GLContext.h

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/*
 *  Copyright (C) 2010 - 2015 Leonid Kostrykin
 *
 *  Chair of Medical Engineering (mediTEC)
 *  RWTH Aachen University
 *  Pauwelsstr. 20
 *  52074 Aachen
 *  Germany
 *
 */

#ifndef GLCONTEXT_H_6014714286
#define GLCONTEXT_H_6014714286

#include <Carna/Carna.h>
#include <Carna/base/CarnaException.h>
#include <Carna/base/noncopyable.h>
#include <Carna/base/Log.h>
#include <memory>

namespace Carna
{

namespace base
{



// ----------------------------------------------------------------------------------
// GLContext
// ----------------------------------------------------------------------------------

class CARNA_LIB GLContext
{

    NON_COPYABLE

    struct Details;
    const std::unique_ptr< Details > pimpl;

protected:

    explicit GLContext( bool isDoubleBuffered );

    friend class RenderState;
    
    void pushRenderState( const RenderState& rs );
    
    void popRenderState();
    
    const RenderState& currentRenderState() const;

public:

    const static unsigned int DEPTH_BUFFER_BIT; 
    const static unsigned int COLOR_BUFFER_BIT; 

    virtual ~GLContext();

    const bool isDoubleBuffered;

    static GLContext& current();

    void makeCurrent() const;

    bool isCurrent() const;

    void setShader( const ShaderProgram& shader );

    const ShaderProgram& shader() const;

    void clearBuffers( unsigned int flags );
    
protected:

    virtual void activate() const = 0;

}; // GLContext



// ----------------------------------------------------------------------------------
// QGLContextAdapter
// ----------------------------------------------------------------------------------

template< typename QGLContext, typename QGLFormat >
class QGLContextAdapter : public GLContext
{

    QGLContext& qglcontext;

public:

    QGLContextAdapter();
    
    static QGLFormat desiredFormat();
    
protected:

    virtual void activate() const override;

}; // QGLContextAdapter


template< typename QGLContext, typename QGLFormat >
QGLContextAdapter< QGLContext, QGLFormat >::QGLContextAdapter()
    : GLContext( QGLContext::currentContext()->format().doubleBuffer() )
    , qglcontext( const_cast< QGLContext& >( *QGLContext::currentContext() ) )
{
    const QGLFormat& format = QGLContext::currentContext()->format();
    if( format.majorVersion() < 3 || ( format.majorVersion() == 3 && format.minorVersion() < 3 ) )
    {
        std::stringstream msg;
        msg << "OpenGL context version " << format.majorVersion() << "." << format.minorVersion() << " is too low.";
        CARNA_FAIL( msg.str() );
    }
    else
    {
        CARNA_ASSERT( format.profile() != QGLFormat::NoProfile );
        std::stringstream msg;
        msg << "Recognized OpenGL " << format.majorVersion() << "." << format.minorVersion() << " context (";
        msg << ( format.profile() == QGLFormat::CoreProfile ? "core" : "compatibility" ) << " profile)";
        Log::instance().record( Log::debug, msg.str() );
    }
}

    
template< typename QGLContext, typename QGLFormat >
QGLFormat QGLContextAdapter< QGLContext, QGLFormat >::desiredFormat()
{
    QGLFormat format = QGLFormat::defaultFormat();
    format.setVersion( 3, 3 );
    format.setProfile( QGLFormat::CompatibilityProfile );
    return format;
}


template< typename QGLContext, typename QGLFormat >
void QGLContextAdapter< QGLContext, QGLFormat >::activate() const
{
    qglcontext.makeCurrent();
}



}  // namespace Carna :: base

}  // namespace Carna

#endif // GLCONTEXT_H_6014714286