Re: [AD] Framerate under the 4.1.x WIP Windows builds is mysteriously slow.

[Peter Hull <peter.hull90@xxxxxxxxxx>]

I've been looking at the DirectX9 documentation and also I have a rough 
idea how OpenGL does things. Is it fair to say that:

The only thing stopping Allegro from using more hardware acceleration 
is that it has a readable 'screen' bitmap?

Under both these systems, the method seems to be that you draw 
everything onto an off-screen buffer, and then show it, using the 
'Present' or 'flip' function. In OpenGL you can't even read the 
off-screen buffer, but in DX9 you can (you have to specially request a 
'lockable back buffer' - which may reduce performance, I don't know)

In many game situations you don't need to read from 'screen', or even 
from the back-buffer. The two obvious examples are floodfill and 
translucency, and the latter would be done by the hardware anyway.

What I'm wondering is whether the future Allegro could have a flag in 
set_gfx_mode() to say that you don't need to read from 'screen,' and in 
that case, better use of acceleration could be made.

Is this correct or have I misunderstood the way Allegro works?

Pete