[PD] GEM mapping units to pixels

[cyrille henry]

chris clepper a écrit :
> You are wondering why a 1:1 perspective works for a 4:3 window?
> 
yes.

cyrille

> On 5/13/07, cyrille henry <cyrille.henry at la-kitchen.fr> wrote:
>>
>> could you also try the test3 patch i just send?
>>
>> thanks
>> Cyrille
>>
>>
>> chris clepper a écrit :
>> > Your example patch works exactly as it should on OSX.
>> >
>> > On 5/13/07, altern <altern2 at gmail.com> wrote:
>> >>
>> >> cyrille henry(e)k dio:
>> >> > hello,
>> >> >
>> >> > altern a écrit :
>> >> >> hi
>> >> >>
>> >> >> do you mean something like the example attached?
>> >> > yes, exactly.
>> >> >
>> >> >> This doesnt work ok for me, the shape should be 10x10 px and is 
>> not,
>> >> > a [rectangle 10 10] should be 20 pixel.
>> >>
>> >> i understand from the rectangle help that [rectangle 10 10] should 
>> be a
>> >> 10 units width by 10 units height square. I get a rectangle which is
>> >> irregular, check the attached screnshot gif
>> >>
>> >> >> also x and y pos are dont match with window size. Translating to
>> 400,
>> >> >> 300 should place the rect in top right corner but I get that with
>> only
>> >> >> 320, 190,  so the units are not mapped to pixels
>> >> > translating to 400 300 should move the center of the rectangle in 
>> the
>> >> > top right corner.
>> >> > if your rectangle is 100 100, then you just have to move it 300 200
>> in
>> >> > order to have the corner of the rectangle in the corner of the gem
>> >> window.
>> >> >
>> >> > your patch work that way here.
>> >>
>> >> check the attachment again, the rect is 10x10 and it is located at
>> >> X=307, Y=167. This should be far from 400, 300 which should be the
>> >> top,right location. So the coordinate system is distorted, 
>> specially on
>> >> the y axis
>> >>
>> >> I also tried with
>> >> dimen 400 400
>> >> perspec 0 400 0 400 999 1001
>> >> If draw a 1 by 1 rect and i get it to the right top corner by
>> >> translating it 320, 320. So pixels are dont match gl units and 
>> moreover
>> >> in the previous example when the gem window is not a square the
>> >> distortion affects differently the X and the Y axis
>> >>
>> >> >>
>> >> >> but maybe i am missing something from what you describe?
>> >> >>
>> >> >> In opengl to achieve this 2D like-pixels to units effect i would
>> >> >> set the perspective to be orthographical with glOrtho command, is
>> >> >> something like this possible in Gem?
>> >> > yes, insert an [ortho] after the gemhead
>> >> >
>> >> >
>> >> > cyrille
>> >> >
>> >> >>
>> >> >> thanks!!
>> >> >>
>> >> >> enrike
>> >> >>
>> >> >> cyrille henry(e)k dio:
>> >> >>> hello,
>> >> >>>
>> >> >>> i tried with :
>> >> >>> dimen 400 300
>> >> >>> view 0 0 1000 // 1000 is in order to put the camera far from the
>> view
>> >> >>> point, to reduce space distortion
>> >> >>> perspec 0 400 0 300 999 1001 // 999 and 1001 limit the render to
>> >> >>> primitive position is between -1 and 1 (because camera is at 1000)
>> >> >>>
>> >> >>>
>> >> >>> and everything is working as expected.
>> >> >>> i just have 1 strange thing : i need to set the [dimen<,
>> [create<  ,
>> >> >>> then [reset< and last [view< and [perspec< if i did not do a 
>> reset,
>> a
>> >> >>> square is not rendered as a square but a rectangle.
>> >> >>>
>> >> >>> anyway, it's working.
>> >> >>>
>> >> >>> cyrille
>> >> >>>
>> >> >>>
>> >> >>> altern a écrit :
>> >> >>>> i tried to pass different view values to gemwin. I can see 
>> that in
>> >> >>>> order to be able to specify location or with with pixels i should
>> >> >>>> set view to
>> >> >>>> view 0 0 2
>> >> >>>> but as soon as i set that the shape is not there any more. 
>> This is
>> >> >>>> an example i am using to test. If i ser view to
>> >> >>>> view 0 0 2.01
>> >> >>>> it is almost there but if i set it to 0 0 2 it is not there any
>> >> >>>> more. I guess it might be because it is either beyond the back
>> limit
>> >> >>>> y or behind the camera?
>> >> >>>>
>> >> >>>> thanks
>> >> >>>>
>> >> >>>> enrike
>> >> >>>>
>> >> >>>>
>> >> >>>> altern(e)k dio:
>> >> >>>>> hi
>> >> >>>>>
>> >> >>>>> I am trying to map GEM units to pixels so that i can position
>> some
>> >> >>>>> videos in the GEM window using pixels values. For this I
>> understand
>> >> >>>>> that
>> >> >>>>> i must match the projection values with the window size. So i am
>> >> doing
>> >> >>>>>
>> >> >>>>> dimen 400 300
>> >> >>>>> perspect 0 400 0 300 1 20
>> >> >>>>>
>> >> >>>>> and i render all objects at z position 1
>> >> >>>>>
>> >> >>>>> translateXYZ 100 100 1
>> >> >>>>>
>> >> >>>>> However I am getting a weird result, the units are far smaller
>> that
>> >> >>>>> pixels, so to move a video 100px in the x i need to change it x
>> >> >>>>> position
>> >> >>>>> by 300 units or something like this. So I am not sure about what
>> i
>> >> am
>> >> >>>>> doing wrong, I am familiar with OpenGL but i never played too
>> much
>> >> >>>>> with
>> >> >>>>> GEM before so I am still getting into it.
>> >> >>>>>
>> >> >>>>> Another small issue is that I would also like to reverse the 
>> Y so
>> >> that
>> >> >>>>> upper left is 0,0 and bottom left would be 0,200 for example, 
>> not
>> >> sure
>> >> >>>>> about how to change this. I guess it is to do with the gemwin
>> >> settings
>> >> >>>>> but i dont get it right.
>> >> >>>>>
>> >> >>>>> thanks
>> >> >>>>>
>> >> >>>>> enrike
>> >> >>>>>
>> >> >>>>>
>> >> >>>>
>> >> >>>>
>> >> >>>> _______________________________________________
>> >> >>>> PD-list at iem.at mailing list
>> >> >>>> UNSUBSCRIBE and account-management ->
>> >> >>>> http://lists.puredata.info/listinfo/pd-list
>> >> >>>>
>> >> >>>>
>> >> >>>
>> >> >>
>> >> >>
>> >> >>
>> >> >>
>> >>
>> ------------------------------------------------------------------------
>> >> >>
>> >> >> #N canvas 393 156 429 320 10;
>> >> >> #X obj 84 210 gemwin;
>> >> >> #X obj 245 163 gemhead;
>> >> >> #X msg 173 82 create \, 1;
>> >> >> #X msg 293 106 0 \, destroy;
>> >> >> #X floatatom 309 164 5 0 0 0 - - -;
>> >> >> #X floatatom 347 164 5 0 0 0 - - -;
>> >> >> #X floatatom 288 215 5 0 0 0 - - -;
>> >> >> #X floatatom 332 215 5 0 0 0 - - -;
>> >> >> #X obj 245 190 translateXYZ 10 10 1;
>> >> >> #X msg 215 50 dimen 400 300;
>> >> >> #X msg 48 73 view 0 0 1000;
>> >> >> #X msg 9 48 perspec 0 400 0 300 999 1001;
>> >> >> #X msg 110 99 reset;
>> >> >> #X obj 50 -8 bng 15 250 50 0 empty empty empty 0 -6 0 10 -262144 -1
>> >> >> -1;
>> >> >> #X obj 50 13 t b b b b b;
>> >> >> #X obj 245 234 rectangle 10 10;
>> >> >> #X connect 1 0 8 0;
>> >> >> #X connect 2 0 0 0;
>> >> >> #X connect 3 0 0 0;
>> >> >> #X connect 4 0 8 1;
>> >> >> #X connect 5 0 8 2;
>> >> >> #X connect 6 0 15 1;
>> >> >> #X connect 7 0 15 2;
>> >> >> #X connect 8 0 15 0;
>> >> >> #X connect 9 0 0 0;
>> >> >> #X connect 10 0 0 0;
>> >> >> #X connect 11 0 0 0;
>> >> >> #X connect 12 0 0 0;
>> >> >> #X connect 13 0 14 0;
>> >> >> #X connect 14 0 11 0;
>> >> >> #X connect 14 1 10 0;
>> >> >> #X connect 14 2 12 0;
>> >> >> #X connect 14 3 2 0;
>> >> >> #X connect 14 4 9 0;
>> >> >>
>> >> >
>> >>
>> >>
>> >> _______________________________________________
>> >> PD-list at iem.at mailing list
>> >> UNSUBSCRIBE and account-management ->
>> >> http://lists.puredata.info/listinfo/pd-list
>> >>
>> >>
>> >>
>> >
>>
>