Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 3 July 2013 22:36, Guillermo Polito guillermopol...@gmail.com wrote:
 I'm just guessing, but if a function receives a pointer, it does not store
 the pointer anywhere but works with the contents, and finally returns while
 VM is blocked, voilá :).

Yes.


 On Wed, Jul 3, 2013 at 10:13 PM, Stéphane Ducasse
 stephane.duca...@inria.fr wrote:



 if you pass a pointer to something in object memory into function,
 make sure GC cannot move the object while function uses/accessing its
 contents.


 How?






-- 
Best regards,
Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Stéphane Ducasse]

ok we should write that in the NB chapter.

On Jul 3, 2013, at 10:36 PM, Guillermo Polito guillermopol...@gmail.com wrote:

 I'm just guessing, but if a function receives a pointer, it does not store 
 the pointer anywhere but works with the contents, and finally returns while 
 VM is blocked, voilá :).
 
 
 On Wed, Jul 3, 2013 at 10:13 PM, Stéphane Ducasse stephane.duca...@inria.fr 
 wrote:
 
 
 if you pass a pointer to something in object memory into function,
 make sure GC cannot move the object while function uses/accessing its 
 contents.
 
 How?
 
 
 

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 2 July 2013 23:04, kilon theki...@yahoo.co.uk wrote:
 Thank you Igor for the clarifications, the reason why I prefer using the
 nativeboost methods is because :

 a) I was not sure if smalltalk types map correctly to C types and which
 Smalltalk types correspond to which C types

well, there's no such thing as 'types' in smalltalk :)


 b) many opengl functions ask for the address of the value and the value
 itself. And I have no clue how to obtain memory addresses of smalltalk
 types.


you don't. The value can have a type, but address don't.
Address is just a location in memory, where the value(s) (could be) stored.

For any function which takes a pointer, you can pass an instance of ByteArray,
or instance of NBExternalAddress to it. In first case, a pointer to
first byte of bytearray
will be passed to function, in second one , the value of address.

So, you either allocate buffer in object memory, or external memory..
fill it with whatever
it needs and pass to function. Does that sounds simple enough?

 c) I was not sure whether Pharo VM or garbage collector would move my data
 making my pointers invalid.

 But if you say its ok, I trust you. When exactly is ok to use smalltalk
 types ?

if you pass a pointer to something in object memory into function,
make sure GC cannot move the object while function uses/accessing its contents.

and it is only for pointers. For arguments which is passed by value
(ints/floats), you don't have to care.

 --
 View this message in context: 
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696955.html
 Sent from the Pharo Smalltalk Developers mailing list archive at Nabble.com.




-- 
Best regards,
Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Stéphane Ducasse]

 
 if you pass a pointer to something in object memory into function,
 make sure GC cannot move the object while function uses/accessing its 
 contents.

How?

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

And I love pharo and what you guys have created , a lot of fun and very
productive. So yes I will definitely help you out in documenting NB. 

Actually my idea was not to publish in a blog. I hate blogs though I have
one I just find it very non flexible so I was thinking instead wikibooks . 

http://en.wikibooks.org/wiki/Help:Contributing
http://en.wikibooks.org/wiki/Help:Contributing  

I was thinking moving the entire nativeboost docs (pdf/latex) to wiki books
so I make it much easier for everyone can contribute. Wikibooks uses
Mediawiki which I am familiar with from the blender wiki when I was making
my python book 

http://wiki.blender.org/index.php/User:Kilon/Python_book_of_magic
http://wiki.blender.org/index.php/User:Kilon/Python_book_of_magic  

Mediawiki is nowhere near as powerful as latex but its way easier to learn
and it literally takes minutes to learn the syntax and you dont need a
special editor you can do it online directly with minimum syntax. This way
everyone can contribute , it only needs an account.  



Stéphane Ducasse wrote
 I love your questions!
 When you will get all your anwsers you have to write a blog about it so
 that we can use that in 
 a chapter so that every body can know how to do it.
 
 Just no time to think right now :( sadly
 
 Stef
 
 On Jul 1, 2013, at 8:40 PM, kilon lt;

 thekilon@.co

 gt; wrote:
 
 Thanks Igor , yes I was aware of String Cr because I have done some
 googling
 around and it did find information on the subject. Apparently it failed
 because I had an error in my source. 
 
 So for our next challenge is learning how to fetch data that a pointer
 points to. 
 
 in this case I have an array that contains my vertex positions , called
 vertexPositions  
 
 vertexPositions
 the positions of vertices to be passed to opengl
 
  ^ #( 0.75  0.75 0.0 1.0 
  0.75  -0.75 0.0 1.0
   -0.75 -0.75 0.0 1.0 )
 
 so far so good
 
 so I create a pointer for that array
 
 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.
 
 and then take that pointer and insert in each position the individual
 values
 from vertexPositions
 
 vertexPositions withIndexDo: [:each :i |
 using nbUInt32AtOffset because we know pointer is 4 bytes :) 
  vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf: 'float')
 put:
 each value.
  Transcript show: ' I am putting to vpos in index: '; show: i-1; show:'
 value: '; show: each value; cr. 
  ].
 
 so far so good.
 
 now the tricky part is that I have a function that expects that Array ,
 not
 the smalltalk version but the C version we just created
 
 gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ... 
 usage:
 GL_STATIC_DRAW.
 
 where you see the dots is where I should pass the data, in this case the
 C
 array
 
 I could do a vpo nbFloat32AtOffset: but that will return me only the
 individual value at the specific point (index) of the array, while I want
 to
 pass the entire array. 
 
 So how I do that ?
 
 I explored NBExternalAdress and I cant find something that would return
 an
 array. Am I missing something obvious here ? 
 
 NBExternalAdress value , returns the number of the address and not that
 data
 contained in that address.
 
 I also see a  NBExternalArray but I am not sure if it is what I should be
 using .  
 
 Igor Stasenko wrote
 On 30 June 2013 21:11, kilon lt;
 
 thekilon@.co
 
 gt; wrote:
 I am not going to post my code here cause it has become too big , you
 can
 find it here
 
 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 lt;http://www.smalltalkhub.com/#!/~kilon/GLTutorialgt;
 
 I tried adding newlines with String cr to my shaders strings, but
 apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to
 C
 \n newlines. So how I do that ?
 
 
 simply replace all occurences of
 Character cr
 with
 Character lf
 (or crlf, if it wants that)
 
 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696465.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.
 
 
 
 
 -- 
 Best regards,
 Igor Stasenko.
 
 
 
 
 
 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p469.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.






--
View this message in context: 
http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696807.html
Sent from the Pharo Smalltalk Developers mailing list archive at Nabble.com.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Camillo Bruni]

I like to see people contributing :), maybe you could do some contribution
on the code-side?

I personally consider well written, executable examples more valuable than 
written documentation outside the image. And I think NativeBoost could 
benefit from some in-image documentation.


On 2013-07-02, at 14:39, kilon theki...@yahoo.co.uk wrote:
 And I love pharo and what you guys have created , a lot of fun and very
 productive. So yes I will definitely help you out in documenting NB. 
 
 Actually my idea was not to publish in a blog. I hate blogs though I have
 one I just find it very non flexible so I was thinking instead wikibooks . 
 
 http://en.wikibooks.org/wiki/Help:Contributing
 http://en.wikibooks.org/wiki/Help:Contributing  
 
 I was thinking moving the entire nativeboost docs (pdf/latex) to wiki books
 so I make it much easier for everyone can contribute. Wikibooks uses
 Mediawiki which I am familiar with from the blender wiki when I was making
 my python book 
 
 http://wiki.blender.org/index.php/User:Kilon/Python_book_of_magic
 http://wiki.blender.org/index.php/User:Kilon/Python_book_of_magic  
 
 Mediawiki is nowhere near as powerful as latex but its way easier to learn
 and it literally takes minutes to learn the syntax and you dont need a
 special editor you can do it online directly with minimum syntax. This way
 everyone can contribute , it only needs an account.  
 
 
 
 Stéphane Ducasse wrote
 I love your questions!
 When you will get all your anwsers you have to write a blog about it so
 that we can use that in 
 a chapter so that every body can know how to do it.
 
 Just no time to think right now :( sadly
 
 Stef
 
 On Jul 1, 2013, at 8:40 PM, kilon lt;
 
 thekilon@.co
 
 gt; wrote:
 
 Thanks Igor , yes I was aware of String Cr because I have done some
 googling
 around and it did find information on the subject. Apparently it failed
 because I had an error in my source. 
 
 So for our next challenge is learning how to fetch data that a pointer
 points to. 
 
 in this case I have an array that contains my vertex positions , called
 vertexPositions  
 
 vertexPositions
 the positions of vertices to be passed to opengl
 
 ^ #( 0.75  0.75 0.0 1.0 
 0.75  -0.75 0.0 1.0
  -0.75 -0.75 0.0 1.0 )
 
 so far so good
 
 so I create a pointer for that array
 
 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.
 
 and then take that pointer and insert in each position the individual
 values
 from vertexPositions
 
 vertexPositions withIndexDo: [:each :i |
using nbUInt32AtOffset because we know pointer is 4 bytes :) 
 vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf: 'float')
 put:
 each value.
 Transcript show: ' I am putting to vpos in index: '; show: i-1; show:'
 value: '; show: each value; cr. 
 ].
 
 so far so good.
 
 now the tricky part is that I have a function that expects that Array ,
 not
 the smalltalk version but the C version we just created
 
 gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ... 
 usage:
 GL_STATIC_DRAW.
 
 where you see the dots is where I should pass the data, in this case the
 C
 array
 
 I could do a vpo nbFloat32AtOffset: but that will return me only the
 individual value at the specific point (index) of the array, while I want
 to
 pass the entire array. 
 
 So how I do that ?
 
 I explored NBExternalAdress and I cant find something that would return
 an
 array. Am I missing something obvious here ? 
 
 NBExternalAdress value , returns the number of the address and not that
 data
 contained in that address.
 
 I also see a  NBExternalArray but I am not sure if it is what I should be
 using .  
 
 Igor Stasenko wrote
 On 30 June 2013 21:11, kilon lt;
 
 thekilon@.co
 
 gt; wrote:
 I am not going to post my code here cause it has become too big , you
 can
 find it here
 
 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 lt;http://www.smalltalkhub.com/#!/~kilon/GLTutorialgt;
 
 I tried adding newlines with String cr to my shaders strings, but
 apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to
 C
 \n newlines. So how I do that ?
 
 
 simply replace all occurences of
 Character cr
 with
 Character lf
 (or crlf, if it wants that)
 
 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696465.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.
 
 
 
 
 -- 
 Best regards,
 Igor Stasenko.
 
 
 
 
 
 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p469.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.
 
 
 
 
 
 
 --
 View this message in context: 
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696807.html
 Sent from the Pharo Smalltalk Developers mailing list archive at Nabble.com.
 

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

Igor got you will try to avoid using #sizeOf: , even for a readability I can
replace it with a simple method returning the same thing depending in
platform.

Now because I am confused lets clarify how the whole things works because I
see many errors in my code and clearly I don't understand how Nativeboost
works.  Note I am a C noob , so excuse me if I say anything stupid here.

As far as functions call are concerned I see 3 possible scenariors 

a ) function(int var). Here the C function expects a simple variable of some
type (int in this case) according to what you told me to make such variable
I will do

var := Nativeboost allocate:( NBExternalType typeof:'int')

if I want to pass a value in that variable then I will do

var nbInt32AtOffset: 0 put: 6

will call that function with 

Object function: var

b) function(int* var) 

how I create the variable (pointer) ?

how I put value in the variable (pointer) ?

c) function( var) 

Now I assume I will create a var variable same way as (a)

var := Nativeboost allocate:( NBExternalType typeof:'int')

but how I pass the address of var to the function ?


I read the pdf of nativeboost but It did not clarify those things or simply
I did not understand. 

Thanks on the instructions about NBExternalArray. So the reason of using
this object is for convenience ?  

 
Igor Stasenko wrote
 On 1 July 2013 20:40, kilon lt;

 thekilon@.co

 gt; wrote:
 Thanks Igor , yes I was aware of String Cr because I have done some
 googling
 around and it did find information on the subject. Apparently it failed
 because I had an error in my source.

 So for our next challenge is learning how to fetch data that a pointer
 points to.

 in this case I have an array that contains my vertex positions , called
 vertexPositions

 vertexPositions
 the positions of vertices to be passed to opengl

 ^ #( 0.75  0.75 0.0 1.0
 0.75  -0.75 0.0 1.0
  -0.75 -0.75 0.0 1.0 )

 so far so good

 so I create a pointer for that array

 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.

 and then take that pointer and insert in each position the individual
 values
 from vertexPositions

 vertexPositions withIndexDo: [:each :i |
using nbUInt32AtOffset because we know pointer is 4 bytes :)
 
 vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf:
 'float') put:
 each value.
 Transcript show: ' I am putting to vpos in index: '; show: i-1;
 show:'
 value: '; show: each value; cr.
 ].

 so far so good.

 
 just one small advice:  do not use #sizeOf: sparingly.. it parsing the
 type
 and doing full type resolution when you do that.
 you can remember the size of the type you need at boot/startup time,
 there is no chance
 it can change within same session :)
 
 but of course for demonstration purposes and readability it good.
 
 now the tricky part is that I have a function that expects that Array ,
 not
 the smalltalk version but the C version we just created

 gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ... 
 usage:
 GL_STATIC_DRAW.

 where you see the dots is where I should pass the data, in this case the
 C
 array

 I could do a vpo nbFloat32AtOffset: but that will return me only the
 individual value at the specific point (index) of the array, while I want
 to
 pass the entire array.

 So how I do that ?

 I explored NBExternalAdress and I cant find something that would return
 an
 array. Am I missing something obvious here ?

 
 just pass NBExternalAdress instance as argument and you done.
 
 NBExternalAdress value , returns the number of the address and not that
 data
 contained in that address.

 I also see a  NBExternalArray but I am not sure if it is what I should be
 using .

 
 arrayClass :=  NBExternalArray ofType: 'float'.
 array := arrayClass new: 5. or externalNew:5 , if you want to
 allocate it in external memory
 
 array at: 1 put: 10.1   use just like normal Array
 
 to pass it to function use:
 
 self soemFunction: array address.
 
 Igor Stasenko wrote
 On 30 June 2013 21:11, kilon 

 thekilon@.co

  wrote:
 I am not going to post my code here cause it has become too big , you
 can
 find it here

 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 lt;http://www.smalltalkhub.com/#!/~kilon/GLTutorialgt;

 I tried adding newlines with String cr to my shaders strings, but
 apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to
 C
 \n newlines. So how I do that ?


 simply replace all occurences of
 Character cr
 with
 Character lf
 (or crlf, if it wants that)

 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696465.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.




 --
 Best regards,
 Igor Stasenko.





 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p469.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

Igor one last thing I forgot to ask about b) how I pass the pointer to the
function ?

Now Camillo , If you guys care about making pharo popular , I mean really
popular you should stop caring what you want or what I want and care more
about what most people want. Democracy sucks but hey thats the way to fame.
I am sorry but I am not buying into the whole argument of self documented
code. Why ? Because I dont trust coders. 

I know however for a fact that as you said it outside documentation ,
assuming its a lengthy one, even if its a bad one,  is a much safer bet to
make sense , especially for a very big library. If the library is very small
sure you can deal with it with class comments and method comments and some
random examples. 

But take Nativeboost for example, understanding Nativeboost without outside
documentation is just , well crazy. There so many issues to discuss and many
concepts to analyse, and if we take into account that people dealing with
Nativeboost are not C coders or experienced with C coding then you will have
loads of user with a big questionmark on top of their heads. Sure those
people should go read a C code, which I do already , but still would I
complain if documentation of NB explained those things to me ? Why would I ,
I am as lazy as the next person.  

Plus I am a user why should I care about class comments and methods
comments, I dont care how the source works I only care how I can use the
library the easiest , quickest way possible. 

Should classes and methods have their comments ?  definitely !!!  This is
open source , its meant to be read , analyzed and modified. Making people
life harder is making it more close source. But I dont believe a user of a
library would prioritize class / method comments and code example over
old-way hardcore documentation. 

I seriously believe pharo would greatly benefit from a wiki and would help
taking it more seriously. Or at least an included documentation tool inside
pharo that will make documentation much easier. I mentioned wikibooks
because its based on already highly successful popular technology. If you
have better recommendation I am open to any ideas. 

So in short yes I will comment class/methods of Nativeboost and yes I will
contribute to wikibooks as well.  


Camillo Bruni-3 wrote
 I like to see people contributing :), maybe you could do some contribution
 on the code-side?
 
 I personally consider well written, executable examples more valuable than 
 written documentation outside the image. And I think NativeBoost could 
 benefit from some in-image documentation.
 
 
 On 2013-07-02, at 14:39, kilon lt;

 thekilon@.co

 gt; wrote:
 And I love pharo and what you guys have created , a lot of fun and very
 productive. So yes I will definitely help you out in documenting NB. 
 
 Actually my idea was not to publish in a blog. I hate blogs though I have
 one I just find it very non flexible so I was thinking instead wikibooks
 . 
 
 http://en.wikibooks.org/wiki/Help:Contributing
 lt;http://en.wikibooks.org/wiki/Help:Contributinggt;  
 
 I was thinking moving the entire nativeboost docs (pdf/latex) to wiki
 books
 so I make it much easier for everyone can contribute. Wikibooks uses
 Mediawiki which I am familiar with from the blender wiki when I was
 making
 my python book 
 
 http://wiki.blender.org/index.php/User:Kilon/Python_book_of_magic
 lt;http://wiki.blender.org/index.php/User:Kilon/Python_book_of_magicgt;  
 
 Mediawiki is nowhere near as powerful as latex but its way easier to
 learn
 and it literally takes minutes to learn the syntax and you dont need a
 special editor you can do it online directly with minimum syntax. This
 way
 everyone can contribute , it only needs an account.  
 
 
 
 Stéphane Ducasse wrote
 I love your questions!
 When you will get all your anwsers you have to write a blog about it so
 that we can use that in 
 a chapter so that every body can know how to do it.
 
 Just no time to think right now :( sadly
 
 Stef
 
 On Jul 1, 2013, at 8:40 PM, kilon lt;
 
 thekilon@.co
 
 gt; wrote:
 
 Thanks Igor , yes I was aware of String Cr because I have done some
 googling
 around and it did find information on the subject. Apparently it failed
 because I had an error in my source. 
 
 So for our next challenge is learning how to fetch data that a pointer
 points to. 
 
 in this case I have an array that contains my vertex positions , called
 vertexPositions  
 
 vertexPositions
 the positions of vertices to be passed to opengl
 
^ #( 0.75  0.75 0.0 1.0 
0.75  -0.75 0.0 1.0
 -0.75 -0.75 0.0 1.0 )
 
 so far so good
 
 so I create a pointer for that array
 
 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions
 size.
 
 and then take that pointer and insert in each position the individual
 values
 from vertexPositions
 
 vertexPositions withIndexDo: [:each :i |
   using nbUInt32AtOffset because we know pointer is 4 bytes :) 
vpos nbFloat32AtOffset: (i-1)*(NBExternalType 

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 2 July 2013 16:27, kilon theki...@yahoo.co.uk wrote:
 Igor got you will try to avoid using #sizeOf: , even for a readability I can
 replace it with a simple method returning the same thing depending in
 platform.

 Now because I am confused lets clarify how the whole things works because I
 see many errors in my code and clearly I don't understand how Nativeboost
 works.  Note I am a C noob , so excuse me if I say anything stupid here.

 As far as functions call are concerned I see 3 possible scenariors

 a ) function(int var). Here the C function expects a simple variable of some
 type (int in this case) according to what you told me to make such variable
 I will do

 var := Nativeboost allocate:( NBExternalType typeof:'int')

 if I want to pass a value in that variable then I will do

 var nbInt32AtOffset: 0 put: 6

 will call that function with

 Object function: var

you found very interesting way to pass simple integer to function :)

if your function is 'function(int var)'
you call it directly:

someobject function: 5
x := 10.
someobject function: x
etc..


 b) function(int* var)

 how I create the variable (pointer) ?

 how I put value in the variable (pointer) ?

pointer = address on memory which holding some value.
every time you see '*', it means that function expects pointer.
And of course, since that function will write or read from that memory location,
it is your responsibility to provide a pointer to valid data, with
enough size etc.
So, the way how you did for first case, is actually applicable for this case.

But it is not necessary to use externally allocated memory.
Sometimes you can safely use object memory, e.g.:

buffer := ByteArray new: 4.
someobject function: buffer.

 c) function( var)

did you meant  'int var'? because otherwise it is not correct declaration.

 Now I assume I will create a var variable same way as (a)

 var := Nativeboost allocate:( NBExternalType typeof:'int')

 but how I pass the address of var to the function ?

this is reference (more from C++).. which in fact just a syntactic sugar,
function still expecting pointer (so consider this to be same as *var)


 I read the pdf of nativeboost but It did not clarify those things or simply
 I did not understand.

 Thanks on the instructions about NBExternalArray. So the reason of using
 this object is for convenience ?

Of course. It is more convenient to deal with array of typed elements
(of type you need),
than manually deal with bunch of raw bytes.


 Igor Stasenko wrote
 On 1 July 2013 20:40, kilon 

 thekilon@.co

  wrote:
 Thanks Igor , yes I was aware of String Cr because I have done some
 googling
 around and it did find information on the subject. Apparently it failed
 because I had an error in my source.

 So for our next challenge is learning how to fetch data that a pointer
 points to.

 in this case I have an array that contains my vertex positions , called
 vertexPositions

 vertexPositions
 the positions of vertices to be passed to opengl

 ^ #( 0.75  0.75 0.0 1.0
 0.75  -0.75 0.0 1.0
  -0.75 -0.75 0.0 1.0 )

 so far so good

 so I create a pointer for that array

 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.

 and then take that pointer and insert in each position the individual
 values
 from vertexPositions

 vertexPositions withIndexDo: [:each :i |
using nbUInt32AtOffset because we know pointer is 4 bytes :)
 
 vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf:
 'float') put:
 each value.
 Transcript show: ' I am putting to vpos in index: '; show: i-1;
 show:'
 value: '; show: each value; cr.
 ].

 so far so good.


 just one small advice:  do not use #sizeOf: sparingly.. it parsing the
 type
 and doing full type resolution when you do that.
 you can remember the size of the type you need at boot/startup time,
 there is no chance
 it can change within same session :)

 but of course for demonstration purposes and readability it good.

 now the tricky part is that I have a function that expects that Array ,
 not
 the smalltalk version but the C version we just created

 gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ...
 usage:
 GL_STATIC_DRAW.

 where you see the dots is where I should pass the data, in this case the
 C
 array

 I could do a vpo nbFloat32AtOffset: but that will return me only the
 individual value at the specific point (index) of the array, while I want
 to
 pass the entire array.

 So how I do that ?

 I explored NBExternalAdress and I cant find something that would return
 an
 array. Am I missing something obvious here ?


 just pass NBExternalAdress instance as argument and you done.

 NBExternalAdress value , returns the number of the address and not that
 data
 contained in that address.

 I also see a  NBExternalArray but I am not sure if it is what I should be
 using .


 arrayClass :=  NBExternalArray ofType: 'float'.
 array := arrayClass new: 5. or externalNew:5 

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

Thank you Igor for the clarifications, the reason why I prefer using the
nativeboost methods is because :

a) I was not sure if smalltalk types map correctly to C types and which
Smalltalk types correspond to which C types

b) many opengl functions ask for the address of the value and the value
itself. And I have no clue how to obtain memory addresses of smalltalk
types.

c) I was not sure whether Pharo VM or garbage collector would move my data
making my pointers invalid.  

But if you say its ok, I trust you. When exactly is ok to use smalltalk
types ?



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 30 June 2013 21:11, kilon theki...@yahoo.co.uk wrote:
 I am not going to post my code here cause it has become too big , you can
 find it here

 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 http://www.smalltalkhub.com/#!/~kilon/GLTutorial

 I tried adding newlines with String cr to my shaders strings, but apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to C
 \n newlines. So how I do that ?


simply replace all occurences of
Character cr
with
Character lf
(or crlf, if it wants that)

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Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

Thanks Igor , yes I was aware of String Cr because I have done some googling
around and it did find information on the subject. Apparently it failed
because I had an error in my source. 

So for our next challenge is learning how to fetch data that a pointer
points to. 

in this case I have an array that contains my vertex positions , called
vertexPositions  

vertexPositions
the positions of vertices to be passed to opengl

^ #( 0.75  0.75 0.0 1.0 
0.75  -0.75 0.0 1.0
 -0.75 -0.75 0.0 1.0 )

so far so good

so I create a pointer for that array

vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.

and then take that pointer and insert in each position the individual values
from vertexPositions

vertexPositions withIndexDo: [:each :i |
   using nbUInt32AtOffset because we know pointer is 4 bytes :) 
vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf: 'float') put:
each value.
Transcript show: ' I am putting to vpos in index: '; show: i-1; show:'
value: '; show: each value; cr. 
].

so far so good.

now the tricky part is that I have a function that expects that Array , not
the smalltalk version but the C version we just created

gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ...  usage:
GL_STATIC_DRAW.

where you see the dots is where I should pass the data, in this case the C
array

I could do a vpo nbFloat32AtOffset: but that will return me only the
individual value at the specific point (index) of the array, while I want to
pass the entire array. 

So how I do that ?

I explored NBExternalAdress and I cant find something that would return an
array. Am I missing something obvious here ? 
 
NBExternalAdress value , returns the number of the address and not that data
contained in that address.

I also see a  NBExternalArray but I am not sure if it is what I should be
using .  

Igor Stasenko wrote
 On 30 June 2013 21:11, kilon lt;

 thekilon@.co

 gt; wrote:
 I am not going to post my code here cause it has become too big , you can
 find it here

 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 lt;http://www.smalltalkhub.com/#!/~kilon/GLTutorialgt;

 I tried adding newlines with String cr to my shaders strings, but
 apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to C
 \n newlines. So how I do that ?

 
 simply replace all occurences of
 Character cr
 with
 Character lf
 (or crlf, if it wants that)
 
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 Nabble.com.

 
 
 
 -- 
 Best regards,
 Igor Stasenko.





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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

Sorry I forgot to  paste how i create the vpos pointer

vpos := NativeBoost allocate: vptrsize.

My questions on how to pass the contents of a C array to a C function as can
be seen in quoted message remains :)


kilon wrote
 Thanks Igor , yes I was aware of String Cr because I have done some
 googling around and it did find information on the subject. Apparently it
 failed because I had an error in my source. 
 
 So for our next challenge is learning how to fetch data that a pointer
 points to. 
 
 in this case I have an array that contains my vertex positions , called
 vertexPositions  
 
 vertexPositions
 the positions of vertices to be passed to opengl
 
   ^ #( 0.75  0.75 0.0 1.0 
   0.75  -0.75 0.0 1.0
-0.75 -0.75 0.0 1.0 )
 
 so far so good
 
 so I create a pointer for that array
 
 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.
 
 and then take that pointer and insert in each position the individual
 values from vertexPositions
 
 vertexPositions withIndexDo: [:each :i |
  using nbUInt32AtOffset because we know pointer is 4 bytes :) 
   vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf: 'float')
 put: each value.
   Transcript show: ' I am putting to vpos in index: '; show: i-1; show:'
 value: '; show: each value; cr. 
   ].
 
 so far so good.
 
 now the tricky part is that I have a function that expects that Array ,
 not the smalltalk version but the C version we just created
 
 gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ... 
 usage: GL_STATIC_DRAW.
 
 where you see the dots is where I should pass the data, in this case the C
 array
 
 I could do a vpo nbFloat32AtOffset: but that will return me only the
 individual value at the specific point (index) of the array, while I want
 to pass the entire array. 
 
 So how I do that ?
 
 I explored NBExternalAdress and I cant find something that would return an
 array. Am I missing something obvious here ? 
  
 NBExternalAdress value , returns the number of the address and not that
 data contained in that address.
 
 I also see a  NBExternalArray but I am not sure if it is what I should be
 using .  
 Igor Stasenko wrote
 On 30 June 2013 21:11, kilon lt;

 thekilon@.co

 gt; wrote:
 I am not going to post my code here cause it has become too big , you
 can
 find it here

 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 lt;http://www.smalltalkhub.com/#!/~kilon/GLTutorialgt;

 I tried adding newlines with String cr to my shaders strings, but
 apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to
 C
 \n newlines. So how I do that ?

 
 simply replace all occurences of
 Character cr
 with
 Character lf
 (or crlf, if it wants that)
 
 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696465.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.

 
 
 
 -- 
 Best regards,
 Igor Stasenko.





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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Stéphane Ducasse]

I love your questions!
When you will get all your anwsers you have to write a blog about it so that we 
can use that in 
a chapter so that every body can know how to do it.

Just no time to think right now :( sadly

Stef

On Jul 1, 2013, at 8:40 PM, kilon theki...@yahoo.co.uk wrote:

 Thanks Igor , yes I was aware of String Cr because I have done some googling
 around and it did find information on the subject. Apparently it failed
 because I had an error in my source. 
 
 So for our next challenge is learning how to fetch data that a pointer
 points to. 
 
 in this case I have an array that contains my vertex positions , called
 vertexPositions  
 
 vertexPositions
 the positions of vertices to be passed to opengl
 
   ^ #( 0.75  0.75 0.0 1.0 
   0.75  -0.75 0.0 1.0
-0.75 -0.75 0.0 1.0 )
 
 so far so good
 
 so I create a pointer for that array
 
 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.
 
 and then take that pointer and insert in each position the individual values
 from vertexPositions
 
 vertexPositions withIndexDo: [:each :i |
  using nbUInt32AtOffset because we know pointer is 4 bytes :) 
   vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf: 'float') put:
 each value.
   Transcript show: ' I am putting to vpos in index: '; show: i-1; show:'
 value: '; show: each value; cr. 
   ].
 
 so far so good.
 
 now the tricky part is that I have a function that expects that Array , not
 the smalltalk version but the C version we just created
 
 gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ...  usage:
 GL_STATIC_DRAW.
 
 where you see the dots is where I should pass the data, in this case the C
 array
 
 I could do a vpo nbFloat32AtOffset: but that will return me only the
 individual value at the specific point (index) of the array, while I want to
 pass the entire array. 
 
 So how I do that ?
 
 I explored NBExternalAdress and I cant find something that would return an
 array. Am I missing something obvious here ? 
 
 NBExternalAdress value , returns the number of the address and not that data
 contained in that address.
 
 I also see a  NBExternalArray but I am not sure if it is what I should be
 using .  
 
 Igor Stasenko wrote
 On 30 June 2013 21:11, kilon lt;
 
 thekilon@.co
 
 gt; wrote:
 I am not going to post my code here cause it has become too big , you can
 find it here
 
 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 lt;http://www.smalltalkhub.com/#!/~kilon/GLTutorialgt;
 
 I tried adding newlines with String cr to my shaders strings, but
 apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to C
 \n newlines. So how I do that ?
 
 
 simply replace all occurences of
 Character cr
 with
 Character lf
 (or crlf, if it wants that)
 
 --
 View this message in context:
 http://forum.world.st/Understanding-NBOpenGL-tp4686514p4696465.html
 Sent from the Pharo Smalltalk Developers mailing list archive at
 Nabble.com.
 
 
 
 
 -- 
 Best regards,
 Igor Stasenko.
 
 
 
 
 
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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 1 July 2013 20:40, kilon theki...@yahoo.co.uk wrote:
 Thanks Igor , yes I was aware of String Cr because I have done some googling
 around and it did find information on the subject. Apparently it failed
 because I had an error in my source.

 So for our next challenge is learning how to fetch data that a pointer
 points to.

 in this case I have an array that contains my vertex positions , called
 vertexPositions

 vertexPositions
 the positions of vertices to be passed to opengl

 ^ #( 0.75  0.75 0.0 1.0
 0.75  -0.75 0.0 1.0
  -0.75 -0.75 0.0 1.0 )

 so far so good

 so I create a pointer for that array

 vptrsize := (NBExternalType sizeOf: 'float')* self vertexPositions size.

 and then take that pointer and insert in each position the individual values
 from vertexPositions

 vertexPositions withIndexDo: [:each :i |
using nbUInt32AtOffset because we know pointer is 4 bytes :) 
 vpos nbFloat32AtOffset: (i-1)*(NBExternalType sizeOf: 'float') 
 put:
 each value.
 Transcript show: ' I am putting to vpos in index: '; show: i-1; show:'
 value: '; show: each value; cr.
 ].

 so far so good.


just one small advice:  do not use #sizeOf: sparingly.. it parsing the type
and doing full type resolution when you do that.
you can remember the size of the type you need at boot/startup time,
there is no chance
it can change within same session :)

but of course for demonstration purposes and readability it good.

 now the tricky part is that I have a function that expects that Array , not
 the smalltalk version but the C version we just created

 gl bufferData_target: GL_ARRAY_BUFFER size: vptrsize  data: ...  usage:
 GL_STATIC_DRAW.

 where you see the dots is where I should pass the data, in this case the C
 array

 I could do a vpo nbFloat32AtOffset: but that will return me only the
 individual value at the specific point (index) of the array, while I want to
 pass the entire array.

 So how I do that ?

 I explored NBExternalAdress and I cant find something that would return an
 array. Am I missing something obvious here ?


just pass NBExternalAdress instance as argument and you done.

 NBExternalAdress value , returns the number of the address and not that data
 contained in that address.

 I also see a  NBExternalArray but I am not sure if it is what I should be
 using .


arrayClass :=  NBExternalArray ofType: 'float'.
array := arrayClass new: 5. or externalNew:5 , if you want to
allocate it in external memory

array at: 1 put: 10.1   use just like normal Array

to pass it to function use:

self soemFunction: array address.

 Igor Stasenko wrote
 On 30 June 2013 21:11, kilon 

 thekilon@.co

  wrote:
 I am not going to post my code here cause it has become too big , you can
 find it here

 http://www.smalltalkhub.com/#!/~kilon/GLTutorial
 http://www.smalltalkhub.com/#!/~kilon/GLTutorial

 I tried adding newlines with String cr to my shaders strings, but
 apparently
 opengl is not convinced. It looks like smalltalk cr is not converted to C
 \n newlines. So how I do that ?


 simply replace all occurences of
 Character cr
 with
 Character lf
 (or crlf, if it wants that)

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 Nabble.com.




 --
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 Igor Stasenko.





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-- 
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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

I am not going to post my code here cause it has become too big , you can
find it here

http://www.smalltalkhub.com/#!/~kilon/GLTutorial
http://www.smalltalkhub.com/#!/~kilon/GLTutorial  

I tried adding newlines with String cr to my shaders strings, but apparently
opengl is not convinced. It looks like smalltalk cr is not converted to C
\n newlines. So how I do that ? 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 28 June 2013 13:11, kilon theki...@yahoo.co.uk wrote:
 found a bug in NBOpengl this function definition is incorrect

 getShaderiv_shader: in shader pname: in pname params: out params
 primitive: #primitiveNativeCall module: #NativeBoostPlugin error:
 primErrorCode

 ^ self
 glApiCall: #( void glGetShaderiv ( GLuint shader , GLenum 
 pname , long*
 params ) )
 index: 793
 attributes: #(
 #category #VERSION_2_0
 #version #'2.0'
 )

 while the function definition is

 void glGetShaderiv(GLuint  shader,  GLenum  pname,  GLint * params);

 so there is no long* in there for params

 as is confirmed from opengl 2.1 reference pages -
 http://www.opengl.org/sdk/docs/man2/ http://www.opengl.org/sdk/docs/man2/

 dont know if this bug has any effect , or maybe not a bug ?


Looks like a bug in openg specs.
But it has no effect. Pointer to long, or pointer to GLInt.. it makes
not difference, at least from side of FFI marshaller,
because it just takes a pointer.

Btw, they switches to XML specs, and old ones are no longer updated..
that means we should rebase bindings generator to read from XML data.

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-- 
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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

I also tried 

gl shaderSource_shader: shader count: 1  string: (NBExternalAddress
fromString: shaderString)  length: (NBExternalObject null) .

still getting Error during FFI call : NIL . 

This is the full method :

createShader: shaderType string: shaderString
 create shader using its source and compile it , return shader

| shader |
shader := gl createShader: shaderType .
gl shaderSource_shader: shader count: 1  string: (NBExternalAddress
fromString: shaderString)  length: (NBExternalObject null) .
gl compileShader: shader.
^ shader

. I also use gl getError to get any possible opengl error in my part , It
reports that there is no such error.I am continuing investigating
Nativeboost 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Henrik Johansen]

On Jun 27, 2013, at 2:22 , Igor Stasenko wrote:

 i think it fails because you passing strange (NBExternalObject null)
 as length parameter.
 i guess you meant  NBExternalAddress null instead.

Speaking of weird external stuff…

NBExternalArray  class  #initElementType:  aTypeName
Initialize the element type and size.

If you want to use a public subclass of me, then make sure you call 
this method
in your class #initialize method.
 

elementType := aTypeName.
elementSize := (NBFFICallout new requestor: self; resolveType: 
elementType) valueSize .
self installAccessors.

Shouldn't that be storageSize?
Or is a disclaimer not to use the class for, say, 'char*' elements more 
appropriate?

Cheers,
Henry

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Stéphane Ducasse]

Igor we should document such mistakes
This is important can you add such comments in class comment?


On Jun 27, 2013, at 5:26 PM, Igor Stasenko siguc...@gmail.com wrote:

 On 27 June 2013 17:14, Henrik Johansen henrik.s.johan...@veloxit.no wrote:
 
 On Jun 27, 2013, at 4:11 , Igor Stasenko wrote:
 
 
 Or is a disclaimer not to use the class for, say, 'char*' elements more
 appropriate?
 
 no , it should be fine.
 
 Was thinking of that in conjunction with putting ST object refs in the 
 External arrays, the trying to pass as parameters, it could be a recipe for 
 disaster :)
 Like, say:
 
 Add a null at end so ExternalArrays basic #readString won't keep on readin'
 string := 'Hello world!' copyWith: (Character value: 0).
 extArray := (NBExternalArray ofType: 'char*') new: 1.
 Tenure the string first, lest we invalidate on next scavenge
 Smalltalk garbageCollectMost.
 extArray at:1 put: string.
 
 X our fingers, and hope GC doesn't move string.
 Often serves as a nice example that it will :)
 (extArray at: 1) readString
 string at: 7 put: $W.
 (extArray at: 1) readString
 
 hehe.. that certainly a recipe for disaster.
 
 That's why there should be no NBExternalValueaddress  (pointing at Ciprian),
 which answers a pointer to oop's first byte, like that given test:
 
 testOutVoidArg
   |x value|
   NBTestExternalValue initialize.
   value := 12345678.
   x := NBTestExternalValue new.
 
   self outputVoidArg: x address value: value.
   
   self assert: x value = value.
 
 may work.
 But actually it will not. And this is **WRONG** in same way as your example.
 
 Cheers,
 Henry
 
 
 
 -- 
 Best regards,
 Igor Stasenko.
 

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 27 June 2013 18:32, Stéphane Ducasse stephane.duca...@inria.fr wrote:

 On Jun 2

 Yes, you right.
 (NBFFICallout new resolveType: 'byte*') valueSize  = 1
 (NBFFICallout new resolveType: 'byte*') storageSize  = 4

 apparently, if one wants array with 'byte*' element type (or any other)
 it should use a pointer size (4), not byte size (1) for it.

 Or is a disclaimer not to use the class for, say, 'char*' elements more
 appropriate?

 no , it should be fine.
 The difference between valueSize and storageSize is a bit confusing,
 and easy to confuse which to use..
 Perhaps they need different naming.
 +1 consider that people will use that during 10 years so good comments + 
 names is KEY

yes, i always in such mode. But sometimes a right term/word/concept
comes after number of interations
(until you, as developer finally really understand what you just did
or what you actually wanted to do ;)

 There also stackSize, which means how many bytes a value of given type
 will take, if pushed on stack , and aligned accordingly

 ... after some more investigation, i found that actually
 storageSize should not be used. There is typeSize instead.

 So, the final expression should be:

 elementType := aTypeName.
 elementSize := (NBFFICallout new requestor: self; resolveType:
 elementType) typeSize.


 and #sizeOf: method should also use typeSize apparently.


 Cheers,
 Henry


 --
 Best regards,
 Igor Stasenko.






-- 
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Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 27 June 2013 18:33, Stéphane Ducasse stephane.duca...@inria.fr wrote:
 Igor we should document such mistakes
 This is important can you add such comments in class comment?


Well, it is a general rule to never operate with pointers to moveable objects,
because objects may change their locations at any moment and you don't
control that.

A pointer to object can be considered non-moving only if:
  - there is no allocation(s) of new objects between obtaining the
pointer value and using it (like passing to external function)
  - you not running any smalltalk code/function you call will NOT call
back and enter smalltalk code
  - you cannot be interrupted by something, which would allow the above.

in short, anything which may cause GC between point where you got the
pointer and point where you going to use it is a recipe for disaster.


-- 
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Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

Ok we solved that problem lest move to the next one.

I have this line of code 

Glint status;

to be used in this

glGetShaderiv(shader, GL_COMPILE_STATUS, status);

Now my first thought was to do this

statusAdress := NativeBoost allocate:  NBOpenGLTypes GLint.

but of course NBOpenGLTypes GLint is not really a message so that fails.

My problem here is that allocate , allocates a specific amount of bytes and
then returns the address. The problem is that there is no gurantee how many
bytes a GLint is.  Is there a method somewhere in NBOpengl that can return
me that amount of bytes of a GLint in the platform that NBOpengl executes ? 

Remember I cant use here a constant number cause there is no guarantees that
GLint will be the same size for every user of NBOpengl. 

This is really fun by the way learning so low level stuff :) 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

My code 

gl shaderSource_shader: shader count: 1  string: shaderString  length: 0.

must not be correct. I try to translate this

glShaderSource(shader, 1, strFileData, NULL);

using the tutorial in here - 
http://www.arcsynthesis.org/gltut/Basics/Tut01%20Making%20Shaders.html
http://www.arcsynthesis.org/gltut/Basics/Tut01%20Making%20Shaders.html  

I made these assumptions here 

a) Nativeboost would take my string shaderString and pass its address to
glShaderSource()
b) that NB would automagically convert 0 to NULL

are these assumptions correct and if yes why I am getting an error during
FFI call: NIL

if no, how I can pass the address of the string and how may I pass NULL as
well ? 

as always you can get my code manually from the NBOpengl repo in smalltalk
hub to take a look at the whole code. I have not added my code to
ConfigurationOfNBOpenGL cause it does not work yet and its a WIP. 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Guy Hylton]

Have you tried

(gl getString: GL_VERSION) readString

or if it does not return an NBExternalAddress

(NBExternalAddress value: (gl getString: GL_VERSION)) readstring




On Sat, Jun 22, 2013 at 4:46 PM, kilon theki...@yahoo.co.uk wrote:

 I am trying to find out what version of Opengl NBOpenGL is using so I do:

 gl getString:GL_VERSION.

 it works and returns me a pointer. I looked at definition of methods and it
 is defined to return a pointer.

 Question is how I get the string that the pointer points too ?



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

No I did not, because I dont have the brain power to assume that
NBExternalAdress will have some methods to make my life easier. And of
course it works like a charm now, thank you very much :) 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

next question .

I have this method.

initializeProgram
create each shader and program

| shaderList strVertexShader strFragmentShader |

strVertexShader  := self createShader: GL_VERTEX_SHADER string:  ( self
vertexShader ).
strFragmentShader  := self createShader:  GL_FRAGMENT_SHADER string: 
(self
fragmentShader) .  
shaderList := #( strVertexShader strFragmentShader ).
self createProgram:  shaderList .
shaderList do: [ :each | gl deleteShader: each  ].


Each time I try to accept the code it complains that strVertexShader and
strFragmentShader are unused and ask for removing them . Why ?

Is this an IDE bug ? Its clear from the code that I use those two local
variables to pass them to the array shaderList. Am I missing something here
? 




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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Marcus Denker]

On Jun 23, 2013, at 4:52 PM, kilon theki...@yahoo.co.uk wrote:

 next question .
 
 I have this method.
 
 initializeProgram
   create each shader and program
 
   | shaderList strVertexShader strFragmentShader |
   
   strVertexShader  := self createShader: GL_VERTEX_SHADER string:  ( self
 vertexShader ).
   strFragmentShader  := self createShader:  GL_FRAGMENT_SHADER string: 
 (self
 fragmentShader) .  
   shaderList := #( strVertexShader strFragmentShader ).
   self createProgram:  shaderList .
   shaderList do: [ :each | gl deleteShader: each  ].
 
 
 Each time I try to accept the code it complains that strVertexShader and
 strFragmentShader are unused and ask for removing them . Why ?
 
 Is this an IDE bug ? Its clear from the code that I use those two local
 variables to pass them to the array shaderList. Am I missing something here
 ? 

Yes:

shaderList := #( strVertexShader strFragmentShader ).

here the Array you create is a so called literal Array. It can not contain 
variables, only literals. The compiler sees is as

#(#strVertexShader #strFragmentShader).

What you need instead is a compile time evaluated Array:

shaderList := {strVertexShader strFragmentShader}.

Marcus
 

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

yeah and I read about that in PBE and of course I forgot about it. That is
why we need the mailing lists. 

Ok that solved the problem partially it does not complain about
strVertexShader but it still complains about strFragmentShader . I use this
code.

 shaderList := {strVertexShader strFragmentShader}. 

Any idea what may still be wrong ? 

strFragmentShader appears to be unused in this method. Ok to remove it ?



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Marcus Denker]

On Jun 23, 2013, at 5:51 PM, kilon theki...@yahoo.co.uk wrote:

 yeah and I read about that in PBE and of course I forgot about it. That is
 why we need the mailing lists. 
 
 Ok that solved the problem partially it does not complain about
 strVertexShader but it still complains about strFragmentShader . I use this
 code.
 
 shaderList := {strVertexShader strFragmentShader}. 
 
 Any idea what may still be wrong ? 
 

There needs to be a dot:

shaderList := {strVertexShader . strFragmentShader}. 

(I guess I forgot to put it in my example)

 strFragmentShader appears to be unused in this method. Ok to remove it ?

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

I am trying to find out what version of Opengl NBOpenGL is using so I do:

gl getString:GL_VERSION.

it works and returns me a pointer. I looked at definition of methods and it
is defined to return a pointer.

Question is how I get the string that the pointer points too ? 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 10 June 2013 03:54, Igor Stasenko siguc...@gmail.com wrote:
 On 9 June 2013 20:47, kilon theki...@yahoo.co.uk wrote:
 Ok I am moving towards the direction you indicated , its just takes time
 because I am clueless.

 Af far as macos is concerned I was sucessful into intialising opengl context
 following your instructions and using clearColor assigned green-blue
 background to it. Works like a charm even changing the code updates the
 window to the corresponding color, live coding in all its glory. I am having
 tons of fun with it.

 I have a strange bug , well it seems that opengl looses a connection with
 memory and i have to reinitialize my GLTutorial1 class and pops a
 framebuffer error. It does it only after some time passes and pharo is idle,
 its a strange bug, but if it starts appearing again I will try to pin point
 it, because my code is not up to the opengl standards yet so it may be me
 that cause this issue.


Sorry, did not replied to this part.
Yes, i found strange behavior as well: it creates context every 2nd time,
and giving error in between.
There could be some wrong code in handling the context..
(it also can be related to GC, because context is not destroyed
directly in my demo,
but released by finalization)

 My problem right now is that I follow the tutorial at arcsynth and I am
 stuck here

 http://www.arcsynthesis.org/gltut/Basics/Tut01%20Following%20the%20Data.html
 http://www.arcsynthesis.org/gltut/Basics/Tut01%20Following%20the%20Data.html

 glBufferData(GL_ARRAY_BUFFER, sizeof(vertexPositions), vertexPositions,
 GL_STATIC_DRAW);

 the question is how i find the size in smalltalk . There is
 bufferData_target:  size:  data:  usage:  which corresponds to that function
 but I have no idea how to convert sizeof() to smalltalk. Any clues ?



 Yes.

 (NBExternalType sizeOf: 'float') * number of floats in your buffer

 or

 (NBExternalType sizeOf: 'double') * number of floats in your buffer

 For arrays of static type, i would recommend you using NBExternalArray,
 which gives you a convenient way to deal with arrays of any static
 type in smalltalk way.
 For passing it as argument to function you can use  'array address' idiom.
 See class comments for details.

 Btw, getting the size of array, in bytes,  would be:

 sizeInBytes
^ self size * self class elementSize

 (i think this method would be nice to have).

 If you want to see my code I have commited it in NBOpengl smalltalkhub the
 latest is NBOpenGL-Morphic-kilon.10 for NBOpenGL-Morphic.



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Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 4 June 2013 11:40, kilon theki...@yahoo.co.uk wrote:
 Ok new problem, NBOpengl seems to not work at all on my UBUNTU 12.10 machine.
 I was trying to do GLViewportMorph new openInWorld , which works fine on my
 iMac and it gave me error: function unavailable.

 So I assumed it cannot find some dynamic library , so I checked around the
 code and found that in package NBXLib-Core
 NBXlibHandlenbLibraryNameOrHandle class method, it returns
 '/usr/lib/libX11.so'. However browsing through the directories its clear
 that the library is not located in there but rather is located as a symlink
 in a) /usr/lib/i386-linux-gnu b) /usr/lib/x86_64-linux-gnu. Both symlink
 point to libx11.so.6.3.0 libraries.

 So knowning that pharo is 32 bit I went for option (a) however still it
 gives me the same error.

 Any idea what it may be ?

 Another question I have is does it not NB check first to see if the library
 is available ? Because it looks weird that it complains about non existent
 functions but does not complain about non existent library.


NB uses a VM API to look for a function in library.
That function provides no error feedback (just success or not).
and also, it combines with loading library as well.
So it is hard to say what exactly happened: did library failed to load or
library loaded fine, but function not found.
(see #loadSymbol:fromModule:  implementation)

To put an end to endless mystery, i propose you to implement a small
diagnostic tool..
There is not much to do:
 - call dlopen()
 - if it fails, call dlerror() , and get details about failure.
 - call dlsym
 - if it fails, call dlerror() , and get details about failure.


 Here is the stack

 NBFFICallout(Object)error:
 NBFFICalloutgenerateCall:module:
 NBGlxAPIcall: in Block: [...]
 NBFFICallout class(NBNativeCodeGen class)generateCode:andRetry: in Block:
 [...]
 BlockClosureon:do:
 NBRecursionDetect classin:during:
 NBFFICallout class(NBNativeCodeGen class)generateCode:andRetry:
 NBFFICallout class(NBNativeCodeGen class)handleFailureIn:nativeCode:
 NBGlxAPIcall:
 NBGlxAPIqueryExtension:errorBase:eventBase:
 NBGLXContextDrivercreateContext:
 NBGLContextDriver classcreateContext:
 NBGLDisplay classextent:
 GLViewportMorphinitializeForNewSession
 GLViewportMorphinitialize
 GLViewportMorph class(Behavior)new
 UndefinedObjectDoIt
 Compilerevaluate:in:to:notifying:ifFail:logged:
 SmalltalkEditorevaluateSelectionAndDo:
 SmalltalkEditorevaluateSelection
 PluggableTextMorphdoIt in Block: [...]
 PluggableTextMorphhandleEdit: in Block: [...]
 TextMorphForEditView(TextMorph)handleEdit:
 PluggableTextMorphhandleEdit:
 PluggableTextMorphdoIt
 Workspace(Object)perform:orSendTo:
 ToggleMenuItemMorph(MenuItemMorph)invokeWithEvent: in Block: [...]
 BlockClosureensure:
 CursorWithMask(Cursor)showWhile:
 ToggleMenuItemMorph(MenuItemMorph)invokeWithEvent:




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-- 
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Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 22 May 2013 20:11, kilon theki...@yahoo.co.uk wrote:
 I am looking at NBGLContextDriver and NBGLDisplay and I see none of that hard
 coded stuff.

Look more carefully: there's a code to manage viewport and setting up
buffers and other things,
like blend more etc in those classes.
It is not platform-specific (because it uses purely only opengl api),
but it doesn't makes it less hardcoded.

 I assume you mean the platform specific packages like NBMacGLContextDriver
 ,NBGLXContextDriver etc. where I see alot of platform specific code inside
 the methods of those classes .


Yes, it has to be platform-specific. But do not confuse hardcoded
stuff with platform-specific code.
Ideally, there should be no hardcoded one, but it is hard to achieve
(for the reasons i mentioned before,
and one of them is platform-specificness, of course).

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-- 
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Igor Stasenko.

Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

ok i see, well I did not mean that we dont need platform specific code, of
course we do. 

thanks for adding me.

I will first try to contribute some example classes that show how nbopengl
can be used in practice. 
And see if I can fix any of the bugs I find. 

No problem if you dont have time, I do and will HOPEFULLY be the very area
will focus from now , so I am here to stay unless I hit a dead end and cant
use opengl properly for some reason. 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

Hey Igor , yes I would love to contrinbute to NBOpenGL for a very long time. 
I could at least fix those small errors like the one I reported and add
documentation to methods and
especially classes. 

I am using pharo 3.0 and GLTTRenderingDemo does not work. I get an error. 

Apparently it cannot find ShortPointArray which is initialised inside
TTCountourConstructionasCompressedPoints

I remember having same issues with pharo 2.0 too. 

I am also confused how to use NBGLCurveRenderer. 

Thank you for your detailed explanation I have tried GLViewportMorphic I see
no errors , so its should work fine. 

I am new to opengl myself , and smalltalk and nativeboost so I try to
understand as much I can before doing actual coding and I feel I am at that
stage that I can do and I would love to contribute my work back to pharo
because I plan to implement at least a basic 3d engine and very basic
MoprhicGL GUI. 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[kilon]

I am looking at NBGLContextDriver and NBGLDisplay and I see none of that hard
coded stuff. 

I assume you mean the platform specific packages like NBMacGLContextDriver
,NBGLXContextDriver etc. where I see alot of platform specific code inside
the methods of those classes . 



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Re: [Pharo-dev] [Pharo-project] Understanding NBOpenGL

[Igor Stasenko]

On 17 May 2013 10:21, kilon theki...@yahoo.co.uk wrote:
 Thank you all for your replies. I have used the solution I get new errors
 now. Is there an example how to create a context with NBOpenGL because the
 examples NBOpenGL is coming with are confusing at best ?


Pharo2.0
Latest update: #20590

(ConfigurationOfNBOpenGL project version: '2.0') load

GLTTRenderingDemo new openInWorld

(works well.. no errors whatsoever)

See a superclass (GLViewportMorph).

The context created using:

display := NBGLDisplay extent: self extent.

To get access to OpenGL API (a subinstance of NBOpenGL)

just use:

display gl.

The actual class, responsible for creating OpenGL context is
one of NBGLContextDriver subclasses, since
it is highly platform-specific.


driver := NBGLContextDriver createContext: 100@100.
gl := driver gl.

The display (NBGLDisplay) wraps around driver and has some initialization
to set up defaults and resource management to make sure resources
released when it garbage collected
(the driver does not, and you must free it explicitly).

To use GL API , just send #gl message to either display or driver:

drawCube

| gl |
gl := display gl.


gl translatef_x: -1.5 y: 0 z: -60.
gl rotatef_angle: rotationAngle x: 0 y: 1  z: 0.

gl
begin: GL_TRIANGLES;

   ...
end.

Please note, that in NBGLContextDriver(s) i hardcoded many things like
pixel format,
and NBOffscreenDisplay rendering into offscreen buffer etc.

That means, if you want to create own initializer, i would start from
making own driver.
Sorry but the stuff there is highly platform specific.
Making a generic driver which would accept some initialization options
(like pixel format, number of buffers etc) while freeing user from
platform-specific horrors is something which could be done in future.
But as i said before, the devil is always in details , and i would
just leave this to application developer.

P.S. If , by chance, you wanna make things less confusing and more
obvious, feel free to contribute to the project,
i can add you as developer.
You can change/improve anything. I only asking to keep
GLTTRenderingDemo working :)

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