kc3-lang/ftgl/src/FTGLTextureFont.cpp

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• Hash : ee107630
  Author :
  Date : 2008-03-03T16:41:35
  

  * Remove svn:executable property from source files.

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• src/FTGLTextureFont.cpp

• #include <cassert>
  #include <string> // For memset
  
  #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( const char* fontFilePath)
  :   FTFont( fontFilePath),
      maximumGLTextureSize(0),
      textureWidth(0),
      textureHeight(0),
      glyphHeight(0),
      glyphWidth(0),
      padding(3),
      xOffset(0),
      yOffset(0)
  {
      remGlyphs = numGlyphs = face.GlyphCount();
  }
  
  
  FTGLTextureFont::FTGLTextureFont( const unsigned char *pBufferBytes, size_t bufferSizeInBytes)
  :   FTFont( pBufferBytes, bufferSizeInBytes),
      maximumGLTextureSize(0),
      textureWidth(0),
      textureHeight(0),
      glyphHeight(0),
      glyphWidth(0),
      padding(3),
      xOffset(0),
      yOffset(0)
  {
      remGlyphs = numGlyphs = face.GlyphCount();
  }
  
  
  FTGLTextureFont::~FTGLTextureFont()
  {
      glDeleteTextures( textureIDList.size(), (const GLuint*)&textureIDList[0]);
  }
  
  
  FTGlyph* FTGLTextureFont::MakeGlyph( unsigned int glyphIndex)
  {
      FT_GlyphSlot ftGlyph = face.Glyph( glyphIndex, FT_LOAD_NO_HINTING);
      
      if( ftGlyph)
      {
          glyphHeight = static_cast<int>( charSize.Height());
          glyphWidth = static_cast<int>( charSize.Width());
          
          if( textureIDList.empty())
          {
              textureIDList.push_back( CreateTexture());
              xOffset = yOffset = padding;
          }
          
          if( xOffset > ( textureWidth - glyphWidth))
          {
              xOffset = padding;
              yOffset += glyphHeight;
              
              if( yOffset > ( textureHeight - glyphHeight))
              {
                  textureIDList.push_back( CreateTexture());
                  yOffset = padding;
              }
          }
          
          FTTextureGlyph* tempGlyph = new FTTextureGlyph( ftGlyph, textureIDList[textureIDList.size() - 1],
                                                          xOffset, yOffset, textureWidth, textureHeight);
          xOffset += static_cast<int>( tempGlyph->BBox().upperX - tempGlyph->BBox().lowerX + padding);
          
          --remGlyphs;
          return tempGlyph;
      }
      
      err = face.Error();
      return NULL;
  }
  
  
  void FTGLTextureFont::CalculateTextureSize()
  {
      if( !maximumGLTextureSize)
      {
          glGetIntegerv( GL_MAX_TEXTURE_SIZE, (GLint*)&maximumGLTextureSize);
          assert(maximumGLTextureSize); // If you hit this then you have an invalid OpenGL context.
      }
      
      textureWidth = NextPowerOf2( (remGlyphs * glyphWidth) + ( padding * 2));
      textureWidth = textureWidth > maximumGLTextureSize ? maximumGLTextureSize : textureWidth;
      
      int h = static_cast<int>( (textureWidth - ( padding * 2)) / glyphWidth);
          
      textureHeight = NextPowerOf2( (( numGlyphs / h) + 1) * glyphHeight);
      textureHeight = textureHeight > maximumGLTextureSize ? maximumGLTextureSize : textureHeight;
  }
  
  
  GLuint FTGLTextureFont::CreateTexture()
  {   
      CalculateTextureSize();
      
      int totalMemory = textureWidth * textureHeight;
      unsigned char* textureMemory = new unsigned char[totalMemory];
      memset( textureMemory, 0, totalMemory);
  
      GLuint textID;
      glGenTextures( 1, (GLuint*)&textID);
  
      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, textureMemory);
  
      delete [] textureMemory;
  
      return textID;
  }
  
  
  bool FTGLTextureFont::FaceSize( const unsigned int size, const unsigned int res)
  {
      if( !textureIDList.empty())
      {
          glDeleteTextures( textureIDList.size(), (const GLuint*)&textureIDList[0]);
          textureIDList.clear();
          remGlyphs = numGlyphs = face.GlyphCount();
      }
  
      return FTFont::FaceSize( size, res);
  }
  
  
  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
  
      FTTextureGlyph::ResetActiveTexture();
      
      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
      
      FTTextureGlyph::ResetActiveTexture();
      
      FTFont::Render( string);
      
      glPopAttrib();
  }
  
  

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