kc3-lang/ftgl/src/FTGLTextureFont.cpp

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  Commit

• Author : henry
  Date : 2002-11-27 07:46:25
  Hash : f73f63a9
  Message : Changes to the glyph loading flags

• src/FTGLTextureFont.cpp

• #include    <string>
  
  #include    "FTGLTextureFont.h"
  #include    "FTTextureGlyph.h"
  
  
  inline GLuint NextPowerOf2( GLuint in)
  {
       in -= 1;
  
       in |= in >> 16;
       in |= in >> 8;
       in |= in >> 4;
       in |= in >> 2;
       in |= in >> 1;
  
       return in + 1;
  }
  
  
  FTGLTextureFont::FTGLTextureFont()
  :   maxTextSize(0),
      textureWidth(0),
      textureHeight(0),
      numTextures(0),
      textMem(0),
      glyphHeight(0),
      glyphWidth(0),
      padding(1),
      remGlyphs(0),
      xOffset(0),
      yOffset(0)
  {}
  
  
  FTGLTextureFont::~FTGLTextureFont()
  {
      glDeleteTextures( numTextures, (const GLuint*)glTextureID);
  }
  
  
  FTGlyph* FTGLTextureFont::MakeGlyph( unsigned int g)
  {
      FT_Glyph* ftGlyph = face.Glyph( g, FT_LOAD_NO_HINTING);
      
      if( ftGlyph)
      {
          // Estimate the glyph size size - global bbox
          glyphHeight = ( charSize.Height());
          glyphWidth = ( charSize.Width());
          
          // Is there a current texture
          if( numTextures == 0)
          {
              glTextureID[0] = CreateTexture();
              xOffset = yOffset = padding;
              ++numTextures;
          }
          
          // will it fit in the current texture
          if( xOffset > ( textureWidth - glyphWidth))
          {
              xOffset = padding;
              yOffset += glyphHeight;
              
              if( yOffset > ( textureHeight - glyphHeight))
              {
                  // no - make a new texture
                  glTextureID[numTextures] = CreateTexture();
                  yOffset = padding;
                  ++numTextures;
              }
          }
          
          // yes - load the glyph
          FTTextureGlyph* tempGlyph = new FTTextureGlyph( *ftGlyph, glTextureID[numTextures - 1],
                                                          xOffset, yOffset, textureWidth, textureHeight);
          
          // FIXME ceiling
          xOffset += static_cast<int>( tempGlyph->BBox().upperX - tempGlyph->BBox().lowerX + padding);
          
          --remGlyphs;
          return tempGlyph;
      }
      
      err = face.Error();
      return NULL;
  }
  
  
  bool FTGLTextureFont::MakeGlyphList()
  {
      if( !maxTextSize)
          glGetIntegerv( GL_MAX_TEXTURE_SIZE, (GLint*)&maxTextSize);
  
      remGlyphs = numGlyphs;
  
      FTFont::MakeGlyphList();
      
      return !err; // FIXME what err?
  }
  
  
  void FTGLTextureFont::GetSize()
  {
      //work out the max width. Most likely maxTextSize
      textureWidth = NextPowerOf2( (remGlyphs * glyphWidth) + padding * 2);
      if( textureWidth > maxTextSize)
      {
          textureWidth = maxTextSize;
      }
      
      int h = static_cast<int>( (textureWidth - padding * 2) / glyphWidth);
          
      textureHeight = NextPowerOf2( (( numGlyphs / h) + 1) * glyphHeight);
      textureHeight = textureHeight > maxTextSize ? maxTextSize : textureHeight;
  }
  
  
  int FTGLTextureFont::CreateTexture()
  {   
      // calc the size
      GetSize();
      
      // allocate some mem and clear it to black
      int totalMem = textureWidth * textureHeight;
      textMem = new unsigned char[totalMem]; // GL_ALPHA texture;
      memset( textMem, 0, totalMem);
  
      // Create the blank texture
      int textID;
      glGenTextures( 1, (GLuint*)&textID);
  
      glPixelStorei( GL_UNPACK_ALIGNMENT, 1);
      glBindTexture( GL_TEXTURE_2D, textID);
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
      glTexImage2D( GL_TEXTURE_2D, 0, GL_ALPHA, textureWidth, textureHeight, 0, GL_ALPHA, GL_UNSIGNED_BYTE, textMem);
  
      delete [] textMem;
  
      return textID;
  }
  
  
  void FTGLTextureFont::render( const char* string)
  {   
      glPushAttrib( GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT);
      
      glEnable(GL_BLEND);
      glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // GL_ONE
      
      FTFont::render( string);
  
      glPopAttrib();
  }
  
  
  void FTGLTextureFont::render( const wchar_t* string)
  {   
      glPushAttrib( GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT);
      
      glEnable(GL_BLEND);
      glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // GL_ONE
      
      FTFont::render( string);
      
      glPopAttrib();
  }