kc3-lang/ftgl/src/FTGLTextureFont.cpp

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• Hash : 4fcbcd3c
  Author :
  Date : 2001-08-08T01:30:04
  

  Changes to the charmap handling and fixed TextureSize()

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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()
  :	glTextureID(0),
  	textMem(0),
  	padding(15),
  	tempGlyph(0),
  	maxTextSize(0),
  	textureSize(0),
  	glyphHeight(0),
  	glyphWidth(0),
  	horizGlyphs(0),
  	vertGlyphs(0)
  
  {}
  
  
  FTGLTextureFont::~FTGLTextureFont()
  {
  	glDeleteTextures( 1, &glTextureID);
  	delete [] textMem;
  }
  
  
  bool FTGLTextureFont::MakeGlyphList()
  {
  	FT_Face* ftFace = face.Face();
  	
  	CreateTexture();
  
  	int currentTextX = padding;
  	int currentTextY = padding + padding;
  	
  	float currTextU = (float)padding / (float)textureSize;
  	float currTextV = (float)padding / (float)textureSize;
  	
  //	numGlyphs = 256; // FIXME hack
  	
  	for( int n = 0; n <= numGlyphs; ++n)
  	{
  		err = FT_Load_Glyph( *ftFace, n, FT_LOAD_DEFAULT);
  		FT_Glyph ftGlyph;
  		
  		err = FT_Get_Glyph( (*ftFace)->glyph, &ftGlyph);
  	
  		unsigned char* data = textMem + ( ( currentTextY * textureSize) + currentTextX);
  		
  		currTextU = (float)currentTextX / (float)textureSize;
  		
  		tempGlyph = new FTTextureGlyph( ftGlyph, n, data, textureSize, currTextU, currTextV);
  		glyphList->Add( tempGlyph);
  		
  		currentTextX += glyphWidth;
  		if( currentTextX > ( textureSize - glyphWidth))
  		{
  			currentTextY += glyphHeight;
  			currentTextX = padding;
  			currTextV = (float)currentTextY / (float)textureSize;
  		}
  	}
  
  	
  	glPixelStorei(GL_UNPACK_ALIGNMENT, 1); //What does this do exactly?
  	glBindTexture( GL_TEXTURE_2D, glTextureID);
  	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, textureSize, textureSize, 0, GL_ALPHA, GL_UNSIGNED_BYTE, textMem);
  
  	return !err;
  }
  
  
  bool FTGLTextureFont::CreateTexture()
  {
  	glGetIntegerv( GL_MAX_TEXTURE_SIZE, &maxTextSize);
  	glGenTextures( 1, &glTextureID);
  
  //	There is a fixed relationship between ppem, point size, and the
  //	resulting pixel size.  The real dimension of the glyphs are not
  //	covered by this.  The field `bbox' in FT_Face gives a maximal bounding
  //	box large enough to hold all bboxes of single glyphs.
  	
  	// calc the area required for this font
  	glyphHeight = ( charSize.Height()) + padding;
  	glyphWidth = ( charSize.Width()) + padding;
  	
  	//FIXME	
  //	textureSize = 1024;
  	int t;
  	for( t = 64; t <= maxTextSize; t *=2)
  	{		
  		int h = static_cast<int>( t / glyphWidth);
  		if( t > ( ( numGlyphs / h) * glyphHeight))
  			break;
  	}
  	
  	textureSize = t;
  	
  	horizGlyphs = static_cast<int>( textureSize / glyphWidth);
  	vertGlyphs = static_cast<int>(( numGlyphs / horizGlyphs) + 1);
  	
  	// build the texture.
  	textMem = new unsigned char[ textureSize * textureSize]; // GL_ALPHA texture;
  	
  	//FIXME
  	for( int i = 0; i < ( textureSize * textureSize); ++i)
  		textMem[i] = 0;
  }
  
  
  void FTGLTextureFont::render( const char* string)
  {	
  	glBindTexture( GL_TEXTURE_2D, glTextureID);
  	
  	// QUADS are faster!? Less function call overhead?
  	glBegin( GL_QUADS);
  		FTFont::render( string);
  	glEnd();
  }
  

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