Box 40, 140, 320, 20, OFF
DrawScreen

Randomize 3

Const noisew = 400
Const noiseh = 300

Dim noisepattern(noisew, noiseh) As Float
Dim prenoise(noisew-1, noiseh-1) As Float
Dim noise(noisew-1, noiseh-1, 1) As Float

Function getinterpnoise#(i, j)
    ii# = Float(i/16.0)
    jj# = Float(j/16.0)
    aa# = noisepattern(RoundDown(ii#)+1, RoundDown(jj#))*(ii#-RoundDown(ii#))+noisepattern(RoundDown(ii#), RoundDown(jj#))*(1.0-(ii#-RoundDown(ii#)))
    bb# = noisepattern(RoundDown(ii#)+1, RoundDown(jj#)+1)*(ii#-RoundDown(ii#))+noisepattern(RoundDown(ii#), RoundDown(jj#)+1)*(1.0-(ii#-RoundDown(ii#)))
    Return bb#*(jj#-RoundDown(jj))+aa#*(1.0-(jj#-RoundDown(jj#)))
EndFunction

For i = 0 To noisew
    For j = 0 To noiseh
        noisepattern(i, j) = Rnd(-1.0, 1.0)
    Next j
    If i Mod 20 = 0 Then
        Box 40, 140, 320, 20, OFF
        Box 42, 142, 316*.333*i/float(noisew), 16
        DrawScreen
    EndIf
Next i

For i = 0 To noisew-1
    For j = 0 To noiseh-1
        prenoise(i, j) = getinterpnoise#(i, j)
    Next j
    If i Mod 20 = 0 Then
        Box 40, 140, 320, 20, OFF
        Box 42, 142, 316*.333*(1.0+i/float(noisew)), 16
        DrawScreen
    EndIf
Next i

For i = 1 To noisew-2
    For j = 1 To noiseh-2
        noise(i, j, 0) = (prenoise(i,j+1)-prenoise(i,j-1))
        noise(i, j, 1) = (prenoise(i+1,j)-prenoise(i-1,j))
    Next j
    If i Mod 20 = 0 Then
        Box 40, 140, 320, 20, OFF
        Box 42, 142, 316*.333*(2.0+i/float(noisew)), 16
        DrawScreen
    EndIf
Next i

Dim parts(9999, 2) As Float
For i = 0 To 1999
    parts(i,2)=-1.0
Next i
ptimer = Timer()

spawn = 10
drawx# = 200
drawy# = 150
t=Timer()-10
Repeat
    spawn = spawn + UpKey() - DownKey()+1
    spawned = 0
    ra = 0
    ang# = 0'WrapAngle(ang+.2)
    cosa# = Cos(ang)
    sina# = Sin(ang)
    kk#=(Timer()-t)/1000.0*60
    t=Timer()
    Lock
        For i = 0 To 9999
            If parts(i,2)>0 Then
                ra = ra + 1
                vx# = noise(Int(parts(i, 0)), Int(parts(i, 1)), 0)
                vy# = noise(Int(parts(i, 0)), Int(parts(i, 1)), 1)
                parts(i,0) = parts(i,0)+vx*kk'+cosa*vx+sina*vy
                parts(i,1) = parts(i,1)+vy*kk-0.3*kk'-sina*vx+cosa*vy-.3
                parts(i,2) = parts(i,2)-1.25*kk
                col = max(0, Min(255, parts(i,2)))
                Color col, (col*.055)^2.0, 0
                For x = parts(i,0)-1 To parts(i,0)+1
                    Line x, parts(i,1)-1, x, parts(i,1)+1
                Next x
            Else
                If spawned<spawn And (KeyDown(cbkeyspace) Or (Timer()Mod 3000)<500) Then
                    kulma = Rand(2)
                    drawx# = (drawx+200+Cos(90+120*kulma)*120)/2.0
                    drawy# = (drawy+170-Sin(90+120*kulma)*120)/2.0
                    parts(i,0) = drawx//Rnd(80.0, 320.0)
                    parts(i,1) = drawy+20//Rnd(180.0, 200.0)
                    parts(i,2) = 255.0
                    spawned = spawned + 1
                EndIf
            EndIf
        Next i
    Unlock
    Color 255, 255, 255
    Text 10, 220, "fp"+"s is "+Str(FPS())
    Text 10, 240, "rendering "+Str(ra)+" particles"
    Text 10, 260, "spawning "+Str(spawned)+" per frame"
    Text 10, 280, "spawn "+spawn
    DrawScreen
Forever