Vkm::Engine::FontAsset Struct Reference

A TrueType font baked to a signed-distance-field atlas. More...

#include <font_asset.h>

Inheritance diagram for Vkm::Engine::FontAsset:

Public Member Functions
const FontGlyph *	glyph (char32_t codepoint) const
	The glyph for codepoint.
float	kern (int left, int right) const
	The kerning between glyph left and glyph right, in baked pixels.
Public Member Functions inherited from Vkm::Engine::Resource
	Resource (const Resource &other)
	Duplicate other's contents and name, but not its identity.
const std::string &	name () const noexcept
	Serializable identity; non-empty and unique within its type once added.
uint64_t	uid () const noexcept
	Process-unique id stamped by add(); names the asset, not the slot it sits in.
uint64_t	version () const noexcept
	Change counter the backend keys GPU re-uploads on; moved by commit().
bool	isHidden () const noexcept
	Added by ResourceManager::addPrivate: not user-facing, not saved.
nlohmann::json &	sourceJson ()
	Mutable source JSON, allocating a null document if there is none.
const nlohmann::json &	sourceJson () const
	Const source JSON; asserts hasSource(), so guard the call with it.

Static Public Member Functions
static constexpr int	glyphIndex (char32_t codepoint)
	Where codepoint sits in the glyph table.
static constexpr char32_t	codepointAt (uint32_t index)
	The codepoint glyph index holds; the inverse of glyphIndex.

Public Attributes
std::vector< uint8_t >	atlasPixels
	Single-channel SDF atlas, atlasSize x atlasSize texels.
uint32_t	atlasSize = 0
	Atlas dimension in texels (square).
float	ascent = 0.0f
float	descent = 0.0f
	Baseline-to-bottom, in baked pixels (negative below the baseline).
float	lineHeight = 0.0f
	Baseline-to-baseline distance for stacked lines, in baked pixels.
std::vector< KerningPair >	kerning
	Sorted on KerningPair::pair; unkerned pairs are absent.

Static Public Attributes
static constexpr uint32_t	ASCII_FIRST = 0x20
	Space.
static constexpr uint32_t	ASCII_LAST = 0x7E
	'~'.
static constexpr uint32_t	LATIN1_FIRST = 0xA0
	No-break space.
static constexpr uint32_t	LATIN1_LAST = 0xFF
	y with diaeresis.
static constexpr uint32_t	MARKS []
	Dashes, curly quotes, the bullet, the ellipsis and the euro sign, ascending.
static constexpr uint32_t	MIP_LEVELS = 4
	How many levels of the atlas a renderer may sample, the full size included.

Detailed Description

A TrueType font baked to a signed-distance-field atlas.

Covers printable ASCII, printable Latin-1 and MARKS; one bake renders cleanly to roughly three times its baked height. Self-contained (pixels, no texture handle), so ResourceManager::swap can keep the slot across a scene load.

Member Function Documentation

glyphIndex()

constexpr int Vkm::Engine::FontAsset::glyphIndex ( char32_t codepoint )

inlinestaticconstexpr

Where codepoint sits in the glyph table.

Parameters

codepoint

The character.

Returns

Its index, or -1 when a bake does not cover it.

codepointAt()

constexpr char32_t Vkm::Engine::FontAsset::codepointAt ( uint32_t index )

inlinestaticconstexpr

The codepoint glyph index holds; the inverse of glyphIndex.

Parameters

index

Glyph table index, below GLYPH_COUNT.

Returns

The character at that index.

glyph()

const FontGlyph * Vkm::Engine::FontAsset::glyph ( char32_t codepoint ) const

inline

The glyph for codepoint.

Parameters

codepoint

The character.

Returns

Its glyph, or nullptr when a bake does not cover it.

kern()

float Vkm::Engine::FontAsset::kern ( int left, int right ) const

inline

The kerning between glyph left and glyph right, in baked pixels.

Parameters

left	Glyph index of the earlier glyph.
right	Glyph index of the one after it.

Returns

The adjustment to the left glyph's advance; zero for a pair the face does not kern.

Member Data Documentation

MIP_LEVELS

uint32_t Vkm::Engine::FontAsset::MIP_LEVELS = 4

staticconstexpr

How many levels of the atlas a renderer may sample, the full size included.

bakeFontSDF's gutter is 2^(MIP_LEVELS - 1) texels; more levels would bleed neighbouring glyphs together.

ascent

float Vkm::Engine::FontAsset::ascent = 0.0f

Baseline-to-top, in baked pixels (positive).

lineHeight

float Vkm::Engine::FontAsset::lineHeight = 0.0f

Baseline-to-baseline distance for stacked lines, in baked pixels.

The face's own ascent - descent + line gap.

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

• resource/asset/font_asset.h