visualfx
Effects for a scene, one line each

// Tunnel: five small stars circle the middle. Trails keep every frame and push it outwards, a little bigger,
// a little turned and a little changed in colour, so five stars become a tunnel you fall through for ever.
// Use: move the mouse or a finger to steer the tunnel. Hold it down to turn the other way.
// Try changing: 2.5, how long a trail lasts; 1.9, how fast it grows; 50, how fast it turns; 140, how fast the colour moves.

const tail = trails(2.5, { zoom: 1.9, spin: 50, hue: 140 })
glow(0.5, { radius: 30 })
vignette(0.5)

let t = 0

function update(dt) {
  t += dt
  tail.spin = mouse.down ? -50 : 50
  tail.x = mouse.inside ? mouse.x : width / 2 + 60 * Math.sin(t * 0.7)
  tail.y = mouse.inside ? mouse.y : height / 2 + 40 * Math.cos(t * 0.9)
}

function draw() {
  background("black")
  const colours = ["gold", "deepskyblue", "hotpink", "springgreen", "white"]
  for (let i = 0; i < 5; i++) {
    const a = t * 1.3 + i * 1.2566
    const r = 50 + 22 * Math.sin(t * 2.3 + i * 2)
    star(tail.x + r * Math.cos(a), tail.y + r * Math.sin(a), 11, 5, colours[i])
  }
}

# Tunnel: five small stars circle the middle. Trails keep every frame and push it outwards, a little bigger,
# a little turned and a little changed in colour, so five stars become a tunnel you fall through for ever.
# Use: move the mouse or a finger to steer the tunnel. Hold it down to turn the other way.
# Try changing: 2.5, how long a trail lasts; 1.9, how fast it grows; 50, how fast it turns; 140, how fast the colour moves.
import math
from pyctures import *
from pyvisualfx import *

tail = trails(2.5, zoom=1.9, spin=50, hue=140)
glow(0.5, radius=30)
vignette(0.5)

t = 0
colours = ["gold", "deepskyblue", "hotpink", "springgreen", "white"]

def update(dt):
    global t
    t += dt
    tail.spin = -50 if mouse.down else 50
    tail.x = mouse.x if mouse.inside else width / 2 + 60 * math.sin(t * 0.7)
    tail.y = mouse.y if mouse.inside else height / 2 + 40 * math.cos(t * 0.9)

def draw():
    background("black")
    for i in range(5):
        a = t * 1.3 + i * 1.2566
        r = 50 + 22 * math.sin(t * 2.3 + i * 2)
        star(tail.x + r * math.cos(a), tail.y + r * math.sin(a), 11, 5, colours[i])

// Kaleidoscope: sixty shapes drift about, and a kaleidoscope folds them into a pattern that never repeats.
// Use: move the mouse or a finger to move the middle of the pattern. Tap to change how many segments it has.
// Try changing: 60, the shapes; 8, the segments; 12, how fast the pattern turns; take the glow away.

const colours = ["gold", "deepskyblue", "tomato", "springgreen", "orchid", "white", "darkorange", "royalblue"]
const shapes = []
for (let i = 0; i < 60; i++) {
  shapes.push({ x: random(0, 800), y: random(0, 500), vx: random(-70, 70), vy: random(-70, 70), size: random(14, 46), colour: pick(colours), sides: random(3, 6), turn: random(0, 360) })
}

const pattern = kaleidoscope(8)
glow(0.45, { threshold: 0.6 })
vignette(0.4)

function update(dt) {
  for (const s of shapes) {
    s.x += s.vx * dt
    s.y += s.vy * dt
    if (s.x < 0 || s.x > width) s.vx = -s.vx
    if (s.y < 0 || s.y > height) s.vy = -s.vy
  }
  pattern.angle += 12 * dt
  if (mouse.inside) {
    pattern.x = mouse.x
    pattern.y = mouse.y
  }
}

function draw() {
  background("#0a0a1e")
  for (const s of shapes) {
    if (s.sides === 6) star(s.x, s.y, s.size, 5, s.colour)
    else if (s.sides === 5) circle(s.x, s.y, s.size * 0.7, { outline: s.colour, thickness: 6 })
    else polygon(s.x, s.y, s.size, s.sides, s.colour)
  }
}

function onMouseDown() {
  pattern.segments = pattern.segments >= 16 ? 4 : pattern.segments + 2
}

# Kaleidoscope: sixty shapes drift about, and a kaleidoscope folds them into a pattern that never repeats.
# Use: move the mouse or a finger to move the middle of the pattern. Tap to change how many segments it has.
# Try changing: 60, the shapes; 8, the segments; 12, how fast the pattern turns; take the glow away.
from pyctures import *
from pyvisualfx import *

colours = ["gold", "deepskyblue", "tomato", "springgreen", "orchid", "white", "darkorange", "royalblue"]
shapes = []
for i in range(60):
    shapes.append({"x": random(0, 800), "y": random(0, 500), "vx": random(-70, 70), "vy": random(-70, 70),
                   "size": random(14, 46), "colour": pick(colours), "sides": random(3, 6)})

pattern = kaleidoscope(8)
glow(0.45, threshold=0.6)
vignette(0.4)

def update(dt):
    for s in shapes:
        s["x"] += s["vx"] * dt
        s["y"] += s["vy"] * dt
        if s["x"] < 0 or s["x"] > width:
            s["vx"] = -s["vx"]
        if s["y"] < 0 or s["y"] > height:
            s["vy"] = -s["vy"]
    pattern.angle += 12 * dt
    if mouse.inside:
        pattern.x = mouse.x
        pattern.y = mouse.y

def draw():
    background("#0a0a1e")
    for s in shapes:
        if s["sides"] == 6:
            star(s["x"], s["y"], s["size"], 5, s["colour"])
        elif s["sides"] == 5:
            circle(s["x"], s["y"], s["size"] * 0.7, outline=s["colour"], thickness=6)
        else:
            polygon(s["x"], s["y"], s["size"], s["sides"], s["colour"])

def on_mouse_down(x, y, button):
    pattern.segments = 4 if pattern.segments >= 16 else pattern.segments + 2

// Lava Lamp: nothing is drawn here at all. metaballs() is a backdrop the graphics card makes by itself:
// blobs that melt into each other. The glow and the wobble are two more lines.
// Use: move the mouse or a finger up and down to warm the lamp: the blobs move faster. Tap for other colours.
// Try changing: "lava" to "neon", "ocean" or "candy"; 8, how many blobs; 1.3, their size; or try plasma() or flow() instead.

const palettes = ["lava", "neon", "ocean", "candy", "sunset"]
let which = 0

const lamp = metaballs("lava", { count: 8, size: 1.3, speed: 0.35 })
wobble(8, { scale: 200 })
glow(0.6, { threshold: 0.3, radius: 44 })
vignette(0.6)

function update(dt) {
  if (mouse.inside) lamp.speed = 0.15 + 1.2 * (1 - mouse.y / height)
}

function draw() {
  background()          // with no colour: the picture is wiped clear, so the backdrop shows
}

function onMouseDown() {
  which = (which + 1) % palettes.length
  lamp.palette = palettes[which]
}

# Lava Lamp: nothing is drawn here at all. metaballs() is a backdrop the graphics card makes by itself:
# blobs that melt into each other. The glow and the wobble are two more lines.
# Use: move the mouse or a finger up and down to warm the lamp: the blobs move faster. Tap for other colours.
# Try changing: "lava" to "neon", "ocean" or "candy"; 8, how many blobs; 1.3, their size; or try plasma() or flow() instead.
from pyctures import *
from pyvisualfx import *

palettes = ["lava", "neon", "ocean", "candy", "sunset"]
which = 0

lamp = metaballs("lava", count=8, size=1.3, speed=0.35)
wobble(8, scale=200)
glow(0.6, threshold=0.3, radius=44)
vignette(0.6)

def update(dt):
    if mouse.inside:
        lamp.speed = 0.15 + 1.2 * (1 - mouse.y / height)

def draw():
    background()          # with no colour: the picture is wiped clear, so the backdrop shows

def on_mouse_down(x, y, button):
    global which
    which = (which + 1) % len(palettes)
    lamp.palette = palettes[which]