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Jan
07-31-2002, 02:57 AM
glFlush tells gl to execute all commands and returns immediatly. glFinish does the same but waits until all commands are executed.
Now my question: How is the best way to use these commands. There are two ways i would think of:

while (active)
{
draw objects

glFlush / glFinish

other code (input, etc.)

SwapBuffers
}

---or

while (active)
{
draw objects

glFlush / glFinish

SwapBuffers

other code (input, etc.)
}

I would prefer the first one, because while the graficscard still calculates you can do input and other stuff and therefore do it syncron. But does SwapBuffers tell the graphiscard only to swap the buffers and then returns or does it really perform the action itself and so waits until the buffers are swapped? Therefore i am not sure if the second method may be faster.
I hope you understand my question.

Jan.

Bob
07-31-2002, 03:04 AM
There's a third way, which is the way I suggest you go for: Skip glFlush/glFinish.

glFinish is usually called inside SwapBuffers anyways. This is because all commands before you swap the buffers must be completed, otherwise you will never know what is draw and what is not.