[osg-users] What wrong with my "SubloadCallback" derived class?

[Zheng Li]

Hi,

I wrote a "SubloadCallback" derived class and attach it to a texture2D object to update image dynamically,but unfortunately the texture image can not be updated,the texture always show a piece of white;below is my code,what wrong happened to it?

void main()
{
	// the class to update texture image dynamically;
	class UpdateTextureCallback : public osg::Texture2D::SubloadCallback
	{
	public:
		osg::ref_ptr<osg::Image> _image;
		SIZE m_szVideo;

	public:
		UpdateTextureCallback(int vwidth,int vheight) 
		{
			m_szVideo.cx = vwidth;
			m_szVideo.cy = vheight;
			_image = osgDB::readImageFile("C:\\test.jpg");
			assert(_image->valid());
			_image->scaleImage(vwidth,vheight,_image->r());
		};

		virtual ~UpdateTextureCallback()
		{
			_image = NULL;
		};

		virtual void load(const osg::Texture2D& texture,osg::State& state) const
		{
			glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,m_szVideo.cx,m_szVideo.cy,0,GL_BGRA_EXT,GL_UNSIGNED_BYTE,NULL);
		};

		virtual void subload(const osg::Texture2D& texture,osg::State& state) const
		{
			readImageFromDevice(_image);
			glTexSubImage2D(GL_TEXTURE_2D,0,0,0,_image->s(),_image->t(),_image->getPixelFormat(),_image->getDataType(),_image->getDataPointer());
		};
	};

	const int VideoWidth = 3840;
	const int VideoHeight = 2160;
	osg::ref_ptr<osg::Texture2D> texVideo = new osg::Texture2D();
	texVideo->setResizeNonPowerOfTwoHint(false);
	texVideo->setTextureSize(VideoWidth,VideoHeight);
	texVideo->setInternalFormat(GL_RGBA);
	texVideo->setSubloadCallback(new UpdateTextureCallback(VideoWidth,VideoHeight));
	
	osg::ref_ptr<osg::Geode> quad = new osg::Geode();
	quad->addDrawable(createDrawable_Quad());
	quad->getOrCreateStateSet()->setTextureAttributeAndModes(0,texVideo.get());

	osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();
	viewer->realize();
	viewer->getCamera()->setAllowEventFocus(false);
	viewer->getCamera()->setProjectionMatrixAsOrtho2D(0,1,0,1);
	viewer->getCamera()->setViewMatrix(osg::Matrix::identity());
	viewer->setSceneData( quad );
	viewer->run();
}

osg::Geometry * createDrawable_Quad(float alpha=1.0f)
{
	osg::ref_ptr<osg::Vec2Array> vertices = new osg::Vec2Array;
	vertices->push_back( osg::Vec2(0,0) );
	vertices->push_back( osg::Vec2(0,1) );
	vertices->push_back( osg::Vec2(1,1) );
	vertices->push_back( osg::Vec2(1,0) );

	osg::ref_ptr<osg::Vec2Array> texcoords = new osg::Vec2Array;
	texcoords->push_back( osg::Vec2(0.0f, 0.0f) );
	texcoords->push_back( osg::Vec2(0.0f, 1.0f) );
	texcoords->push_back( osg::Vec2(1.0f, 1.0f) );
	texcoords->push_back( osg::Vec2(1.0f, 0.0f) );

	osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array();
	colors->push_back(osg::Vec4(1.0f,1.0f,1.0f,alpha));

	osg::ref_ptr<osg::Geometry> quad = new osg::Geometry;
	quad->setVertexArray( vertices.get() );
	quad->setColorArray(colors.get());
	quad->setColorBinding( osg::Geometry::BIND_OVERALL );
	quad->setTexCoordArray( 0, texcoords.get() );
	quad->addPrimitiveSet( new osg::DrawArrays(GL_QUADS, 0, 4) );
	return quad.release();
}
 

Thank you!

Cheers,
Zheng

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http://forum.openscenegraph.org/viewtopic.php?p=66611#66611