PNG Decoder reads RGBA(0,0,0,$FF) as 0

[Deeem2031]

Code: Select all

InitSprite()
InitSprite3D()
OpenWindowedScreen(OpenWindow(0,0,0,800,600,"",#PB_Window_SystemMenu|#PB_Window_ScreenCentered), 0,0,800,600,0,0,0)

UsePNGImageDecoder()
LoadSprite(0, "bg_00.png", #PB_Sprite_Texture)
CreateSprite3D(0, 0)
LoadSprite(1, "bg_01.png", #PB_Sprite_Texture)
CreateSprite3D(1, 1)

ZoomSprite3D(0, 800, 600)
ZoomSprite3D(1, 800, 600)
Repeat
  
  Start3D()
  DisplaySprite3D(1, 0, 0)
  DisplaySprite3D(0, 0, 0)
  Stop3D()
  FlipBuffers()
    
  Select WindowEvent()
    Case #PB_Event_CloseWindow
      quit = #True
  EndSelect
Until quit

bg_00.png: http://www.deeem2031.de/PB/bg_00.png
bg_01.png: http://www.deeem2031.de/PB/bg_01.png

The result:



As you can see there are yellow pixels even thought the second DisplaySprite3D() should cover the whole screen. My guess is that the png decoder decodes the pixels with a RGBA(0,0,0,$FF) value as RGBA(0,0,0,0).

P.S.: Or DisplaySprite3D somehow interprets RGBA(0,0,0,$FF) as RGBA(0,0,0,0)

[c4s]

[OFFTOPIC]
Is this a screenshot from Conspiracy's "Beyond"?
...Oh I love this demo!
[/OFFTOPIC]

[Deeem2031]

[OFFTOPIC]
Is this a screenshot from Conspiracy's "Beyond"?
...Oh I love this demo!
[/OFFTOPIC]

Yes. (The next version of eirstt will use screenshots of this demo as background images.)

[Fred]

By default, PB use the 0,0,0 color as transparent (can be changed with TransparentSpriteColor()), unless you speficy otherwise. To use the 32 bits alpha channel info instead, you need to use the '#PB_Sprite_AlphaBlending' flag:

Code: Select all

InitSprite()
InitSprite3D()
OpenWindowedScreen(OpenWindow(0,0,0,800,600,"",#PB_Window_SystemMenu|#PB_Window_ScreenCentered), 0,0,800,600,0,0,0)

UsePNGImageDecoder()
LoadSprite(0, "bg_00.png", #PB_Sprite_Texture | #PB_Sprite_AlphaBlending)
CreateSprite3D(0, 0)
LoadSprite(1, "bg_01.png", #PB_Sprite_Texture | #PB_Sprite_AlphaBlending)
CreateSprite3D(1, 1)

ZoomSprite3D(0, 800, 600)
ZoomSprite3D(1, 800, 600)
Repeat
 
  Start3D()
  DisplaySprite3D(1, 0, 0)
  DisplaySprite3D(0, 0, 0)
  Stop3D()
  FlipBuffers()
   
  Select WindowEvent()
    Case #PB_Event_CloseWindow
      quit = #True
  EndSelect
Until quit