PureBasic Forums - English

Posted: **Sat Aug 21, 2004 12:50 am**

I'm Creating a Faster way to draw with the use of the DrawingBuffer() command (along with the other ones too)
and i need a bit of help to understand the how to "poke" the color data into the buffer at a x and y
i kinda have an idea for some modes but for others i don't have a clue like 8 bit and 15bit

also converting colors that rgb() puts out to work with this

Posted: **Sat Aug 21, 2004 7:49 am**

I guess this will help :

when you code a :

Plot(x, y, Color)

the PokeL equivalent is :

PokeL(DrawingBuffer() + y * DrawingBufferPitch() + x * 4, Color)

Then the best is to store :

DrawingBuffer = DrawingBuffer()
DrawingBufferPitch = DrawingBufferPitch()

somewhere just after StartDrawing(ScreenOutput()),

and to loop Pokes after.

Also when doing part or full screen pokes, will allow you to loop considering rows and lines so that you can do something like this :

Code: Select all

  Left = 100
  Top = 100
  Right = 300
  Bottom = 300
  If InitSprite() And InitKeyboard() And OpenScreen(1024, 768, 32, "Screen")
      Repeat
        FlipBuffers(0)
        StartDrawing(ScreenOutput())
          DrawingBuffer = DrawingBuffer()
          DrawingBufferPitch = DrawingBufferPitch()

          Address = DrawingBuffer ; a full screen paint
          For y = 0 To 767
            For x = 0 To 1023
              Color = #Blue
              PokeL(Address, (Color & $FF0000) >> 16 + (Color & $00FF00) + (Color & $0000FF) << 16)
              Address + 4
            Next
          Next

          For y = Top To Bottom ; a part screen paint
            Address = DrawingBuffer + y * DrawingBufferPitch + 4 * Left
            For x = Left To Right
              Color = Random($FFFFFF)
              PokeL(Address, (Color & $FF0000) >> 16 + (Color & $00FF00) + (Color & $0000FF) << 16)
              Address + 4
            Next
          Next

        StopDrawing()
        ExamineKeyboard()
      Until KeyboardPushed(#PB_Key_Escape)
  EndIf
End

As you see, you will probably have to switch the color attribute from RGB to BGR (see DrawingBufferPixelFormat() function to know the color format).

The better way would be to code in ASM for a good optimization of your code. But you will probably it is not easy to go as fast or faster than PureBasic does.

Also be really carefull never address outside the screen's pixels. This means you will probably have to place tests to check if pixel's coordinates are inside the screen range.

Rgrds

Posted: **Sat Aug 21, 2004 11:50 pm**

thanks for the info!

but i still need a way to convert rgb data (seprate varibles) to the require bit depth (8 bit we could proably skip but if you can supply me with that great)

Posted: **Sun Aug 22, 2004 2:39 pm**

I guess something like this would work fine without to slow your program too much.

If I do not mistake it is exhaustive and does not use anything else PureBasic.

Tell me if this meets your needs, testing it in # configurations.

Rgrds

Code: Select all

;
;Make DrawingBuffer parameters global to save some lines and performances.
Global Drawingbuffer.l, DrawingbufferPitch.l, DrawingBufferPixelFormat.l

;
; A sample code procedure to convert the color if necessary
;
Procedure ConvertPixelColorToRawPixelColor(Color.l)
    Select DrawingBufferPixelFormat
      Case #PB_PixelFormat_24Bits_BGR
        ProcedureReturn (Color & $FF0000) >> 16 + (Color & $00FF00) + (Color & $0000FF) << 16
      Case #PB_PixelFormat_32Bits_BGR
        ProcedureReturn (Color & $FF0000) >> 16 + (Color & $00FF00) + (Color & $0000FF) << 16
      Default
        ProcedureReturn Color
  EndIf
EndProcedure

; ... in your main or procedure opening the drawings :
  StartDrawing(ScreenOutput()) ; or SpriteOutput()
    DrawingBuffer = DrawingBuffer()
    DrawingbufferPitch = DraxingBufferPitch()
    DrawingBufferPixelFormat = DrawingBufferPixelFormat()
    ; ... draw whatever you want
  StopDrawing()
  ; etc

PureBasic Forums - English

using drawingbuffer

using drawingbuffer