gls_sorted_drawable.h

#ifndef GLS_SORTED_DRAWABLE_H
#define GLS_SORTED_DRAWABLE_H

namespace disti {

// Interface for a drawable object
class GlsSortedDrawable
{
public:
    // virtual destructor
    virtual ~GlsSortedDrawable() {}

    // Allows for static casting in compare functions
    // See RegisterClassID
    virtual unsigned int SortedDraw_ClassID() = 0;
    
    // Compare two GlsSortedDrawable objects to determine the sort order
    // \param other object to compare to
    // \returns true if this object should draw before other
    virtual bool SortedDraw_Compare(GlsSortedDrawable& other) = 0;

    // Comparison that should be used if the
    // derived class is unsure
    inline bool SortedDraw_CompareDefault(GlsSortedDrawable& o)
    {
        // Group objects by ClassID
        return SortedDraw_ClassID() < o.SortedDraw_ClassID();
    }

    // Try to merge two adjecently-sorted GlsSortedDrawable nodes
    // \param lastObj pointer to the previous GlsSortedDrawable in the sort order
    virtual void SortedDraw_OptimizeMerge(GlsSortedDrawable& lastObj) = 0;
/*
    // Return true if this object should be depth sorted
    virtual bool SortedDraw_ShouldDepthSort() { return false; }

    // Return position of the object for depth sorting purposes
    virtual void SortedDraw_GetViewPosition(Vector& pos) {}
*/
    // Draw the object using the current OpenGL context
    // Use lastDrawnObj to avoid redundant state changes
    // \param lastObj pointer to the GlsSortedDrawable that was drawn (may be NULL)
    virtual void SortedDraw(GlsSortedDrawable* lastObj) = 0;

    // Tell an object to restore the OpenGLDefaultState after drawing
    // Objects should call this if lastDrawnObj has an unknown class
    // The Group will also call this after the last object is drawn
    virtual void SortedDrawCleanup() = 0;

    //Whether or not this can be re-ordered, or if it is part of an preserved order set
    virtual bool SortedDraw_ReorderAtWill() { return true; }

    // Returns a new ClassID
    // Typically only called once by each GlsSortedDrawable implementation
    static unsigned int RegisterNewClassID(const char* debugStr = NULL);
};

}

#endif