Share My Creation Bezier Curve

Gigatron

Member
Licensed User
Hi all

Befor sleeping i ported nice Bezier curves from , Brian Postma...

here is the code and attached project file.

Enjoy



B4X:
Sub Process_Globals
   'These global variables will be declared once when the application starts.
   'These variables can be accessed from all modules.
   Dim time As Timer
End Sub

Sub Globals
   'These global variables will be redeclared each time the activity is created.
   'These variables can only be accessed from this module.

   Dim cnv As Canvas
   Dim stpanel As Panel
   Dim xitbtn As Button
    Dim clr As Int
   Dim rc As Rect

   Dim   angle1,angle2 As Float
   angle1=0
   angle2= 0
   
     Dim   xcenter,ycenter As Int
     Dim   radius1, radius2 As Float
     Dim numdots  As  Int :numdots = 8  '32 Slow 
    Dim numpolys As  Int :numpolys= 8  '16 slow 
    Dim x1(32),x2(32) As Int
    Dim y1(32),y2(32) As Int
   Dim pi As Double
   'pi= 3.141592653589793238462643383279502884197
   pi=cPI
   Dim dangle1 As Float : dangle1=pi/128
   Dim dangle2 As Float : dangle2=pi/128
   
   'Dim t As Double 
    
End Sub

Sub Activity_Create(FirstTime As Boolean)
      Activity.LoadLayout("starscroll")   'nothing special just stpanel + exitbtn  
      cnv.Initialize(stpanel)
      
   xcenter = stpanel.width / 2
    ycenter = stpanel.height / 2
    radius1= xcenter - 2
    radius2= ycenter - 150
   
        rc.Initialize(0,0,480,860)
            
      
         time.Initialize("time",1)
         time.Enabled=True

End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub B1 (t As Double)
Return(t*t)
End Sub

Sub B2 (t As Double)
Return(2*t*(1-t))
End Sub

Sub B3 (t As Double)
Return((1-t)*(1-t))
End Sub

Sub time_Tick
   drawCurves
  
End Sub
Sub drawCurves
    
     cnv.DrawRect(rc,Colors.Black,True,2dip)        ' Remplissage ecran avec couleur 0000 
   
     For i=0 To numdots-1
      x1(i) = xcenter+(radius1/2) * Cos (angle1+(i)*pi*2/numdots)
      y1(i) = ycenter+(radius2/2) * Sin (angle1+(i)*pi*2/numdots)
      x2(i) = xcenter+(radius1) * Cos (angle2+(i)*pi*2/numdots)
      y2(i) = ycenter+(radius2) * Sin (angle2+(i)*pi*2/numdots)
     drawCurve(xcenter,ycenter,x1(i),y1(i),x2(i),y2(i))
    Next
    angle1 =angle1+ dangle1
    angle2 =angle2- dangle2
    
   stpanel.Invalidate
End Sub


Sub drawcurve(xx1,yy1,xx2,yy2,xx3,yy3)
   Dim i As Double :i=0
   Dim col As Int : col=255
   Dim x,y As Double
   Dim xold As Int
   xold=xx3
   yold=yy3
   Do While i<1
   col=col-128/numpolys
   
    x = xx1*B1(i) + xx2*B2(i) + xx3*B3(i)
      y = yy1*B1(i) + yy2*B2(i) + yy3*B3(i) 
       
      cnv.DrawLine(xold,yold,x,y,Colors.White,2dip)
     xold=x
      yold=y
      i=i+1/numpolys
   
   
   Loop
End Sub


Sub xitbtn_Click
   activity.Finish
End Sub
 

Attachments

kcorey

Member
Licensed User
Redux

Hi Gigatron,

Thanks for publishing this!

I was intrigued by your bezier curve example, but wanted to play with it a bit to see if I could speed it up.

Here's a first cut. I took as much of the work out of the loop as I could find, and put in a couple of slider bars so that you can dynamically change the numpolys and numdots on the fly (0-23) for both.

-Ken
 

Attachments

NeoTechni

Well-Known Member
Licensed User
This code doesn't really look reusable. It looks like it's made for one specific situation.
 
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