kc3-lang/ftgl/src/FTGLTextureFont.cpp

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• Hash : be741365
  Author :
  Date : 2001-08-27T22:03:36
  

  If we get a NULL FT_Glyph we now report an error.

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• src/FTGLTextureFont.cpp

• #include	"GL/gl.h"
  
  #include	"FTGLTextureFont.h"
  #include	"FTGlyphContainer.h"
  #include	"FTGL.h"
  #include	"FTTextureGlyph.h"
  
  
  typedef unsigned long	UInt32; // a mac thing?
  
  
  inline UInt32 NextPowerOf2( UInt32 in)
  {
       in -= 1;
  
       in |= in >> 16;
       in |= in >> 8;
       in |= in >> 4;
       in |= in >> 2;
       in |= in >> 1;
  
       return in + 1;
  }
  
  
  FTGLTextureFont::FTGLTextureFont()
  :	numTextures(1),
  	textMem(0),
  	padding(1),
  	tempGlyph(0),
  	maxTextSize(0),
  	textureWidth(0),
  	textureHeight(0),
  	glyphHeight(0),
  	glyphWidth(0)
  {}
  
  
  FTGLTextureFont::~FTGLTextureFont()
  {
  	glDeleteTextures( numTextures, (const GLuint*)glTextureID);
  }
  
  
  bool FTGLTextureFont::MakeGlyphList()
  {
  	if( !maxTextSize)
  		glGetIntegerv( GL_MAX_TEXTURE_SIZE, (GLint*)&maxTextSize);
  	
  	glyphHeight = ( charSize.Height()) + padding;
  	glyphWidth = ( charSize.Width()) + padding;
  	
  	GetSize();
  	int totalMem;
  	
  	if( textureHeight > maxTextSize)
  	{
  		numTextures = static_cast<int>( textureHeight / maxTextSize) + 1;
  		if( numTextures > 15)
  			numTextures = 15;
  		
  		int heightRemain = NextPowerOf2( textureHeight % maxTextSize);
  		totalMem = ((maxTextSize * ( numTextures - 1)) + heightRemain) * textureWidth;
  
  		glGenTextures( numTextures, (GLuint*)&glTextureID[0]);
  
  		textMem = new unsigned char[totalMem]; // GL_ALPHA texture;
  		std::memset( textMem, 0, totalMem);
  			
  		unsigned int glyphNum = 0;
  		unsigned char* currTextPtr = textMem;
  		
  		for( int x = 0; x < numTextures - 1; ++x)
  		{
  			glyphNum = FillGlyphs( glyphNum, glTextureID[x], textureWidth, maxTextSize, currTextPtr);
  			
  			CreateTexture( x, textureWidth, maxTextSize, currTextPtr);
  			
  			currTextPtr += ( textureWidth * maxTextSize);
  			++glyphNum;
  		}
  		
  		glyphNum = FillGlyphs( glyphNum, glTextureID[numTextures - 1], textureWidth, heightRemain, currTextPtr);
  		CreateTexture( numTextures - 1, textureWidth, heightRemain, currTextPtr);
  	}
  	else
  	{
  		textureHeight = NextPowerOf2( textureHeight);
  		totalMem = textureWidth * textureHeight;
  		
  		glGenTextures( numTextures, (GLuint*)&glTextureID[0]);
  
  		textMem = new unsigned char[totalMem]; // GL_ALPHA texture;
  		std::memset( textMem, 0, totalMem);
  
  		FillGlyphs( 0, glTextureID[0], textureWidth, textureHeight, textMem);
  		CreateTexture( 0, textureWidth, textureHeight, textMem);
  	}
  
  	delete [] textMem;
  	return !err;
  }
  
  
  unsigned int FTGLTextureFont::FillGlyphs( unsigned int glyphStart, int id, int width, int height, unsigned char* textdata)
  {
  	int currentTextX = padding;
  	int currentTextY = padding;// + padding;
  	
  	float currTextU = (float)padding / (float)width;
  	float currTextV = (float)padding / (float)height;
  	
  //	numGlyphs = 256; // FIXME hack
  	unsigned int n;
  	
  	for( n = glyphStart; n <= numGlyphs; ++n)
  	{
  		FT_Glyph* ftGlyph = face.Glyph( n, FT_LOAD_NO_HINTING);
  		
  		if( ftGlyph)
  		{
  			unsigned char* data = textdata + (( currentTextY * width) + currentTextX);
  			
  			currTextU = (float)currentTextX / (float)width;
  			
  			tempGlyph = new FTTextureGlyph( *ftGlyph, n, id, data, width, height, currTextU, currTextV);
  			glyphList->Add( tempGlyph);
  			
  			currentTextX += glyphWidth;
  			if( currentTextX > ( width - glyphWidth))
  			{
  				currentTextY += glyphHeight;
  				if( currentTextY > ( height - glyphHeight))
  					return n;
  					
  				currentTextX = padding;
  				currTextV = (float)currentTextY / (float)height;
  			}
  		}
  		else
  		{
  			err = face.Error();
  		}
  	}
  
  	return n;
  }
  
  
  void FTGLTextureFont::GetSize()
  {
  	//work out the max width. Most likely maxTextSize!
  	textureWidth = NextPowerOf2( numGlyphs * glyphWidth);
  	if( textureWidth > maxTextSize)
  	{
  		textureWidth = maxTextSize;
  	}
  	
  	int h = static_cast<int>( textureWidth / glyphWidth);
  	textureHeight = (( numGlyphs / h) + 1) * glyphHeight;
  }
  
  
  void FTGLTextureFont::CreateTexture( int id, int width, int height, unsigned char* data)
  {
  	glPixelStorei( GL_UNPACK_ALIGNMENT, 1); //What does this do exactly?
  	glBindTexture( GL_TEXTURE_2D, glTextureID[id]);
  	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
  	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
  	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  	glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
  	glTexImage2D( GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, data);
  }
  
  
  void FTGLTextureFont::render( const char* string)
  {	
  	glPushAttrib( GL_ENABLE_BIT | GL_HINT_BIT | GL_LINE_BIT | GL_PIXEL_MODE_BIT);
  	
  	glEnable(GL_BLEND);
   	glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // GL_ONE
   	
  	glBindTexture( GL_TEXTURE_2D, (GLuint)FTTextureGlyph::activeTextureID);
  
   	// QUADS are faster!? Less function call overhead?
   	glBegin( GL_QUADS);
   		FTFont::render( string);
   	glEnd();
  	
  	glPopAttrib();
  }
  

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