Re: What's the poop on point sprites?

It kinda sux that Apple is tying my hands in order to get customers to upgrade their hardware/software. I have a fall back, and I can just test for Tiger/Leopard at runtime. I was hoping there was a well known work around (like, turn on flat shading or something). I guess not, and if this is the will of "The Jobs", then so be it. Reason #458322 why Leopard runs faster than Tiger ;-)

The Apple guys on this list have always been great and very helpful. I may yet hear from them, but I can imagine that no one wants their name at the end of a message that states "we abandoned OpenGL on PPC under Tiger" ;-) Not that any Apple OpenGL developers did, I'm sure this was a policy decision, and a couple of the guys who haunt this list probably spoke up at a meeting some months ago, but got shot down.

Richard

On Oct 30, 2007, at 1:39 PM, John Stiles wrote:

On PowerPC machines running Tiger, OpenGL didn't receive any updates since 10.4.3 so there were a lot of long-standing bugs that didn't get addressed until Leopard. If you can't require Leopard, you are basically on your own to work around the issues. Intel was a little more lucky and got several updates during 10.4's lifespan, though whether it will see any future updates is an open quesion.

You should probably be more specific about which configurations work and which do not... that might help narrow down the issues more specifically. OS version, Intel-or-PowerPC and GPU type are the most important variables.

From: mac-opengl-bounces+jstiles=email@hidden on behalf of Richard S. Wright Jr.
Sent: Tue 10/30/2007 10:09 AM
To: OpenGL Mailing List List
Subject: What's the poop on point sprites?

I'm using point sprites and a custom shader to render a star field in
an astronomy program. Switching to this method makes my star fields
almost "free", so it's a very desirable optimization (they are
rendered via a VBO). I have four test machines, and depending on how I
move the shells around (a metaphor for you non-american readers) I get
a variety of results:

Newer machines running Tiger or Leopard... wow, that's fast and pretty.

Older machines, depending on the order of operations, or changes to
the shader... locks up machine completely with a test shader (OS X
10.4.11), or stars are always green (same machine), or points do not
obey GL_VERTEX_PROGRAM_POINT_SIZE.
I've never seen a single OpenGL feature behave so many different ways
on different machines/configurations. Point sprites really don't seem
to me to be _that_ hard to implement...

A search of the archives reveals that all these problems have been
reported before, but no one from Apple seems to have any response (or
if so, I have missed them). Older ATI hardware with 9600 based
chipsets... is this EVER going to be fixed? I'm running the newest
10.4.11 PPC build and my whole machine just freak'n hangs. I would be
happy to at least hear "this is a hardware limitation and we just
can't fix it". At least that would show up in the archives and all us
point sprite fan boys could give up our false hopes ;-)

Richard

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References:
	>What's the poop on point sprites? (From: "Richard S. Wright Jr." <email@hidden>)
	>RE: What's the poop on point sprites? (From: "John Stiles" <email@hidden>)