qt and gl/cl inerop

[giugio]

hеllo.
I'm trying to use an interop with opengl and opencl in qt.
this is my code:

GLuint id = 0;
	glGenBuffers(1, &id);
	glBindBuffer(GL_ARRAY_BUFFER, id);
	glBufferData(GL_ARRAY_BUFFER, lSize, NULL, GL_STATIC_DRAW);
 
	int err;
	cl::BufferGL buff;
	buff= cl::BufferGL(context, CL_MEM_WRITE_ONLY, id, &err);
 
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	vertexBufferObject = id;

GLuint id = 0;
	glGenBuffers(1, &id);
	glBindBuffer(GL_ARRAY_BUFFER, id);
	glBufferData(GL_ARRAY_BUFFER, lSize, NULL, GL_STATIC_DRAW);

	int err;
	cl::BufferGL buff;
	buff= cl::BufferGL(context, CL_MEM_WRITE_ONLY, id, &err);
	
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	vertexBufferObject = id;

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I get always the same error:
-60: CL_INVALID_GL_OBJECT.
i omitted the construction of the gl/cl context code, but I'm was try this without qt and all works fine.
When i use the code in qt i get the error.
What can be?
the threads and contexts that are used in qt?
How i can resolve?
But I wish understand and use my own library, rather than use an already done library .
thanks.

[amleto]

show your COMPLETE & COMPILABLE example that works, and then show your COMPLETE & COMPILABLE example that doesn't work.

Please explain how this is a qt question.

[giugio]

thanks.
but I must gain some information, before post my code:
I'm trying to work with
http://doc.qt.digia.com/opencl-snaps...contextgl.html.
I not understand the
supportsObjectSharing
and the

/*!
    Constructs a new OpenCL context object that is suitable for use
    with OpenGL objects.
*/
QCLContextGL::QCLContextGL()
    : QCLContext(), d_ptr(new QCLContextGLPrivate())
{
}

/*!
    Constructs a new OpenCL context object that is suitable for use
    with OpenGL objects.
*/
QCLContextGL::QCLContextGL()
    : QCLContext(), d_ptr(new QCLContextGLPrivate())
{
}

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in the qclcontextgl.cpp line:81.
1)I'm not understand what is a 1)context and what is a 2)contextprivate.
Is related to multithreading?
where i can found documentation on this arg?
thanks.

[amleto]

1 - http://www.dyn-lab.com/articles/cl-gl.html

2 - you don't need to worry about it - it is the qt implementation. It wont be thread related.

[giugio]

this is my qglwidget constructor for try to create interoperability:
i use this lib :http://doc.qt.digia.com/opencl-snaps...contextgl.html

CTest::CTest(HINSTANCE hPrevInstance, int nShowCmd)
{
	m_hPrevInstance = hPrevInstance;
	m_nShowCmd = nShowCmd;
	CApplication::m_Draw = bind(&CTest::Draw, this);
	CApplication::m_Create = bind(&CTest::CreateInit, this);
 
	setMouseTracking(true);
	m_pTimer = new QTimer(this);
	connect(m_pTimer, SIGNAL(timeout()), this , SLOT(OnIdleOpenGl()) ); 
	makeCurrent();
	context.create();
 
	vert = NULL;
	if (!vert) {
		vert = new QGLBuffer(QGLBuffer::VertexBuffer);
        vert->setUsagePattern(QGLBuffer::DynamicDraw);
        if (!vert->create()) {
            delete vert;
            vert = 0;
 
        }
    }
    if (vert) {
        vert->bind();
        vert->allocate(sizeof(GLfloat) * 4 * 4);
        if (!vert->map(QGLBuffer::WriteOnly)) {
            // No point using a vertex buffer if we cannot map it.
            vert->unmap();
            vert->release();
            delete vert;
            vert = 0;
           } else {
            vert->unmap();
            vert->release();
        }
 
	}
	QCLBuffer BBB;
	 if (context.supportsObjectSharing()) {
		BBB = context.createGLBuffer(vert,QCLMemoryObject::WriteOnly);
	 }
 
	m_pTimer->setInterval( 3 );
	m_pTimer->start();	
}

CTest::CTest(HINSTANCE hPrevInstance, int nShowCmd)
{
	m_hPrevInstance = hPrevInstance;
	m_nShowCmd = nShowCmd;
	CApplication::m_Draw = bind(&CTest::Draw, this);
	CApplication::m_Create = bind(&CTest::CreateInit, this);
	
	setMouseTracking(true);
	m_pTimer = new QTimer(this);
	connect(m_pTimer, SIGNAL(timeout()), this , SLOT(OnIdleOpenGl()) ); 
	makeCurrent();
	context.create();

	vert = NULL;
	if (!vert) {
		vert = new QGLBuffer(QGLBuffer::VertexBuffer);
        vert->setUsagePattern(QGLBuffer::DynamicDraw);
        if (!vert->create()) {
            delete vert;
            vert = 0;
            
        }
    }
    if (vert) {
        vert->bind();
        vert->allocate(sizeof(GLfloat) * 4 * 4);
        if (!vert->map(QGLBuffer::WriteOnly)) {
            // No point using a vertex buffer if we cannot map it.
            vert->unmap();
            vert->release();
            delete vert;
            vert = 0;
           } else {
            vert->unmap();
            vert->release();
        }
        
	}
	QCLBuffer BBB;
	 if (context.supportsObjectSharing()) {
		BBB = context.createGLBuffer(vert,QCLMemoryObject::WriteOnly);
	 }

	m_pTimer->setInterval( 3 );
	m_pTimer->start();	
}

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but this:
context.supportsObjectSharing()
return false
and this if i remove the test:
BBB = context.createGLBuffer(vert,QCLMemoryObject::Write Only);
return a void openclbuffer.

thanks

[amleto]

looks like your conext should acquire() the qclbuffer

[giugio]

in the bezierpatch demo of the library all work fine, but i'm not understand why!

[giugio]

how i can understand the thread related problematics in qt and opengl?
thanks.

[amleto]

what thread 'problematics'?