OpenSubdiv/opensubdiv/osd/cpuEvalLimitController.h

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#ifndef OSD_CPU_EVAL_LIMIT_CONTROLLER_H
#define OSD_CPU_EVAL_LIMIT_CONTROLLER_H

#include "../version.h"

#include "../osd/evalLimitContext.h"
#include "../osd/cpuEvalLimitContext.h"
#include "../osd/vertexDescriptor.h"

namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {

/// \brief CPU controler for limit surface evaluation.
///
/// A CPU-driven controller that can be called to evaluate samples on the limit
/// surface for a given EvalContext.
///
class OsdCpuEvalLimitController {

public:
    /// Constructor.
    OsdCpuEvalLimitController();

    /// Destructor.
    ~OsdCpuEvalLimitController();
    
    /// \brief Represents a location on the limit surface
    struct OsdEvalCoords {
        int face;   // Ptex unique face ID
        float u,v;  // local u,v
    };
    
    /// \brief Vertex interpolation of samples at the limit
    ///
    /// Evaluates "vertex" interpolation of a sample on the surface limit.
    ///
    /// Warning : this function is re-entrant but it breaks the Osd API pattern
    /// by requiring the client code to bind and unbind the vertex buffers to
    /// the EvalLimitContext. 
    ///
    /// Ex :
    /// \code
    /// evalCtxt->BindVertexBuffers( ... );
    ///
    /// parallel_for( int index=0; i<nsamples; ++index ) {
    ///    evalCtrlr->EvalLimitSample( coord, evalCtxt, index );
    /// }
    ///
    /// evalCtxt->UnbindVertexBuffers();
    /// \endcode
    ///
    /// @param coords   location on the limit surface to be evaluated
    ///
    /// @param context  the EvalLimitContext that the controller will evaluate
    ///
    /// @param index    the index of the vertex in the output buffers bound to the 
    ///                 context
    ///
    /// @return the number of samples found (0 if the location was tagged as a hole
    ///         or the coordinate was invalid)
    ///
    template<class VERTEX_BUFFER, class OUTPUT_BUFFER>
    int EvalLimitSample( OpenSubdiv::OsdEvalCoords const & coords, 
                         OsdCpuEvalLimitContext * context,
                         unsigned int index ) {    
        if (not context)
            return 0;
            
        int n = _EvalLimitSample( coords, context, index );
        
        return n;
    }

private:

    int _EvalLimitSample( OpenSubdiv::OsdEvalCoords const & coords, 
                          OsdCpuEvalLimitContext const * context,
                          unsigned int index );

};

} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;

} // end namespace OpenSubdiv

#endif /* OSD_CPU_EVAL_LIMIT_CONTROLLER_H */