[osg-users] Possible bug in pragmatic shader composition and optimizers

[Sebastian Messerschmidt]

Me again,

I've attached a minimal example which illustrates the problem.
It seems the combination
osgUtil::Optimizer::SHARE_DUPLICATE_STATE | 
osgUtil::Optimizer::STATIC_OBJECT_DETECTION

causes the both geometries to be rendered as if the define was not set.
If the optimizer is not run the geometries are rendered as expected.

Cheers
Sebastian

> Hi,
>
> I've got some code, where I set up a define inside for an 
> osg::Geometry via
>
> geometry.getOrCreateStateSet()->setDefine("MY_DEFINE")
>
> The geometry is a sibling to another geometry not setting the define.
> It works well if I don't run an osg::Optimizer, but running it 
> effectively removes the define.
> Since I don't have the source code at hand, I cannot inspect this 
> issue right now.
>
> The optimizer is set up to use the SHARE_DUPLICATE_STATE, so I suspect 
> the problem to be inside the logic which determines if two statesets 
> are equal.
> I'm using OSG 3.3.9 on Windows 7 64bit
>
> cheers
> Sebastian
>
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-------------- next part --------------
#include "osgViewer/Viewer"
#include <osg/PositionAttitudeTransform>

#include <osgDB/ReadFile>
#include <osgUtil/Optimizer>


std::string vert_source = 
	"void main()\n \
	{\n\
	gl_Position = ftransform();\n\
	}\n\
	";

std::string frag_source = 
	"void main()\n \
	{\n\
	#pragma import_defines ( TEST_DEFINE )\n\
	#ifdef TEST_DEFINE\n\
	  gl_FragColor = vec4(1,0,0,1);\n\
	#else\n\
	  gl_FragColor = vec4(0,1,0,1);\n\
	#endif\n\
	}\n\
	";


void applyShader(const std::string& vert_source, const std::string& frag_source, osg::StateSet* ss)
{
	osg::Program* program = new osg::Program;
	osg::Shader* vertex_shader = new osg::Shader(osg::Shader::VERTEX);
	vertex_shader->setShaderSource(vert_source);
	osg::Shader* fragment_shader = new osg::Shader(osg::Shader::FRAGMENT);
	fragment_shader->setShaderSource(frag_source);
	program->addShader(vertex_shader);
	program->addShader(fragment_shader);

	ss->setAttributeAndModes(program, osg::StateAttribute::ON);
}


int main(int argc, char** argv)
{


	osg::ref_ptr<osg::Group> scene_root = new osg::Group;
	
	osgViewer::Viewer viewer;
	viewer.getCamera()->setDefaults();

	osg::Node* axes = osgDB::readNodeFile("axes.osgt");
	if (!axes)
	{
		std::cout << "Didn't find axes.osgb" << std::endl;
		exit(1);
	}
	osg::PositionAttitudeTransform* pat_1 = new osg::PositionAttitudeTransform;
	osg::PositionAttitudeTransform* pat_2 = new osg::PositionAttitudeTransform;
	pat_1->setPosition(osg::Vec3(-5,0,0));
	pat_2->setPosition(osg::Vec3(5,0,0));
	pat_1->addChild(axes);
	pat_2->addChild(axes);

	scene_root->addChild(pat_2);
	scene_root->addChild(pat_1);

	applyShader(vert_source, frag_source, pat_1->getOrCreateStateSet());
	applyShader(vert_source, frag_source, pat_2->getOrCreateStateSet());

	pat_2->getOrCreateStateSet()->setDefine("TEST_DEFINE");

	osgUtil::Optimizer opt;
	opt.optimize(scene_root, 
		osgUtil::Optimizer::SHARE_DUPLICATE_STATE | osgUtil::Optimizer::STATIC_OBJECT_DETECTION
		);
	//opt.optimize(scene_root);
	viewer.setSceneData(scene_root);

	viewer.setUpViewInWindow(10,10,255,255,0);
	viewer.run();

}