/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2005 The OGRE Team
Also see acknowledgements in Readme.html

This program 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 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.
-----------------------------------------------------------------------------
*/
#include "OgreStableHeaders.h"

#include "OgreException.h"
#include "OgreLogManager.h"
#include "OgreRoot.h"
#include "OgreStringConverter.h"

#include "OgreGLRenderSystem.h"

#include "OgreGLXUtils.h"

#include <GL/glxext.h>

namespace Ogre {
    struct visual_attribs
    {
       /* X visual attribs */
       int id;
       int klass;
       int depth;
       int redMask, greenMask, blueMask;
       int colormapSize;
       int bitsPerRGB;
    
       /* GL visual attribs */
       int supportsGL;
       int transparentType;
       int transparentRedValue;
       int transparentGreenValue;
       int transparentBlueValue;
       int transparentAlphaValue;
       int transparentIndexValue;
       int bufferSize;
       int level;
       int rgba;
       int doubleBuffer;
       int stereo;
       int auxBuffers;
       int redSize, greenSize, blueSize, alphaSize;
       int depthSize;
       int stencilSize;
       int accumRedSize, accumGreenSize, accumBlueSize, accumAlphaSize;
       int numSamples, numMultisample;
       int visualCaveat;
    };
   
   
   
    FBConfigData::FBConfigData():
        configID(0), visualID(0), bufferSize(0), level(0), doubleBuffer(0), stereo(0),
        auxBuffers(0), renderType(0),
        redSize(0), greenSize(0), blueSize(0), alphaSize(0),
        depthSize(0), stencilSize(0),
        accumRedSize(0), accumGreenSize(0), accumBlueSize(0), accumAlphaSize(0),      
        drawableType(0), caveat(0),
        maxPBufferWidth(0), maxPBufferHeight(0), maxPBufferPixels(0)
    {
        memset(this, 0, sizeof(FBConfigData));
    }
    FBConfigData::FBConfigData(Display *dpy, GLXFBConfig config)
    {
        memset(this, 0, sizeof(FBConfigData));
        
        glXGetFBConfigAttrib(dpy, config, GLX_FBCONFIG_ID, &configID);
        glXGetFBConfigAttrib(dpy, config, GLX_VISUAL_ID, &visualID);
        glXGetFBConfigAttrib(dpy, config, GLX_BUFFER_SIZE, &bufferSize);
        glXGetFBConfigAttrib(dpy, config, GLX_LEVEL, &level);
        glXGetFBConfigAttrib(dpy, config, GLX_DOUBLEBUFFER, &doubleBuffer);
        glXGetFBConfigAttrib(dpy, config, GLX_STEREO, &stereo);
        glXGetFBConfigAttrib(dpy, config, GLX_AUX_BUFFERS, &auxBuffers);
        glXGetFBConfigAttrib(dpy, config, GLX_RENDER_TYPE, &renderType);
        glXGetFBConfigAttrib(dpy, config, GLX_RED_SIZE, &redSize);
        glXGetFBConfigAttrib(dpy, config, GLX_GREEN_SIZE, &greenSize);
        glXGetFBConfigAttrib(dpy, config, GLX_BLUE_SIZE, &blueSize);
        glXGetFBConfigAttrib(dpy, config, GLX_ALPHA_SIZE, &alphaSize);
        glXGetFBConfigAttrib(dpy, config, GLX_DEPTH_SIZE, &depthSize);
        glXGetFBConfigAttrib(dpy, config, GLX_STENCIL_SIZE, &stencilSize);
        glXGetFBConfigAttrib(dpy, config, GLX_ACCUM_RED_SIZE, &accumRedSize);
        glXGetFBConfigAttrib(dpy, config, GLX_ACCUM_GREEN_SIZE, &accumGreenSize);
        glXGetFBConfigAttrib(dpy, config, GLX_ACCUM_BLUE_SIZE, &accumBlueSize);
        glXGetFBConfigAttrib(dpy, config, GLX_ACCUM_ALPHA_SIZE, &accumAlphaSize);
        glXGetFBConfigAttrib(dpy, config, GLX_DRAWABLE_TYPE, &drawableType);
        glXGetFBConfigAttrib(dpy, config, GLX_CONFIG_CAVEAT, &caveat);
        glXGetFBConfigAttrib(dpy, config, GLX_MAX_PBUFFER_WIDTH, &maxPBufferWidth);
        glXGetFBConfigAttrib(dpy, config, GLX_MAX_PBUFFER_HEIGHT, &maxPBufferHeight);
        glXGetFBConfigAttrib(dpy, config, GLX_MAX_PBUFFER_PIXELS, &maxPBufferPixels);
    }
    String FBConfigData::toString() const
    {
        std::stringstream ss;
        ss << "configID=" << configID;
        ss << " visualID=" << visualID;
        ss << " bufferSize=" << bufferSize;
        ss << " level=" << level;
        ss << " doubleBuffer=" << doubleBuffer;
        ss << " stereo=" << stereo;
        ss << " auxBuffers=" << auxBuffers;
        ss << " renderType=" << renderType;
        ss << " redSize=" << redSize;
        ss << " greenSize=" << greenSize;
        ss << " blueSize=" << blueSize;
        ss << " alphaSize=" << alphaSize;
        ss << " depthSize=" << depthSize;
        ss << " stencilSize=" << stencilSize;
        ss << " accumRedSize=" << accumRedSize;
        ss << " accumGreenSize=" << accumGreenSize;
        ss << " accumBlueSize=" << accumBlueSize;
        ss << " accumAlphaSize=" << accumAlphaSize;
        ss << " drawableType=" << drawableType;
        ss << " caveat=" << caveat;
        ss << " maxPBufferWidth=" << maxPBufferWidth;
        ss << " maxPBufferHeight=" << maxPBufferHeight;
        ss << " maxPBufferPixels=" << maxPBufferPixels;
        return ss.str();
    }
    
    bool GLXUtils::LoadIcon(Display *mDisplay, Window rootWindow, const std::string &name, Pixmap *pix, Pixmap *mask) 
    {
     Image img;
     int mWidth, mHeight;
       char *data, *bitmap;
       try {
          // Try to load image
           img.load(name, ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME);
         mWidth = img.getWidth();
           mHeight = img.getHeight();
         if(img.getFormat() != PF_A8R8G8B8)
             // Image format must be RGBA
               return 0;
      } catch(Exception &e) {
            // Could not find image; never mind
            return false;
      }
    
     // Allocate space for image data
       data = (char*)malloc(mWidth * mHeight * 4); // Must be allocated with malloc
       // Allocate space for transparency bitmap
      int wbits = (mWidth+7)/8;
      bitmap = (char*)malloc(wbits * mHeight);
    
      // Convert and copy image
      const char *imgdata = (const char*)img.getData();
      int sptr = 0, dptr = 0;
        for(int y=0; y<mHeight; y++) {
         for(int x=0; x<mWidth; x++) {
              data[dptr + 0] = 0;
                data[dptr + 1] = imgdata[sptr + 0];
                data[dptr + 2] = imgdata[sptr + 1];
                data[dptr + 3] = imgdata[sptr + 2];
                // Alpha threshold
             if(((unsigned char)imgdata[sptr + 3])<128) {
                   bitmap[y*wbits+(x>>3)] &= ~(1<<(x&7));
             } else {
                   bitmap[y*wbits+(x>>3)] |= 1<<(x&7);
                }
              sptr += 4;
             dptr += 4;
         }
      }
    
     /* put my pixmap data into the client side X image data structure */
       XImage *image = XCreateImage (mDisplay, NULL, 24, ZPixmap, 0,
                                    data,
                                      mWidth, mHeight, 8,
                                    mWidth*4);
       image->byte_order = MSBFirst; // 0RGB format
    
      /* tell server to start managing my pixmap */
      Pixmap retval = XCreatePixmap(mDisplay, rootWindow, mWidth,
                                      mHeight, 24);
    
       /* copy from client to server */
       GC context = XCreateGC (mDisplay, rootWindow, 0, NULL);
        XPutImage(mDisplay, retval, context, image, 0, 0, 0, 0,
                  mWidth, mHeight);
    
       /* free up the client side pixmap data area */
     XDestroyImage(image); // also cleans data
      XFreeGC(mDisplay, context);
    
       *pix = retval;
     *mask = XCreateBitmapFromData(mDisplay, rootWindow, bitmap, mWidth, mHeight);
      free(bitmap);
      return true;
    }


    
    static void
    get_visual_attribs(Display *dpy, XVisualInfo *vInfo,
                       struct visual_attribs *attribs) 
    {
     const char *ext = glXQueryExtensionsString(dpy, vInfo->screen);
    
       memset(attribs, 0, sizeof(struct visual_attribs));
    
        attribs->id = vInfo->visualid;
    #if defined(__cplusplus) || defined(c_plusplus)
    
        attribs->klass = vInfo->c_class;
    #else
    
        attribs->klass = vInfo->class;
    #endif
    
     attribs->depth = vInfo->depth;
     attribs->redMask = vInfo->red_mask;
        attribs->greenMask = vInfo->green_mask;
        attribs->blueMask = vInfo->blue_mask;
      attribs->colormapSize = vInfo->colormap_size;
      attribs->bitsPerRGB = vInfo->bits_per_rgb;
    
        if (glXGetConfig(dpy, vInfo, GLX_USE_GL, &attribs->supportsGL) != 0)
           return;
        glXGetConfig(dpy, vInfo, GLX_BUFFER_SIZE, &attribs->bufferSize);
       glXGetConfig(dpy, vInfo, GLX_LEVEL, &attribs->level);
      glXGetConfig(dpy, vInfo, GLX_RGBA, &attribs->rgba);
        glXGetConfig(dpy, vInfo, GLX_DOUBLEBUFFER, &attribs->doubleBuffer);
        glXGetConfig(dpy, vInfo, GLX_STEREO, &attribs->stereo);
        glXGetConfig(dpy, vInfo, GLX_AUX_BUFFERS, &attribs->auxBuffers);
       glXGetConfig(dpy, vInfo, GLX_RED_SIZE, &attribs->redSize);
     glXGetConfig(dpy, vInfo, GLX_GREEN_SIZE, &attribs->greenSize);
     glXGetConfig(dpy, vInfo, GLX_BLUE_SIZE, &attribs->blueSize);
       glXGetConfig(dpy, vInfo, GLX_ALPHA_SIZE, &attribs->alphaSize);
     glXGetConfig(dpy, vInfo, GLX_DEPTH_SIZE, &attribs->depthSize);
     glXGetConfig(dpy, vInfo, GLX_STENCIL_SIZE, &attribs->stencilSize);
     glXGetConfig(dpy, vInfo, GLX_ACCUM_RED_SIZE, &attribs->accumRedSize);
      glXGetConfig(dpy, vInfo, GLX_ACCUM_GREEN_SIZE, &attribs->accumGreenSize);
      glXGetConfig(dpy, vInfo, GLX_ACCUM_BLUE_SIZE, &attribs->accumBlueSize);
        glXGetConfig(dpy, vInfo, GLX_ACCUM_ALPHA_SIZE, &attribs->accumAlphaSize);
    
     /* get transparent pixel stuff */
      glXGetConfig(dpy, vInfo,GLX_TRANSPARENT_TYPE, &attribs->transparentType);
      if (attribs->transparentType == GLX_TRANSPARENT_RGB) {
         glXGetConfig(dpy, vInfo, GLX_TRANSPARENT_RED_VALUE, &attribs->transparentRedValue);
            glXGetConfig(dpy, vInfo, GLX_TRANSPARENT_GREEN_VALUE, &attribs->transparentGreenValue);
            glXGetConfig(dpy, vInfo, GLX_TRANSPARENT_BLUE_VALUE, &attribs->transparentBlueValue);
          glXGetConfig(dpy, vInfo, GLX_TRANSPARENT_ALPHA_VALUE, &attribs->transparentAlphaValue);
        } else if (attribs->transparentType == GLX_TRANSPARENT_INDEX) {
            glXGetConfig(dpy, vInfo, GLX_TRANSPARENT_INDEX_VALUE, &attribs->transparentIndexValue);
        }
    
     /* multisample attribs */
       if (ext && strstr("GLX_ARB_multisample", ext) == 0) {
          	glXGetConfig(dpy, vInfo, GLX_SAMPLE_BUFFERS_ARB, &attribs->numMultisample);
            glXGetConfig(dpy, vInfo, GLX_SAMPLES_ARB, &attribs->numSamples);
       }
       else {
         attribs->numSamples = 0;
           attribs->numMultisample = 0;
       }
    
      if (ext && strstr(ext, "GLX_EXT_visual_rating")) {
         glXGetConfig(dpy, vInfo, GLX_VISUAL_CAVEAT_EXT, &attribs->visualCaveat);
       } else {
           attribs->visualCaveat = GLX_NONE_EXT;
      }
    }
    
    /*
     * Examine all visuals to find the so-called best one.
     * We prefer deepest RGBA buffer with depth, stencil and accum
     * that has no caveats.
     * @author Brian Paul (from the glxinfo source)
     */
    int GLXUtils::findBestVisual(Display *dpy, int scrnum, int multiSample) 
    {
        XVisualInfo theTemplate;
       XVisualInfo *visuals;
      int numVisuals;
        long mask;
     int i;
     struct visual_attribs bestVis;
	 int msDiff;
    
        /* get list of all visuals on this screen */
       theTemplate.screen = scrnum;
       mask = VisualScreenMask;
       visuals = XGetVisualInfo(dpy, mask, &theTemplate, &numVisuals);
        if(numVisuals == 0 || visuals == 0) {
          /* something went wrong */
         if(visuals)
                XFree(visuals);
            return -1;
     }
    
     /* init bestVis with first visual info */
      get_visual_attribs(dpy, &visuals[0], &bestVis);
    
       /* try to find a "better" visual */
        for (i = 1; i < numVisuals; i++) {
         struct visual_attribs vis;
    
            get_visual_attribs(dpy, &visuals[i], &vis);
    
           	/* always skip visuals that are slow */
         	if (vis.visualCaveat == GLX_SLOW_VISUAL_EXT)
         	    continue;
		 	/* skip visual if it doesn't have the desired number of multisamples */
			if (multiSample != -1 && vis.numSamples != multiSample)
			   continue;
    
         /* see if this vis is better than bestVis */
		   
           if ((!bestVis.supportsGL && vis.supportsGL) ||
                         (bestVis.visualCaveat != GLX_NONE_EXT) ||
                          (!bestVis.rgba && vis.rgba) ||
                         (!bestVis.doubleBuffer && vis.doubleBuffer) ||
                         (bestVis.redSize < vis.redSize) ||
                         (bestVis.greenSize < vis.greenSize) ||
                         (bestVis.blueSize < vis.blueSize) ||
                           (bestVis.alphaSize < vis.alphaSize) ||
                         (bestVis.depthSize < vis.depthSize) ||
                         (bestVis.stencilSize < vis.stencilSize) ||
                         (bestVis.accumRedSize < vis.accumRedSize)) 
			{
               /* found a better visual */
                bestVis = vis;
			}
         
      }
    
     XFree(visuals);
    	if (multiSample != -1 && bestVis.numSamples != multiSample)
			// We found no visual with the desired FSAA
			return -1;
       return bestVis.id;
    }

    /**
     * Class to sort FBConfig records by best match
     */
    class FBConfigMatchSort
    {
    public:
        FBConfigMatchSort(Display *dpy, const int *idealattribs): dpy(dpy), mIdeal(idealattribs) { }
        
        Display *dpy;
        const int *mIdeal;
        bool operator()(const GLXFBConfig & a, const GLXFBConfig & b)
        {
            for(int idx = 0; mIdeal[idx] != None; idx += 2)
            {
                int valuea, valueb;
                int valueideal = mIdeal[idx+1];
                glXGetFBConfigAttrib(dpy, a, mIdeal[idx], &valuea);
                glXGetFBConfigAttrib(dpy, b, mIdeal[idx], &valueb);
                // Distance to a smaller than distance to b?
                if(std::abs(valuea - valueideal) < std::abs(valueb - valueideal))
                    return true;
            }
            return false;
        }
    };


    GLXFBConfig GLXUtils::findBestMatch(Display *dpy, int scrnum, const int *attribs, const int *idealattribs)
    {
        // Create vector of existing config data formats        
        GLXFBConfig * fbConfigs;
        int nConfigs;
        fbConfigs = glXChooseFBConfig(dpy, scrnum, attribs, &nConfigs);
        if (nConfigs == 0 || !fbConfigs) 
            OGRE_EXCEPT(Exception::UNIMPLEMENTED_FEATURE, "glXChooseFBConfig() failed: Couldn't find a suitable pixel format", "GLRenderTexture::createPBuffer");

        // Sort by best match
        std::sort(fbConfigs, fbConfigs+nConfigs, FBConfigMatchSort(dpy, idealattribs));
        
        GLXFBConfig retval = fbConfigs[0];
        XFree(fbConfigs);
        
        return retval;
    }

};