Turn vertex points on/off, so fragment points turn on/off
Skybuck Flying
I am newb to gpgpu programming so I wonder if the following is possible and
what technique for it could be used to achieve it
(I saw someone else mention GL_POINTS so I will go on that):
The idea is as follows:
There is an array of verteces for example 1000 verteces.
Each vertex translates to a "pixel" / fragment.
So there should be 1000 pixels as well.
The vertex shader will be called first and each vertex must decide if it's
to be on or off based on some condition.
Each vertex that is on should trigger a fragment/pixel shader.
Therefore only the pixel/fragment associated with the vertex should execute
the pixel/fragment shader to make it as efficient/fast as possible.
So that's idea and I have a couple of questions about that:
1. Is this possible somehow ?
2. What techniques exist ?
3. Which technique would be fastest ?
I would prefer to use OpenGL + CG on DirectX9 cards like NVIDIA GTX 7900.
DirectX solutions would be interesting too.
(I posted this question on gpgpu forum as well (except above two lines), so
I am shotgunning multiple resources for some possible answers ;) :))
Thanks for any help ! God bless you !
Bye,
Skybuck.
Skybuck Flying
It seems easy enough, however there is one little peculiar thing; the last
horizontal line does not get any points ? Weird... anybody have an
explanation for that ?
Here is the code:
(By changing the Z value from 0 to -2 or 2 the points will disappear... but
not when setting it to -1 or 1... why is that ? that's kinda strange too ;))
procedure CreateVertexPoints( ParaWidth : integer; ParaHeight : integer );
var
vX : integer;
vY : integer;
// vZ : integer;
begin
glBegin(GL_POINTS);
for vY := 0 to ParaHeight-1 do
begin
for vX := 0 to ParaWidth-1 do
begin
glVertex3f( vX, vY, 0 );
end;
end;
glEnd;
end;
procedure TForm1.mOpenGLGLInit(Sender: TObject);
begin
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0, mOpenGL.Width, mOpenGL.Height, 0.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glViewport(0, 0, mOpenGL.Width, mOpenGL.Height );
end;
procedure TForm1.mOpenGLGLPaint(Sender: TObject);
begin
glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
glLoadIdentity;
CreateVertexPoints( mOpenGL.Width, mOpenGL.Height );
end;
Bye,
Skybuck.
Skybuck Flying
I read a posting somewhere how pixels are supposed to fall into the middle
or so...
So far there seem to be two solutions:
1. glVertex3f( 0.5 + vX, 0.5 + vY, 0 );
2. gluOrtho2D(0.0-0.5, mOpenGL.Width-0.5, mOpenGL.Height-0.5, 0.0 - 0.5);
Last solution would probably be better for two reasons:
1. First of all it's only done once.
2. Second of all I don't need to fuss around in all glVertex calls and such
which would be nice ! ;)
Bye,
Skybuck.
Skybuck Flying
programming...
Could this disturb the values by -0.5 ?
Hmm...
Well for now I can let it in... this is also advantage of solution 2...
If it needs to be removed then only in one place does it need to be removed
! ;)
Bye,
Skybuck.
Skybuck Flying
monitor... kinda strange...
I am not sure if this is a locked speed of TOpenGL, Delphi, Windows or
something else... like maybe swapping buffers always being that slow... I
don't know...
Hmm.
Bye,
Skybuck.
Skybuck Flying
Searched and again found the answer in 3 seconds lol.
It's because of the double buffering... apperently it waits for a vertical
retrace.
Turn that off and it runs at 29000 fps LOL. (Not drawing anything except
black background ;) :))
Now I measure performance of the "slow" immediate vertex drawing mode :)
Here goes:
Ok for 500x400 verteces it achieves 160.72 fps.
The screen blinks a lot and the last lines are missing... but at least this
gives a bit of an indication how slow it is (?) ;)
I also tried adding glFinish before measurements but that don't matter much
in this case ;)
Yeah going from 29000 fps to 160 fps is bad :)
Bye,
Skybuck ;) :) LOL.
Skybuck Flying
The idea is now to create a 4096x4096 vertex array in 3D Studio Max 9 or
so...
So that this file can be loaded into FX Composer 2.5 so that I can directly
program the shader in FX Composer 2.5 and see how it works out ! ;)
Hihi.
3D Studio 4.0 for DOS used to have some kind of generation/duplication
functionality to quickly duplicate objects probably even verteces now I go
figure this out for 3D Studio Max 9 ;)
Bye,
Skybuck.
Skybuck Flying
with 3D Studio:
1. First of all the plane is limited to 1000 by 1000 segments.
2. Second of FX Composer 2.5 cannot import MAX files ?
3. Third of all exporting to 3DS is problematic: 3D Studio Max 9 shows
warnings: Object(Plane01) has too many faces(more than 64K) to export.
Seems like this is a 3DS 4.0 file format limitation ? Ouch !
Well I don't need the faces... I just need the verteces... maybe I can
delete the triangles/faces... that would leave 1000x1000 verteces or so...
one million verteces... maybe it will complain again...
Hmmm...
I also wondering which tool would be better for developing shaders:
1. 3D Studio Max ?
or
2. FX Composer 2.5 ?
I know FX Composer 2.5 has a shader debugger... but does 3D Studio Max have
a shader debugger ??? Hmm.
Bye,
Skybuck.
Skybuck Flying
I tried the wave front (obj) format... but it's some kind of fucked up
format that generates like 200+++ MB...
I had to terminate 3D Studio Max... just in case... ;)
I kinda new that would happen... maybe it's some kind of length text file
format... don't know, don't care ;)
Well hmm shitty... me must find good efficient format ;)
Bye,
Skybuck.
Skybuck Flying
time... I don't wanna wait for it... life is too short ;)
Had to terminate 3D Studio Max 9 again... it used something like 1 GB of ram
during export.
I shall try one more time by trying to delete the faces or so... maybe that
helps but I doubt it ;)
Bye,
Skybuck.
Skybuck Flying
"delete isolated verteces".
However exporting to 3DS format now gives the other warning I feared:
"Object [Plane01] has too many vertices (more than 64K) to export.
I tried opening the partial file or so in FX Composer (the file with the
face) but composer didn't show anything... first time I actually test
importing... maybe I should first do a small test to see if that would work
and how it would look but ok.
So far it seems 3DS format is seriously limited to 16 bit which means
everything having a limit of 64K
So best I can do is SQRT(64000) which is: 252x252 = 63504
However normally it's something like 256*256 = 65536
However C loops will fail under that condition so I fear 3DS Max 9 will spin
for ever when trying to save or load it...
Would be interesting to see... so I will attempt creating exactly 65536 or
65535 vertices to see what happens ;) :)
Bye,
Skybuck.
Skybuck Flying
I did some testing that was kinda interesting :)
A plane of 255 by 255 segments creates exactly 65536 verteces.
Exporting to 3DS fails.
I deleted one vertec.
Exporting to 3DS fails.
Apperently the programmers/file format designers were paranoid enough to
limit it to 64000 ;)
So now I create a plane of (252-1) by (252-1) segments and that should be
the maximum square that will fit into 64000 verteces... it would almost
create double the ammount of faces so those need to be deleted and then I
can finally export something into FX Composer 2.5...
Would be funny if FX Composer is stubern enough to delete the unused
verteces... I hope not... but I fear the worst ! ;) :)
Bye,
Skybuck =D
Skybuck Flying
This kinda sux.
Well new calculation:
Maximum number of faces is 64000
Each square needs to faces so new figure is 32000
SQRT(3200) = (178-1) by (178-1)
This should create the maximum allowable plane with faces for 3DS...
Gonna try it now... if that fails then I am gonna try a fricking teapot
lol... to see if it's gonna work at all :)
Bye,
Skybuck.
Skybuck Flying
and 32K verteces ?!?!?
Ouch ! Sigh...
Well just to test out my theories I guess I will have to seriously constrain
myself and limit myself to
10x10 faces... I hope it can handle that ?!? Gjez ! =D
LOL.
Bye,
Skybuck =D LOL.
Skybuck Flying
Giving me exactly 10 by 10 grid of verteces...
Now I try to write a vertex shader only to see how it can affect verteces...
According to docs it can fully change vertex locations... so that will be
most interesting to witness ! ;)
Bye,
Skybuck.
Skybuck Flying
Here is my simple vertex shader... nice thing about vertex shader is it only
requires a position more or less...
FX Composer is nice enough to provide a formula/code for camera/world
projection or something like that... never understood matrices me but it
gets the job then here is my little vertex shader:
Here is my first little vertex shader:
/*
% Description of my shader.
% Second line of description for my shader.
keywords: material classic
date: YYMMDD
*/
float4x4 WorldViewProj : WorldViewProjection;
float4 mainVS(float3 pos : POSITION) : POSITION{
float3 test;
test = pos;
// makes the plane all spikey
// test.y = test.y + cos(test.x/10)*100 + cos(test.z/10)*80;
// makes the plane wavey like a bowl
test.y = test.y + cos(test.x/100)*60 + cos(test.z/100)*50;
return mul(WorldViewProj, float4(test.xyz, 1.0));
}
float4 mainPS() : COLOR {
return float4(1.0, 1.0, 1.0, 1.0);
}
technique technique0 {
pass p0 {
CullFaceEnable = false;
VertexProgram = compile vp40 mainVS();
FragmentProgram = compile fp40 mainPS();
}
}
This is exactly what I need this kinda of vertex shader capabilities...
It will probably do just fine for the intended purposes ! ;) :)
I don't know if it will be fast... but probably... only other alternative I
know so far is modifieing the verteces outside of the shader... like in c or
delphi code... this would have benefit of only having to modify a few
verteces only... but question is can object be updated easily/partially like
that ?!? And how long would it take... kinda interesting question...
But for now I am betting on somehow keeping the verteces all inside the
graphics cards and trying to manipulate them repeatedly.
It's to bad that FX Composer can't handle so many vertices otherwise I could
have used it's performance indicator... but anyway I try that now to see
what kind of performance it gives for this simple shader ! ;) :)
Well I am also running 3D Studio so maybe these numbers not so representive
but ok here goes... later I will test them so more... but first I want more
vertices for kicks ! I need them too hihi.
For Geforce 8400 GS it says something like:
regs:
normal 5
fp16 5
fp32 5
what does this mean, how many registers it uses ?
Cycles:
5,5,5
MPIX/sec
1799,
1799,
1799.
I guess that's for the simple pixel shader.
Ah yes now I see I have to select "show vertex shader"
For vertex shader it says:
Regs: 5
Cycles: 23
MVert/s : 23
Regs 5 probably means 5 registers used ?
Cycles 23 probably means how many cycles it takes to execute the shader ?
MVert/s is probably how many vertices it can shade in millions...
So that would be 23 million verteces... that's not bad for 2 cosines, 2
multiplies and 3 addition and some assigments :)
23 million fricking verteces hmmmm.... suppose a redcode warrior would
execute that many cosines and such that would mean 287.5 warriors would run
per second ! HMMM juicy ! =D LOL.
Sounds to good to be true... there is probably some overhead here and there
for opengl calls and such...
But things are starting to look nice...
Actually it is too good to be true... since these are just 10 by 10
vertices... ultimately... it would be pretty full: 4096 x 4096 verteces is
what I want... but I can't test that with FX composer...
I did do some tests with some code yesterday that looked fast though... so
could be true ! ;) :)
This is way too much fun ! LOL.
Bye,
Skybuck =D
Nicolas Bonneel
hem.. I really don't want to hurt you but...just as a side note... do
you realize that with your average writing rate on these newsgroup
(maybe a hundred lines every 10 minutes), nobody is reading what you're
writing ?
Probably you could consider posting once a day with the summary of your
deeper thoughts instead of posting every single question that you get at
every instant, and that your solving by yourself in the next minutes ?
It will make the newsgroup more readable (although it's already good
that you're not starting a new topic each time), but more importantly,
you will be read by peoples and you will get answers to your questions!
People here have jobs and won't spend their night reading your tens of
messages! However, reading and answering a short message a day is feasible.
Also, you can consider putting a follow-up to a single newsgroup instead
of cross-posting, but at this point, this is a detail...
Thank you very much for your understanding! :) But I'm sure you can
benefit from this advice :p
--
Nicolas Bonneel
http://www-sop.inria.fr/reves/Nicolas.Bonneel/
Skybuck Flying
Read what interests you, skip the rest ;)
Bye,
Skybuck =D
Charles E Hardwidge
news:53694$4aa12d52$d53372a9$20...@cache3.tilbu1.nb.home.nl...
> Read it like a newspaper ;)
>
> Read what interests you, skip the rest ;)
You're trolling like the point and shoot guy does in the photography
newsgroups. It's a good way to be ignored.
Follow-ups trimmed.
--
Charles E Hardwidge
Troll
Nicolas Bonneel wrote:
> [snip]
>
> hem.. I really don't want to hurt you
Look! There is one! Hang on to this guy, SF, he may be the only one.
> you realize that with your average writing rate on these newsgroup
> (maybe a hundred lines every 10 minutes), nobody is reading what you're
> writing ?
I've had SF on the ignore list for a long time, I don't see any of his
posts, neither long and drolling nor short and trolling.
> Probably you could consider posting once a day with the summary of your
> deeper thoughts instead of posting every single question that you get at
> every instant, and that your solving by yourself in the next minutes ?
Must mention option #3: Just go away.
> Thank you very much for your understanding!
Careful, you'll wear him out.
Nicolas Bonneel
> Read it like a newspaper ;)
>
oh, ok, you're not here to ask questions (although it appears so),
you're writing here either to show off or to hold a blog. There are web
tools for that.
> Read what interests you, skip the rest ;)
no: as soon as you see 10 messages which are each posted at 15 minutes
of interval (and I'm nice) and contains >100 lines each, everyone just
SKIP it. It means the message is not read *at all*, and I'm not even
aware if it would have interested me if I had taken the time to read it,
even partly (or to open it). In brief, we just see the length of the
message, not its content.
Troll
>
> oh, ok, you're not here to ask questions (although it appears so),
> you're writing here either to show off or to hold a blog.
You're catching on!
> There are web
> tools for that.
>
And a willing audience here, too, it appears.
> <snipped drivel>
>
> SKIP it. It means the message is not read *at all*, and I'm not even
> aware if it would have interested me if I had taken the time to read it,
I went one better and don't even see that. He can post his
ramblings all day long for all I care.
Skybuck Flying
Google will index my postings... and who knows... maybe some day, some where
out there in space ! you might find one of my postings usefull and actually
answers one of your questions ! ;) :)
Bye,
Skybuck.
Olumide
Google also indexes blogs and journals. A developers journal would
suit your monologues. Also, I've suggested in the past that you
consider posting on the nVIDIA developers forum where the real gpu
experts live and talk, not here on general graphics algorithms.
And why so much cross posting to alt.comp.lang.borland-delphi,
alt.comp.periphs.videocards.nvidia, comp.graphics.algorithms,
comp.graphics.api.opengl, microsoft.public.directx.graphics?????
Skybuck Flying
Today I had an idea which I wonder if it's been done before... maybe not so
that could mean I invented it ! ;)
The idea is as follows:
To speed up the vertex on/off idea the following is uses:
1. Vertex array or vertex buffer
2. Render to texture.
The render to texture could render to the vertex array/buffer/data itself to
prepare the vertex coordinates for the next round/pass.
So for example the pixel shader could modify the Z of each vertex to turn it
on/off in/for 2D ortho mode...
I am not sure if it's possible to directly write the output verteces of the
vertex shaders to some buffer... that could be an interesting feature to
have as wel... could be I say, not sure about it ! ;)
Just documentating some idea's for future use probably.
Bye,
Skybuck.