Re: [osg-users] [Depth Buffer rendering]

[Mathieu Schoutteten]

Hi Wojtek,
it works ! thanks a lot for your precious answear.
For those who will be interrested, i'll post later the complete source code
with corrections.
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Re: [osg-users] [Depth Buffer rendering]

[Mathieu Schoutteten]

In fact i've got a new problem (perhaps it's normal), the transformations
applied with texgen are not take into account when i use my shader. Do you
have any idea of how to proceed ? I attach a screen capture of my problem.
Thanks

On Fri, Jun 13, 2008 at 4:53 PM, Mathieu Schoutteten [EMAIL PROTECTED]
wrote:

 Hi Wojtek,
 it works ! thanks a lot for your precious answear.
 For those who will be interrested, i'll post later the complete source code
 with corrections.

attachment: capture.JPG___
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Re: [osg-users] [Depth Buffer rendering]

[Wojciech Lewandowski]

Hi Mathieu,
Good ;-). 

Regarding your question, I am no sure what can be an issue now. Maybe if I saw 
your shader it could be simpler ;-) 

I will try to guess then.

If you use vertex shader then you need to replicate texgen computations. Once 
again I recommend Emulating OpenGL functionality from OpenGL Shading Language 
book.  This is an excerpt replicating texgen in vertex shader:
 
vec4 ecPosition  = gl_ModelViewMatrix * gl_Vertex;

gl_TexCoord[i].s = dot(ecPosition, gl_EyePlaneS[i]);
gl_TexCoord[i].t = dot(ecPosition, gl_EyePlaneT[i]);
gl_TexCoord[i].p = dot(ecPosition, gl_EyePlaneR[i]);
gl_TexCoord[i].q = dot(ecPosition, gl_EyePlaneQ[i]);

But if you only use fragment shader then maybe the reason is that you use 
uniform texture2D function but need to use projective texturing ie 
texture2DProj:

vec4 tex =  texture2DProj( depthTexture, gl_TexCoord[i] );



I am leaving for one week. I hope it helps. If not maybe others on this forum 
will offer some assistance.

Cheers,
Wojtek

  - Original Message - 
  From: Mathieu Schoutteten 
  To: OpenSceneGraph Users 
  Sent: Friday, June 13, 2008 5:42 PM
  Subject: Re: [osg-users] [Depth Buffer rendering]


  In fact i've got a new problem (perhaps it's normal), the transformations 
applied with texgen are not take into account when i use my shader. Do you have 
any idea of how to proceed ? I attach a screen capture of my problem.
  Thanks


  On Fri, Jun 13, 2008 at 4:53 PM, Mathieu Schoutteten [EMAIL PROTECTED] 
wrote:

Hi Wojtek,
it works ! thanks a lot for your precious answear.
For those who will be interrested, i'll post later the complete source code 
with corrections.





--


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[osg-users] [Depth Buffer rendering]

[Mathieu Schoutteten]

Hello,
I would like to create an effect (using osgFX) which render the depth
buffer. I'm using a RTT and then apply the texture to the object but i'm
having some problem for mapping correctly the texture on the object (see
capture in attachment). My RTT camera must be similar to my viewer camera,
so i've tried to play with the matrix but without success. In fact for my
program, the texture should be use as an input of a shader.
can someone help me ? am i doing the right things ?
Thanks,
Mathieu

Here is a fragment of the code i'm using:
/
const unsigned int tex_depth_width = 1024;
const unsigned int tex_depth_height = 1024;

osg::Texture2D* _tex_depth = new osg::Texture2D;
_tex_depth-setTextureSize(tex_depth_width, tex_depth_height);
_tex_depth-setInternalFormat(GL_DEPTH_COMPONENT);
_tex_depth-setWrap(osg::Texture2D::WRAP_S,
osg::Texture2D::CLAMP_TO_BORDER);
_tex_depth-setWrap(osg::Texture2D::WRAP_T,
osg::Texture2D::CLAMP_TO_BORDER);
_tex_depth-setFilter(osg::Texture2D::MIN_FILTER,
osg::Texture2D::LINEAR);
_tex_depth-setFilter(osg::Texture2D::MAG_FILTER,
osg::Texture2D::LINEAR);

osg::Camera* camera = new osg::Camera;
camera-setClearMask( GL_DEPTH_BUFFER_BIT );
camera-setClearColor( osg::Vec4(1.0f,1.0f,1.0f,1.0f) );
//camera-setReferenceFrame(osg::Camera::ABSOLUTE_RF);
camera-setComputeNearFarMode( osg::Camera::DO_NOT_COMPUTE_NEAR_FAR );
camera-setViewport(0, 0, tex_depth_width, tex_depth_height);
camera-setViewMatrix( osg::Matrix::identity() );
camera-setRenderOrder(osg::Camera::PRE_RENDER);
camera-setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
camera-attach(osg::Camera::DEPTH_BUFFER, _tex_depth);
camera-addChild( _scene );

root-addChild( camera );
root-addChild( _scene );

const unsigned int tex_depth_unit = 0;
osg::StateSet* ss = new osg::StateSet;
ss-setTextureAttributeAndModes(tex_depth_unit, _tex_depth,
osg::StateAttribute::OVERRIDE | osg::StateAttribute::ON);
_scene-setStateSet( ss );
///
attachment: depthbuffer.JPG___
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Re: [osg-users] [Depth Buffer rendering]

[Mathieu Schoutteten]

i post my source code for more clarity.. Maybe someone already try to have
the same effect.
DepthBuffer.cpp include a main method for test.
#include DepthBuffer.h
#include osgFX/Registry

#include osgViewer/Viewer
#include osgDB/ReadFile

namespace
{
osgFX::Registry::Proxy proxy(new osgFX::DepthBuffer);

class DefaultTechnique: public osgFX::Technique 
{
public:
DefaultTechnique(osg::Texture2D* tex_depth)
: osgFX::Technique(),
_tex_depth(tex_depth) {}

META_Technique(GLSL Depth Buffer, GLSL Depth Buffer);

void getRequiredExtensions(std::vectorstd::string 
extensions) const
{
//extensions.push_back( GL_ARB_shader_objects );
//extensions.push_back( GL_ARB_vertex_shader );
//extensions.push_back( GL_ARB_fragment_shader );
}

protected:
void define_passes()
{
const unsigned int tex_depth_unit = 0;

osg::ref_ptrosg::StateSet ss = new osg::StateSet;
ss-setTextureAttributeAndModes(tex_depth_unit, 
_tex_depth.get(), osg::StateAttribute::ON | osg::StateAttribute::OVERRIDE);
/*
ss-setTextureMode(tex_depth_unit, GL_TEXTURE_GEN_S, 
osg::StateAttribute::ON);
ss-setTextureMode(tex_depth_unit, GL_TEXTURE_GEN_T, 
osg::StateAttribute::ON);
ss-setTextureMode(tex_depth_unit, GL_TEXTURE_GEN_R, 
osg::StateAttribute::ON);
ss-setTextureMode(tex_depth_unit, GL_TEXTURE_GEN_Q, 
osg::StateAttribute::ON);
*/
addPass(ss.get());
}
private:
osg::ref_ptrosg::Texture2D _tex_depth;

};

}

///

osgFX::DepthBuffer::DepthBuffer()
:   Effect()
{
}

osgFX::DepthBuffer::DepthBuffer(const DepthBuffer copy, const osg::CopyOp 
copyop)
:   Effect(copy, copyop),
_tex_depth(static_castosg::Texture2D* (copyop(copy._tex_depth.get(
{
}

void osgFX::DepthBuffer::setUpEffect(osg::Group* root, osg::Node* object)
{
const unsigned int tex_depth_width = 1024;
const unsigned int tex_depth_height = 1024;

_tex_depth = new osg::Texture2D;
_tex_depth-setTextureSize(tex_depth_width, tex_depth_height);
_tex_depth-setInternalFormat(GL_DEPTH_COMPONENT);
//_tex_depth-setWrap(osg::Texture2D::WRAP_R, 
osg::Texture2D::CLAMP_TO_BORDER);
//_tex_depth-setWrap(osg::Texture2D::WRAP_S, 
osg::Texture2D::CLAMP_TO_BORDER);
//_tex_depth-setWrap(osg::Texture2D::WRAP_T, 
osg::Texture2D::CLAMP_TO_BORDER);
_tex_depth-setFilter(osg::Texture2D::MIN_FILTER, 
osg::Texture2D::LINEAR);
_tex_depth-setFilter(osg::Texture2D::MAG_FILTER, 
osg::Texture2D::LINEAR);  

osg::Camera* camera = new osg::Camera;
camera-setName(DepthBufferCamera);
camera-setClearColor( osg::Vec4(1.0f,1.0f,1.0f,1.0f) );
camera-setClearMask( GL_DEPTH_BUFFER_BIT );
camera-setReferenceFrame(osg::Camera::RELATIVE_RF);
camera-setComputeNearFarMode( osg::Camera::DO_NOT_COMPUTE_NEAR_FAR );
camera-setViewport(0, 0, tex_depth_width, tex_depth_height);
camera-setProjectionMatrix( osg::Matrix::identity() );
camera-setViewMatrix( osg::Matrix::identity() );
camera-setRenderOrder(osg::Camera::PRE_RENDER);
camera-setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
camera-attach(osg::Camera::DEPTH_BUFFER, _tex_depth.get());
camera-addChild( object );
root-addChild( camera );

dirtyTechniques();
}

bool osgFX::DepthBuffer::define_techniques()
{
addTechnique( new DefaultTechnique(_tex_depth.get()) );
return true;
}

int main(int argc, char *argv[])
{
osgViewer::Viewer viewer;

osg::ref_ptrosg::Group rootNode = new osg::Group;
osg::ref_ptrosg::Node objectNode = osgDB::readNodeFile(cow.osg);


osg::ref_ptrosgFX::DepthBuffer effect = new osgFX::DepthBuffer;
effect-setUpEffect(rootNode.get(), objectNode.get());
effect-addChild( objectNode.get() );
rootNode-addChild( effect.get() );

viewer.setSceneData( rootNode.get() );

return viewer.run();
}#ifndef _DEPTHBUFFER_HPP_
#define _DEPTHBUFFER_HPP_

#include osgFX/Export
#include osgFX/Effect
#include osg/Texture2D

namespace osgFX
{
class DepthBuffer : public osgFX::Effect
{
public:
DepthBuffer();
DepthBuffer(const DepthBuffer copy, const osg::CopyOp copyop 
= osg::CopyOp::SHALLOW_COPY);

// effect class informations

Re: [osg-users] [Depth Buffer rendering]

[Wojciech Lewandowski]

Hi Mathieu,

Sorry I don't have the time to compile and test your code, but I saw the 
screenshot and it looks like your depth texture gets rendered and applied to 
the object. What you may need to do is to make sure you set up RTT camera 
transform exactly as main camera transforms, and texture coordinates are 
properly generated to span the whole window.


In other words I guess that you want to have texcoords match pixel locations 
in the final output screen. Ie you want texcorrds on the objects to 
span -1..1x-1..1 range on the output window. Right ?


If yes, then you could use simple shader, or add a texgen node to produce 
proper texcoords for the output scene. This texgen should use EYE_LINEAR 
coords and its transform should be set to projection matrix of RTT camera 
and main camera.


I am also not sure if seeting your effect camera to RELATIVE_RF gurantees 
using the same projection for RTT camera as for main camera. One could be 
sure if he forces this explicitly

eg:
   camera-setProjectionMatrix( 
viewer-getCamera()-getProjectionMatrix() );


To add texgen node try adding following lines to your code:

   camera-setProjectionMatrix( 
viewer-getCamera()-getProjectionMatrix() );


   osg::TexGenNode * texGenNode = new osg::TexGenNode;
   _scene-addChild( texGenNode );
   texGenNode-setTextureUnit( 0 );
   texGenNode-getTexGen()-setMode( osg::TexGen::EYE_LINEAR );
   texGenNode-getTexGen()-setPlanesFromMatrix
   (
   camera-getProjectionMatrix() *
   osg::Matrix::translate(1,1,1) *  // remap -1..1x-1..1 range
   osg::Matrix::scale(0.5,0.5,0.5)  //  to 0..1 x 0..1 range
   );

One final note, it looks like you use cow.osg model. AFAIK this model 
already contains texgen using SPHERE mapping mode. To avoid conflicts for 
tests I suggest you use other model.


Hope it helps, and no guarrantees,   I have no time to verify if everything 
what I wrote is 100% correct.


Cheers,
Wojtek

- Original Message - 
From: Mathieu Schoutteten

To: osg-users@lists.openscenegraph.org
Sent: Thursday, June 12, 2008 4:35 PM
Subject: Re: [osg-users] [Depth Buffer rendering]


i post my source code for more clarity.. Maybe someone already try to have 
the same effect.

DepthBuffer.cpp include a main method for test.




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