Instead of deleting items with 'delete' or 'free' simply add a 'deleted'
bit to the nodes and set or reset it depending if the node is used or not.
Then when walking the list, add an 'if' check to ignore the nodes with the
'deleted' bit on. Or you can move the 'deleted' nodes into a free nodes
list.
This is a technique often used on lazy memory allocation/de-allocation
algorithms and with node memory pools.
On Wed, Jul 4, 2018 at 5:45 PM, Sreyansh Jain <sreyanshjai...@gmail.com>
wrote:
> Hi,
>
> I've converted most of the 'rt_brep_shot' code to C and some of it to
> OpenCL already.
>
> I wanted to know the best way to implement the *erase* function. I've
> taken 'hits' as pointer to array (*struct brep_hit *hits;*). While *begin*
> and *end* are easily implemented, I'm stuck at direct implementation of
> *erase*.
>
>
>
> Warm Regards,
>
> Sreyansh
>
>
> On Thu, Jun 21, 2018 at 9:19 PM Vasco Alexandre da Silva Costa <
> vasco.co...@gmail.com> wrote:
>
>> Basically the game plan to tackle NURBS I can think of is the one I sent
>> to the list on March 20th:
>>
>> "With regards to BREP support, that should be more complex, since, for
>> one, that is coded in C++ and also uses an auxiliary library also in C++.
>> In order to run that on OpenCL 1.2 you would likely need to port C++
>> parts of the library to OpenCL/C, including the generic ray-BREP
>> intersection code, and the primitive-BREP conversion functions for any
>> primitives you need to support.
>>
>> It should also be possible, as a first step, to basically just make a
>> function that serializes the NURBS surfaces, etc, of the BREP form of
>> the primitive, pass that serialized form to the GPU, and then port just the
>> generic ray-BREP intersection code, rather than doing the whole BREP
>> conversion on the OpenCL side as well. i.e. serialize just the 'ON_Brep *'
>> of the primitives, then pass that to the OpenCL side which then performs
>> the actual intersections.
>>
>> For example, this is the Ellipsoid->BREP conversion function: (you need
>> to serialize and send to OpenCL the output of this)
>> https://svn.code.sf.net/p/brlcad/code/brlcad/trunk/src/
>> librt/primitives/ell/ell_brep.cpp
>>
>> It outputs the 'ON_Brep *' for that primitive.
>>
>> This contains the generic ray-BREP intersection function 'rt_brep_shot':
>> (what you need to convert to OpenCL)
>> https://svn.code.sf.net/p/brlcad/code/brlcad/trunk/src/
>> librt/primitives/brep/brep.cpp
>>
>> In case you decide to tackle this, it is probably best to first make a
>> simplified ANSI C version of 'rt_brep_shot' since that should be easier to
>> port to OpenCL/C."
>>
>>
>> On Thu, Jun 21, 2018 at 2:35 PM, Christopher Sean Morrison <
>> brl...@mac.com> wrote:
>>
>>> Sreyansh,
>>>
>>> rt_brep_prep() and rt_brep_shot() are the entry points for BREP/NURBS
>>> ray tracing. They use the openNURBS toolkit for data structures and our
>>> libbrep library for surface evaluation. That’s currently a very
>>> complicated C/C++ interaction between librt, libbrep, and openNURBS.
>>>
>>> Vasco may have a better idea, but what may make sense is to extract all
>>> of the evaluation functions in openNURBS used by rt_brep_shot() into
>>> libbrep. Then you'll only have to concern yourself with OpenCL code in one
>>> place and not worry about openNURBS for ray tracing — it would only be used
>>> for import/export (reading from and writing to disk).
>>>
>>> As for examples, openNURBS is the 3DM file format. So that means you
>>> can import a 3DM model (e.g., from GrabCAD or Google searches). You could
>>> also just use our db/nist examples.
>>>
>>> Cheers!
>>> Sean
>>>
>>>
>>> On Jun 21, 2018, at 4:55 AM, Sreyansh Jain <sreyanshjai...@gmail.com>
>>> wrote:
>>>
>>> Hi,
>>>
>>> Can you give me a detailed procedure with examples on what exactly to do
>>> for BREP support? Right now, I'm converting the rt_brep_shot() function
>>> from C++ to C since that would be easy to port to OpenCL/C.
>>>
>>>
>>> On Sat, Jun 16, 2018 at 3:07 AM Sreyansh Jain <sreyanshjai...@gmail.com>
>>> wrote:
>>>
>>>> Also, I've worked it out that after installing Ubuntu 16.04, apart from
>>>> the dependencies mentioned in https://brlcad.org/wiki/Compiling, you
>>>> need to install package* libgl1-mesa-dev *for opengl support. It's
>>>> working for me now in Ubuntu 16.04 as well. Can you check once and update?
>>>>
>>>> On Sat, Jun 16, 2018 at 2:16 AM Sreyansh Jain <sreyanshjai...@gmail.com>
>>>> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> @Vasco: Thank you for the first evaluation results and feedback. I'm
>>>>> done with both the METABALL and PIPE shot routines. I'm unable to do do
>>>>> OpenCL kernels for memory size computation for bu_lists/arrays and
>>>>> allocation. Any previous example which I can refer to?
>>>>>
>>>>> @Sean: I deployed the superell patch in my local system, but results
>>>>> were not showing up. I'm sure they don't have any unintended changes. I've
>>>>> checked my code thoroughly. It should be my local installation problem.
>>>>> Can
>>>>> you check and let me know if it's working?
>>>>>
>>>>> On Fri, Jun 8, 2018 at 1:14 AM Christopher Sean Morrison <
>>>>> brl...@mac.com> wrote:
>>>>>
>>>>>> Sorry to hear your system crashed. Good job backing up your data.
>>>>>> We need to get you set up so you are able to directly save changes as you
>>>>>> go.
>>>>>>
>>>>>> Have you made sure your changes still apply to trunk? You should
>>>>>> manually inspect it also to make sure it doesn’t have unintended changes.
>>>>>> If you have, I may be able to test it later today.
>>>>>>
>>>>>> Thank you for letting us know!
>>>>>>
>>>>>> Cheers!
>>>>>> Sean
>>>>>>
>>>>>> On Jun 6, 2018, at 5:54 PM, Sreyansh Jain <sreyanshjai...@gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> Hey,
>>>>>>
>>>>>> My system crashed. While I've had the backup of most of the files,
>>>>>> the very recent ones got lost. I wanted to inform that my work will be a
>>>>>> bit slowed for few days while I'll be working on my friend's laptop and
>>>>>> get
>>>>>> mine fixed.
>>>>>>
>>>>>> Also, did you check whether there's problem with my superell patch or
>>>>>> did I not properly apply it in my system?
>>>>>>
>>>>>> Thanks.
>>>>>>
>>>>>> On Tue, Jun 5, 2018, 9:11 PM Vasco Alexandre da Silva Costa <
>>>>>> vasco.co...@gmail.com> wrote:
>>>>>>
>>>>>>> On Tue, Jun 5, 2018 at 7:29 AM, Sreyansh Jain <
>>>>>>> sreyanshjai...@gmail.com> wrote:
>>>>>>>
>>>>>>>> Okay, let me look into it.
>>>>>>>>
>>>>>>>> I've started with METABALL primitive, although it is incomplete I
>>>>>>>> believe (metaball method). Should I retain both new and old code
>>>>>>>> (shootalgo=2 and shootalgo=3) or just one in OpenCL?
>>>>>>>>
>>>>>>>
>>>>>>> For starters just pick one of those. You can start with the default
>>>>>>> (new) code.
>>>>>>>
>>>>>>>
>>>>>>>> Also, how do I take input/define *ap->a_onehit *, *rp->r_min* and
>>>>>>>> *rp->r_max
>>>>>>>> *in OpenCL?
>>>>>>>>
>>>>>>>
>>>>>>> You can start by just assuming that ap->a_onehit is TRUE. If you do
>>>>>>> need that in the rendering phase, you can pass it as a parameter to the
>>>>>>> respective kernels in https://svn.code.sf.net/p/
>>>>>>> brlcad/code/brlcad/trunk/src/librt/primitives/primitive_
>>>>>>> util.c:clt_frame() which is called in https://svn.code.sf.net/p/
>>>>>>> brlcad/code/brlcad/trunk/src/rt/do.c:clt_run().
>>>>>>>
>>>>>>> As for rp->r_min, and rp->r_max IIRC those are the rmin,rmax bounds
>>>>>>> determined in rt_in_rpp() in rt.cl. You can get their values from
>>>>>>> bounds->p_min,bounds->p_max in rt.cl:shootray(). You'll have to
>>>>>>> pass those to the shot() function and then the respective METABALL shot
>>>>>>> function.
>>>>>>>
>>>>>>> Regards,
>>>>>>> -vasc
>>>>>>> ------------------------------------------------------------
>>>>>>> ------------------
>>>>>>> Check out the vibrant tech community on one of the world's most
>>>>>>> engaging tech sites, Slashdot.org <http://slashdot.org/>!
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>>>>>>>
>>>>>> ------------------------------------------------------------
>>> ------------------
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>>>
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>>
>>
>> --
>> Vasco Alexandre da Silva Costa
>> PhD in Computer Engineering (Computer Graphics)
>> Instituto Superior Técnico/University of Lisbon, Portugal
>> ------------------------------------------------------------
>> ------------------
>> Check out the vibrant tech community on one of the world's most
>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot______
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>>
>
> ------------------------------------------------------------
> ------------------
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> _______________________________________________
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> https://lists.sourceforge.net/lists/listinfo/brlcad-devel
>
>
--
Vasco Alexandre da Silva Costa
PhD in Computer Engineering (Computer Graphics)
Instituto Superior Técnico/University of Lisbon, Portugal
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