1.1 --- a/MiniDisplay/FutabaVfd.cpp	Fri May 30 10:56:20 2014 +0200
     1.2 +++ b/MiniDisplay/FutabaVfd.cpp	Fri May 30 13:45:14 2014 +0200
     1.3 @@ -4,6 +4,11 @@
     1.4  #include <string.h>
     1.5  
     1.6  
     1.7 +#ifdef DEBUG_FRAME_DIFF
     1.8 +#include <QImage>
     1.9 +#include <QTextStream>
    1.10 +#endif
    1.11 +
    1.12  //
    1.13  //
    1.14  //
    1.15 @@ -378,7 +383,7 @@
    1.16          if (iNeedFullFrameUpdate<3)
    1.17              {
    1.18              //TODO: enable this once SendModifiedPixelBlocks works
    1.19 -            //iNeedFullFrameUpdate++;
    1.20 +            iNeedFullFrameUpdate++;
    1.21              SetPixelBlock(0,0,63,FrameBufferSizeInBytes(),iFrameNext->Ptr());
    1.22              }
    1.23          else
    1.24 @@ -387,14 +392,18 @@
    1.25              }
    1.26  		//Swap device front and back buffer
    1.27  		SetDisplayPosition(iDisplayPositionX,OffScreenY());
    1.28 -		//Swap host buffers
    1.29 -        //BitArray* nextFrame=iFrameNext;
    1.30 -        //iFrameCurrent = iFramePrevious;
    1.31 -        //iFrameNext = iFramePrevious;
    1.32  
    1.33 +        //Cycle through our frame buffers
    1.34 +        //We keep track of previous frame which is in fact our device back buffer.
    1.35 +        //We can then compare previous and next frame and send only the differences to our device.
    1.36 +        //This mechanism allows us to reduce traffic over our USB bus thus improving our frame rate from 14 FPS to 30 FPS.
    1.37 +        //Keep our previous frame pointer
    1.38          BitArray* previousFrame=iFramePrevious;
    1.39 +        //Current frame becomes the previous one
    1.40          iFramePrevious = iFrameCurrent;
    1.41 +        //Next frame becomes the current one
    1.42          iFrameCurrent = iFrameNext;
    1.43 +        //Next frame is now our former previous
    1.44          iFrameNext = previousFrame;
    1.45  		}
    1.46  	}
    1.47 @@ -414,10 +423,10 @@
    1.48      int w=WidthInPixels();
    1.49      int h=HeightInPixels();
    1.50  
    1.51 -    BitArray block(16*16);
    1.52  
    1.53  
    1.54      //TODO: optimize with memcmp and 16 inc
    1.55 +    /*
    1.56      for (int i=0;i<w;i++)
    1.57          {
    1.58          for (int j=0;j<h;j++)
    1.59 @@ -434,34 +443,61 @@
    1.60                  }
    1.61              }
    1.62          }
    1.63 +    */
    1.64  
    1.65 -    /*
    1.66 +    BitArray nextBlock(16*16);
    1.67 +    BitArray previousBlock(16*16);
    1.68 +
    1.69      for (int i=0;i<w;i+=16)
    1.70          {
    1.71          for (int j=0;j<h;j+=16)
    1.72              {
    1.73              //aX*HeightInPixels()+aY
    1.74 -            int offset=(i*w/8)+(j/8);
    1.75 -            if (memcmp(iNextFrame->Ptr()+offset,iCurrentFrame->Ptr()+offset,32 )) //32=(16*16/8)
    1.76 +            //int offset=(i*w/8)+(j/8);
    1.77 +
    1.78 +#ifdef DEBUG_FRAME_DIFF
    1.79 +            QImage imagePrevious(16,16,QImage::Format_RGB32);
    1.80 +            QImage imageNext(16,16,QImage::Format_RGB32);
    1.81 +#endif
    1.82 +
    1.83 +            //Get both our blocks from our buffers
    1.84 +            for (int x=i;x<i+16;x++)
    1.85 +                {
    1.86 +                for (int y=j;y<j+16;y++)
    1.87 +                    {
    1.88 +                    nextBlock.SetBitValue((x-i)*16+(y-j),(*iFrameNext)[x*h+y]);
    1.89 +                    previousBlock.SetBitValue((x-i)*16+(y-j),(*iFramePrevious)[x*h+y]);
    1.90 +
    1.91 +#ifdef DEBUG_FRAME_DIFF
    1.92 +                    imageNext.setPixel(x-i,y-j,(nextBlock[(x-i)*16+(y-j)]?0xFFFFFFFF:0x00000000));
    1.93 +                    imagePrevious.setPixel(x-i,y-j,(previousBlock[(x-i)*16+(y-j)]?0xFFFFFFFF:0x00000000));
    1.94 +#endif
    1.95 +                    }
    1.96 +                }
    1.97 +
    1.98 +#ifdef DEBUG_FRAME_DIFF
    1.99 +            QString previousName;
   1.100 +            QString nextName;
   1.101 +            QTextStream(&previousName) << "p" << i << "x" << j << ".png";
   1.102 +            QTextStream(&nextName) << "n" << i << "x" << j << ".png";
   1.103 +            imagePrevious.save(previousName);
   1.104 +            imageNext.save(nextName);
   1.105 +#endif
   1.106 +
   1.107 +
   1.108 +            //if (memcmp(iFrameNext->Ptr()+offset,iFramePrevious->Ptr()+offset,32 )) //32=(16*16/8)
   1.109 +            if (memcmp(nextBlock.Ptr(),previousBlock.Ptr(),32 )!=0) //32=(16*16/8)
   1.110                  {
   1.111                  //We need to update that block
   1.112 -
   1.113 -                for (int x=i;x<i+16;x++)
   1.114 -                    {
   1.115 -                    for (int y=i;y<j+16;y++)
   1.116 -                        {
   1.117 -                        block.SetBitValue((x-i)*h+(y-j),(*iNextFrame)[x*h+y]);
   1.118 -                        }
   1.119 -                    }
   1.120 -                SetPixelBlock(i,j,15,32,block.Ptr());
   1.121 +                SetPixelBlock(i,j,15,32,nextBlock.Ptr());
   1.122 +                //SetPixelBlock(i,j,15,32,0xFF/*nextBlock.Ptr()*/);
   1.123                  //SetDisplayPosition(iDisplayPositionX,OffScreenY());
   1.124                  //SetDisplayPosition(iDisplayPositionX,OffScreenY());
   1.125  
   1.126 -                //SetPixelBlock(i,j,15,32,iNextFrame->Ptr()+offset);
   1.127 +                //SetPixelBlock(i,j,15,32,iFrameNext->Ptr()+offset);
   1.128                  }
   1.129              }
   1.130          }
   1.131 -    */
   1.132  
   1.133      }
   1.134