Cool Twister Effect with Small Basic

Question

I've been following the demoscene for years.  I wanted to contribute some Small Basic code here that uses a twister effect that is seen in many of the demos. 

Though this version is not the most efficient, it does illustrate the use of SIN when to come up with some cool graphical effects.  The next version I plan on prerendering the SIN data into an Array and then draw the frames from the coordinates in the array (much faster than calculating each row before drawing :) )

Let me know what you think!

http://smallbasic.com/program/?FKF358

Answer 1

Hello tonyrocks!

I've liked a lot your math graph demo!

Here's a modded version using GraphicsWindow.PenWidth to draw thicker lines to fill up the void left by skipping lines due to Step 3.

Twister 1.2 -> FKF358-1  :  4 color lines

Twister 1.3 -> FKF358-2  :  8 color lines

Twister 1.5 -> FKF358-3  :  using arrays

---

Click on "Propose As Answer" if some post solves your problem or "Vote As Helpful" if some post has been useful to you! (^_^)

Answer 2

Finally I got all calculations stored up inside a 3D array ( x[ang][y][line] ) !

Twister 2.0 -> FKF358-4

Twister 2.2 -> FKF358-7

' Twister (v2.2)
' date @ 2012/Aug
' program by tonyrocks
' modded   by GoToLoop

' http://social.msdn.microsoft.com/Forums/en-US/smallbasic
'/thread/abc69be0-b2a9-4bb2-b5aa-c652f4258308

' FKF358-7

GraphicsWindow.Title = "Twister"
GraphicsWindow.BackgroundColor = "Black"

GraphicsWindow.Width  = 640
GraphicsWindow.Height = 480
gw = GraphicsWindow.Width  - 1
gh = GraphicsWindow.Height - 1  '{Ajusted to For condition}

set     = gw/2        'Set screen offset
size    = 180         'Set size
twist   = 315         'Set twist amplitude
delay   = 130         'Set Delay

angMax  = 45          'Set max angle 
angMax  = angMax - 1  '{Ajusted to For condition}

ruggy   = 9           'how rugged lines are
GraphicsWindow.PenWidth = ruggy + 1

'Set color to each line:
colors = "0=Maroon;1=DarkRed;2=Red;3=SkyBlue;4=DodgerBlue;5=Blue;6=Navy;7=Indigo;"
colorsIndex = Array.GetItemCount(colors)   '# of colors = # of lines to draw at each row
angStep     = 360/(colorsIndex)            'angle gap for lines of each color
colorsIndex = colorsIndex - 1              '{Ajusted to For condition}

'Store all calcs in array x[ang][y][line]:
For ang=0 To angMax                'Angle loop
  amp = Math.Sin(ang)*gh + twist   'Set the amplitude and change it based on gh & ang
  
  For y=0 To gh Step ruggy         'Row loop
    calc = y/amp + ang             'Pre-calc
    
    For line=0 To colorsIndex      'Coordinates to draw each line
      x[ang][y][line] = Math.Round( Math.Sin(calc + angStep*line) * size ) + set
    EndFor
    
    x[ang][y][line] = x[ang][y][0] 'Extra redundant line = 1st line
  EndFor
  
EndFor

GraphicsWindow.TextInput = Pause   'Turns pause & exit keys on
GraphicsWindow.MouseDown = Pause   'Same for mouse clicks

'Main twister routine
Twist:

For ang=0 To angMax
  
  While isPaused
    Program.Delay(150)             'Resume/Halt execution by key presses
  EndWhile
  
  GraphicsWindow.Title = "Twister    •••    Angle = " + ang
  
  Program.Delay(delay)             'Delay before clearing the screen:
  GraphicsWindow.Clear()
  
  For y=0 To gh Step ruggy
    xx = x[ang][y]                 'Create a 1D sub-array outta 3D x[ang][y][line]
    x1 = xx[0]                     '1st horizontal coordinate
    
    For line=0 To colorsIndex
      x2 = xx[line+1]              'Destination horizontal coordinate
      
      If x1<x2 Then
        GraphicsWindow.PenColor = colors[line]
        GraphicsWindow.DrawLine(x1,y  x2,y)
      EndIf
      
      x1 = x2                      'Now 1st coordinate = last used 2nd coordinate
    EndFor
  EndFor
  
EndFor

'Do it again!:
Goto Twist

'Pause animation
Sub Pause
  
  If GraphicsWindow.LastKey = "Escape" Then
    Sound.PlayClickAndWait()
    Program.End()
  ElseIf isPaused Then
    isPaused = "False"
  Else
    isPaused = "True"
  EndIf
  
EndSub

---

Click on "Propose As Answer" if some post solves your problem or "Vote As Helpful" if some post has been useful to you! (^_^)

Answer 3

oh nice!  Thanks for making this better :)

Answer 4

There were some bugs I had to iron out!

Small Basic version -> FKF358-7

I've just started learning a Java/JS-based language called Processing. As an exercise, I've converted Twister 2.1 to it!

Processing version  -> Twister

---

Click on "Propose As Answer" if some post solves your problem or "Vote As Helpful" if some post has been useful to you! (^_^)