batchku

i would like to make a vertex program that applies a certain deformation to a plane based on the contents of a jitter matrix. i.e., i have a plane and i'd like to displace certain points on this plane based on a jit-matrix that i'm writing into with jit.lcd or some such.

i'm not sure how to access the contents of a jit.matrix from within my glsl shader program.

i would like to make a vertex program that applies a certain deformation to a plane based on the contents of a jitter matrix.  i.e., i have a plane and i'd like to displace certain points on this plane based on a jit-matrix that i'm writing into with jit.lcd or some such.

a-simple-question-about-programmable-shaders

You could tranfer the lcd contents to a texture and access the texture from

within the shader. Ofcouse you'll have to bind both the texture and shader

program to the plane using the normal @texture and @shader attributes.

Instead of using the rgba values to influence the color of the plane, you

can then use them to do something else. I'm not really sure you can access

the texture "sampler2D" in the vertex program, but I suspect you can.

> i would like to make a vertex program that applies a certain deformation

> to a plane based on the contents of a jitter matrix. i.e., i have a plane

> and i'd like to displace certain points on this plane based on a jit-matrix

> that i'm writing into with jit.lcd or some such.

> i'm not sure how to access the contents of a jit.matrix from within my

You could tranfer the lcd contents to a texture and access the texture from
within the shader. Ofcouse you'll have to bind both the texture and shader
program to the plane using the normal @texture and @shader attributes.
Instead of using the rgba values to influence the color of the plane, you
can then use them to do something else. I'm not really sure you can access
the texture "sampler2D" in the vertex program, but I suspect you can.

On 8/25/06, Ali Momeni  wrote:
>
>
> i would like to make a vertex program that applies a certain deformation
> to a plane based on the contents of a jitter matrix.  i.e., i have a plane
> and i'd like to displace certain points on this plane based on a jit-matrix
> that i'm writing into with jit.lcd or some such.
>
> i'm not sure how to access the contents of a jit.matrix from within my
> glsl shader program.
>
> any hints?
>
> thanks,
> a
>
>


however, what i need is to access particular positions in my texture within my vertext program. is tex0 indexted like a matrix, as in tex0[x][y] would be the x,y point in my texture?

i'm with you so far;
however, what i need is to access particular positions in my texture within my vertext program.  is tex0 indexted like a matrix, as in tex0[x][y] would be the x,y point in my texture?


You access a texture by instantiating a the sampler2D for every texture.

Then to access its content you call the texture2D method with 2 arguments.

The first being the texture id, tex0, and the second one being the array of

texture coordinates (st / xy in case of a 2D texture). You can use the

coordinates generated automatically by opengl (according to the texturing

mode), but in your case you would calculate the coordinates yourself. So the

answer is yes, you can access your texture like an array, only not like

tex0[x,y] but through use of the texture2D method.

I don't have experience with this either, but I have the orange book sitting

next to me:-) I suggest you check it out online.

> however, what i need is to access particular positions in my texture

> within my vertext program. is tex0 indexted like a matrix, as in tex0[x][y]

You access a texture by instantiating a the sampler2D for every texture.
Then to access its content you call the texture2D method with 2 arguments.
The first being the texture id, tex0, and the second one being the array of
texture coordinates (st / xy in case of a 2D texture). You can use the
coordinates generated automatically by opengl (according to the texturing
mode), but in your case you would calculate the coordinates yourself. So the
answer is yes, you can access your texture like an array, only not like
tex0[x,y] but through use of the texture2D method.

I don't have experience with this either, but I have the orange book sitting
next to me:-)  I suggest you check it out online.

On 8/25/06, Ali Momeni  wrote:
>
>
> i'm with you so far;
> however, what i need is to access particular positions in my texture
> within my vertext program.  is tex0 indexted like a matrix, as in tex0[x][y]
> would be the x,y point in my texture?
>


still with you, i've discovered texture2DRect but am not sure how to provide the vec2 coor for the point i wanna access.

first, is the 2nd argument of texture2DRect in integers as in the pixel position in the texture, or is it a float between 0. and 1. for x and y?

and second, how could i access the automattically generated coordinates by OpenGL?

say, you happen to have a linke for the orange book online? or you bought the hard copy....

say, you happen to have a linke for the orange book online?  or you bought the hard copy....


it seems that i'm not allowed to use textures from the outside like tex0 and tex1 and ... in a vertex program.

ERROR: Implementation limit of 0 active vertex shader samplers (e.g., maximum number of supported image units) exceeded, vertex shader uses 1 samplers

• error: -- END GLSL INFO LOG: jDang:/Users/ali/Documents/_for-MaxMSP/_current/shaders/gravity-lighting1.jxs --

this so called implementation limit of 0 seems to be rather low, no? :)

ah, now i have a new problem.
it seems that i'm not allowed to use textures from the outside like tex0 and tex1 and ... in a vertex program.

i get this error:
 --
ERROR: Implementation limit of 0 active vertex shader samplers (e.g., maximum number of supported image units) exceeded, vertex shader uses 1 samplers
• error: -- END GLSL INFO LOG: jDang:/Users/ali/Documents/_for-MaxMSP/_current/shaders/gravity-lighting1.jxs --

Texture access is not allowed in the current version of vertex

programs that both OSX and Windows support. For this, you're going to

have to wait for the next version of GLSL to make its way from

standard to actually being implemented in the OS. This kind of thing

and a new type of shader called Geometry shaders are what's coming in

For now, you're going to have to use a per-vertex value such as color,

tangent, bitangent, or specular array (basically one of jit.gl.mesh's

inputs). You'll access these using the built in GLSL variables for

accessing fixed function values like gl_Color or gl_Normal and just

ignore the name and use it how you want. So, this is entirely

possible to do now, just not with textures. If you need more

direction on how to do this, let me know and I'll see if I can whip

Hi Ali,
Texture access is not allowed in the current version of vertex
programs that both OSX and Windows support.  For this, you're going to
have to wait for the next version of GLSL to make its way from
standard to actually being implemented in the OS.  This kind of thing
and a new type of shader called Geometry shaders are what's coming in
the future.

For now, you're going to have to use a per-vertex value such as color,
tangent, bitangent, or specular array (basically one of jit.gl.mesh's
inputs).  You'll access these using the built in GLSL variables for
accessing fixed function values like gl_Color or gl_Normal and just
ignore the name and use it how you want.  So, this is entirely
possible to do now, just not with textures.  If you need more
direction on how to do this, let me know and I'll see if I can whip
out an example.

first, is the 2nd argument of texture2DRect in integers as in the pixel

> position in the texture, or is it a float between 0. and 1. for x and y?

> and second, how could i access the automattically generated coordinates by

> say, you happen to have a linke for the orange book online? or you bought

my bad, I made a wrong assumption that the orange book was available online

too, just like the other opengl books. I have a hardcopy. About the errors

you're getting.. I can't help with that. Like I said I don't have experience

with this stuff. It's time for someone with more knowledge to take over.

first, is the 2nd argument of texture2DRect in integers as in the pixel
> position in the texture, or is it a float between 0. and 1. for x and y?

> and second, how could i access the automattically generated coordinates by
> OpenGL?

> say, you happen to have a linke for the orange book online?  or you bought
> the hard copy....

my bad, I made a wrong assumption that the orange book was available online
too, just like the other opengl books. I have a hardcopy. About the errors
you're getting.. I can't help with that. Like I said I don't have experience
with this stuff. It's time for someone with more knowledge to take over.

ah, i see; so the implimentation limit of 0 is not a jitter thing but rather a GLSL standard thing.

as for the present solution, i think i understand;

i need to get the data from outside (i.e. from jitter) into my glsl thru other means...

so if i want to displace points on my plane forinstance, i should write color/normal/... values into the vector for the shape to which i'm applying my shader, and then recover them in my glsl code with gl_Color, gl_Normal and such....?

if you happen to have a little example easily whipped out, i'd be most grateful.

hi wes,
ah, i see; so the implimentation limit of 0 is not a jitter thing but rather a GLSL standard thing.

as for the present solution, i think i understand;
i need to get the data from outside (i.e. from jitter) into my glsl thru other means...
so if i want to displace points on my plane forinstance, i should write color/normal/... values into the vector for the shape to which i'm applying my shader, and then recover them in my glsl code with gl_Color, gl_Normal and such....?
if you happen to have a little example easily whipped out, i'd be most grateful.

These are the state variables that you can bind vertex shader

attributes to. The correspond precisely to their jit.gl.mesh's

I had a patch lying around that already did this, so here you go.

----------------------------Vertex Displace

-----------------------------------------------vertex distaplce

shader-----------------------------------

    Textured glass-like material lit with a point light w/ two specular

        Primary Specular Multiplier

        Secondary Specular Multiplier

These are the state variables that you can bind vertex shader
attributes to.  The correspond precisely to their jit.gl.mesh's
namesake.:

"POSITION"
"NORMAL"
"TANGENT"
"BITANGENT"
"TEXCOORD"

I had a  patch lying around that already did this, so here you go.
There's a patch and a shader:

----------------------------Vertex Displace
Patch---------------------------------


-----------------------------------------------vertex distaplce
shader-----------------------------------

	Textured glass-like material lit with a point light w/ two specular
components calculated per pixel.
		Position of Light Source
		Position
		Tangent
		Primary Specular Color
		Secondary Specular Color
		Base Color
		Primary Specular Multiplier
		Secondary Specular Multiplier
		Specularity Adjustment

i get the patch but i'm not sure if you included all of the shader called vd.attr2.jxs....

i get the patch but i'm not sure if you included all of the shader called  vd.attr2.jxs....

On Aug 25, 2006, at 9:59 AM, Ali Momeni wrote:

> as for the present solution, i think i understand;

> i need to get the data from outside (i.e. from jitter) into my glsl 

> so if i want to displace points on my plane forinstance, i should 

> write color/normal/... values into the vector for the shape to 

> which i'm applying my shader, and then recover them in my glsl code 

This is probably easiest to accomplish using jit.gl.mesh.

FWIW, ALI, since you need to submit the data as another matrix of 

information, you might find this easier to do with standard CPU based 

jitter matrix operator objects if it's not an incredibly complex 

> as for the present solution, i think i understand;
> i need to get the data from outside (i.e. from jitter) into my glsl  
> thru other means...
> so if i want to displace points on my plane forinstance, i should  
> write color/normal/... values into the vector for the shape to  
> which i'm applying my shader, and then recover them in my glsl code  
> with gl_Color, gl_Normal and such....?

FWIW, ALI, since you need to submit the data as another matrix of  
information, you might find this easier to do with standard CPU based  
jitter matrix operator objects if it's not an incredibly complex  
calculation.

Here you go again. It was at the bottom of my previous email:

if what you mean is that i might as well do everything on the CPU with jitter, then yes, i can and have tried that; it works fine and i get about 16fps on my macbook pro; i'd like to get about 60fps so i thought i'd try another route.... :)

thanks joshua.
if what you mean is that i might as well do everything on the CPU with jitter, then yes, i can and have tried that; it works fine and i get about 16fps on my macbook pro; i'd like to get about 60fps so i thought i'd try another route.... :)


incidentally, i just tried my jitter/CPU patch which i'd developed with 4.6 beta 1 and jitter 1.6 UB beta 1 and it now crashes max.

•error: jit.gl.pbuffer: unable to get a valid pixel format!

•error: jit.gl.texture: error attaching texture to readback mecahnism for capture!

oddly enough, the patch works in 4.5.7/1.6 running in rosette on my machine!

must be a readback from GPU problem cuz i use the gaussian blur shader and try get back the data into a jitter matrix...

•error: jit.gl.pbuffer: unable to get a valid pixel format!
•error: jit.gl.texture: error attaching texture to readback mecahnism for capture!

oddly enough, the patch works in 4.5.7/1.6 running in rosette on my machine!  

Yes, please please please post a proper bug report with instructions

about making it crash and a patch that demonstrates. Otherwise, this

is hairy stuff and it's never going to get fixed.

Yes, please please please post a proper bug report with instructions
about making it crash and a patch that demonstrates.  Otherwise, this
is hairy stuff and it's never going to get fixed.

i'm trying to do unlike my usual self and actually reduce the complicated patch to the sipmlest version that crashes, but i'm getting very confused with something.

• error: jit.gl.texture: error attaching texture to readback mechanism for capture!

jit.gl.texture: error submitting texture data: GL Error: Invalid operation

• error: jit.gl.texture: unable to create texture!

but i don't have any jit.gl.texture objects in my patch...?!

i have a "jit.gl.slab.gauss6x foo" abstraction, a "jit.gl.videoplane", and a "jit.gl.render" and that's it for gl objects... who's causing the errors?

alright,
i'm trying to do unlike my usual self and actually reduce the complicated patch to the sipmlest version that crashes, but i'm getting very confused with something.

• error: jit.gl.texture: error attaching texture to readback mechanism for capture!
jit.gl.texture: error submitting texture data: GL Error: Invalid operation
• error: jit.gl.texture: unable to create texture!
jit.gl.texture: error submitting texture data: GL Error: Invalid operation

but i don't have any jit.gl.texture objects in my patch...?!
i have a "jit.gl.slab.gauss6x foo" abstraction, a "jit.gl.videoplane", and a "jit.gl.render" and that's it for gl objects... who's causing the errors?

On Aug 25, 2006, at 11:38 AM, Ali Momeni wrote:

> • error: jit.gl.texture: unable to create texture!

> jit.gl.texture: error submitting texture data: GL Error: Invalid 

> but i don't have any jit.gl.texture objects in my patch...?!

> i have a "jit.gl.slab.gauss6x foo" abstraction, a 

> "jit.gl.videoplane", and a "jit.gl.render" and that's it for gl 

jit.gl.slab internally uses a texture for each input as well as the 

> i get hundreds of these:
> • error: jit.gl.texture: unable to create texture!
> jit.gl.texture: error submitting texture data: GL Error: Invalid  
> operation
>
> but i don't have any jit.gl.texture objects in my patch...?!
> i have a "jit.gl.slab.gauss6x foo" abstraction, a  
> "jit.gl.videoplane", and a "jit.gl.render" and that's it for gl  
> objects... who's causing the errors?

jit.gl.slab internally uses a texture for each input as well as the  
output.

> • error: jit.gl.texture: error attaching texture to readback 

Btw, make sure that jit.gl.slab's args (in this case "foo"), are 

using the same name as the rendering context! This is something which 

may have worked by chance in 1.5.X but not 1.6

> i get hundreds of these:
> • error: jit.gl.texture: error attaching texture to readback  
> mechanism for capture!
> jit.gl.texture: error submitting texture data: GL Error: Invalid  
> operation
>
> i have a "jit.gl.slab.gauss6x foo" abstraction, a  
> "jit.gl.videoplane", and a "jit.gl.render" and that's it for gl  
> objects... who's causing the errors?

Btw, make sure that jit.gl.slab's args (in this case "foo"), are  
using the same name as the rendering context! This is something which  
may have worked by chance in 1.5.X but not 1.6

indeed my gaussian blur has the same context name as my rendered.

i wonder if what i'm trying to do (deform the vertext positions 3d form based on a matrix that i create in jitter) isn't more easily done with one of the other languages supported by jitters programmable shaders implementation like Cg or arb....

i know very little about them and how they differ from glsl...

i wonder if what i'm trying to do (deform the vertext positions 3d form based on a matrix that i create in jitter) isn't more easily done with one of the other languages supported by jitters programmable shaders implementation like Cg or arb....
i know very little about them and how they differ from glsl...

On Aug 26, 2006, at 3:25 AM, Ali Momeni wrote:

> i wonder if what i'm trying to do (deform the vertext positions 3d 

> form based on a matrix that i create in jitter) isn't more easily 

> done with one of the other languages supported by jitters 

> programmable shaders implementation like Cg or arb....

> i know very little about them and how they differ from glsl...

Not likely. They all expose roughly the same HW functionality.

> i wonder if what i'm trying to do (deform the vertext positions 3d  
> form based on a matrix that i create in jitter) isn't more easily  
> done with one of the other languages supported by jitters  
> programmable shaders implementation like Cg or arb....
> i know very little about them and how they differ from glsl...

a simple question about programmable shaders