source: code/branches/objecthierarchy/src/orxonox/gui/OgreCEGUIRenderer.cpp @ 2013

/************************************************************************
    filename:   OgreCEGUIRenderer.cpp
    created:    11/5/2004
    author:             Paul D Turner
    
    purpose:    Implementation of Renderer class for Ogre engine
*************************************************************************/
/*************************************************************************
    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
*************************************************************************/

#include "OrxonoxStableHeaders.h"
#include <CEGUIImagesetManager.h>
#include <CEGUIImageset.h>
#include <CEGUIImage.h>
#include <CEGUIExceptions.h>
#include <CEGUISystem.h>

#include "OgreCEGUIRenderer.h"
#include "OgreCEGUITexture.h"
#include "OgreCEGUIResourceProvider.h"

#include <OgreRenderSystem.h>
#include <OgreRoot.h>
#include <OgreHardwareBufferManager.h>
#include <OgreRenderWindow.h>

// Start of CEGUI namespace section
namespace CEGUI
{
/*************************************************************************
    Constants definitions
*************************************************************************/
const size_t    OgreCEGUIRenderer::VERTEX_PER_QUAD                      = 6;
const size_t    OgreCEGUIRenderer::VERTEX_PER_TRIANGLE          = 3;
const size_t    OgreCEGUIRenderer::VERTEXBUFFER_INITIAL_CAPACITY        = 256;
const size_t    OgreCEGUIRenderer::UNDERUSED_FRAME_THRESHOLD = 50000; // halfs buffer every 8 minutes on 100fps

/*************************************************************************
    Utility function to create a render operation and vertex buffer to render quads
*************************************************************************/
static void createQuadRenderOp(Ogre::RenderOperation &d_render_op, 
    Ogre::HardwareVertexBufferSharedPtr &d_buffer, size_t nquads)
{
    using namespace Ogre;
    // Create and initialise the Ogre specific parts required for use in rendering later.
    d_render_op.vertexData = new VertexData;
    d_render_op.vertexData->vertexStart = 0;

    // setup vertex declaration for the vertex format we use
    VertexDeclaration* vd = d_render_op.vertexData->vertexDeclaration;
    size_t vd_offset = 0;
    vd->addElement(0, vd_offset, VET_FLOAT3, VES_POSITION);
    vd_offset += VertexElement::getTypeSize(VET_FLOAT3);
    vd->addElement(0, vd_offset, VET_COLOUR, VES_DIFFUSE);
    vd_offset += VertexElement::getTypeSize(VET_COLOUR);
    vd->addElement(0, vd_offset, VET_FLOAT2, VES_TEXTURE_COORDINATES);

    // create hardware vertex buffer
    d_buffer = HardwareBufferManager::getSingleton().createVertexBuffer(vd->getVertexSize(0), nquads,  
        HardwareBuffer::HBU_DYNAMIC_WRITE_ONLY_DISCARDABLE, false);

    // bind vertex buffer
    d_render_op.vertexData->vertexBufferBinding->setBinding(0, d_buffer);

    // complete render operation basic initialisation
    d_render_op.operationType = RenderOperation::OT_TRIANGLE_LIST;
    d_render_op.useIndexes = false;
}

static void destroyQuadRenderOp(Ogre::RenderOperation &d_render_op, 
    Ogre::HardwareVertexBufferSharedPtr &d_buffer)
{
    delete d_render_op.vertexData;
    d_render_op.vertexData = 0;
    d_buffer.setNull();
}

/*************************************************************************
    Constructor
*************************************************************************/
OgreCEGUIRenderer::OgreCEGUIRenderer(Ogre::RenderWindow* window, Ogre::uint8 queue_id, bool post_queue, uint max_quads)
{
    constructor_impl(window, queue_id, post_queue, max_quads);
}


/*************************************************************************
    Constructor (specifying scene manager)
*************************************************************************/
OgreCEGUIRenderer::OgreCEGUIRenderer(Ogre::RenderWindow* window, Ogre::uint8 queue_id, bool post_queue, uint max_quads, Ogre::SceneManager* scene_manager)
{
    constructor_impl(window, queue_id, post_queue, max_quads);

    // hook into ogre rendering system
    setTargetSceneManager(scene_manager);
}


/*************************************************************************
    Destructor
*************************************************************************/
OgreCEGUIRenderer::~OgreCEGUIRenderer(void)
{
    setTargetSceneManager(NULL);

    if (d_ourlistener)
    {
        delete d_ourlistener;
    }

    // cleanup vertex data we allocated in constructor
    destroyQuadRenderOp(d_render_op, d_buffer);
    destroyQuadRenderOp(d_direct_render_op, d_direct_buffer);

    destroyAllTextures();
}


/*************************************************************************
    add's a quad to the list to be rendered
*************************************************************************/
void OgreCEGUIRenderer::addQuad(const Rect& dest_rect, float z, const Texture* tex, const Rect& texture_rect, const ColourRect& colours, QuadSplitMode quad_split_mode)
{
    // if not queueing, render directly (as in, right now!). This is used for the mouse cursor.
    if (!d_queueing)
    {
        renderQuadDirect(dest_rect, z, tex, texture_rect, colours, quad_split_mode);
    }
    else
    {
        d_sorted = false;
        QuadInfo quad;
        
        // set quad position, flipping y co-ordinates, and applying appropriate texel origin offset
        quad.position.d_left    = dest_rect.d_left;
        quad.position.d_right   = dest_rect.d_right;
        quad.position.d_top             = d_display_area.getHeight() - dest_rect.d_top;
        quad.position.d_bottom  = d_display_area.getHeight() - dest_rect.d_bottom;
        quad.position.offset(d_texelOffset);

        // convert quad co-ordinates for a -1 to 1 co-ordinate system.
        quad.position.d_left    /= (d_display_area.getWidth() * 0.5f);
        quad.position.d_right   /= (d_display_area.getWidth() * 0.5f);
        quad.position.d_top             /= (d_display_area.getHeight() * 0.5f);
        quad.position.d_bottom  /= (d_display_area.getHeight() * 0.5f);
        quad.position.offset(Point(-1.0f, -1.0f));

        quad.z                          = -1 + z;
        quad.texture            = ((OgreCEGUITexture*)tex)->getOgreTexture();
        quad.texPosition        = texture_rect;

        // covert colours for ogre, note that top / bottom are switched.
        quad.topLeftCol         = colourToOgre(colours.d_bottom_left);
        quad.topRightCol        = colourToOgre(colours.d_bottom_right);
        quad.bottomLeftCol      = colourToOgre(colours.d_top_left);
        quad.bottomRightCol     = colourToOgre(colours.d_top_right);
        
        // set quad split mode
        quad.splitMode = quad_split_mode;

        d_quadlist.insert(quad);
    }
}



/*************************************************************************
perform final rendering for all queued renderable quads.
*************************************************************************/
void OgreCEGUIRenderer::doRender(void)
{
    // Render if overlays enabled and the quad list is not empty

    // ORXONOX CHANGE: Even render when OverlaysEnabled is deactivated
    // The reason is that we don't want the HUD to be shown in the viewport of the
    // GUI (uses its own viewport to be able render on top of all viewports).
    // But since we don't use overlays in the GUI, it doesn't matter.
    // ORXONOX REVERT: Changes are not in place anymore, but might be in the future!
    if (d_render_sys->_getViewport()->getOverlaysEnabled() && !d_quadlist.empty())
    //if (!d_quadlist.empty())
    {
        /// Quad list needs to be sorted and thus the vertex buffer rebuilt. If not, we can
        /// reuse the vertex buffer resulting in a nice speed gain.
        if(!d_sorted)
        {
            sortQuads();
            /// Resize vertex buffer if it is too small
            size_t size = d_buffer->getNumVertices();
            size_t requestedSize = d_quadlist.size()*VERTEX_PER_QUAD;
            if(size < requestedSize)
            {
                /// Double buffer size until smaller than requested size
                while(size < requestedSize)
                    size = size * 2;
                /// Reallocate the buffer
                destroyQuadRenderOp(d_render_op, d_buffer);
                createQuadRenderOp(d_render_op, d_buffer, size);
            }
            else if(requestedSize < size/2 && d_underused_framecount >= UNDERUSED_FRAME_THRESHOLD)
            {
                /// Resize vertex buffer if it has been to big for too long
                size = size / 2;
                destroyQuadRenderOp(d_render_op, d_buffer);
                createQuadRenderOp(d_render_op, d_buffer, size);
                /// Reset underused framecount so it takes another UNDERUSED_FRAME_THRESHOLD to half again
                d_underused_framecount = 0;
            }
            /// Fill the buffer
            QuadVertex* buffmem;
            buffmem = (QuadVertex*)d_buffer->lock(Ogre::HardwareVertexBuffer::HBL_DISCARD);
            // iterate over each quad in the list
            for (QuadList::iterator i = d_quadlist.begin(); i != d_quadlist.end(); ++i)
            {
                const QuadInfo& quad = (*i);
                // setup Vertex 1...
                buffmem->x = quad.position.d_left;
                buffmem->y = quad.position.d_bottom;
                buffmem->z = quad.z;
                buffmem->diffuse = quad.topLeftCol;
                buffmem->tu1 = quad.texPosition.d_left;
                buffmem->tv1 = quad.texPosition.d_bottom;
                ++buffmem;
    
                // setup Vertex 2...
                
                // top-left to bottom-right diagonal
                if (quad.splitMode == TopLeftToBottomRight)
                {
                    buffmem->x = quad.position.d_right;
                    buffmem->y = quad.position.d_bottom;
                    buffmem->z = quad.z;
                    buffmem->diffuse = quad.topRightCol;
                    buffmem->tu1 = quad.texPosition.d_right;
                    buffmem->tv1 = quad.texPosition.d_bottom;
                }
                // bottom-left to top-right diagonal
                else
                {
                    buffmem->x = quad.position.d_right;
                    buffmem->y = quad.position.d_top;
                    buffmem->z = quad.z;
                    buffmem->diffuse = quad.bottomRightCol;
                    buffmem->tu1 = quad.texPosition.d_right;
                    buffmem->tv1 = quad.texPosition.d_top;
                }
                ++buffmem;
    
                // setup Vertex 3...
                buffmem->x = quad.position.d_left;
                buffmem->y = quad.position.d_top;
                buffmem->z = quad.z;
                buffmem->diffuse = quad.bottomLeftCol;
                buffmem->tu1 = quad.texPosition.d_left;
                buffmem->tv1 = quad.texPosition.d_top;
                ++buffmem;
    
                // setup Vertex 4...
                buffmem->x = quad.position.d_right;
                buffmem->y = quad.position.d_bottom;
                buffmem->z = quad.z;
                buffmem->diffuse = quad.topRightCol;
                buffmem->tu1 = quad.texPosition.d_right;
                buffmem->tv1 = quad.texPosition.d_bottom;
                ++buffmem;
    
                // setup Vertex 5...
                buffmem->x = quad.position.d_right;
                buffmem->y = quad.position.d_top;
                buffmem->z = quad.z;
                buffmem->diffuse = quad.bottomRightCol;
                buffmem->tu1 = quad.texPosition.d_right;
                buffmem->tv1 = quad.texPosition.d_top;
                ++buffmem;
    
                // setup Vertex 6...
                
                // top-left to bottom-right diagonal
                if (quad.splitMode == TopLeftToBottomRight)
                {
                    buffmem->x = quad.position.d_left;
                    buffmem->y = quad.position.d_top;
                    buffmem->z = quad.z;
                    buffmem->diffuse = quad.bottomLeftCol;
                    buffmem->tu1 = quad.texPosition.d_left;
                    buffmem->tv1 = quad.texPosition.d_top;
                }
                // bottom-left to top-right diagonal
                else
                {
                    buffmem->x = quad.position.d_left;
                    buffmem->y = quad.position.d_bottom;
                    buffmem->z = quad.z;
                    buffmem->diffuse = quad.topLeftCol;
                    buffmem->tu1 = quad.texPosition.d_left;
                    buffmem->tv1 = quad.texPosition.d_bottom;
                }
                ++buffmem;
            }
    
            // ensure we leave the buffer in the unlocked state
            d_buffer->unlock();
        }
        
        /// Render the buffer
        d_bufferPos = 0;
        bool first = true;

        // Iterate over each quad in the list and render it
        QuadList::iterator i = d_quadlist.begin();
        while(i != d_quadlist.end())
        {
            
            d_currTexture = i->texture;
            d_render_op.vertexData->vertexStart = d_bufferPos;
            for (; i != d_quadlist.end(); ++i)
            {
                const QuadInfo& quad = (*i);
                if (d_currTexture != quad.texture)
                {
                    /// If it has a different texture, render this quad in next operation
                    /// also need to reset render states
                    first = true;
                    break;
                }
                d_bufferPos += VERTEX_PER_QUAD;
            }
            d_render_op.vertexData->vertexCount = d_bufferPos - d_render_op.vertexData->vertexStart;
            /// Set texture, and do the render
            d_render_sys->_setTexture(0, true, d_currTexture);
            if (first)
            {
                initRenderStates();
                first = false;
            }
            d_render_sys->_render(d_render_op);
        }

    }
    /// Count frames to check if utilization of vertex buffer was below half the capacity for 500,000 frames
    if(d_bufferPos < d_buffer->getNumVertices()/2)
       d_underused_framecount++;
    else
       d_underused_framecount = 0;
}


/*************************************************************************
    clear the queue
*************************************************************************/
void OgreCEGUIRenderer::clearRenderList(void)
{
    d_sorted = true;
    d_quadlist.clear();
}


/*************************************************************************
    create an empty texture
*************************************************************************/
Texture* OgreCEGUIRenderer::createTexture(void)
{
    OgreCEGUITexture* tex = new OgreCEGUITexture(this);
    d_texturelist.push_back(tex);
    return tex;
}


/*************************************************************************
    create a texture and load it with the specified file.
*************************************************************************/
Texture* OgreCEGUIRenderer::createTexture(const String& filename, const String& resourceGroup)
{
    OgreCEGUITexture* tex = (OgreCEGUITexture*)createTexture();
    tex->loadFromFile(filename, resourceGroup);

    return tex;
}


/*************************************************************************
    create a texture and set it to the specified size
*************************************************************************/
Texture* OgreCEGUIRenderer::createTexture(float size)
{
    OgreCEGUITexture* tex = (OgreCEGUITexture*)createTexture();
    tex->setOgreTextureSize((uint)size);

    return tex;
}


/*************************************************************************
    destroy the given texture
*************************************************************************/
void OgreCEGUIRenderer::destroyTexture(Texture* texture)
{
    if (texture != NULL)
    {
        OgreCEGUITexture* tex = (OgreCEGUITexture*)texture;

        d_texturelist.remove(tex);
        delete tex;
    }
}


/*************************************************************************
    destroy all textures still active
*************************************************************************/
void OgreCEGUIRenderer::destroyAllTextures(void)
{
    while (!d_texturelist.empty())
    {
        destroyTexture(*(d_texturelist.begin()));
    }
}


/*************************************************************************
    setup states etc    
*************************************************************************/
void OgreCEGUIRenderer::initRenderStates(void)
{
    using namespace Ogre;

    // set-up matrices
    d_render_sys->_setWorldMatrix(Matrix4::IDENTITY);
    d_render_sys->_setViewMatrix(Matrix4::IDENTITY);
    d_render_sys->_setProjectionMatrix(Matrix4::IDENTITY);

    // initialise render settings
    d_render_sys->setLightingEnabled(false);
    d_render_sys->_setDepthBufferParams(false, false);
    d_render_sys->_setDepthBias(0, 0);
    d_render_sys->_setCullingMode(CULL_NONE);
    d_render_sys->_setFog(FOG_NONE);
    d_render_sys->_setColourBufferWriteEnabled(true, true, true, true);
    d_render_sys->unbindGpuProgram(GPT_FRAGMENT_PROGRAM);
    d_render_sys->unbindGpuProgram(GPT_VERTEX_PROGRAM);
    d_render_sys->setShadingType(SO_GOURAUD);
    d_render_sys->_setPolygonMode(PM_SOLID);

    // initialise texture settings
    d_render_sys->_setTextureCoordCalculation(0, TEXCALC_NONE);
    d_render_sys->_setTextureCoordSet(0, 0);
    d_render_sys->_setTextureUnitFiltering(0, FO_LINEAR, FO_LINEAR, FO_POINT);
    d_render_sys->_setTextureAddressingMode(0, d_uvwAddressMode);
    d_render_sys->_setTextureMatrix(0, Matrix4::IDENTITY);
    d_render_sys->_setAlphaRejectSettings(CMPF_ALWAYS_PASS, 0);
    d_render_sys->_setTextureBlendMode(0, d_colourBlendMode);
    d_render_sys->_setTextureBlendMode(0, d_alphaBlendMode);
    d_render_sys->_disableTextureUnitsFrom(1);

    // enable alpha blending
    d_render_sys->_setSceneBlending(SBF_SOURCE_ALPHA, SBF_ONE_MINUS_SOURCE_ALPHA);
}


 
/*************************************************************************
    sort quads list according to texture        
*************************************************************************/
void OgreCEGUIRenderer::sortQuads(void)
{
    if (!d_sorted)
    {
        d_sorted = true;
    }

}

/*************************************************************************
render a quad directly to the display
*************************************************************************/
void OgreCEGUIRenderer::renderQuadDirect(const Rect& dest_rect, float z, const Texture* tex, const Rect& texture_rect, const ColourRect& colours, QuadSplitMode quad_split_mode)
{
    // ORXONOX CHANGE: Even render when OverlaysEnabled is deactivated
    // The reason is that we don't want the HUD to be shown in the viewport of the
    // GUI (uses its own viewport to be able render on top of all viewports).
    // But since we don't use overlays in the GUI, it doesn't matter.
    // ORXONOX REVERT: Changes are not in place anymore, but might be in the future!
    if (d_render_sys->_getViewport()->getOverlaysEnabled())
    //if (true)
    {
        z = -1 + z;

        Rect final_rect;

        // set quad position, flipping y co-ordinates, and applying appropriate texel origin offset
        final_rect.d_left       = dest_rect.d_left;
        final_rect.d_right      = dest_rect.d_right;
        final_rect.d_top        = d_display_area.getHeight() - dest_rect.d_top;
        final_rect.d_bottom     = d_display_area.getHeight() - dest_rect.d_bottom;
        final_rect.offset(d_texelOffset);

        // convert quad co-ordinates for a -1 to 1 co-ordinate system.
        final_rect.d_left       /= (d_display_area.getWidth() * 0.5f);
        final_rect.d_right      /= (d_display_area.getWidth() * 0.5f);
        final_rect.d_top        /= (d_display_area.getHeight() * 0.5f);
        final_rect.d_bottom     /= (d_display_area.getHeight() * 0.5f);
        final_rect.offset(Point(-1.0f, -1.0f));

        // convert colours for ogre, note that top / bottom are switched.
        uint32 topLeftCol       = colourToOgre(colours.d_bottom_left);
        uint32 topRightCol      = colourToOgre(colours.d_bottom_right);
        uint32 bottomLeftCol    = colourToOgre(colours.d_top_left);
        uint32 bottomRightCol= colourToOgre(colours.d_top_right);

        QuadVertex*     buffmem = (QuadVertex*)d_direct_buffer->lock(Ogre::HardwareVertexBuffer::HBL_DISCARD);

        // setup Vertex 1...
        buffmem->x      = final_rect.d_left;
        buffmem->y      = final_rect. d_bottom;
        buffmem->z      = z;
        buffmem->diffuse = topLeftCol;
        buffmem->tu1    = texture_rect.d_left;
        buffmem->tv1    = texture_rect.d_bottom;
        ++buffmem;

        // setup Vertex 2...
        
        // top-left to bottom-right diagonal
        if (quad_split_mode == TopLeftToBottomRight)
        {
            buffmem->x  = final_rect.d_right;
            buffmem->y = final_rect.d_bottom;
            buffmem->z  = z;
            buffmem->diffuse = topRightCol;
            buffmem->tu1        = texture_rect.d_right;
            buffmem->tv1        = texture_rect.d_bottom;
            ++buffmem;
        }
        // bottom-left to top-right diagonal
        else
        {
            buffmem->x  = final_rect.d_right;
            buffmem->y = final_rect.d_top;
            buffmem->z  = z;
            buffmem->diffuse = bottomRightCol;
            buffmem->tu1        = texture_rect.d_right;
            buffmem->tv1        = texture_rect.d_top;
            ++buffmem;
        }

        // setup Vertex 3...
        buffmem->x      = final_rect.d_left;
        buffmem->y      = final_rect.d_top;
        buffmem->z      = z;
        buffmem->diffuse = bottomLeftCol;
        buffmem->tu1    = texture_rect.d_left;
        buffmem->tv1    = texture_rect.d_top;
        ++buffmem;

        // setup Vertex 4...
        buffmem->x      = final_rect.d_right;
        buffmem->y      = final_rect.d_bottom;
        buffmem->z      = z;
        buffmem->diffuse = topRightCol;
        buffmem->tu1    = texture_rect.d_right;
        buffmem->tv1    = texture_rect.d_bottom;
        ++buffmem;

        // setup Vertex 5...
        buffmem->x      = final_rect.d_right;
        buffmem->y      = final_rect.d_top;
        buffmem->z      = z;
        buffmem->diffuse = bottomRightCol;
        buffmem->tu1    = texture_rect.d_right;
        buffmem->tv1    = texture_rect.d_top;
        ++buffmem;

        // setup Vertex 6...
        
        // top-left to bottom-right diagonal
        if (quad_split_mode == TopLeftToBottomRight)
        {
            buffmem->x  = final_rect.d_left;
            buffmem->y = final_rect.d_top;
            buffmem->z  = z;
            buffmem->diffuse = bottomLeftCol;
            buffmem->tu1        = texture_rect.d_left;
            buffmem->tv1        = texture_rect.d_top;
        }
        // bottom-left to top-right diagonal
        else
        {
            buffmem->x  = final_rect.d_left;
            buffmem->y = final_rect.d_bottom;
            buffmem->z  = z;
            buffmem->diffuse = topLeftCol;
            buffmem->tu1        = texture_rect.d_left;
            buffmem->tv1        = texture_rect.d_bottom;
        }

        d_direct_buffer->unlock();

        //
        // perform rendering...
        //
        d_render_sys->_setTexture(0, true, ((OgreCEGUITexture*)tex)->getOgreTexture()->getName());
        initRenderStates();
        d_direct_render_op.vertexData->vertexCount = VERTEX_PER_QUAD;
        d_render_sys->_render(d_direct_render_op);
    }

}

/*************************************************************************
    convert ARGB colour value to whatever the Ogre render system is
    expecting.  
*************************************************************************/
uint32 OgreCEGUIRenderer::colourToOgre(const colour& col) const
{
    Ogre::ColourValue cv(col.getRed(), col.getGreen(), col.getBlue(), col.getAlpha());

    uint32 final;
    d_render_sys->convertColourValue(cv, &final);

    return final;
}


/*************************************************************************
    Set the scene manager to be used for rendering the GUI.     
*************************************************************************/
void OgreCEGUIRenderer::setTargetSceneManager(Ogre::SceneManager* scene_manager)
{
    // unhook from current scene manager.
    if (d_sceneMngr != NULL)
    {
        d_sceneMngr->removeRenderQueueListener(d_ourlistener);
        d_sceneMngr = NULL;
    }

    // hook new scene manager if that is not NULL
    if (scene_manager != NULL)
    {
        d_sceneMngr = scene_manager;
        d_sceneMngr->addRenderQueueListener(d_ourlistener);
    }

}


/*************************************************************************
    Set the target render queue for GUI rendering.      
*************************************************************************/
void OgreCEGUIRenderer::setTargetRenderQueue(Ogre::uint8 queue_id, bool post_queue)
{
    d_queue_id          = queue_id;
    d_post_queue        = post_queue;

    if (d_ourlistener != NULL)
    {
        d_ourlistener->setTargetRenderQueue(queue_id);
        d_ourlistener->setPostRenderQueue(post_queue);
    }

}


/*************************************************************************
    perform main work of the constructor
*************************************************************************/
void OgreCEGUIRenderer::constructor_impl(Ogre::RenderWindow* window, Ogre::uint8 queue_id, bool post_queue, uint max_quads)
{
    using namespace Ogre;

    // initialise the renderer fields
    d_queueing          = true;
    d_queue_id          = queue_id;
    d_currTexture.isNull();
    d_post_queue        = post_queue;
    d_sceneMngr         = NULL;
    d_bufferPos         = 0;
    d_sorted            = true;
    d_ogre_root         = Root::getSingletonPtr();
    d_render_sys        = d_ogre_root->getRenderSystem();
    // set ID string
    d_identifierString = "CEGUI::OgreRenderer - Official Ogre based renderer module for CEGUI";

    // Create and initialise the Ogre specific parts required for use in rendering later.
    // Main GUI
    createQuadRenderOp(d_render_op, d_buffer, VERTEXBUFFER_INITIAL_CAPACITY);
    d_underused_framecount = 0;

    // Mouse cursor
    createQuadRenderOp(d_direct_render_op, d_direct_buffer, VERTEX_PER_QUAD);

    // Discover display settings and setup d_display_area
    d_display_area.d_left       = 0;
    d_display_area.d_top        = 0;
    d_display_area.d_right      = window->getWidth();
    d_display_area.d_bottom     = window->getHeight();

    // initialise required texel offset
    d_texelOffset = Point((float)d_render_sys->getHorizontalTexelOffset(), -(float)d_render_sys->getVerticalTexelOffset());

    // create listener which will handler the rendering side of things for us.
    d_ourlistener = new CEGUIRQListener(this, queue_id, post_queue);

    // Initialise blending modes to be used.
    d_colourBlendMode.blendType = Ogre::LBT_COLOUR;
    d_colourBlendMode.source1   = Ogre::LBS_TEXTURE;
    d_colourBlendMode.source2   = Ogre::LBS_DIFFUSE;
    d_colourBlendMode.operation = Ogre::LBX_MODULATE;

    d_alphaBlendMode.blendType  = Ogre::LBT_ALPHA;
    d_alphaBlendMode.source1    = Ogre::LBS_TEXTURE;
    d_alphaBlendMode.source2    = Ogre::LBS_DIFFUSE;
    d_alphaBlendMode.operation  = Ogre::LBX_MODULATE;

    d_uvwAddressMode.u = Ogre::TextureUnitState::TAM_CLAMP;
    d_uvwAddressMode.v = Ogre::TextureUnitState::TAM_CLAMP;
    d_uvwAddressMode.w = Ogre::TextureUnitState::TAM_CLAMP;
}


/*************************************************************************
    Create a texture from an existing Ogre::TexturePtr object   
*************************************************************************/
Texture* OgreCEGUIRenderer::createTexture(Ogre::TexturePtr& texture)
{
    OgreCEGUITexture* t = (OgreCEGUITexture*)createTexture();

    if (!texture.isNull())
    {
        t->setOgreTexture(texture);
    }

    return t;

}

/*************************************************************************
    Create a resource provider object
*************************************************************************/
ResourceProvider* OgreCEGUIRenderer::createResourceProvider(void)
{
    d_resourceProvider = new OgreCEGUIResourceProvider();
    return d_resourceProvider;
}

/*************************************************************************
Set the size of the display in pixels.  
*************************************************************************/
void OgreCEGUIRenderer::setDisplaySize(const Size& sz)
{
    if (d_display_area.getSize() != sz)
    {
        d_display_area.setSize(sz);

        EventArgs args;
        fireEvent(EventDisplaySizeChanged, args, EventNamespace);
    }

}

/*************************************************************************
    Callback from Ogre invoked before other stuff in our target queue
    is rendered
*************************************************************************/
void CEGUIRQListener::renderQueueStarted(Ogre::uint8 id, const Ogre::String& invocation, 
                                         bool& skipThisQueue)
{
    if ((!d_post_queue) && (d_queue_id == id))
    {
        CEGUI::System::getSingleton().renderGUI();
    }

}


/*************************************************************************
Callback from Ogre invoked after other stuff in our target queue
is rendered
*************************************************************************/
void CEGUIRQListener::renderQueueEnded(Ogre::uint8 id, const Ogre::String& invocation, bool& repeatThisQueue)
{
    if ((d_post_queue) && (d_queue_id == id))
    {
        CEGUI::System::getSingleton().renderGUI();
    }

}

} // End of  CEGUI namespace section