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发信人: ziya (阿水 ), 信区: CAD
标  题: OpenGL FAQ 3
发信站: BBS 荔园晨风站 (Sun Dec  6 14:30:14 1998), 站内信件

Q_3_01:  Who needs to license OpenGL?  Who doesn't?

A:  Companies which will be creating or selling binaries of the

OpenGL library will need to license OpenGL.  Typical examples of

licensees include hardware vendors, such as Digital Equipment,

and IBM who would distribute OpenGL with the system software on

their workstations or PCs.  Also, some software vendors, such as

Portable Graphics and Template Graphics, have a business in creating

and distributing versions of OpenGL, and they need to license OpenGL.

Applications developers do NOT need to license OpenGL.  If a

developer wants to use OpenGL, that developer needs to obtain

copies of a linkable OpenGL library for a particular machine.

Those OpenGL libraries may be bundled in with the development

and/or run-time options or may be purchased from a third-party

software vendor, without licensing the source code or use of the

OpenGL(R) trademark.

Since many implementations will be a shared library on a hardware

platform, the royalty sometimes will be charged for each hardware

platform.  In those cases, it would not be charged for each

application which used OpenGL.

In general, licensing a source code implementation of OpenGL

would not be useful for an application developer, because the

binary created from that implementation would not be accelerated

and optimized to run on the graphics hardware of a machine.

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Q_3_02:  What are the conformance tests?

A:  The conformance tests are a suite of programs which judge the

success of an OpenGL implementation.  Each implementor is

required to run these tests and pass them in order to call their

implementation with the registered trademark OpenGL.  Passing the

conformance tests ensures source code compatibility of

applications across all OpenGL implementations.

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Q_3_03:  What is Silicon Graphics policy on "free" implementations

         of APIs which resemble the OpenGL API?

Silicon Graphics, as licensor of the OpenGL(R) trademark, does not

permit non-licensed use of the OpenGL trademark, nor does it permit

non-licensed use of the OpenGL conformance tests.  Silicon Graphics

provides a source code sample implementation of OpenGL, but only to

companies and organizations which agree to the terms and conditions of

an OpenGL license.

Silicon Graphics does give permission to others to create and distribute

their own implementations of the OpenGL API, provided they do not

state nor imply they have the right to use the OpenGL(R) trademark to

name their product, nor make claims to conformance based upon the ARB

controlled OpenGL conformance tests.  Silicon Graphics agrees to allow

others to copy the OpenGL header files, as much as is necessary, for

the creation of other implementations.

Silicon Graphics is in no way associated nor endorsing these

other graphics libraries.  Silicon Graphics does not make any

claims or guarantees as to the quality, performance, nor

completeness of an unlicensed library.

------

Q_3_04:  What is Mesa 3D and where can I get it?

From brianp@ssec.wisc.edu (Brian Paul)

The "Mesa 3-D graphics library" (or just Mesa) is a free

implementation of the OpenGL API.  It has been compiled and

tested on most major Unix/X systems.  All you should need is an

ANSI C compiler and X.

There is a WWW page at http://www.ssec.wisc.edu/~brianp/Mesa.html

You can get Mesa by anonymous ftp from iris.ssec.wisc.edu in the

pub/misc/ directory.

Mesa is currently in beta release.  Some features are not yet

implemented and you may find new bugs.  See the WWW page for

updated information.

Pedro Vazquez (vazquez@iqm.unicamp.br) has set up a mailing list

for users of the Mesa 3-D graphics library.  Anyone who uses Mesa

and/or wants to be kept up to date on Mesa developments is

invited to subscribe.

To subscribe to the list send the following message to

listserv@iqm.unicamp.br

subs mesa <your name>

set mesa mail ack

For example:

subs mesa Brian Paul

set mesa mail ack

The second line tells the list processor to send you a copy of

your own messages.

You will receive a welcome message from the list server when you

have been added to the list.  It tells you how to post messages

to the list, how to unsubscribe, etc.

------

Q_3_05:  How does a university or research institution acquire access

         to OpenGL source code?

A:  There is a university/research institution licensing program.  A

university license entitles the institution to generate binaries and

copy them anywhere, so long as nothing leaves the institution.  The

OpenGL source and derived binaries can only be used for non-commercial

purposes on-campus.

A university license costs $500 US.  This license provides source

code for a sample implementation of OpenGL.  This source code is

best designed for porting onto a system which supports the X

Window System.  You can drop this into the X Consortium's X11

server source tree and build a server with the OpenGL extension.

To do this properly, you should have the MIT source for an X

Server and some experience modifying it.

Note that this gets you a software renderer only.  If your

machine includes a graphics accelerator, the sample

implementation is not designed to take any advantage of it.

To obtain a university license, contact John Schimpf, OpenGL

Licensing Manager at Silicon Graphics (jsch@sgi.com).  Please

provide a mailing address, telephone and fax number.

Universities may also be interested in Mesa 3D.  See Q12.

------

Q_3_06:  How is a commercial license acquired?

If you need a license or would like more information, call John

Schimpf at (415)390-3062 or e-mail him at jsch@sgi.com.  There are

licenses available restricted to site (local) usage, or

permitting redistribution of binary code.  The limited source

license provides a sample implementation of OpenGL for $50,000.

The license for commerical redistribution of OpenGL binaries has

two most commonly chosen levels.  Level 1 costs $25,000.  Level 2

costs $100,000, and includes the sample implementation of OpenGL.

Both levels require a $5 royalty for every copy of the OpenGL

binary, which is redistributed.

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Q_3_07:  How is the OpenGL governed?  Who decides what changes can be made?

A:  OpenGL is controlled by an independent board, the Architecture

Review Board (ARB).  Each member of the ARB has one vote.  The

permanent members of the ARB are Digital Equipment, IBM, Intel,

Microsoft, and Silicon Graphics.  Additional members will be added

over time.  The ARB governs the future of OpenGL, proposing and

approving changes to the specification, new releases, and conformance

testing.

------

Q_3_08:  Who are the current ARB members?

A:  In alphabetical order:  Digital Equipment, Evans & Sutherland,

IBM, Intel, Intergraph, Microsoft, and Silicon Graphics.

------

Q_3_09:  What is the philosophy behind the structure of the ARB?

A:  The ARB is intended to be able to respond quickly and flexibly to

evolutionary changes in computer graphics technology.  The ARB is

currently "lean and mean" to encourage speedy communication and

decision-making.  Its members are highly motivated in ensuring the

success of OpenGL.

------

Q_3_10:  How does the OpenGL ARB operate logistically?  When does the

         ARB have meetings?

A:  ARB meetings are held about once a quarter.  The meetings rotate

among sites hosted by the ARB members.  To learn the date and place of

the next OpenGL ARB meeting, watch the news group comp.graphics.opengl

for posting announcing the next "OpenGL ARB meeting", check the

Web site http://www.sgi.com/Technology/openGL/arb.location.html

or e-mail opengl-secretary@sgi.com and ask for the information.

Meetings are run by a set of official by-laws.  A copy of the

by-laws may be requested from the Secretary of the OpenGL ARB.

Minutes to the ARB meeting are posted to comp.graphics.opengl

and are available via ftp://sgigate.sgi.com/pub/opengl/arb/

------

Q_3_11:  How do additional members join the OpenGL ARB?

A:  The intention is that additional members may be added on a

permanent basis or for a one-year term.  The one-year term members

would be voting members, added on a rotating basis, so that

different viewpoints (such as ISV's) could be incorporated into new

releases.  Under the by-laws, SGI formally nominates new members.

------

Q_3_12:  So if I'm not a member of the ARB, am I shut out of the

         decision making process?

A:  There are many methods by which you can influence the evolution of

OpenGL.

1) Contribute to the comp.graphics.opengl news group.  Most members of

the ARB read the news group religiously.

2) Contact any member of the ARB and convince that member that your

proposal is worth their advocacy.  Any ARB member may present a

proposal, and all ARB members have equal say.

3) Come to OpenGL ARB and speak directly to ARB.

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Q_3_13:  Are ARB meetings open to observers?

A:  The ARB meeting will be open to observers, but we want to keep the

meeting small.  Currently, up to five non-voting representatives

who inform the ARB secretary in advance, can observe and participate in

the ARB meeting.  At any time, the ARB reserves the right to change

the number of observers.

------

Q_3_14:  What benchmarks exist for OpenGL?

A:

     OpenGL Performance Characterization for the GPC:

         http://sunsite.unc.edu/gpc/opc.html

     Viewperf 3.0 source:

         ftp://net1.uspro.fairfax.va.us/pub/gpc/opc/viewperf/

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