Example: Section 7.7 (pages 222-224) Explorations with the Mandelbrot Set

[Lionheart008]

this example didn't work complete. rendering abort at about 53 per cent.

[code=thinbasic]' Empty GUI script created on 03-04-2010 16:47:52 by (ThinAIR)

' Example: Section 7.7 (page 222-224), Explorations with the Mandlebrot Set

' From Stan Blank's Book:
' "Python Programming in OpenGL
' "A Graphical Approach to Programming

' Converted by Stan Blank, this version is slightly downgraded in detail by Petr Schreiber
' Using the Predator-Prey framework by Michael Clease
' Last modified: February 28, 2010

' thinBasic does not use GLUT, we use instead tbgl
Uses "TBGL"

' insert Eros Olmi's new iComplex module
Uses "iComplex"


Function TBMain()

' Handle for our window
Local hWnd As DWord
Local Width As Long
Local Height As Long
Local n As Long
Local x,y, zz As Double

' Declare iComplex variables
Local z, c As tComplex

'# Initial values of width And height
width = 680
height = 500
'
' Create and show window
hWnd = TBGL_CreateWindowEx("Frankos_Mandelbrot Set", Width, Height, 32, %TBGL_WS_WINDOWED Or %TBGL_WS_CLOSEBOX Or %TBGL_WS_DONTSIZE)
TBGL_ShowWindow

' -- Set background from default black to white
TBGL_BackColor(0,0,0)

' -- Init OpenGl, like gluOrtho2D in example code
TBGL_RenderMatrix2D( -2, -1.5, 1, 1.5 )

TBGL_PointSize 1

' Resets status of all keys
TBGL_ResetKeyState()

Local percent As Double
Local p,v As Double

' -- Create new GBuffer
Local gbMandelbrot As DWord = TBGL_GBufferCreate(%TBGL_POINTS, %TBGL_2D)
Local MandelbrotIndex As Long
Local MandelbrotVertex(160000) As tbgl_tVector2f ' -- TYPE from TBGL
Local MandelbrotColor (320000) As tbgl_tRGB ' -- TYPE from TBGL
p = -0.001*Cos(GetTickCount/5000)*100

' -- Fill it with data
For x = -2 To 1 Step 0.0055

For y = -1.5 To 1.5 Step 0.0055
Incr MandelbrotIndex
Incr MandelbrotColor(MandelbrotIndex).r

' Set complex points
c = iComplex_Set(x,y)
z = iComplex_Set(x,y)
v = iComplex_Set(x,y)
n = 0

For n = 1 To 50
' Equation is z = z*z + c
z = iComplex_Mul(z,z)
z = iComplex_Add(z,c)
z = iComplex_Sin(z)
'z = iComplex_sub(z,v)

' Distance from origin to complex point
zz = iComplex_Abs(z)

' if distance is > 2.0, then point is NOT in the M-Set
' so plot it... the M-Set will be black
If zz > 2.0 Then
MandelbrotColor (MandelbrotIndex).R = 455 '--> ? problem
MandelbrotVertex(MandelbrotIndex).x = x
MandelbrotVertex(MandelbrotIndex).y = y
End If
Next
Next

' -- Write status
percent = (x-(-2))/3*100
TBGL_SetWindowTitle(hWnd, Format$(percent, "#.00")+"%, rendering full detail")
DoEvents

' -- Dynamically say to TBGL where the data are, this is just pointer gymnastics, no copy
TBGL_GBufferDefineFromArray(gbMandelbrot, %TBGL_DYNAMIC, MandelbrotIndex, MandelbrotVertex(1), MandelbrotColor(1))

' -- Redraw
TBGL_ClearFrame
TBGL_GBufferRender(gbMandelbrot)
TBGL_DrawFrame

' -- Escape sooner?
If TBGL_GetWindowKeyOnce(hWnd, %VK_ESCAPE) Then Exit For

Next

TBGL_SetWindowTitle(hWnd, "Behold - the Mandlebrot! ")

' Main loop
While TBGL_IsWindow(hWnd)

TBGL_ClearFrame

TBGL_GBufferRender(gbMandelbrot)

TBGL_DrawFrame

If TBGL_GetWindowKeyOnce(hWnd, %VK_ESCAPE) Then Exit While

Wend

TBGL_DestroyWindow

End Function
[/code]

perhaps somebody can help to fix this code that's run fine or give hint where I can do that, would be nice ?

best regards, frank

[Petr Schreiber]

Hi Frank,

the reason of failing is obvious - array not big enough.
Try to think how to calculate how much points it will have, if you go from -2 to 1 by 0.0055 and -1.5 to 1.5 by 0.0055.

Three hints:

• 1-(-2) = 3, 1.5-(-1.5) = 3
• step is not well chosen
• size of vertex and color array does not match

Petr

[Charles Pegge]

By bending the algorithm, distorted structures can be produced. as shown in the images below. You
can see where additional Asm instructions may be inserted. (The fsin & fmul instructions commented out).

I've also improved the navigation by using smaller steps and improved the frame rate a bit though I cannot match Joshy's fractal program!
(http://community.thinbasic.com/index...;topicseen#new)

Charles

[code=thinbasic]
mov edx,shmo
mov ecx,0
(
'zzman=zzman*zzman+zzcor 'COMPLEX OPERATIONS
'esc=zzman.r * zzman.r + zzman.i * zzman.i
'if esc>lmt then jmp fwd xff
fld qword zzman.r
fmul st(0),st(0)
fld qword zzman.i
fmul st(0),st(0)
'fsin
fsubp st(1),st(0)
fld qword zzman.r
fmul qword zzman.i
'fsin
fadd st(0),st(0)
fadd qword zzcor.i
fst qword zzman.i
(
cmp edx,3 : jz exit
fmul st(0),st(0)
'fmul st(0),st(0)
)
fstp qword esc
fadd qword zzcor.r
fst qword zzman.r
(
cmp edx,3 : jz exit
fmul st(0),st(0)
'fmul st(0),st(0)
)
fadd qword esc
fst qword esc
fld qword lmt
fcomip st(1)
fcomp st(0),st(0)
jb exit
inc ecx : cmp ecx,maxit : jl long repeat
)
mov i,ecx
[/code]




http://picasaweb.google.co.uk/charle...eat=directlink



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[Lionheart008]

@petr: thanks! so I found after a while and three coffees one good solution for me !

[code=thinbasic]' Empty GUI script created on 03-04-2010 16:47:52 by (ThinAIR)

' Example: Section 7.7 (page 222-224), Explorations with the Mandlebrot Set

' From Stan Blank's Book:
' "Python Programming in OpenGL
' "A Graphical Approach to Programming

' Converted by Stan Blank, this version is slightly downgraded in detail by Petr Schreiber

Uses "TBGL"

' insert Eros Olmi's new iComplex module
Uses "iComplex"


Function TBMain()

' Handle for our window
Local hWnd As DWord
Local Width As Long
Local Height As Long
Local n As Long
Local x,y, zz As Double

' Declare iComplex variables
Local z, c As tComplex

'# Initial values of width And height
width = 400
height = 400
'
' Create and show window
hWnd = TBGL_CreateWindowEx("Frankos_Mandelbrot Set", Width, Height, 32, %TBGL_WS_WINDOWED Or %TBGL_WS_CLOSEBOX Or %TBGL_WS_DONTSIZE)
TBGL_ShowWindow

' -- Set background from default black to white
TBGL_BackColor(0,0,0)

' -- Init OpenGl, like gluOrtho2D in example code
'TBGL_RenderMatrix2D( -2, -1.5, 1, 1.5 )
TBGL_RenderMatrix2D( -2, -2.5, 2, 2.5 )

TBGL_PointSize 1

' Resets status of all keys
TBGL_ResetKeyState()

Local percent As Double
Local p,v As Double

' -- Create new GBuffer
Local gbMandelbrot As DWord = TBGL_GBufferCreate(%TBGL_POINTS, %TBGL_2D)
Local MandelbrotIndex As Long
Local MandelbrotVertex(220000) As tbgl_tVector2f ' -- TYPE from TBGL
Local MandelbrotColor (220000) As tbgl_tRGB ' -- TYPE from TBGL
p = -0.001*Cos(GetTickCount/5000)*100

' -- Fill it with data
'For x = -2 To 1.4 Step 0.00988 'ok
For x = -2 To 2 Step 0.00988

For y = -2.5 To 2.5 Step 0.00988
Incr MandelbrotIndex
'Incr MandelbrotColor(MandelbrotIndex).r

' Set complex points
c = iComplex_Set(x,y)
z = iComplex_Set(x,y)
v = iComplex_Set(x,y)
n = 0

For n = 1 To 30
' Equation is z = z*z + c
z = iComplex_Mul(z,z)
z = iComplex_Add(z,c)
z = iComplex_Sin(z)
'z = iComplex_sub(z,v)

' Distance from origin to complex point
zz = iComplex_Abs(z)

' if distance is > 2.0, then point is NOT in the M-Set
' so plot it... the M-Set will be black
If zz > 2.0 Then
MandelbrotColor (MandelbrotIndex).R = 255
MandelbrotColor (MandelbrotIndex).B = 255
MandelbrotVertex(MandelbrotIndex).x = x
MandelbrotVertex(MandelbrotIndex).y = y
End If
Next
Next

' -- Write status
percent = (x-(-2))/3*100
TBGL_SetWindowTitle(hWnd, Format$(percent, "#.00")+"%, rendering full detail")
DoEvents

' -- Dynamically say to TBGL where the data are, this is just pointer gymnastics, no copy
TBGL_GBufferDefineFromArray(gbMandelbrot, %TBGL_DYNAMIC, MandelbrotIndex, MandelbrotVertex(1), MandelbrotColor(1))

' -- Redraw
TBGL_ClearFrame
TBGL_GBufferRender(gbMandelbrot)
TBGL_DrawFrame

' -- Escape sooner?
If TBGL_GetWindowKeyOnce(hWnd, %VK_ESCAPE) Then Exit For

Next

TBGL_SetWindowTitle(hWnd, "Behold - the other Mandlebrot! ")

' Main loop
While TBGL_IsWindow(hWnd)

TBGL_ClearFrame

TBGL_GBufferRender(gbMandelbrot)

TBGL_DrawFrame

If TBGL_GetWindowKeyOnce(hWnd, %VK_ESCAPE) Then Exit While

Wend

TBGL_DestroyWindow

End Function
[/code]

I don't give up

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

2) part:

Question!

(last edit: this morning)

about my thoughts for mandlebrot calculations:

a) first and good attempt:

Local MandelbrotVertex(160000) As tbgl_tVector2f ' -- TYPE from TBGL
Local MandelbrotColor (160000) As tbgl_tRGB ' -- TYPE from TBGL

' -- Fill it with data
For x = -2 To 1 Step 0.0075 '--> difference 3.0

For y = -1.5 To 1.5 Step 0.0075 '--> difference 3.0

b) my thoughts for bigger arranges, just an example.

Local MandelbrotVertex(260000) As tbgl_tVector2f ' -- TYPE from TBGL
Local MandelbrotColor (260000) As tbgl_tRGB ' -- TYPE from TBGL

' -- Fill it with data
For x = -2 To 3 Step 0.0025 '--> difference 5.0

For y = -1.5 To 3.5 Step 0.0025 '--> difference 5.0

=> that's calculation could be correct ?

best regards, frank

[Petr Schreiber]

Hi Frank,

you were on the right track with the differences.
The total amount of items in array is equal to:

(difference/step+1) * (difference/step+1)

(so (5/0.0025+1) * (5/0.0025+1) = 4 004 001 in your second example).


Petr

[Apongea]

Have you successfully resolved the issue with the Mandelbrot set rendering, and how do you plan to optimize the array size for larger arrangements in your calculations?