source: OGRE/trunk/ogre_dependencies/Dependencies/include/CEGUI/CEGUIRenderer.h @ 692

/************************************************************************
        filename:       CEGUIRenderer.h
        created:        20/2/2004
        author:         Paul D Turner
        
        purpose:        Defines interface for abstract Renderer class
*************************************************************************/
/*************************************************************************
    Crazy Eddie's GUI System (http://www.cegui.org.uk)
    Copyright (C)2004 - 2005 Paul D Turner (paul@cegui.org.uk)

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*************************************************************************/
#ifndef _CEGUIRenderer_h_
#define _CEGUIRenderer_h_

#include "CEGUIBase.h"
#include "CEGUIString.h"
#include "CEGUIRect.h"
#include "CEGUIColourRect.h"
#include "CEGUIEventSet.h"


// Start of CEGUI namespace section
namespace CEGUI
{
/*!
\brief
        Enumerated type that contains the valid flags that can be to use when rendering image
*/
enum OrientationFlags {
        FlipHorizontal          = 1,    //!< Horizontal flip the image
        FlipVertical            = 2,    //!< Vertical flip the image
        RotateRightAngle        = 4             //!< Rotate the image anticlockwise 90 degree
};

/*!
\brief
        Enumerated type that contains the valid diagonal-mode that specify how a quad is split into triangles when rendered with fx. a 3D API
*/
enum QuadSplitMode
{
        TopLeftToBottomRight,   //!< Diagonal goes from top-left to bottom-right
        BottomLeftToTopRight    //!< Diagonal goes from bottom-left to top-right
};


/*!
\brief
        Abstract class defining the interface for Renderer objects.

        Objects derived from Renderer are the means by which the GUI system interfaces
        with specific rendering technologies.  To use a rendering system or API to draw
        CEGUI imagery requires that an appropriate Renderer object be available.
*/
class CEGUIEXPORT Renderer : public EventSet
{
public:
        static const String EventNamespace;                             //!< Namespace for global events

        /*************************************************************************
                Event name constants
        *************************************************************************/
        /*!
                event that fires when the underlying display size had changed.
                
                It is important that all Renderer implementers fire this properly as the
                system itself subscribes to this event.
        */
        static const String EventDisplaySizeChanged;


        /*************************************************************************
                Abstract interface methods
        *************************************************************************/
        /*!
        \brief
                Add a quad to the rendering queue.  All clipping and other adjustments should have been made prior to calling this.

        \param dest_rect
                Rect object describing the destination area (values are in pixels)

        \param z
                float value specifying the z co-ordinate / z order of the quad

        \param tex
                pointer to the Texture object that holds the imagery to be rendered

        \param texture_rect
                Rect object holding the area of \a tex that is to be rendered (values are in texture co-ordinates).

        \param colours
                ColourRect object describing the colour values that are to be applied when rendering.
        
        \param quad_split_mode
                One of the QuadSplitMode values specifying the way quads are split into triangles

        \return
                Nothing
        */
        virtual void    addQuad(const Rect& dest_rect, float z, const Texture* tex, const Rect& texture_rect, const ColourRect& colours, QuadSplitMode quad_split_mode) = 0;


        /*!
        \brief
                Perform final rendering for all quads that have been queued for rendering

                The contents of the rendering queue is retained and can be rendered again as required.  If the contents is not required call clearRenderList().

        \return
                Nothing
        */
        virtual void    doRender(void) = 0;


        /*!
        \brief
                Clears all queued quads from the render queue.
        
        \return
                Nothing
        */
        virtual void    clearRenderList(void) = 0;


        /*!
        \brief
                Enable or disable the queueing of quads from this point on.

                This only affects queueing.  If queueing is turned off, any calls to addQuad will cause the quad to be rendered directly.  Note that
                disabling queueing will not cause currently queued quads to be rendered, nor is the queue cleared - at any time the queue can still
                be drawn by calling doRender, and the list can be cleared by calling clearRenderList.  Re-enabling the queue causes subsequent quads
                to be added as if queueing had never been disabled.

        \param setting
                true to enable queueing, or false to disable queueing (see notes above).

        \return
                Nothing
        */
        virtual void    setQueueingEnabled(bool setting) = 0;


        /*!
        \brief
                Creates a 'null' Texture object.

        \return
                a newly created Texture object.  The returned Texture object has no size or imagery associated with it, and is
                generally of little or no use.
        */
        virtual Texture*        createTexture(void) = 0;


        /*!
        \brief
                Create a Texture object using the given image file.

        \param filename
                String object that specifies the path and filename of the image file to use when creating the texture.

    \param resourceGroup
        Resource group identifier to be passed to the resource provider when loading the texture file.

        \return
                a newly created Texture object.  The initial contents of the texture memory is the requested image file.

        \note
                Textures are always created with a size that is a power of 2.  If the file you specify is of a size that is not
                a power of two, the final size will be rounded up.  Additionally, textures are always square, so the ultimate
                size is governed by the larger of the width and height of the specified file.  You can check the ultimate sizes
                by querying the texture after creation.
        */
        virtual Texture*        createTexture(const String& filename, const String& resourceGroup) = 0;


        /*!
        \brief
                Create a Texture object with the given pixel dimensions as specified by \a size.  NB: Textures are always square.

        \param size
                float value that specifies the size to use for the width and height when creating the new texture.

        \return
                a newly created Texture object.  The initial contents of the texture memory is undefined / random.

        \note
                Textures are always created with a size that is a power of 2.  If you specify a size that is not a power of two, the final
                size will be rounded up.  So if you specify a size of 1024, the texture will be (1024 x 1024), however, if you specify a size
                of 1025, the texture will be (2048 x 2048).  You can check the ultimate size by querying the texture after creation.
        */      
        virtual Texture*        createTexture(float size) = 0;


        /*!
        \brief
                Destroy the given Texture object.

        \param texture
                pointer to the Texture object to be destroyed

        \return
                Nothing
        */
        virtual void            destroyTexture(Texture* texture) = 0;

        
        /*!
        \brief
                Destroy all Texture objects.

        \return
                Nothing
        */
        virtual void            destroyAllTextures(void) = 0;


        /*!
        \brief
                Return whether queueing is enabled.

        \return
                true if queueing is enabled, false if queueing is disabled.
        */
        virtual bool    isQueueingEnabled(void) const = 0;


        /*!
        \brief
                Return the current width of the display in pixels

        \return
                float value equal to the current width of the display in pixels.
        */
        virtual float   getWidth(void) const    = 0;


        /*!
        \brief
                Return the current height of the display in pixels

        \return
                float value equal to the current height of the display in pixels.
        */
        virtual float   getHeight(void) const   = 0;


        /*!
        \brief
                Return the size of the display in pixels

        \return
                Size object describing the dimensions of the current display.
        */
        virtual Size    getSize(void) const             = 0;


        /*!
        \brief
                Return a Rect describing the screen

        \return
                A Rect object that describes the screen area.  Typically, the top-left values are always 0, and the size of the area described is
                equal to the screen resolution.
        */
        virtual Rect    getRect(void) const             = 0;


        /*!
        \brief
                Return the maximum texture size available

        \return
                Size of the maximum supported texture in pixels (textures are always assumed to be square)
        */
        virtual uint    getMaxTextureSize(void) const   = 0;


        /*!
        \brief
                Return the horizontal display resolution dpi

        \return
                horizontal resolution of the display in dpi.
        */
        virtual uint    getHorzScreenDPI(void) const    = 0;


        /*!
        \brief
                Return the vertical display resolution dpi

        \return
                vertical resolution of the display in dpi.
        */
        virtual uint    getVertScreenDPI(void) const    = 0;


        /*************************************************************************
                Basic stuff we provide in base class
        *************************************************************************/
        /*!
        \brief
                Reset the z co-ordinate for rendering.
        
        \return
                Nothing
        */
        void    resetZValue(void)                               {d_current_z = GuiZInitialValue;}


        /*!
        \brief
                Update the z co-ordinate for the next major UI element (window).

        \return
                Nothing
        */
        void    advanceZValue(void)                             {d_current_z -= GuiZElementStep;}


        /*!
        \brief
                return the current Z value to use (equates to layer 0 for this UI element).

        \return
                float value that specifies the z co-ordinate to be used for layer 0 on the current GUI element.
        */
        float   getCurrentZ(void) const                 {return d_current_z;}


        /*!
        \brief
                return the z co-ordinate to use for the requested layer on the current GUI element.

        \param layer
                Specifies the layer to return the Z co-ordinate for.  Each GUI element can use up to 10 layers, so valid inputs are 0 to 9 inclusive.
                If you specify an invalid value for \a layer, results are undefined.

        \return
                float value that specifies the Z co-ordinate for layer \a layer on the current GUI element.
        */
        float   getZLayer(uint layer) const             {return d_current_z - ((float)layer * GuiZLayerStep);}


    /*!
    \brief
        Return identification string for the renderer module.  If the internal id string has not been
        set by the Renderer module creator, a generic string of "Unknown renderer" will be returned.

    \return
        String object holding a string that identifies the Renderer in use.
    */
    const String& getIdentifierString() const;

    virtual ResourceProvider* createResourceProvider(void);

protected:
        /*************************************************************************
                Construction and Destruction
        *************************************************************************/
        Renderer(void);

public:         // for luabind support
        virtual ~Renderer(void);

private:
        /*************************************************************************
                Implementation constants
        *************************************************************************/
        static const float      GuiZInitialValue;               //!< Initial value to use for 'z' each frame.
        static const float      GuiZElementStep;                //!< Value to step 'z' for each GUI element.
        static const float      GuiZLayerStep;                  //!< Value to step 'z' for each GUI layer.


        /*************************************************************************
                Implementation Data
        *************************************************************************/
        float   d_current_z;            //!< The current z co-ordinate value.

protected:
    ResourceProvider* d_resourceProvider;      //!< Holds the pointer to the ResourceProvider object.
    String d_identifierString;                 //!< String that holds some id information about the renderer.
};

} // End of  CEGUI namespace section


#endif  // end of guard _CEGUIRenderer_h_