kc3-lang/ftgl/src/FTGLTextureFont.cpp

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  Commit

• Author : henry
  Date : 2001-11-12 22:28:36
  Hash : d58c7be1
  Message : Refactored texture fonts to ba able to load glyphs on the fly...uses glTexSubImage2D. They are now more in line with the rest of the fonts.

• src/FTGLTextureFont.cpp

• #include	"FTGLTextureFont.h"
  #include	"FTGlyphContainer.h"
  #include	"FTTextureGlyph.h"
  
  using namespace std;
  
  //#include "mmgr.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()) + padding;
  		glyphWidth = ( charSize.Width()) + padding;
  		
  		// 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);
  		
  		xOffset += tempGlyph->BBox().x2 - tempGlyph->BBox().x1;
  		
  		--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); //What does this do exactly?
  	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_HINT_BIT | GL_LINE_BIT | GL_PIXEL_MODE_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_HINT_BIT | GL_LINE_BIT | GL_PIXEL_MODE_BIT);
  	
  	glEnable(GL_BLEND);
   	glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // GL_ONE
   	
   	FTFont::render( string);
  	
  	glPopAttrib();
  }