Rob Ramirez

i'm trying to get my lua, shader and gl chops up to snuff.

there's some great example shaders in the apple developer examples folder.

a couple that i've tried to implement require the use of the gl commands glActiveTexture and glUseProgramARB.

below is a snippet of the code i'm trying to implement (a fur shader example):

glBindTexture(GL_TEXTURE_2D, noiseTexture);

glBindTexture(GL_TEXTURE_2D, colorTexture);

glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

by my best translation, is is drawing the object once with a flat color, then enabling the shader program, and drawing it 10 more times, changing a parameter to the shader each time.

my first guess was lua, but it doesn't quite cut it:

two gl.texture objects are sent into this:

fur = jit.new("jit.gl.shader", this.drawto)

    gl.Disable('COLOR_MATERIAL');    

    gl.BlendFunc ('SRC_ALPHA', 'ONE_MINUS_SRC_ALPHA');

    local textures = { noiseTexName, colorTexName }

my only thought at this point is that i can possibly use the shader message to my gl objects to mimic the functionality of glUseProgramObjectARB, is it possible to turn a shader on and off in one render::draw command?

what about the glActiveTexture? i'm not even sure what this does for this particular example, so it's hard to find a suitable replacement. i'm pretty sure gl.texture handles this stuff, but how would i make one texture object active over the other?

well, i'm not expecting much, but any ideas would be appreciated.

shader is attached in case anyone cares to take a peak.

hello.
i'm trying to get my lua, shader and gl chops up to snuff.
there's some great example shaders in the apple developer examples folder.

a couple that i've tried to implement require the use of the gl commands glActiveTexture and glUseProgramARB.
below is a snippet of the code i'm trying to implement (a fur shader example):

glColor3f(0.9, 0.65, 0.4);
glEnable(GL_COLOR_MATERIAL);
glCallList(objectList);
glUseProgramObjectARB(program_object);
glColor3f(1.0, 1.0, 1.0);
glDisable(GL_COLOR_MATERIAL);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, noiseTexture);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, colorTexture);
glActiveTexture(GL_TEXTURE0);
glEnable(GL_BLEND);
glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_CULL_FACE);
for (i = 1; i < 10; i++)
{
  //set shader param
  glCallList(objectList);
}
glUseProgramObjectARB(NULL);

by my best translation, is is drawing the object once with a flat color, then enabling the shader program, and drawing it 10 more times, changing a parameter to the shader each time.
my first guess was lua, but it doesn't quite cut it:
a snippet of the last attempt.
two gl.texture objects are sent into this:

fur = jit.new("jit.gl.shader", this.drawto)
fur.file = "fur.jxs"
fur.automatic = 0
fur.name = "fur_shader"

function noiseTex(texture, name)
	noiseTexName = name
end

function colorTex(texture, name)
	colorTexName = name
end

function draw()
	gl.Color(0.9, 0.65, 0.4);
	gl.Enable('COLOR_MATERIAL');
	drawObject()
	gl.Color(1.0, 1.0, 1.0);
	gl.Disable('COLOR_MATERIAL');	
	gl.Enable('BLEND');
	gl.BlendFunc ('SRC_ALPHA', 'ONE_MINUS_SRC_ALPHA');
	local textures = { noiseTexName, colorTexName }
	fur.texture = textures	
	gl.Enable('CULL_FACE');
	for i=1, 10 do
		-- set shader param
		fur:draw()
		drawObject()
	end
end

my only thought at this point is that i can possibly use the shader message to my gl objects to mimic the functionality of glUseProgramObjectARB, is it possible to turn a shader on and off in one render::draw command?
what about the glActiveTexture?  i'm not even sure what this does for this particular example, so it's hard to find a suitable replacement. i'm pretty sure gl.texture handles this stuff, but how would i make one texture object active over the other?

well, i'm not expecting much, but any ideas would be appreciated.
shader is attached in case anyone cares to take a peak.

glactivetexture-and-gluseprogramobject

To use a shader with geometry in Lua, you do the following:

To use multiple textures (equivalent of active texture/bind texture stuff) do

shader:bind()
drawobject()
shader:unbind()

This is equivalent to
glUseProgramARB(myProgram)
drawobject()
glUseProgramARB(NULL)

jit.gl.bindtexture(tex1.name, 0)
jit.gl.bindtexture(tex2.name, 1)
drawobject()
jit.gl.unbindtexture(tex1.name, 1)
jit.gl.unbindtexture(tex2.name, 0)

I messed up the names in the unbindtexture part (they're reversed) but

I messed up the names in the unbindtexture part (they're reversed) but
you get the point.

3D textues, possible with jit.gl.texture?

the doc says it can take a matrix with less than 3 dimensions, but it defaults to 3 dimensions correct?

it appears if i try to send a jit.gl.texture a 3d matrix, it doesn't work. i guess it's not supposed to.

3D textues, possible with jit.gl.texture?
the doc says it can take a matrix with less than 3 dimensions, but it defaults to 3 dimensions correct?

it appears if i try to send a jit.gl.texture a 3d matrix, it doesn't work.  i guess it's not supposed to.


I haven't tried in a while, but I believe I did get it to work once.

> 3D textues, possible with jit.gl.texture?

> the doc says it can take a matrix with less than 3 dimensions, but it defaults to 3 dimensions correct?

> it appears if i try to send a jit.gl.texture a 3d matrix, it doesn't work. i guess it's not supposed to.

I haven't tried in a while, but I believe I did get it to work once.
Try setting @rectangle 0.

On 9/16/07, Robert Ramirez  wrote:
>
> indeed i do.
> many thanks.
>
> one last quick question.
>
> 3D textues, possible with jit.gl.texture?
> the doc says it can take a matrix with less than 3 dimensions, but it defaults to 3 dimensions correct?
>
> it appears if i try to send a jit.gl.texture a 3d matrix, it doesn't work.  i guess it's not supposed to.
>


well, i gave it the community college try, but no worky.

maybe you (anyone) can sprinkle some pixy dust on it

just bang one of the bfg's and turn on the metro.

well, i gave it the community college try, but no worky.
maybe you (anyone) can sprinkle some pixy dust on it

just bang one of the bfg's and turn on the metro.
shader attached.

It seems that it worked after jit.normalizing jit.bfg output(patch 

below), but I'm not totally sure how it should look in the end.

It seems that it worked after jit.normalizing jit.bfg output(patch  
below), but I'm not totally sure how it should look in the end.

> It seems that it worked after jit.normalizing jit.bfg output(patch 

> below), but I'm not totally sure how it should look in the end.

You also skipped the slab and applied the shader directly to the 

gridshape. And you didn't check the shader.

> It seems that it worked after jit.normalizing jit.bfg output(patch  
> below), but I'm not totally sure how it should look in the end.

Hey, that's not the only thing you did!
You also skipped the slab and applied the shader directly to the  
gridshape. And you didn't check the shader.

however! you still made it work better than it did, so thanks for that.

if you have the apple developer package installed, compile the example/cocoa/glsl showcase xcode proj and check out the erode shader. that's what it's supposed to look like.

however! you still made it work better than it did, so thanks for that.
i think it's close.

if you have the apple developer package installed, compile the example/cocoa/glsl showcase xcode proj and check out the erode shader.  that's what it's supposed to look like.


I think you're making this more complex than it needs to be. To get

this to work, you only need jit.gl.shader and jit.gl.texture and some

geometry to draw using the shader. Here's how I would do it:

1) Make a 3D texture test with jit.gl.texture @rectangle 0 and sending

it a simple test 3D matrix like a gradient volume. Then use a super

simple shader to test the values and compare to the gradient to see if

2) Next, incorporate the erode shader based on experience in step 1.

> however! you still made it work better than it did, so thanks for that.

> if you have the apple developer package installed, compile the example/cocoa/glsl showcase xcode proj and check out the erode shader. that's what it's supposed to look like.

I think you're making this more complex than it needs to be.  To get
this to work, you only need jit.gl.shader and jit.gl.texture and some
geometry to draw using the shader.  Here's how I would do it:

1) Make a 3D texture test with jit.gl.texture @rectangle 0 and sending
it a simple test 3D matrix like a gradient volume.  Then use a super
simple shader to test the values and compare to the gradient to see if
you're accessing the texture properly.

On 9/17/07, Robert Ramirez  wrote:
>
> however! you still made it work better than it did, so thanks for that.
> i think it's close.
>
> if you have the apple developer package installed, compile the example/cocoa/glsl showcase xcode proj and check out the erode shader.  that's what it's supposed to look like.
>


glActiveTexture and glUseProgramObject