nxtOSEK/samples_c++/cc/sprite_devl/CompressedSprite.h

   1 class Sprite\r
   2 {\r
   3 public:\r
   4         Sprite(const char* sprite);\r
   5         ~Sprite();\r
   6         char const * const getDecompressedSprite(U8 frameNumber);\r
   7 private:\r
   8         void decompressSprite(U8 frameNumber);\r
   9 \r
  10         //compressed data\r
  11         char mSentinal;\r
  12         U8 mNumFrames;\r
  13         U8 mWidth;\r
  14         U8 mHeight;\r
  15         \r
  16         U16 mNumflagBytes;\r
  17         char const * mCompressedSprite;\r
  18         char const * mCompressedFlags;\r
  19         char const * mFrameOffsets;\r
  20 \r
  21         //char *mDecompressBuffer;\r
  22         char mDecompressBuffer[100];\r
  23 \r
  24         //uncompressed data\r
  25         U8 mCurrentFrame;\r
  26 \r
  27     //1 byte - sentinel value\r
  28         //1 byte - num frames\r
  29     //1 byte - width\r
  30     //1 byte - height\r
  31         //1 byte - offset to compressed offset data\r
  32     //max 32 bytes for 255 framse for compressed flag bitfield\r
  33     //max 512 bytes for data offset into frames\r
  34 \r
  35         static const U8 mSentinalIndex = 0;\r
  36         static const U8 mNumFramesIndex = 1;\r
  37         static const U8 mWidthIndex = 2;\r
  38         static const U8 mHeightIndex = 3;\r
  39         static const U8 mNumFlagBytes = 4;\r
  40         static const U8 mHeaderPad00 = 5;\r
  41         static const U8 mStartOfCompressedFlags = 6;\r
  42 \r
  43         static const U8 mInvalidFrameNumber = 255;\r
  44 \r
  45 };\r
  46 \r
  47 Sprite::Sprite(const char* sprite)\r
  48 :       mSentinal(sprite[mSentinalIndex])\r
  49 ,       mNumFrames(sprite[mNumFramesIndex])\r
  50 ,       mWidth(sprite[mWidthIndex])\r
  51 ,       mHeight(sprite[mHeightIndex])\r
  52 ,       mCurrentFrame(mInvalidFrameNumber)\r
  53 {\r
  54         //mDecompressBuffer = new char[(mWidth*mHeight)/8];\r
  55         //memset(mDecompressBuffer, 0, (mWidth*mHeight)/8);\r
  56 \r
  57         mNumflagBytes = sprite[mNumFlagBytes];\r
  58         \r
  59         mCompressedFlags = &sprite[mStartOfCompressedFlags];\r
  60 \r
  61         int bufferOffset = 0;\r
  62         bufferOffset += mStartOfCompressedFlags + mNumflagBytes;\r
  63 \r
  64         mFrameOffsets = &sprite[bufferOffset];\r
  65 \r
  66         bufferOffset = bufferOffset + (mNumFrames * 2);\r
  67         mCompressedSprite = &sprite[bufferOffset];\r
  68 }\r
  69 \r
  70 Sprite::~Sprite()\r
  71 {\r
  72         //delete [] mDecompressBuffer;\r
  73 }\r
  74 \r
  75 char const * const Sprite::getDecompressedSprite(U8 frameNumber)\r
  76 {\r
  77         if(mCurrentFrame != frameNumber)\r
  78         {\r
  79                 decompressSprite(frameNumber);\r
  80         }\r
  81         return mDecompressBuffer;\r
  82 }\r
  83 \r
  84 void Sprite::decompressSprite(U8 frameNumber)\r
  85 {\r
  86         int numCompressedBytes = 0;\r
  87         char const *frameToDecompress = 0;\r
  88 \r
  89         if(frameNumber == 0)\r
  90         {\r
  91                 numCompressedBytes = reinterpret_cast<const unsigned short*>(mFrameOffsets)[frameNumber];\r
  92                 frameToDecompress = mCompressedSprite;\r
  93         }\r
  94         else\r
  95         {\r
  96                 unsigned short nextOffset = reinterpret_cast<const unsigned short*>(mFrameOffsets)[frameNumber];\r
  97                 unsigned short currentOffset = reinterpret_cast<const unsigned short*>(mFrameOffsets)[frameNumber - 1];\r
  98 \r
  99                 numCompressedBytes = nextOffset - currentOffset;\r
 100                 frameToDecompress = &mCompressedSprite[currentOffset];\r
 101         }\r
 102 \r
 103         if(mCompressedFlags[frameNumber/8] & (1<<frameNumber))\r
 104         {\r
 105                 //decompress the frame\r
 106                 int i = 0;\r
 107                 int uncmpBuffer = 0;\r
 108 \r
 109                 while(i < numCompressedBytes)\r
 110                 {\r
 111                         char character = frameToDecompress[i];\r
 112                         if(mSentinal == character)\r
 113                         {\r
 114                                 unsigned char numChars = frameToDecompress[i + 1];\r
 115 \r
 116                                 for(int j = 0; j < numChars; ++j)\r
 117                                 {\r
 118                                         if(uncmpBuffer < (mWidth*mHeight)/8)\r
 119                                         {\r
 120                                                 mDecompressBuffer[uncmpBuffer++] = frameToDecompress[i + 2];\r
 121                                         }\r
 122                                 }\r
 123          \r
 124                                 i += 3;\r
 125                         }\r
 126                         else\r
 127                         {\r
 128                                 if(uncmpBuffer < (mWidth*mHeight)/8)\r
 129                                 {\r
 130                                         mDecompressBuffer[uncmpBuffer++] = character;\r
 131                                 }\r
 132                                 i++;\r
 133                         }\r
 134                 }\r
 135         }\r
 136         else\r
 137         {\r
 138                 memcpy(mDecompressBuffer, frameToDecompress, (mWidth*mHeight)/8);\r
 139         }\r
 140 }\r