panner.h

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/*
    Copyright (C) 2004-2011 Paul Davis

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifndef __ardour_panner_h__
#define __ardour_panner_h__

#include <cmath>
#include <cassert>
#include <vector>
#include <string>
#include <iostream>

#include "pbd/cartesian.h"
#include "pbd/signals.h"
#include "pbd/stateful.h"

#include "ardour/libardour_visibility.h"
#include "ardour/types.h"
#include "ardour/automation_control.h"
#include "ardour/automatable.h"


/* This section is for actual panners to use. They will include this file,
 * declare ARDOURPANNER_DLL_EXPORTS during compilation, and ... voila.
 */

#ifdef ARDOURPANNER_DLL_EXPORTS // defined if we are building a panner implementation
    #define ARDOURPANNER_API LIBARDOUR_DLL_EXPORT
  #else
    #define ARDOURPANNER_API LIBARDOUR_DLL_IMPORT
  #endif 
#define ARDOURPANNER_LOCAL LIBARDOUR_DLL_LOCAL

namespace ARDOUR {

class Session;
class Pannable;
class BufferSet;
class AudioBuffer;
class Speakers;

class LIBARDOUR_API Panner : public PBD::Stateful, public PBD::ScopedConnectionList
{
public:
        Panner (boost::shared_ptr<Pannable>);
        ~Panner ();

        virtual boost::shared_ptr<Speakers> get_speakers() const { return boost::shared_ptr<Speakers>(); }

        virtual ChanCount in() const = 0;
        virtual ChanCount out() const = 0;

        virtual void configure_io (ARDOUR::ChanCount /*in*/, ARDOUR::ChanCount /*out*/) {}

        /* derived implementations of these methods must indicate
           whether it is legal for a Controllable to use the
           value of the argument (post-call) in a call to
           Controllable::set_value().

           they have a choice of:

           * return true, leave argument unchanged
           * return true, modify argument
           * return false
        */

        virtual bool clamp_position (double&) { return true; }
        virtual bool clamp_width (double&) { return true; }
        virtual bool clamp_elevation (double&) { return true; }

        virtual std::pair<double, double> position_range () const { return std::make_pair (-DBL_MAX, DBL_MAX); }
        virtual std::pair<double, double> width_range () const { return std::make_pair (-DBL_MAX, DBL_MAX); }
        virtual std::pair<double, double> elevation_range () const { return std::make_pair (-DBL_MAX, DBL_MAX); }

        virtual void set_position (double) { }
        virtual void set_width (double) { }
        virtual void set_elevation (double) { }

        virtual double position () const { return 0.0; }
        virtual double width () const { return 0.0; }
        virtual double elevation () const { return 0.0; }

        virtual PBD::AngularVector signal_position (uint32_t) const { return PBD::AngularVector(); }

        virtual void reset () = 0;

        /* azimut, width or elevation updated -> recalc signal_position ->  emit Changed */
        PBD::Signal0<void> SignalPositionChanged;

        void      set_automation_state (AutoState);
        AutoState automation_state() const;
        void      set_automation_style (AutoStyle);
        AutoStyle automation_style() const;

        virtual std::set<Evoral::Parameter> what_can_be_automated() const;
        virtual std::string describe_parameter (Evoral::Parameter);
        virtual std::string value_as_string (boost::shared_ptr<AutomationControl>) const;

        bool touching() const;

        static double azimuth_to_lr_fract (double azi) {
                /* 180.0 degrees=> left => 0.0 */
                /* 0.0 degrees => right => 1.0 */

                /* humans can only distinguish 1 degree of arc between two positions,
                   so force azi back to an integral value before computing
                */

                return 1.0 - (rint(azi)/180.0);
        }

        static double lr_fract_to_azimuth (double fract) {
                /* fract = 0.0 => degrees = 180.0 => left */
                /* fract = 1.0 => degrees = 0.0 => right */

                /* humans can only distinguish 1 degree of arc between two positions,
                   so force azi back to an integral value after computing
                */

                return rint (180.0 - (fract * 180.0));
        }

        virtual void distribute (BufferSet& ibufs, BufferSet& obufs, gain_t gain_coeff, pframes_t nframes);
        virtual void distribute_automated (BufferSet& ibufs, BufferSet& obufs,
                                           framepos_t start, framepos_t end, pframes_t nframes,
                                           pan_t** buffers);

        int set_state (const XMLNode&, int version);
        XMLNode& get_state ();
        
        boost::shared_ptr<Pannable> pannable() const { return _pannable; }

        static bool equivalent (pan_t a, pan_t b) {
                return fabsf (a - b) < 0.002; // about 1 degree of arc for a stereo panner
        }

        static bool equivalent (const PBD::AngularVector& a, const PBD::AngularVector& b) {
                /* XXX azimuth only, at present */
                return fabs (a.azi - b.azi) < 1.0;
        }

        virtual void freeze ();
        virtual void thaw ();

protected:
        boost::shared_ptr<Pannable> _pannable;

        virtual void distribute_one (AudioBuffer&, BufferSet& obufs, gain_t gain_coeff, pframes_t nframes, uint32_t which) = 0;
        virtual void distribute_one_automated (AudioBuffer&, BufferSet& obufs,
                                               framepos_t start, framepos_t end, pframes_t nframes,
                                               pan_t** buffers, uint32_t which) = 0;

        int32_t _frozen;
};

} // namespace

extern "C" {
struct LIBARDOUR_API PanPluginDescriptor {
        std::string name;
        std::string panner_uri;
        std::string gui_uri;
        int32_t in;
        int32_t out;
        uint32_t priority;
        ARDOUR::Panner* (*factory)(boost::shared_ptr<ARDOUR::Pannable>, boost::shared_ptr<ARDOUR::Speakers>);
};
}

#endif /* __ardour_panner_h__ */