But if you clear the buffer (using Cls), in the end you will only see the last rectangle that was drawn. I see 5 rectangles because you draw one, flip it to front, and flip front to back. Front was empty so back is now empty. You draw one, and so on: of every two rectangles you draw, each of them will end up on a different buffer. (Or, on one of the two images that you are flipping between back and front.)
When you see 10 rectangles, this means that when you do flip, the back is flipped to the front *but the front is not flipped to the back*. So you draw a rectangle, flip it to front. You draw a second rectangle next to the first one and flip the result, two rectangles, to front. This way, you will have all 10 rectangles in the end.
So with respect to dependency on video card, I think the difference between two cards would be in the effect of the Flip command, with these two possibilities:
a) Flip has the effect of *interchanging* the contents of back and front
b) Flip has the effect of copying back to front
My video card (5 rectangles) would be doing "a" while your video cards (10 rectangles) would be doing "b".
Or could it be a difference between the way Flip is operating in Blitz 2D versus Blitz Plus? (As I am using Blitz 2d.)
When you see 10 rectangles, this means that when you do flip, the back is flipped to the front *but the front is not flipped to the back*. So you draw a rectangle, flip it to front. You draw a second rectangle next to the first one and flip the result, two rectangles, to front. This way, you will have all 10 rectangles in the end.
So with respect to dependency on video card, I think the difference between two cards would be in the effect of the Flip command, with these two possibilities:
a) Flip has the effect of *interchanging* the contents of back and front
b) Flip has the effect of copying back to front
My video card (5 rectangles) would be doing "a" while your video cards (10 rectangles) would be doing "b".
Or could it be a difference between the way Flip is operating in Blitz 2D versus Blitz Plus? (As I am using Blitz 2d.)