please don't make any assumptions regarding the status of the drawing buffer after calling .swapBuffers(), it is "dirty" and you should .clear() it before drawing to it (or copy a full-screen background image).

Depending on hardware, some models re-use a previous frame drawing buffer w/o clearing it - where others start a brand new one (since that's faster for the GPU they have). You can make it rule of thumb - when you do .swapBuffers(), immediately follow with .clear()

"RokuNB" wrote:
Depending on hardware, some models re-use a previous frame drawing buffer w/o clearing it - where others start a brand new one (since that's faster for the GPU they have). 

Sure 'nuf. Thank you.

I have been doing my screen.clear() on the next cycle, before the next draw stuff and screen.swapbuffers()

FUNCTION drawStuff(gS AS INTEGER, screen, mainRCC, cmpz, cmpz2, hudC, mapC, hitBC1, hitBC2)
 IF m.mAA.doLMap THEN updateLMapPlayer() ELSE spriteManage()
 checkMonStep(gS)
 screen.Clear(&h000000FF)
 drawStuffMulti(gS, screen, mainRCC, cmpz, cmpz2, hudC, mapC, hitBC1, hitBC2)
 screen.SwapBuffers()
END FUNCTION