[Mesa-dev] [PATCH 0/11] implement GL_ARB_debug_output

Brian Paul brianp at vmware.com
Tue May 3 16:33:33 PDT 2011

On 05/02/2011 04:59 PM, nobled wrote:
> git repo:
> https://github.com/nobled/mesa.git
> (branch: arb_debug_output, rebased on bd661a933b18fccd7102d05932774ee61a90ec9e)
> web interface:
> https://github.com/nobled/mesa/commits/arb_debug_output
> spec:
> http://www.opengl.org/registry/specs/ARB/debug_output.txt
> This series adds almost everything needed to advertise the extension
> GL_ARB_debug_output. The only thing missing is the ability to pass an
> array of IDs to glDebugMessageControlARB with the parameter 'source'
> Since the *ControlARB stuff was the part I was least certain about, I
> also broke it up into even smaller patches. What I think is needed to
> fill in the missing functionality is a structure that works like C++'s
> std::map, with a GLuint/GLboolean key/value pair. There would also
> need to be, for each map, three std::set-like structures that record
> the HIGH, MEDIUM, and LOW-severity message IDs. Otherwise it wouldn't
> be possible for clients to make calls like this that impact all
> messages of a certain severity level:
>                           GL_DEBUG_SEVERITY_LOW_ARB, 0, NULL, GL_TRUE);
> Does mesa have structures like those in the auxiliary code somewhere?
> Or is there a way to wrap the C++ STL in C code?

To map GLuint to 'something' we typically use the hash table in hash.c 
  Otherwise, you could make something based on simple_list.h.  I 
believe we're talking about a pretty small set of GLuints, right?  So 
linear search wouldn't be a big deal?

> Open question: The app might pass 'implementation-dependent' message
> IDs to glDebugMessageControlARB that don't actually exist in mesa. The
> spec doesn't say whether we should give an error or silently ignore
> IDs like that.
> Also an open question: what to do when apps misbehave and send the
> same source/type/message ID tuple to glDebugMessageInsertARB twice or
> more, but with different severity levels each time, and then they call
> glDebugMessageControlARB on all messages with a certain severity.
> Should mesa use the latest-specified severity as the canonical one, or
> the first?

I haven't even read the spec for this extension yet so I don't have 
any answers for you.

I did a quick review of your patches and they mostly look OK.  I'll 
post specific comments in a bit.

It looks like almost all the changes are confined to errors.c and 
mtypes.h so I'm not too worried about regressions or a big impact on 
the rest of the code.

I'm OK with you committing what you have and following up with changes 
if/when the above questions get answered.


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