MOPPI FONT fileformat

The font is saved in the Moppi Font format as bitmap. Also texture coordinate
information and the number of pixels to advance after each character is written
to the file. The number of pixels to advance is important for fonts which are
not monospaced.


** FILE LAYOUT

Data types:
	char		is a 8-bit character
	BYTE		is a 8-bit unsigned integer
	WORD		is a 16-bit unsigned integer

Size:			Description:

char[4]		Header, should read "mofo". Should be tested.
BYTE			First character. This is index in ASCII table.
BYTE			Last character. There will be (last_char - first_char)
			characters in this file.
WORD			Max font height in pixels
WORD			Texture width. This is quaranteed to be power of 2.
WORD			Texture height. This most likely is not power of 2.

for each char
	WORD		Number of pixels to advance after this char.

for each char
	WORD		Min X. Coordinates in the texture.
	WORD		Min Y.
	WORD		Max X.
	WORD		Max Y.

BYTE[TW * TH]	The font data. (TW = texture width, TH = texture height).



** EXAMPLE CODE


uint8*	g_pData = 0;
uint16*	g_pWidths = 0;
uint16*	g_pCoords = 0;
uint32	g_ui32FirstGlyph;
uint32	g_ui32LastGlyph;
uint32	g_ui32FontHeight;
uint32	g_ui32GlyphCount;
uint32	g_ui32TexWidth;
uint32	g_ui32TexHeight;


//
// Loads a font file from specified file.
//
bool
load_mofo( const char* szName )
{
	FILE*		fp;

	if( (fp = fopen( szName, "rb" )) == 0 ) {
		return false;
	}

	uint8		ui8Header[4];
	uint8		ui8Tmp;
	uint16	ui16Tmp;

	// Read and test header.
	fread( ui8Header, sizeof( ui8Header ), 1, fp );
	if( ui8Header[0] != 'm' || ui8Header[1] != 'o' ||
		ui8Header[2] != 'f' || ui8Header[3] != 'o' )
		return false;

	// Read first char.
	fread( &ui8Tmp, sizeof( ui8Tmp ), 1, fp );
	g_ui32FirstGlyph = ui8Tmp;

	// Read last char.
	fread( &ui8Tmp, sizeof( ui8Tmp ), 1, fp );
	g_ui32LastGlyph = ui8Tmp;

	// Calculate number of characters and allocate space for texture coords
	// and character advances.
	g_ui32GlyphCount = g_ui32LastGlyph - g_ui32FirstGlyph;
	g_pWidths = new uint16[g_ui32GlyphCount];
	g_pCoords = new uint16[g_ui32GlyphCount * 4];

	// Read font height.
	fread( &ui16Tmp, sizeof( ui16Tmp ), 1, fp );
	g_ui32FontHeight = ui16Tmp;

	// Read texture size.
	fread( &ui16Tmp, sizeof( ui16Tmp ), 1, fp );
	g_ui32TexWidth = ui16Tmp;
	fread( &ui16Tmp, sizeof( ui16Tmp ), 1, fp );
	g_ui32TexHeight = ui16Tmp;

	// Widths
	fread( g_pWidths, g_ui32GlyphCount * sizeof( uint16 ), 1, fp );

	// Tex coords
	fread( g_pCoords, g_ui32GlyphCount * 4 * sizeof( uint16 ), 1, fp );

	// Allocate the texture data.
	// nearest_power function returns nearest power of 2 value of the
	// argument.
	uint32	ui32DataSize = g_ui32TexWidth * nearest_power( g_ui32TexHeight );
	delete g_pData;
	g_pData = new uint8[ui32DataSize];
	if( !g_pData ) {
		fclose( fp );
		return false;
	}

	memset( g_pData, 0, ui32DataSize );
	fread( g_pData, g_ui32TexWidth * g_ui32TexHeight, 1, fp );

	fclose( fp );

	g_ui32TexHeight = nearest_power( g_ui32TexHeight );

	return true;
}

//
// Returns the width of a character.
//
uint16
get_glyph_width( uint32 ui32Index )
{
	if( ui32Index >= g_ui32FirstGlyph && ui32Index < g_ui32LastGlyph ) {
		uint32	ui32Offset = (ui32Index - g_ui32FirstGlyph) * 4;
		return g_pCoords[ui32Offset + 2] - g_pCoords[ui32Offset + 0];
	}
	return 0;
}

//
// Returns the advance of a character.
//
uint16
get_glyph_advance( uint32 ui32Index )
{
	if( ui32Index >= g_ui32FirstGlyph && ui32Index < g_ui32LastGlyph )
		return g_pWidths[ui32Index - g_ui32FirstGlyph];
	return g_ui32FontHeight / 2;
}


//
// Scales the texture coordinates from the file to range 0..1.
//
void
get_glyph_coords( uint32 ui32Index, float32& f32U0, float32& f32V0, 
			float32& f32U1, float32& f32V1 )
{
	if( ui32Index >= g_ui32FirstGlyph && ui32Index < g_ui32LastGlyph ) {
		float32	f32MultX = 1.0f / (float)g_ui32TexWidth;
		float32	f32MultY = 1.0f / (float)g_ui32TexHeight;
		uint32	ui32Offset = (ui32Index - g_ui32FirstGlyph) * 4;
		f32U0 =  (float32)g_pCoords[ui32Offset] * f32MultX;
		f32V0 =  (float32)g_pCoords[ui32Offset + 1] * f32MultY;
		f32U1 =  (float32)g_pCoords[ui32Offset + 2] * f32MultX;
		f32V1 =  (float32)g_pCoords[ui32Offset + 3] * f32MultY;
	}
	else
		f32U0 = f32V0 = f32U1 = f32V1 = 0;
}

//
// Draw character
//
int32
draw_char( int32 i32X, int32 i32Y, char cChar )
{
	int32		i32Width, i32Height;
	float32	f32U0, f32V0, f32U1, f32V1;

	// Get character texture coordinates
	get_glyph_coords( cChar, f32U0, f32V0, f32U1, f32V1 );

	// Get size of the character
	i32Width = get_glyph_width( cChar );
	i32Height = g_ui32FontHeight;

	// Draw the character as quad
	glBegin( GL_QUADS );

	glTexCoord2f( f32U0, f32V1 );
	glVertex2i( i32X, i32Y );
		
	glTexCoord2f( f32U1, f32V1 );
	glVertex2i( i32X + i32Width, i32Y );
		
	glTexCoord2f( f32U1, f32V0 );
	glVertex2i( i32X + i32Width, i32Y + i32Height );

	glTexCoord2f( f32U0, f32V0 );
	glVertex2i( i32X, i32Y + i32Height );

	glEnd();

	// Return how much we advanced.
	return get_glyph_advance( cChar );
}

//
// Draw string
//
void
draw_text( int32 i32X, int32 i32Y, const char* szText )
{
	for( uint32 i = 0; i < strlen( szText ); i++ )
		i32X += draw_char( i32X, i32Y, szText[i] );
}



MOPPI FONT CONVERTER version 1.0

Copyright (c) 2000 Moppi Productions.
All Rights Reserved.
<memon@inside.org>
http://moppi.inside.org/demopaja/

LICENSE AND WARRANTY

The Moppi Font Converter is free software. 

This software is provided "AS IS", with out warranty of any kind,
either expressed or implied, including but not limited to the
implied warranties of merchanbility and/or fitness for a
particular purpose. The author shall not be held liable
for any damage to you, your computer, or to anyone or anything
else, that may result from its use or misuse. You use this
software at your own risk.

Usage of this software indicates your acceptance of this
license agreement and warranty.

This software can be distributed unmodified with no restrictions,
provided any charge is to cover distribution costs only. This
software can be freely placed on CDs or magazine floppy disks,
etc. with a permission of the author.

All trademarks and other registered names contained in
the Moppi Font Converter package are the property of their
respective owners.
1/1/2001


        MOPPI FONT CONVERTER v1.01


The Moppi Font Converter converts True Type Fonts
to bitmap fonts. The file format it saves is .mofo.
This file format can be used in the Moppi Demopaja.

The Moppi Font Converter uses it's own rasterizer
to convert the files so the antialiasing should be
a little better than using using plain GDI calls.
The rasterizer is not very good at very small font
sizes (< 10).

This package also includes description of the file
format used, so feel free to use the files created
with this software on your own projects, etc.


History:

Version 1.01  1/1/2001
- corrected bug which caused the last character
  index to be 0 when all characters was visible

Version 1.0  12/31/2000
- first release


http://moppi.inside.org/demopaja/