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glyphvertices.ts
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glyphvertices.ts
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/* spellchecker: disable */
import { vec2, vec3 } from 'gl-matrix';
/* spellchecker: enable */
/**
* Vertex cloud that describes each glyph that is to be rendered on the screen.
*/
export class GlyphVertices {
static readonly FLOATS_PER_TEXCOORD = 4;
static readonly FLOATS_PER_ORIGIN = 3;
static readonly FLOATS_PER_TANGENT = 3;
static readonly FLOATS_PER_UP = 3;
/** @see {@link origins} */
protected _origins: Float32Array;
/** @see {@link tangents} */
protected _tangents: Float32Array;
/** @see {@link ups} */
protected _ups: Float32Array;
/** @see {@link texCoords} */
protected _texCoords: Float32Array;
/**
* Concatenates multiple glyph vertices into a single new glyph vertices object.
* @param array - Array of glyph vertices. Undefined glyph vertices will be ignored.
*/
static concat(array: Array<GlyphVertices | undefined>): GlyphVertices {
let length = 0;
array.forEach((vertices) => length += vertices ? vertices.length : 0);
const concatenated = new GlyphVertices(length);
let offset = 0;
/* tslint:disable-next-line:prefer-for-of */
for (let index = 0; index < array.length; ++index) {
const vertices = array[index];
if (vertices === undefined || vertices!.length === 0) {
continue;
}
concatenated._texCoords.set(vertices._texCoords, offset * GlyphVertices.FLOATS_PER_TEXCOORD);
concatenated._origins.set(vertices._origins, offset * GlyphVertices.FLOATS_PER_ORIGIN);
concatenated._tangents.set(vertices._tangents, offset * GlyphVertices.FLOATS_PER_TANGENT);
concatenated._ups.set(vertices._ups, offset * GlyphVertices.FLOATS_PER_UP);
offset += vertices.length;
}
return concatenated;
}
/**
* Constructs a specialized arrays representing glyph vertex data.
* @param numberOfGlyphs - The number of glyph vertices required (number of glyphs).
*/
constructor(numberOfGlyphs: number) {
const length = Math.max(0, numberOfGlyphs);
this._texCoords = new Float32Array(length * GlyphVertices.FLOATS_PER_TEXCOORD);
this._origins = new Float32Array(length * GlyphVertices.FLOATS_PER_ORIGIN);
this._tangents = new Float32Array(length * GlyphVertices.FLOATS_PER_TANGENT);
this._ups = new Float32Array(length * GlyphVertices.FLOATS_PER_UP);
}
/**
* Efficiently reduces the size of all underlying float arrays (copies data if reduced).
* @param numberOfGlyphs - Target number of glyphs to reduce the vertices to.
*/
shrink(numberOfGlyphs: number): void {
const length = Math.max(0, numberOfGlyphs);
if (this.length === length) {
return;
}
/* Utility that slices the underlying buffer to the required length in bytes, and then creates a new
float 32 array view to that buffer. */
const shrink = (array: Float32Array, length: number, components: number) =>
array = new Float32Array(
array.buffer.slice(0, length * array.BYTES_PER_ELEMENT * components),
0, length * components);
shrink(this._texCoords, length, GlyphVertices.FLOATS_PER_TEXCOORD);
shrink(this._origins, length, GlyphVertices.FLOATS_PER_ORIGIN);
shrink(this._ups, length, GlyphVertices.FLOATS_PER_TANGENT);
shrink(this._tangents, length, GlyphVertices.FLOATS_PER_UP);
}
/**
* Typed vec2 view to the lower left texture coordinate of the glyph at given index.
* @param index - Index of the glyph to return the lower left texture coordinate of.
*/
uvLowerLeft(index: number): vec2 {
const begin = index * GlyphVertices.FLOATS_PER_TEXCOORD + 0;
return this._texCoords.subarray(begin, begin + 2) as vec2;
}
/**
* Typed vec2 view to the upper right texture coordinate of the glyph at given index.
* @param index - Index of the glyph to return the upper right texture coordinate of.
*/
uvUpperRight(index: number): vec2 {
const begin = index * GlyphVertices.FLOATS_PER_TEXCOORD + 2;
return this._texCoords.subarray(begin, begin + 2) as vec2;
}
/**
* Typed vec3 view to the origin of the glyph at given index.
* @param index - Index of the glyph to return the origin of.
*/
origin(index: number): vec3 {
const begin = index * GlyphVertices.FLOATS_PER_ORIGIN;
return this._origins.subarray(begin, begin + GlyphVertices.FLOATS_PER_ORIGIN) as vec3;
}
/**
* Typed vec3 view to the tangent of the glyph at given index.
* @param index - Index of the glyph to return the tangent of.
*/
tangent(index: number): vec3 {
const begin = index * GlyphVertices.FLOATS_PER_TANGENT;
return this._tangents.subarray(begin, begin + GlyphVertices.FLOATS_PER_TANGENT) as vec3;
}
/**
* Typed vec3 view to the up vector of the glyph at given index.
* @param index - Index of the glyph to return the up vector of.
*/
up(index: number): vec3 {
const begin = index * GlyphVertices.FLOATS_PER_UP;
return this._ups.subarray(begin, begin + GlyphVertices.FLOATS_PER_UP) as vec3;
}
/**
* Number of glyph vertices.
*/
get length(): number {
return this._origins.length / GlyphVertices.FLOATS_PER_ORIGIN;
}
/**
* Read-access to all glyph vertices' origins in a single typed buffer.
*/
get origins(): Float32Array {
return this._origins;
}
/**
* Read-access to all glyph vertices' tangent vectors in a single typed buffer.
*/
get tangents(): Float32Array {
return this._tangents;
}
/**
* Read-access to all glyph vertices' up vectors in a single typed buffer.
*/
get ups(): Float32Array {
return this._ups;
}
/**
* Read-access to all glyph vertices' texture coordinates (lower left and upper right) in a single typed buffer.
*/
get texCoords(): Float32Array {
return this._texCoords;
}
}