//This file is part of Photon (http://photon.sourceforge.net)
//Copyright (C) 2004-2005 James Turk
//
// Author:
//  James Turk (jpt2433@rit.edu)
//
// Version:
//  $Id: VideoCore.hpp,v 1.1 2005/03/02 08:40:11 cozman Exp $

#ifndef PHOTON_VIDEO_VIDEOCORE_HPP
#define PHOTON_VIDEO_VIDEOCORE_HPP

#include "types.hpp"
#include "AppCore.hpp"
#include "util/Singleton.hpp"

namespace photon
{
namespace video
{

// Class: VideoCore
//  Photon's <Singleton> core for graphics behavior.  Defines the interface 
//  through which all graphics related functions are performed.
//
//  VideoCore is the Core that interfaces with the actual drawing/updating of
//  the display.
//
// See Also:
//  <AppCore>
//
// Parent:
//  <Singleton>
class VideoCore : public util::Singleton<VideoCore>
{

// Group: Display Management
public: 
    // Function: clearDisplay
    //  Clears the display. 
    void clear();
    
    // Function: update
    //  Updates the video display.
    void update();

// Group: Viewport 
//  Functions to set the working viewport and perspective. Orthographic and
//  standard 3D perspective modes are available.
public:
    // Function: setOrthoView
    //  Sets new ortho viewport within a rectangular portion of the screen.
    //  All drawing is relative to the rectangle, x,y becomes 0,0 and anything  
    //  drawn outside rect is clipped.
    // 
    // Parameters:
    //  x - X coord for top left corner of new viewport.
    //  y - Y coord for top left corner of new viewport.
    //  viewWidth - Width of new viewport.
    //  viewHeight - Height of new viewport.
    //  orthoWidth - Width of ortho perspective.
    //  orthoHeight - Height of ortho perspective.
    void setOrthoView(int x, int y, int viewWidth, int viewHeight, 
                            scalar orthoWidth, scalar orthoHeight);
    
    // Function: setOrthoView
    //  Sets entire screen as current viewport with a given ortho perspective.
    // 
    // Parameters:
    //  width - Width of view.
    //  height - Height of view.
    void setOrthoView(scalar width, scalar height);
    
    // Function: setOrthoView
    //  Sets entire screen as current viewport with a given ortho perspective.
    void setOrthoView();

// Group: Perspective
public:
    // Function: setPerspectiveView
    //  Creates a viewport with a given 3D perspective inside of a rectangular
    //  portion of the screen.
    // 
    // Parameters:
    //  x - X coord for top left corner of new viewport.
    //  y - Y coord for top left corner of new viewport.
    //  width - Width of new viewport.
    //  height - Height of new viewport.
    //  fovy - The y axis field of view angle, in degrees.
    //  zNear - Distance from viewer to near clipping plane.
    //  zFar - Distance from viewer to far clipping plane.
    void setPerspectiveView(int x, int y, int width, int height, 
                                scalar fovy, scalar zNear, scalar zFar);
    
    // Function: setPerspectiveView
    //  Sets entire screen as current viewport with a given 3D perspective.
    //
    //  Same as call to setPerspective
    // 
    // Parameters:
    //  fovy - The y axis field of view angle, in degrees.
    //  zNear - Distance from viewer to near clipping plane.
    //  zFar - Distance from viewer to far clipping plane.
    void setPerspectiveView(scalar fovy, scalar zNear, scalar zFar);
    
// Group: Viewport/Projection 
//  These functions are called by the above Ortho/Perspective functions, very 
//  rarely do they need to be called directly.
public:
    // Function: setViewport
    //  Set the current viewport rectangle within the screen.
    void setViewport(int x, int y, int width, int height);
    
    // Function: setOrthoProjection
    //  Sets an orthographic projection matrix.
    // 
    // Parameters:
    //  width - Width of view.
    //  height - Height of view.
    void setOrthoProjection(scalar width, scalar height);
    
    // Function: setPerspectiveProjection
    //  Sets a perspective projection matrix.
    // 
    // Parameters:
    //  fovy - The y axis field of view angle, in degrees.
    //  zNear - Distance from viewer to near clipping plane.
    //  zFar - Distance from viewer to far clipping plane.
    void setPerspectiveProjection(scalar fovy, scalar zNear, scalar zFar);

// behind the scenes
private: 
    void initOpenGL();
    
// data members
private:
    AppCore& appCore_;
    uint viewportWidth_;
    uint viewportHeight_;
    
// Singleton-required code
private:
    VideoCore();
    ~VideoCore();

    friend class util::Singleton<VideoCore>;
    friend class std::auto_ptr<VideoCore>;
};

}
}

#endif  //PHOTON_VIDEO_VIDEOCORE_HPP