RE_ContextSpecificObject.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        RE_ContextSpecificObject.h ( RE Library, C++)
 *
 * COMMENTS:
 *      This base class is for OpenGL objects that are context-specific,
 *      rather than shared. Example objects are:
 *
 *      - Vertex Array Objects
 *      - Occlusion Query Objects
 *      - Timer Objects
 *
 *      These objects are defined to be non-sharable by the OpenGL spec, even
 *      if two contexts belong to the same share-set.
 */
#ifndef RE_ContextSpecificObject_h
#define RE_ContextSpecificObject_h

#include "RE_API.h"
#include "RE_Render.h"
#include "RE_Server.h"
#include <UT/UT_Assert.h>
#include <UT/UT_NonCopyable.h>

class RE_API RE_ContextSpecificObject
{
public:
             RE_ContextSpecificObject() : myContext(nullptr) {}
    virtual ~RE_ContextSpecificObject() {}

    UT_NON_COPYABLE(RE_ContextSpecificObject)

    virtual bool                   init(RE_Render *r) = 0;

    void        initContext(RE_Render *r);
    bool        matchesContext(RE_Render *r) const;
    void        clearContext() { myContext = nullptr; }

protected:
    RE_Render   *getMyRender();

    // Call in subclasses to ensure that the incoming render context matches
    // the context this object was created with.
    bool         initOrCheckRender(RE_Render *r)
    {
        UT_ASSERT(r);

        auto render_context = (RE_Server::useNewWindowDrawable()
                ? r->getDrawableContext() : r->getContext());

        if (myContext == nullptr)
        {
            myContext = render_context;
            return true;
        }
        else if (myContext == render_context)
            return true;

        UT_ASSERT(!"Mismatched GL context with context-specific object");
        return false;
    }
    
private:
    RE_OGLContext       myContext;
};

// To be used within derived classes.
#define RE_CONTEXT_CHECK(r) UT_ASSERT(matchesContext(r))

#endif