Particle fountain: Difference between revisions
Created Nim solution.
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(Created Nim solution.) |
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""")
fountain()
</syntaxhighlight>
=={{header|Nim}}==
{{trans|Julia}}
{{libheader|SDL2}}
Note that for key events, the scan code doesn’t take in account the keyboard layout. So we check the "sym" value instead.
<syntaxhighlight lang="Nim">import std/[lenientops, math, monotimes, random, times]
import sdl2
type ParticleFountain[N: static Positive] = object
positions: array[1..2 * N, float]
velocities: array[1..2 * N, float]
lifetimes: array[1..N, float]
points: array[1..N, Point]
numPoints: int
saturation: float
spread: float
range: float
reciprocate: bool
proc initParticleFountain[N: static Positive](): ParticleFountain[N] =
ParticleFountain[N](saturation: 0.4, spread: 1.5, range: 1.5)
proc update(pf: var ParticleFountain; w, h: cint; df: float) =
var
xidx = 1
yidx = 2
pointidx = 0
template recip(pf: ParticleFountain): float =
if pf.reciprocate: pf.range * sin(epochTime() / 1000) else: 0.0
for idx in 1..pf.N:
var willDraw = false
if pf.lifetimes[idx] <= 0:
if rand(1.0) < df:
pf.lifetimes[idx] = 2.5 # Time to live.
# Starting position.
pf.positions[xidx] = w / 20
pf.positions[yidx] = h / 10
# Starting velocity.
pf.velocities[xidx] = 10 * (pf.spread * rand(1.0) - pf.spread / 2 + pf.recip())
pf.velocities[yidx] = (rand(1.0) - 2.9) * h / 20.5
willDraw = true
else:
if pf.positions[yidx] > h / 10 and pf.velocities[yidx] > 0:
pf.velocities[yidx] *= -0.3 # "Bounce".
pf.velocities[yidx] += df * h / 10 # Adjust velocity.
pf.positions[xidx] += pf.velocities[xidx] * df # Adjust position x.
pf.positions[yidx] += pf.velocities[yidx] * df # Adjust position y.
pf.lifetimes[idx] -= df
willDraw = true
if willDraw:
# Gather all of the points that are going to be rendered.
inc pointIdx
pf.points[pointidx] = (cint(pf.positions[xidx] * 10), cint(pf.positions[yidx] * 10))
inc xidx, 2
yidx = xidx + 1
pf.numPoints = pointidx
func hsvToRgb(h, s, v: float): (byte, byte, byte) =
let hp = h / 60.0
let c = s * v
let x = c * (1 - abs(hp mod 2 - 1))
let m = v - c
var (r, g, b) = if hp <= 1: (c, x, 0.0)
elif hp <= 2: (x, c, 0.0)
elif hp <= 3: (0.0, c, x)
elif hp <= 4: (0.0, x, c)
elif hp <= 5: (x, 0.0, c)
else: (c, 0.0, x)
r += m
g += m
b += m
result = (byte(r * 255), byte(g * 255), byte(b * 255))
proc fountain(particleNum = 3000; w = 800; h = 800) =
var w = w.cint
var h = h.cint
discard sdl2.init(INIT_VIDEO or INIT_EVENTS)
let window = createWindow("Nim Particle System!", SDL_WINDOWPOS_CENTERED_MASK,
SDL_WINDOWPOS_CENTERED_MASK, w, h, SDL_WINDOW_RESIZABLE)
let renderer = createRenderer(window, -1, 0)
clearError()
var df = 0.0001
var pf = initParticleFountain[3000]()
var close = false
var frames = 0
block Simulation:
while not close:
let dfStart = getMonoTime()
var event: Event
while bool(pollEvent(event)):
case event.kind
of QuitEvent:
break Simulation
of WindowEvent:
if event.window.event == WindowEvent_Resized:
w = event.window.data1
h = event.window.data2
of KeyDown:
let comm = event.key.keysym.sym
case comm
of K_UP:
pf.saturation = min(pf.saturation + 0.1, 1.0)
of K_DOWN:
pf.saturation = max(pf.saturation - 0.1, 0.0)
of K_PAGEUP:
pf.spread = min(pf.spread + 1.0, 50.0)
of K_PAGEDOWN:
pf.spread = max(pf.spread - 0.1, 0.2)
of K_LEFT:
pf.range = min(pf.range + 0.1, 12.0)
of K_RIGHT:
pf.range = max(pf.range - 0.1, 0.1)
of K_SPACE:
pf.reciprocate = not pf.reciprocate
of K_Q:
break Simulation
else:
discard
else:
discard
pf.update(w, h, df)
renderer.setDrawColor(0x0, 0x0, 0x0, 0xff)
renderer.clear()
let (red, green, blue) = hsvToRgb(epochTime() mod 5 * 72, pf.saturation, 1.0)
renderer.setDrawColor(red, green, blue, 0x7f)
renderer.drawPoints(pf.points[1].addr, pf.numPoints.cint)
renderer.present()
inc frames
df = (getMonoTime() - dfStart).inMilliseconds.float / 1000
sdl2.quit()
randomize()
echo """
Use UP and DOWN arrow keys to modify the saturation of the particle colors.
Use PAGE UP and PAGE DOWN keys to modify the "spread" of the particles.
Toggle reciprocation off / on with the SPACE bar.
Use LEFT and RIGHT arrow keys to modify angle range for reciprocation.
Press the "q" key to quit.
"""
fountain()
</syntaxhighlight>
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