[osg-users] OpenGL Error 'invalid value' when using osg::LineWidth

[Brett Sackstein]

Hello, I'm using osg and osgEarth to create a program. I try to draw a path that follows another node in the scene such that when I set its position, I add an additional GL_POINT vertex and a pair of LINE_STRIP vertices for a new anchor point for two geodes. However, I'm constantly being spammed in my application output with the invalid value error. 

I have been pulling my hair out because I spent hours figuring out which geometry was causing it. This is the format of my code upon construction:


Code:
PathNode::PathNode(IPathObject *pathObject, osgEarth::MapNode* mapNode) : CommonMapNode(pathObject, mapNode), osg::Group(), m_crossedDateLine(false), m_offset(0.0){

m_lineColorArray = new osg::Vec4Array;
m_glPointColorArray = new osg::Vec4Array;

m_lineVertexArray = new osg::Vec3Array;
m_glPointVertexArray = new osg::Vec3Array;

m_lineGeom = new osg::Geometry;
m_lineGeom->setUseDisplayList(false);
m_lineGeom->setUseVertexArrayObject(true);
m_lineGeom->setUseVertexBufferObjects(true);
m_lineGeom->setDataVariance(osg::Object::DataVariance::DYNAMIC);

m_glPointGeom = new osg::Geometry;
m_glPointGeom->setUseDisplayList(false);
m_glPointGeom->setUseVertexArrayObject(true);
m_glPointGeom->setUseVertexBufferObjects(true);
m_glPointGeom->setDataVariance(osg::Object::DataVariance::DYNAMIC);

m_lineStripGeode = new osg::Geode;
m_glPointGeode = new osg::Geode;

m_lineStripGeode->getOrCreateStateSet()->setRenderBinDetails(0, "RenderBin", osg::StateSet::OVERRIDE_PROTECTED_RENDERBIN_DETAILS);
m_glPointGeode->getOrCreateStateSet()->setRenderBinDetails(0, "RenderBin", osg::StateSet::OVERRIDE_PROTECTED_RENDERBIN_DETAILS);

m_lineStripGeode->getOrCreateStateSet()->setMode(GL_BLEND, osg::StateAttribute::ON);
m_glPointGeode->getOrCreateStateSet()->setMode(GL_BLEND, osg::StateAttribute::ON);

//Line Geometry
m_lineGeom->setVertexArray(m_lineVertexArray);
m_lineGeom->setDataVariance(osg::Object::DataVariance::DYNAMIC);
m_lineDrawArray = new osg::DrawArrays(osg::PrimitiveSet::LINE_STRIP, 0, m_lineVertexArray->size());
m_lineDrawArray->setDataVariance(osg::Object::DataVariance::DYNAMIC);
m_lineGeom->addPrimitiveSet(m_lineDrawArray);
m_lineWidth = new osg::LineWidth(getHandle()->getLineWidth());
m_lineGeom->getOrCreateStateSet()->setMode(GL_LINE_SMOOTH, osg::StateAttribute::ON);
m_lineGeom->getOrCreateStateSet()->setAttributeAndModes(m_lineWidth, osg::StateAttribute::OVERRIDE | osg::StateAttribute::ON | osg::StateAttribute::PROTECTED);
m_lineGeom->setColorArray(m_lineColorArray, osg::Array::BIND_PER_VERTEX);

//Line Geode
m_lineStripGeode->addDrawable(m_lineGeom);
m_lineStripGeode->setDataVariance(osg::Object::DataVariance::DYNAMIC);
m_lineStripGeode->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OVERRIDE | osg::StateAttribute::OFF | osg::StateAttribute::PROTECTED);
m_lineStripGeode->getOrCreateStateSet()->setMode(GL_BLEND, osg::StateAttribute::ON);
m_lineStripGeode->getOrCreateStateSet()->setMode(GL_LINE_SMOOTH, osg::StateAttribute::ON);
m_lineStripGeode->addCullCallback(new osgEarth::HorizonCullCallback);

//GL Point Geometry
m_glPointGeom->setColorArray(m_glPointColorArray, osg::Array::BIND_OVERALL);
m_glPointGeom->setVertexArray(m_glPointVertexArray);

m_glPointsDrawArray = new osg::DrawArrays(osg::PrimitiveSet::POINTS, 0, m_glPointVertexArray->size());
m_glPointGeom->addPrimitiveSet(m_glPointsDrawArray);
m_glPointGeom->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OVERRIDE | osg::StateAttribute::OFF | osg::StateAttribute::PROTECTED);
osg::ref_ptr<osg::Point> pointAttributes = new osg::Point(5);
m_glPointGeom->getOrCreateStateSet()->setAttributeAndModes(pointAttributes, osg::StateAttribute::ON);
m_glPointGeom->setColorArray(m_glPointColorArray, osg::Array::BIND_PER_VERTEX);

//GL Point Geode
m_glPointGeode->addDrawable(m_glPointGeom);

addChild(m_lineStripGeode);
addChild(m_glPointGeode);
}




It turns out the lines:


Code:
m_lineWidth = new osg::LineWidth(getHandle()->getLineWidth());
m_lineGeom->getOrCreateStateSet()->setAttributeAndModes(m_lineWidth, osg::StateAttribute::OVERRIDE | osg::StateAttribute::ON | osg::StateAttribute::PROTECTED);




Is what is causing this error to spam my output. Nothing visually seems incorrect. All colors and points are correct. Nothing is blinking or acting strange. What I don't understand with this "path" that I've created is that I actually have a "line" equivalent class that literally does the same thing, but with only 2 points and not 1 to n points and doesn't use GL_POINT at all for the end points. 

I figured out if I just don't add the osg::LineWidth to the m_lineGeom variable, then the error disappears, but I need the ability to set the line's width. Can anybody explain what may be causing this to print even though nothing about my lines look ill-formed? Thanks for any help.

- Blanky

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