Rene, I think you and I agree on all the principles, but we disagree on how we think reality stacks up.
discussion responses inline below, but what I'm most interested in is having objective data that would drive a decision.
On Tue, Feb 3, 2009 at 4:36 PM, René Dudfield
<renesd@xxxxxxxxx> wrote:
Many older opengl calls have been broken. Many opengl calls are
broken on all sorts of different drivers. Some calls are broken in a
BSOD way, and others fail silently. This is why engines use so many
work arounds and different opengl paths and avoid all sorts of
different opengl calls that are known to crash. Opengl programs will
fail on many, many more computers than the SDL directx driver -- I can
point you at stats where some games have recorded the number of
crashes.
We must be talking about different parts of opengl, because that has not been my experience at all with the 2d paths on opengl. Sending verts, Tris, display lists, textures, colors, turning off lighting & the zbuffer, setting the blend mode - the opengl 1.2 way of doing all those things is still absolutely 100% standard opengl stuff in 2.x and works perfectly well with any sane well-formed data. There may be rare exceptions like some drivers deal differently with zero area tri's and some weird bad cases. Also, antialiasing and rects and lines are all unreliable crap that maybe should never be used. But there is definitely no issue with the core parts of the API used for simple 2d being deprectated and untested on modern cards and drivers, like there is with directX versions.
If you use fancy extension modules (programmable shaders, accumulation buffers, etc) you may have a world of driver compatibility stuff to deal with I grant you, but with SDL 1.2's very simple HWSURFACE blit needs, you'd never touch any of that.
... anyways, that's all not really relevant to SDL's use of directX, cause there's no openGL to switch to for windows :(
the problem with SDL 1.2's directx support is that it's written for directX 5 - the api between directX 5 and 7 got major overhauls - in particular all the 2d stuff in 5 got stripped out, gamma and palettes were ditched, the rendering pipeline was changed. Then in direct x 8.1, the programmable pipeline was introduced. Then in directX 9.0, the fixed function pipeline was removed entirely. Finally, in directX 10, a bunch of backwards compatibility (including letting you talk in the language of 5) was removed entirely.
doesn't all that make one think running DirectX 5 code as the default for XP is maybe not a good idea?
This particular instance of directx crashing is because it's most
likely overwriting memory somewhere. Normal use will *not* cause this
crash. Developing to this API may cause this crash -- like developing
to all other APIs on all other platforms. Using pygame should not be
able to cause memory overwrites... however Lenard
I agree - the python process is not able to corrupt and overwrite memory of anything other than it's own process without some drivers help.
That's kind of my point - I'm saying when SDL tries to talk directX 5 with the installed directX, directX is translating that to directX 7,8 or 9 driver language (but not to version 10 driver language...) and talking with the driver, which has most likely not been tested at all for that kind of translation (MS didn't make it a requirement to be certified, and a lot of drivers didn't even do certification). The end result being the driver corrupts stuff cause it couldn't handle what pygame/SDL told it.
We don't disagree here, right?
Using directx as default on older computers makes sense because they
are using the older drivers.
sure in extreme cases that's true, but how "older" are we talking here? SDL uses directX 5, which came out in 1997, almost 12 years ago. directx 7 came out in 2000, almost 9 years ago. Also, Windows 2000 has a minimum of DirectX 7, Me has a minimum of 7.1 and XP has a minimum of 8.1
So the only machine I would agree that SDL's directX is definitely "best" for is around 10-12 years old and win 98. everything after that seems up in the air to me. I know Vista is currently windib default, but I think XP should be too.
maybe we just roll back the directx default to one more OS edition backwards?
Making a real time application like a game go too slow is breaking the
game. This will happen on older computers by making the windib driver
the default on older versions of windows.
sure, I will agree making a game going "too slow" is breaking the game. But there's degrees of things. If some things went a little slower (but not too slow) but other computers weren't getting messed up until they are rebooted, that seems worth it to me.
I mean, making a computer messed up until it's rebooted seems very serious breakage to me, which is what Lenard experienced. I'd say that's some really messed up behavior that's much worse than a game running too slow.
Also, as far as what will and won't more a game too slow - I'll agree with windib making games too slow on win 98 and below, for sure. 2000 and Me I'd say I wouldn't know. on XP though, I'd rather see the SDL default being the pygame default unless it's obvious from tests or other data that windib makes games "too slow"
The SDL directx driver is tested by video driver companies. Even the
intel drivers fixed their problem they were having with SDL programs,
so newer drivers (as in < 2 years) have fixed the crashes.
that doesn't mean they tested with pygame - it doesn't mean they tested SDL with all of pygame's features either. I agree we may be able to get pygames usage more in line with common SDL stuff, but if our usage is not tested, it's not tested.
Also, are you sure they fixed stuff that happened with SDL programs that used directX backend? I'm sure they fix stuff with SDL 1.2, but SDL moved to windib default, for all Windows OS. And SDL + OpenGL is a popular combo, much more that SDL + HWSURFACE in my experience.
Note: the windib driver is chosen as default for most new computers.
You mean for Vista computers, right? there's no age check per se, right?
Some OpenGL failure stats for you.
Some stats to give you more of an idea:
http://www.catnapgames.com/blog/181
http://www.steampowered.com/status/survey.html (note only directx +
other stats)
ref: http://forums.indiegamer.com/showpost.php?p=139044&postcount=8
well all that data just talks about the availability of openGL on windows and Mac - it's nothing to do with api revisions becoming poorly supported over time, which is the point I wanted to make about DirectX. However, I think it was a mistake on my part to bring up OpenGL, sorry to confuse the issue.