Author Topic: Palm WebOS - Bug in USESCREEN  (Read 1561 times)

Offline Kitty Hello

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Palm WebOS - Bug in USESCREEN
« on: 2011-Jul-18 »

there's a driver bug in the WebOS platforms, that does not allow you to draw to an off-screen, paste that screen and draw again on it.
When you do SHOWSCREEN, the contents of the off-screen are pasted to the back buffer with the last state it has, no matter at what position you draw it. Like:

Code: (glbasic) [Select]
CREATESCREEN 0,0, 100,100
DRAWSPRITE 0,0,0 // draw the "still empty" screen
    PRINT "TEST",0,0

This will print "TEST" to your screen. The DRAWSPRITE is buffered and executed only after the showscreen. So, if you need to reuse an offscreen, create a 2nd one, instead.
I think they buffer all GL calls for even more graphics power and flush on swapping the buffers.