glMultiDrawArraysIndirect usage

Hello everyone!

I'm having some problems using the glMultiDrawArraysIndirect draw function.

I have a buffer bound to GL_DRAW_INDIRECT_BUFFER containing the correct draw commands.
If i use the glDrawArraysIndirect function passing 0 or another buffer offset, it works.

However, when I try the Multi version of the function, I'm not able to make it work.
Instead of a long "indirect" offset argument, the Multi function takes a Buffer argument.
I tried different approaches, but without success:
- passing null as buffer (to have a 0 offset in the GL_DRAW_INDIRECT_BUFFER): the whole machine crashes

- passing a ByteBuffer with four bytes all initialized to 0 (also in this case to have a 0 offset): the function causes GL_INVALID_OPERATION

- passing an IntBuffer with one integer initialized to 0: the function causes GL_INVALID_OPERATION again.

In native OpenGL, passing NULL as the "indirect" pointer works fine. However, in JOGL I'm not able to achieve the same result.

Just some more information: I'm using the GL4 interface and my graphics card supports OpenGL 4.3.

Can anybody help me?

Thank you!

Hi

In the meantime, until we understand what's wrong, you can use the workaround mentioned in the documentation:
http://www.opengl.org/sdk/docs/man/xhtml/glMultiDrawArraysIndirect.xml

If stride is zero, null should be accepted.

Hi, and thanks for your answer.

You're right, I made a mistake. null is actually accepted and treated as a 0 offset in the bound buffer.

However I would like to understand if and how it is possible to specify a different offset. Whatever value I pass in the "indirect" buffer argument it gives me GL_INVALID_OPERATION.

Anyway, if I don't have any buffer bound to GL_DRAW_INDIRECT_BUFFER and I pass to the function a buffer argument which directly contains the drawing command structures, then it works fine. The problem appears only when a buffer is bound to GL_DRAW_INDIRECT_BUFFER, in which case the "indirect" argument should be interpreted as an offset in the bound buffer.

We are facing the same problem here.
Sound like there is a missing entry point:

glMultiDrawArraysIndirect(int mode, int type, long indirect_offset, int drawcount, int stride)

On 02/01/2014 12:10 AM, eban [via jogamp] wrote:
> We are facing the same problem here.
> Sound like there is a missing entry point:
>
> glMultiDrawArraysIndirect(int mode, int type, long indirect_offset, int
> drawcount, int stride)
>
>
"If a buffer is bound to the GL_DRAW_INDIRECT_BUFFER binding at the time
 of a call to glMultiDrawArraysIndirect, indirect
 is interpreted as an offset, in basic machine units, into that buffer and the
parameter"

Yes, it is missing. And this might also be a requirement for core profiles,
where CPU sourced buffers are not allowed ?!

Please file a bug report and copy/paste the information - thank you!

~Sven

On 02/06/2014 11:44 AM, Sven Gothel wrote: If anybody can provide a unit test - that would be great.
  <https://jogamp.org/bugzilla/show_bug.cgi?id=974>

~Sven

Thanks, in which release will it be included ?

On 02/21/2014 05:16 PM, eban [via jogamp] wrote:
> Thanks, in which release will it be included ?
>

Next 2.1.5 ..

~Sven