[Xr] What happended to the idea of getting rid of the xrs argument?
spitzak at d2.com
Thu Jun 12 09:18:54 PDT 2003
On Wednesday 11 June 2003 07:57 pm, David Forster wrote:
> void SwfRender(XrState* xrs, SwfAnimation *swf, int time);
My main concern with this solution is that it requires the existence of
XrState to be declared in the header files for almost every part of the
toolkit. I have some worry that this will make it difficult to emulate Xr on
Windows, which I would like to do, so that fltk programs can use Xr directly
but be portable to Windows. This problem can be mostly eliminated by
declaring that XrState really is a structure (not a C++ class, macro, or
typedef). Then a header file can say "struct XrState" instead of including
the Xr.h header.
> In fact, as an aside, this might be a good example where I want thread
> safety. I might not want to block all other rendering while my SWF
> render strains over a complex animation. So I'd have my SwfRender()
> loop run on it's own thread with it's own XrState*.
Absolutley, any static XrState must be per-thread, just like it is in OpenGL.
One advantage I see of having the Xr library do this is that the method used
for this is hidden inside the implementation and can be changed per platform,
as thread-local variables are not standardized yet. If I use a global XrState
I will probably not be thread-safe.
> I'm actully working on some code where I might use a global XrState*
> object, and have written my own wrapper. You can grab it at:
Actually this looks like a reasonable solution, because the names of the
functions are agreed on, which would make cut & paste work. I could in fact
make fltk declare the "xrs" functions on Windows and use this on X. Fltk
would provide a small header that does the Windows emulation, and declares
your current/push/pop macros and then includes your header. Note in my case
the xrs calls will work before the first push is done, as I expect I will use
a single xrs and do SetTargetSurface on it to change windows, unless somebody
tells me that that is a bad idea.
,~,~,~,~ ~ ~ ~ ~
/\_ _|_========___ Bill Spitzak
~~~/\/\\~~~~~~\____________/~~~~~~~~ spitzak at d2.com
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