cugl::Font::Atlas Class Reference

#include <CUFont.h>

Public Member Functions
	Atlas ()
	~Atlas ()
void	dispose ()
bool	init (Font *parent, std::deque< Uint32 > &glyphset)
bool	hasGlyph (Uint32 a) const
bool	hasGlyphs (const std::vector< Uint32 > &glyphs) const
bool	hasGlyphs (const std::string glyphs) const
bool	getQuad (Uint32 thechar, Vec2 &offset, Mesh< SpriteVertex2 > &mesh, const Rect rect) const
void	getQuad (Uint32 thechar, Vec2 &offset, Mesh< SpriteVertex2 > &mesh) const
bool	build ()
bool	materialize ()

Static Public Member Functions
static std::shared_ptr< Atlas >	alloc (Font *parent, std::deque< Uint32 > &glyphset)

Public Attributes
std::shared_ptr< Texture >	texture
std::unordered_map< Uint32, Rect >	glyphmap

Detailed Description

This class represents a single font atlas.

A font atlas is a collection of pre-rendered glyphs, together with a directory of the bounds for each glyph. This directory information makes it very easy to quickly construct a textured quad mesh for a series of glyphys.

An font may have more than one atlas, particulary if the font size is large and there are a large number of supported glyphs. In that case, the atlases typically support a disjoint set of glyphs. However, we do not enforce this.

Constructor & Destructor Documentation

Atlas()

cugl::Font::Atlas::Atlas

(

)

Creates an uninitialized atlas with no parent font.

NEVER USE A CONSTRUCTOR WITH NEW. If you want to allocate an object on the heap, use one of the static constructors instead.

~Atlas()

cugl::Font::Atlas::~Atlas ( )

inline

Deletes this atlas, diposing of all its resources.

Member Function Documentation

alloc()

static std::shared_ptr< Atlas > cugl::Font::Atlas::alloc ( Font *  parent, std::deque< Uint32 > &  glyphset  )

inlinestatic

Returns a newly allocated atlas for the given font and glyphset

This allocator will perform the layout computation, but it will not create any textures or SDL surfaces. It will consume glyphs from the provided glyphset as it adds them to the atlas. So if it successfully adds all glyphs, the value glyphset will be emptied.

It is possible for the atlas to reject some glyphs. This is typically because the resulting texture size would exceed the maximum allowable texture size. In that case, the remaining elements in glyphset are glyphs that must be processed by another atlas.

If this atlas cannot process any of the elements in glyphset (because they are unsupported), then this method returns nullptr.

Parameters

parent	The parent font of this atlas
glyphset	The glyphs to add to this atlas

Returns

a newly allocated atlas for the given font and glyphset

build()

bool cugl::Font::Atlas::build

(

)

Builds the texture data for this given atlas.

This method does not generate the OpenGL texture, but does all other work in creates the atlas. In particular it creates the image buffer so that texture creation is just one OpenGL call. This creation will happen once materialize() is called. As a result, it is safe to call this method outside of the main thread.

Returns

true if atlas creation was successful

dispose()

void cugl::Font::Atlas::dispose

(

)

Deletes the atlas resources and resets all attributes.

This will delete the parent font as well. You must reinitialize the atlas to use it.

getQuad() [1/2]

void cugl::Font::Atlas::getQuad	(	Uint32	thechar,
		Vec2 &	offset,
		Mesh< SpriteVertex2 > &	mesh
	)		const

Creates a single quad to render this character and stores it in mesh

This method will append the vertices to the provided mesh and update the indices to include these new vertices. Once the quad is generated, the offset will be adjusted to contain the next place to render a character. This method will not generate anything if the character is not supported by this atlas.

Parameters

thechar	The character to convert to render data
offset	The (unkerned) starting position of the quad
mesh	The mesh to store the vertices

getQuad() [2/2]

bool cugl::Font::Atlas::getQuad	(	Uint32	thechar,
		Vec2 &	offset,
		Mesh< SpriteVertex2 > &	mesh,
		const Rect	rect
	)		const

Creates a single quad to render this character and stores it in mesh

This method will append the vertices to the provided mesh and update the indices to include these new vertices. Once the quad is generated, the offset will be adjusted to contain the next place to render a character. This method will not generate anything if the character is not supported by this atlas.

The quad is adjusted so that all of the vertices fit in the provided rectangle. This may mean that no quad is generated at all.

Parameters

thechar	The character to convert to render data
offset	The (unkerned) starting position of the quad
rect	The bounding box for the quad
mesh	The mesh to store the vertices

hasGlyph()

bool cugl::Font::Atlas::hasGlyph

(

Uint32

a

)

const

Returns true if this font has a glyph for the given (UNICODE) character.

The Unicode representation uses the endianness native to the platform. Therefore, this value should not be serialized. Use UTF8 to represent unicode in a platform-independent manner.

Note that control characters (like newline) never have glyphs. However, spaces do.

Parameters

a	The Unicode character to check.

Returns

true if this font has a glyph for the given (UNICODE) character.

hasGlyphs() [1/2]

bool cugl::Font::Atlas::hasGlyphs

(

const std::string

glyphs

)

const

Returns true if this atlas has all of the given glyphs

We assume that the string represents the glyphs in a UTF8 encoding.

Note that control characters (like newline) never have glyphs. However, spaces do.

Parameters

glyphs

The UTF8 glyphs to check.

Returns

true if this atlas has all of the given glyphs

hasGlyphs() [2/2]

bool cugl::Font::Atlas::hasGlyphs

(

const std::vector< Uint32 > &

glyphs

)

const

Returns true if this atlas has all of the given unicode glyphs

The Unicode representation uses the endianness native to the platform. Therefore, this value should not be serialized. Use UTF8 to represent unicode in a platform-independent manner.

Note that control characters (like newline) never have glyphs. However, spaces do.

Parameters

glyphs

The Unicode characters to check.

Returns

true if this atlas has all of the given unicode glyphs

init()

bool cugl::Font::Atlas::init	(	Font *	parent,
		std::deque< Uint32 > &	glyphset
	)

Initializes an atlas for the given font and glyphset

This initializer will perform the layout computation, but it will not create any textures or SDL surfaces. It will consume glyphs from the provided glyphset as it adds them to the atlas. So if it successfully adds all glyphs, the value glyphset will be emptied.

It is possible for the atlas to reject some glyphs. This is typically because the resulting texture size would exceed the maximum allowable texture size. In that case, the remaining elements in glyphset are glyphs that must be processed by another atlas.

If this atlas cannot process any of the elements in glyphset (because they are unsupported), then this method returns false.

Parameters

parent	The parent font of this atlas
glyphset	The glyphs to add to this atlas

Returns

true if the atlas was successfully initialized

materialize()

bool cugl::Font::Atlas::materialize

(

)

Creates the OpenGL texture for this atlas.

This method must be called on the main thread. It is only safe to call this method after a succesful call to build().

Returns

true if texture creation was successful.

Member Data Documentation

glyphmap

std::unordered_map<Uint32,Rect> cugl::Font::Atlas::glyphmap

The location of each glyph in the atlas texture. This includes padding.

texture

std::shared_ptr<Texture> cugl::Font::Atlas::texture

The texture (may be null if not materialized)

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The documentation for this class was generated from the following file:

• cugl/include/cugl/render/CUFont.h