at the last season makes the world jump on New Year's Day. Here is how to run the year around in a circle, for real years or for a world with its own length.
Make shadows get longer toward evening and swing from one side to the other
A farm or garden game with a day cycle feels dead when the shadows stay the same. If you stretch them with a simple factor, they become absurdly long at sunrise and sunset, or flip when the sun goes down. Here is how to tie the shadow to the sun's height and keep it tame at the edges of the day.
Let a shooting star cross the sky now and then, never two in a hurry
A shooting star is a small gift in a quiet night scene, a moment of wonder or a sign in a story. Random chance each frame brings clusters of three, then nothing for minutes, and a replay never shows the same sky. Here is how to give the night a calm, repeatable rhythm with a promised minimum gap.
Get smooth, natural-looking randomness from a seed, the same on every run
Fresh random numbers each frame make things buzz, and random values joined by straight lines look like a sawtooth. For drifting clouds, wandering lights or terrain you want a gentle wobble that you can ask for at any moment and that repeats exactly. Here is the standard way to do it.
Make snow or falling leaves loop forever without keeping a list of flakes
Hundreds of flakes, each with its own position kept and updated, cost memory and break when the window is resized, the game is paused or a frame takes long. If every flake is computed from the clock and its number alone, it just works. Here is that approach, including a sense of depth.
Let snow or petals pile up on a ledge into a mound that slides off when steep
Collecting snow on a roof or petals on a path is a lovely idle detail, but a pile that only gets taller turns into a needle. Real piles spread out when they get too steep, and on a narrow ledge the extra falls off the edge. Here is a rule that keeps the total honest and the shape believable.
Let snow pile up while it falls and melt away in patches, not all at once
A winter chapter is stronger when the world changes with the weather: the snow builds, the ground shows through as it warms, and the last white lies in the shade. The easy way, one number that fades a white overlay, looks like a filter. Here is how to get depth, patches and a result that does not depend on the step size.
Make a burst of sparks or confetti spread evenly, with a fixed number of slots
Random directions leave gaps and clumps, so a burst looks lopsided, and many bursts on screen at once can slow the game or fill memory. Here is a way to spread particles evenly at any count and a fixed pool that quietly recycles the oldest when full.
Lower the effects on a slow phone, and raise them again without flickering
A casual game runs on a ten-year-old phone and on a new one. Letting the game choose how many sparkles to draw sounds easy until it flips up and down every second, because lowering the load is exactly what makes it look fast enough to raise again. Here is how to make it settle.
Leave a sparkle trail behind a dragging finger with even spacing
If the sparkles appear once per frame, a slow drag piles them into a blob and a fast flick leaves gaps like a dotted line. The trail should look the same at any speed and on any phone. Here is the way to place them, including what to do when the finger jumps.
Let stars come out one by one as dusk deepens, bright ones first
A night sky that switches on all at once looks like a texture swap. Real stars come out in order, the brightest first, and they stay out once seen. Here is how to tie the sky to the light level so every star has its own moment, none flicker in and out, and the horizon stays dim.
Make stars twinkle each in their own rhythm and appear as night falls
A star field where everything blinks together looks like a Christmas light, and random flicker each frame looks like noise on a bad screen. Real twinkling is slow, uneven and different for every star. Here is a cheap way to give hundreds of stars their own rhythm that never changes between runs.