[bmx] TWaveform, TCompositeWaveform by tesuji [ 1+ years ago ]

[BlitzBot]

Title : TWaveform, TCompositeWaveform
Author : tesuji
Posted : 1+ years ago

Description : Waveforms can be used wherever there's a need for oscillating data - eg platform height
Complex waveforms can be formed by blending multiple simple waveforms together aka analog waveform synthesis
Basic waves catered for are Sine, Triangle & Square

Code :

Code (blitzmax) Select Expand

' ------------------------------------------
' TWaveform, TCompositeWaveform example
' Waveforms can be used wherever there's a need for oscillating data - eg platform height
' Complex waveforms can be formed by blending multiple simple waveforms together aka analog waveform synthesis
' x axis range 0..1 y axis range -1..+1
' Tesuji 2010
' ------------------------------------------

SuperStrict

Graphics 1024,768,32

Local blobImage:TImage = CreateBlobImage(32)
MidHandleImage blobImage

' setup waveform examples

' basic sine wave
Local wave:TCompositeWaveform = TCompositeWaveform.Create( [TWaveform.Create(TWaveform.SINE)] )
Local blob1:TTestBlob = TTestBlob.Create(0, wave, blobImage, 0,128,255)

wave = TCompositeWaveform.Create( ..
[ ..
TWaveform.Create(TWaveform.SINE, 16), ..
TWaveform.Create(TWaveform.TRI, 3) ..
    ] ..
)
Local blob2:TTestBlob = TTestBlob.Create(1, wave, blobImage, 255,128,0)

wave = TCompositeWaveform.Create( ..
[ ..
TWaveform.Create(TWaveform.SINE), ..
TWaveform.Create(TWaveform.TRI, 4), ..
TWaveform.Create(TWaveform.SQUARE, 2) ..
    ] ..
)
Local blob3:TTestBlob = TTestBlob.Create(2, wave, blobImage, 64,255,64)

wave = TCompositeWaveform.Create( [TWaveform.Create(TWaveform.SINE, 3), TWaveform.Create(TWaveform.SINE, 4)] )
Local blob4:TTestBlob = TTestBlob.Create(3, wave, blobImage, 196,196,0)

Local x:Int = 0

While Not KeyHit(KEY_ESCAPE)

' motion blur cls
SetBlend ALPHABLEND
SetColor 0,0,0
SetAlpha .075
If KeyDown(KEY_SPACE) Then SetAlpha .02
DrawRect 0,0,GraphicsWidth(),GraphicsHeight()

SetColor 0,0,0
SetBlend ALPHABLEND
SetAlpha .5
DrawRect 0,0,GraphicsWidth(),64

blob1.render(x Mod GraphicsWidth())
blob2.render((x+(GraphicsWidth()*.25)) Mod GraphicsWidth())
blob3.render((x+(GraphicsWidth()*.5)) Mod GraphicsWidth())
blob4.render((x+(GraphicsWidth()*.75)) Mod GraphicsWidth())

x :+ 2

Flip

Wend

End

Function createBlobImage:TImage(size:Int=48)
Cls
Local cm:Float = 256/Float(size)
For Local r:Int = 0 To size-1
SetColor r*cm,r*cm,r*cm
DrawOval r/2,r/2,size-r,size-r
Next
Local pixmap:TPixmap = GrabPixmap(0,0,size,size)
Return LoadImage(pixmap)
End Function

' ------------------------------------------------------
Type TTestBlob

Field number:Int = 0
Field osc:TCompositeWaveform
Field img:TImage
Field red:Int,green:Int,blue:Int

Function Create:TTestBlob(number:Int=0, osc:TCompositeWaveform, img:TImage, red:Int, green:Int, blue:Int)
Local o:TTestBlob = New TTestBlob
o.number = number
o.osc = osc
o.img = img
o.red = red
o.green = green
o.blue = blue
Return o
End Function

Method render(position:Float)

Local v:Float = osc.value(position*(1.0/GraphicsWidth()))
SetAlpha .75
SetBlend LIGHTBLEND
SetColor red,green,blue
DrawImage img, position, (GraphicsHeight()*.5)+(v*(GraphicsHeight()*.5)*.5)

SetAlpha .5
DrawText "oscillator "+number+" value: "+v, 0,number*16
DrawText osc.toString(), 300,number*16

End Method


End Type

' ---------------------------------------------------------------------------------------------------------

' -------------------------------------------------------------------------
' Represents a simple waveform
' Sine, Triangle or Square wave
' frequency dictates the number of wave cycles in the time period provided
' -------------------------------------------------------------------------
Type TWaveform

Const SINE:Int = 0
Const TRI:Int = 1
Const SQUARE:Int = 2

Field labels:String[] = ["Sine","Triangle","Square"]

Field waveformType:Int
Field amplitude:Float = 1.0
Field frequency:Float = 1.0
Field offset:Float = 0.0

Function Create:TWaveform(waveformType:Int, frequency:Float=1.0, amplitude:Float=1.0)
Local w:TWaveform = New TWaveform
w.waveformType = waveFormType
w.frequency = frequency
w.amplitude = amplitude
Return w
End Function

' provide the waveform y position at the given x axis position
' time should be in the range 0.0 to 1.0
' output is given in the range of -ve amplitude to +ve amplitude

Method value:Float(time:Float)

Local v:Float = 1.0
If amplitude > 0.0
Select waveformType
Case SINE v = (Sin(frequency*(time+offset)*360))*amplitude
Case SQUARE v = (((Ceil((time+offset) * frequency * 2) Mod 2.0)*2)-1) * amplitude
Case TRI
v = (((((time+offset+.25) * frequency * 2) Mod 1.0)*2)-1)
If (Ceil((time+offset+.25) * frequency * 2) Mod 2.0) = 0.0 Then v = -v
End Select
End If

Return v

End Method

Method toString:String()
Return labels[waveformType] +" "+Left(frequency,3)
End Method

End Type

' ---------------------------------------------------
' represents a blending of multiple simple waveforms
' ---------------------------------------------------
Type TCompositeWaveform

Field waveforms:TWaveform[]
Field amplitude:Float = 1.0

Function Create:TCompositeWaveform(waveforms:TWaveform[], amplitude:Float=1.0)
Local mw:TCompositeWaveform = New TCompositeWaveform
mw.waveforms = waveforms
mw.amplitude = amplitude
Return mw
End Function

' provide the blended amplitude of all waveforms for the given x axis position
' time should be in the range 0.0 to 1.0

Method value:Float(time:Float)

Local v:Float = 1.0
For Local w:TWaveform = EachIn waveforms
v :* w.value(time)
Next

Return v*amplitude

End Method

Method toString:String()
Local s:String
For Local w:TWaveform = EachIn waveforms
s :+ "[" + w.toString() + "] "
Next
Return s
End Method

End Type

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