DrawingBuffer() and Brushes

[Michael Vogel]

I found out, that on some graphic cards there is an impact, when the DrawingBuffer() command is used (should only return a memory value)

On a Mobility Radeon, the polygon in the following is not seen, only when removing the three DrawingBuffer lines...

On other graphic cards I did not have this effect, so I don't know if I wrote some wrong code, it's a hardware or software bug?!

Code: Select all

Global Dim Polygon(8)

InitSprite()
win=OpenWindow(1,0,0,600,600,"3D-View",#PB_Window_ScreenCentered|#PB_Window_BorderLess)
	OpenWindowedScreen(win,0,0,600,600,0,0,0)

	polygon(0)=0
	polygon(1)=0
	polygon(2)=500
	polygon(3)=0
	polygon(4)=500
	polygon(5)=500
	polygon(6)=0
	polygon(7)=500

Repeat
windc=StartDrawing(ScreenOutput())

	DxMem=DrawingBuffer()
	DxMul=DrawingBufferPitch()
	DxPix=DrawingBufferPixelFormat()

DrawingMode(#PB_2DDrawing_Transparent)

winbrush=CreateSolidBrush_($ffff)
SelectObject_(windc,winbrush)
Polygon_(windc,@Polygon(),4)
DeleteObject_(winbrush)
StopDrawing()
FlipBuffers()

Until WaitWindowEvent(10) = #WM_CHAR

[Trond]

I also have this effect on a ProSavage DDR.

[thefool]

Same on radeon 9600 xt 256

[ABBKlaus]

and same on Radeon X800GTO²

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maybe someone could post the error codes in english

Code: Select all

ProcedureDLL.s GetLastError()
  err=GetLastError_()
  Debug err
  buffer.l=0 
  ferr=FormatMessage_(#FORMAT_MESSAGE_ALLOCATE_BUFFER|#FORMAT_MESSAGE_FROM_SYSTEM,0,err,0,@buffer,0,0)
  If buffer<>0
    errormsg$=PeekS(buffer)
    LocalFree_(buffer)
    errormsg$=RemoveString(errormsg$,Chr(13)+Chr(10))
    ProcedureReturn errormsg$
  EndIf
EndProcedure

Global Dim Polygon(8) 

InitSprite() 
win=OpenWindow(1,0,0,600,600,"3D-View",#PB_Window_ScreenCentered|#PB_Window_BorderLess) 
   OpenWindowedScreen(win,0,0,600,600,0,0,0) 

   polygon(0)=0 
   polygon(1)=0 
   polygon(2)=500 
   polygon(3)=0 
   polygon(4)=500 
   polygon(5)=500 
   polygon(6)=0 
   polygon(7)=500 

Repeat 
 windc=StartDrawing(ScreenOutput()) 

   DxMem=DrawingBuffer() 
   err$=GetLastError()
   debug err$
   CallDebugger
   ;DxMul=DrawingBufferPitch() 
   ;DxPix=DrawingBufferPixelFormat() 

   ;DrawingMode(#PB_2DDrawing_Transparent) 

   ;winbrush=CreateSolidBrush_($ffff) 
   ;old=SelectObject_(windc,winbrush) 
   ;Polygon_(windc,@Polygon(),4) 
   ;DeleteObject_(winbrush)
   ;SelectObject_(windc,old) 
 StopDrawing() 

 FlipBuffers() 

Until WaitWindowEvent(10) = #WM_CHAR

[Rescator]

Not sure it's actually a bug, Fred need to clarify this.
My guess is that it's a documentation error regarding DrawingBuffer()

This example works. (sorry, quick and dirty just to show the difference)

Code: Select all

Global Dim Polygon(8)

InitSprite()
win=OpenWindow(1,0,0,600,600,"3D-View",#PB_Window_ScreenCentered|#PB_Window_BorderLess)
   OpenWindowedScreen(win,0,0,600,600,0,0,0)

   polygon(0)=0
   polygon(1)=0
   polygon(2)=500
   polygon(3)=0
   polygon(4)=500
   polygon(5)=500
   polygon(6)=0
   polygon(7)=500

Repeat
windc=StartDrawing(ScreenOutput())
If windc

   DxMem=DrawingBuffer()
   DxMul=DrawingBufferPitch()
   DxPix=DrawingBufferPixelFormat()
 StopDrawing()

 windc=StartDrawing(ScreenOutput())
 If windc
  
  DrawingMode(#PB_2DDrawing_Transparent)
  
  winbrush=CreateSolidBrush_($ffff)
  SelectObject_(windc,winbrush)
  Polygon_(windc,@Polygon(),4)
  DeleteObject_(winbrush)
  StopDrawing()
 EndIf
EndIf
FlipBuffers()

Until WaitWindowEvent(10) = #WM_CHAR

Yep! StopDrawing() must be done then drawing has to be restarted again to do/use other gfx functions.
The reason for this is that I supect PB enteres into direct buffer manipulation,
so you must do StopDrawing() so PB can go back to normal buffering.

You also have to take great care exactly "when" you edit the graphics memory buffer directly.
You either should do it at the very start of your routine before any other gfx effects,
or at the very end when you are done with your gfx functions.

If you place DrawingBuffer() after all your other processing so that only StopDrawing is next your code works.
I have no idea why it behaves like this, but as I said. I'm unsure if this is a bug or a windows "feature"

[Michael Vogel]

Start/StopDrawing costs a lot of time, I'll try to do a fast 3D rotation, so I needed to reduce these commands when possible.

I think I've solved it (at least for my special case), now the polygon (press 'c' in view mode to change color themes), boxes, text and lines ('a' changes the antialiasing mode) live all together in one StartStop Drawing code segment...

If you like to see the result...
>>> http://sudokuprogram.googlepages.com/forerunner.exe
you may also need
>>> http://sudokuprogram.googlepages.com/MichaelVogel.hst