[osg-users] Problems with MRT

[Rômulo Cerqueira]

Hi,

just updating my progress:

What have I got so far? 
[ ✓ ] Allow rendering for color or depth buffers on the same camera;
[ ✓ ] Display only the color buffer in the post render camera;
[ ✓ ] Read color or depth buffer in the final draw callback;
[ ✗ ] Write collected image (color or depth) in disk - only images as GL_UNSIGNED_BYTE, instead of GL_FLOAT.

I changed the buffer reader in my callback (readImageFromCurrentTexture() instead of readPixels()), however I still got problems when I render floating textures...

This is my current code:


Code:
// OSG includes
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgViewer/Viewer>
#include <osg/Camera>
#include <osg/Geode>
#include <osg/Geometry>
#include <osg/Texture2D>

struct SnapImage : public osg::Camera::DrawCallback {
    SnapImage(osg::GraphicsContext* gc, osg::Texture2D* tex1, osg::Texture2D* tex2 ) {
        if (gc->getTraits()) {
            _texColor = tex1;
            _texDepth = tex2;
        }
    }

    virtual void operator () (osg::RenderInfo& renderInfo) const {
        // color buffer
        renderInfo.getState()->applyTextureAttribute(0, _texColor);
        osg::ref_ptr<osg::Image> mColor = new osg::Image();
        mColor->readImageFromCurrentTexture(renderInfo.getContextID(), true, GL_UNSIGNED_BYTE);
        osgDB::ReaderWriter::WriteResult wrColor = osgDB::Registry::instance()->writeImage(*mColor, "./Test-color.png", NULL);
        if (!wrColor.success()) {
            osg::notify(osg::WARN) << "Color image: failed! (" << wrColor.message() << ")" << std::endl;
        }

        // depth buffer
        renderInfo.getState()->applyTextureAttribute(0, _texDepth);
        osg::ref_ptr<osg::Image> mDepth = new osg::Image();
        mDepth->readImageFromCurrentTexture(renderInfo.getContextID(), true, GL_UNSIGNED_BYTE);
        osgDB::ReaderWriter::WriteResult wrDepth = osgDB::Registry::instance()->writeImage(*mDepth, "./Test-depth.png", NULL);
        if (!wrDepth.success()) {
            osg::notify(osg::WARN) << "Depth image: failed! (" << wrDepth.message() << ")" << std::endl;
        }
    }
    osg::ref_ptr<osg::Texture2D> _texColor;
    osg::ref_ptr<osg::Texture2D> _texDepth;
};

osg::Camera* setupMRTCamera( osg::ref_ptr<osg::Camera> camera, std::vector<osg::Texture2D*>& attachedTextures, int w, int h ) {
    camera->setClearColor( osg::Vec4() );
    camera->setClearMask( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    camera->setRenderTargetImplementation( osg::Camera::FRAME_BUFFER_OBJECT );
    camera->setRenderOrder( osg::Camera::PRE_RENDER, 0 );
    camera->setViewport( 0, 0, w, h );

    osg::Texture2D* tex = new osg::Texture2D;
    tex->setTextureSize( w, h );
    tex->setInternalFormat( GL_RGB );
    tex->setSourceFormat( GL_RGBA );
    tex->setSourceType( GL_UNSIGNED_BYTE );
    tex->setResizeNonPowerOfTwoHint( false );
    tex->setFilter( osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR );
    tex->setFilter( osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR );
    attachedTextures.push_back( tex );
    camera->attach( osg::Camera::COLOR_BUFFER, tex );

    tex = new osg::Texture2D;
    tex->setTextureSize(w,h);
    tex->setSourceFormat(GL_DEPTH_COMPONENT);
    tex->setInternalFormat(GL_DEPTH_COMPONENT);
    tex->setSourceType(GL_UNSIGNED_BYTE);
    attachedTextures.push_back( tex );
    camera->attach( osg::Camera::DEPTH_BUFFER, tex );

    return camera.release();
}


int main() {
    osg::ref_ptr< osg::Group > root( new osg::Group );
    root->addChild( osgDB::readNodeFile( "/home/romulo/Tools/OpenSceneGraph-Data/cow.osg" ) );
    unsigned int winW = 800;
    unsigned int winH = 600;

    osgViewer::Viewer viewer;
    viewer.setUpViewInWindow( 0, 0, winW, winH );
    viewer.setSceneData( root.get() );
    viewer.realize();

    // setup MRT camera
    std::vector<osg::Texture2D*> attachedTextures;
    osg::Camera* mrtCamera ( viewer.getCamera() );
    setupMRTCamera( mrtCamera, attachedTextures, winW, winH );

    // set RTT textures to quad
    osg::Geode* geode( new osg::Geode );
    geode->addDrawable( osg::createTexturedQuadGeometry(
        osg::Vec3(-1,-1,0), osg::Vec3(2.0,0.0,0.0), osg::Vec3(0.0,2.0,0.0)) );
    geode->getOrCreateStateSet()->setTextureAttributeAndModes( 0, attachedTextures[0] );
    geode->getOrCreateStateSet()->setMode( GL_LIGHTING, osg::StateAttribute::OFF );
    geode->getOrCreateStateSet()->setMode( GL_DEPTH_TEST, osg::StateAttribute::OFF );

    // configure postRenderCamera to draw fullscreen textured quad
    osg::Camera* postRenderCamera( new osg::Camera );
    postRenderCamera->setClearMask( 0 );
    postRenderCamera->setRenderTargetImplementation( osg::Camera::FRAME_BUFFER, osg::Camera::FRAME_BUFFER );
    postRenderCamera->setReferenceFrame( osg::Camera::ABSOLUTE_RF );
    postRenderCamera->setRenderOrder( osg::Camera::POST_RENDER );
    // postRenderCamera->setViewMatrix( osg::Matrixd::identity() );
    // postRenderCamera->setProjectionMatrix( osg::Matrixd::identity() );
    postRenderCamera->addChild( geode );
    root->addChild(postRenderCamera);

    // setup the callback
    SnapImage* finalDrawCallback = new SnapImage(viewer.getCamera()->getGraphicsContext(), attachedTextures[0], attachedTextures[1]);
    mrtCamera->setFinalDrawCallback(finalDrawCallback);

    return (viewer.run());
}



... 

Thank you!

Cheers,
Rômulo[/code][/i]

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