Feat：The first version of text system

package.json

@@ -38,6 +38,7 @@
     "@rollup/plugin-node-resolve": "^11.0.1",
     "@rollup/plugin-replace": "^2.3.4",
     "@types/jest": "^26.0.20",
+    "@types/offscreencanvas": "^2019.6.4",
     "@typescript-eslint/eslint-plugin": "^4.12.0",
     "@typescript-eslint/parser": "^4.12.0",
     "babel-jest": "^26.6.3",

packages/core/src/2d/dynamic-atlas/DynamicTextAtlas.ts

@@ -0,0 +1,95 @@
+import { Rect } from "@oasis-engine/math";
+import { Engine } from "../../Engine";
+import { Texture2D } from "../../texture/Texture2D";
+import { Sprite } from "../sprite/Sprite";
+
+/**
+ * Dynamic atlas for text.
+ */
+export class DynamicTextAtlas {
+  private static _region: Rect = new Rect();
+
+  private _texture: Texture2D;
+  private _width: number;
+  private _height: number;
+
+  private _space: number = 1;
+  private _curX: number = 1;
+  private _curY: number = 1;
+  private _nextY: number = 1;
+
+  private _sprites: Record<number, Sprite> = {};
+
+  constructor(engine: Engine, width: number, height: number) {
+    this._width = width;
+    this._height = height;
+    this._texture = new Texture2D(engine, width, height);
+    this._texture._addRefCount(1);
+  }
+
+  /**
+   * Destroy atlas, it will release the texture.
+   */
+  public destroy() {
+    this._sprites = {};
+    this._texture.destroy(true);
+  }
+
+  /**
+   * Add a sprite.
+   * @param sprite - the sprite to add
+   * @param imageSource - The source of texture
+   * @returns true if add sprite success, otherwise false
+   */
+  public addSprite(sprite: Sprite, imageSource: TexImageSource | OffscreenCanvas): boolean {
+    const { _space: space, _texture: texture } = this;
+    const { width, height } = imageSource;
+
+    const endX = this._curX + width + space;
+    if (endX >= this._width) {
+      this._curX = space;
+      this._curY = this._nextY + space;
+    }
+
+    const endY = this._curY + height + space;
+    if (endY > this._nextY) {
+      this._nextY = endY;
+    }
+
+    if (this._nextY >= this._height) {
+      return false;
+    }
+
+    texture.setImageSource(imageSource, 0, false, false, this._curX, this._curY);
+    texture.generateMipmaps();
+
+    const { _width, _height } = this;
+    const region = DynamicTextAtlas._region;
+    region.setValue(this._curX / _width, this._curY / _height, width / _width, height / _height);
+
+    // destroy origin texture.
+    sprite.texture && sprite.texture.destroy();
+    // Update atlas texture.
+    sprite.atlasRegion = region;
+    sprite.texture = texture;
+    this._curX = endX + space;
+
+    return true;
+  }
+
+  /**
+   * Remove a sprite.
+   * @param sprite - the sprite to remove
+   * @returns true if remove sprite success, otherwise false
+   */
+  public removeSprite(sprite: Sprite): boolean {
+    const id = sprite.instanceId;
+    const { _sprites } = this;
+    if (_sprites[id]) {
+      delete _sprites[id];
+      return true;
+    }
+    return false;
+  }
+}
+

packages/core/src/2d/dynamic-atlas/DynamicTextAtlasManager.ts

@@ -0,0 +1,126 @@
+import { Sprite } from "../sprite/Sprite";
+import { Engine } from "../../Engine";
+import { DynamicTextAtlas } from "./DynamicTextAtlas";
+
+/**
+ * Dynamic atlas manager for text.
+ */
+export class DynamicTextAtlasManager {
+  private _maxAtlasCount: number = 2;
+  private _textureSize: number = 1024;
+  private _atlases: Array<DynamicTextAtlas> = [];
+  private _atlasIndex: number = -1;
+  private _spritesInAtlasIndex: Record<number, number> = {};
+
+  /**
+   * Indicates how many atlases should be created.
+   */
+  get maxAtlasCount(): number {
+    return this._maxAtlasCount;
+  }
+
+  set maxAtlasCount(val: number) {
+    this._maxAtlasCount = val;
+  }
+
+  /**
+   * Indicates the size of the texture.
+   */
+  get textureSize(): number {
+    return this._textureSize;
+  }
+
+  set textureSize(val: number) {
+    this._textureSize = Math.min(val, 2048);
+  }
+
+  /**
+   * @internal
+   */
+  constructor(public readonly engine: Engine) {}
+
+  /**
+   * Add a sprite to atlas.
+   * @param sprite - the sprite to add
+   * @param imageSource - The source of texture
+   * @returns true if add sprite success, otherwise false
+   */
+  public addSprite(sprite: Sprite, imageSource: TexImageSource | OffscreenCanvas): boolean {
+    // Remove sprite if the sprite has been add.
+    const { _spritesInAtlasIndex, _atlases } = this;
+    const id = sprite.instanceId;
+    const atlasIndex = _spritesInAtlasIndex[id];
+    if (atlasIndex) {
+      _atlases[atlasIndex].removeSprite(sprite);
+      delete _spritesInAtlasIndex[id];
+    }
+
+    if (this._atlasIndex >= this._maxAtlasCount) {
+      return false;
+    }
+
+    let atlas = _atlases[this._atlasIndex];
+    if (!atlas) {
+      atlas = this._createAtlas();
+    }
+
+    if (atlas.addSprite(sprite, imageSource)) {
+      _spritesInAtlasIndex[id] = this._atlasIndex;
+      return true;
+    }
+
+    if (this._atlasIndex + 1 >= this._maxAtlasCount) {
+      this._atlasIndex = this._maxAtlasCount;
+      return false;
+    }
+
+    atlas = this._createAtlas();
+    if (atlas.addSprite(sprite, imageSource)) {
+      _spritesInAtlasIndex[id] = this._atlasIndex;
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Remove a sprite from atlas.
+   * @param sprite - the sprite to remove
+   * @returns true if remove sprite success, otherwise false
+   */
+  public removeSprite(sprite: Sprite): boolean {
+    if (!sprite) return false;
+
+    const { _atlases } = this;
+    for (let i = _atlases.length - 1; i >= 0; --i) {
+      const atlas = _atlases[i];
+      if(atlas.removeSprite(sprite)) {
+        delete this._spritesInAtlasIndex[i];
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  /**
+   * Reset all atlases.
+   */
+  public reset() {
+    const { _atlases } = this;
+    for (let i = 0, l = _atlases.length; i < l; ++i) {
+      _atlases[i].destroy();
+    }
+
+    _atlases.length = 0;
+    this._atlasIndex = -1;
+    this._spritesInAtlasIndex = {};
+  }
+
+  private _createAtlas(): DynamicTextAtlas {
+    this._atlasIndex++;
+    const { _textureSize } = this;
+    const atlas = new DynamicTextAtlas(this.engine, _textureSize, _textureSize);
+    this._atlases.push(atlas);
+    return atlas;
+  }
+}

packages/core/src/2d/enums/FontStyle.ts

@@ -0,0 +1,11 @@
+/**
+ * The style of the font.
+ */
+export enum FontStyle {
+  /** Set font without style */
+  None = 0x0,
+  /** Set font bold */
+  Bold = 0x1,
+  /** Set font italic */
+  Italic = 0x2
+}

packages/core/src/2d/enums/TextAlignment.ts

@@ -0,0 +1,23 @@
+/**
+ * The horizontal alignment of the text.
+ */
+export enum TextHorizontalAlignment {
+  /** Align left horizontally */
+  Left = 0,
+  /** Align center horizontally */
+  Center = 1,
+  /** Align right horizontally */
+  Right = 2
+}
+
+/**
+ * The vertical alignment of the text.
+ */
+export enum TextVerticalAlignment {
+  /** Align top vertically */
+  Top = 0,
+  /** Align center vertically */
+  Center = 1,
+  /** Align bottom vertically */
+  Bottom = 2
+}

packages/core/src/2d/enums/TextOverflow.ts

@@ -0,0 +1,9 @@
+/**
+ * The way to handle the situation where wrapped text is too tall to fit in the height.
+ */
+export enum OverflowMode {
+  /** Overflow when the text is too tall */
+  Overflow = 0,
+  /** Truncate with height when the text is too tall */
+  Truncate = 1
+}

packages/core/src/2d/index.ts

@@ -1,4 +1,8 @@
 export { SpriteMaskInteraction } from "./enums/SpriteMaskInteraction";
 export { SpriteMaskLayer } from "./enums/SpriteMaskLayer";
+export { TextHorizontalAlignment, TextVerticalAlignment } from "./enums/TextAlignment";
+export { OverflowMode } from "./enums/TextOverflow";
+export { FontStyle } from "./enums/FontStyle";
 export { SpriteAtlas } from "./atlas/SpriteAtlas";
 export * from "./sprite/index";
+export * from "./text/index";

packages/core/src/2d/text/Font.ts

@@ -0,0 +1,50 @@
+import { RefObject } from "../../asset/RefObject"
+import { Engine } from "../../Engine";
+import { UpdateFlag } from "../../UpdateFlag";
+import { UpdateFlagManager } from "../../UpdateFlagManager";
+
+/**
+ * Font.
+ */
+export class Font extends RefObject {
+  private _name: string = "Arial";
+  private _updateFlagManager: UpdateFlagManager = new UpdateFlagManager();
+
+  /**
+   * The name of the font.
+   */
+  get name(): string {
+    return this._name;
+  }
+
+  set name(value: string) {
+    value = value || "Arial";
+    if (this._name !== value) {
+      this._name = value;
+      this._updateFlagManager.distribute();
+    }
+  }
+
+  /**
+   * Create a font instance.
+   * @param engine - Engine to which the font belongs
+   * @param name - The name of font
+   */
+  constructor(engine: Engine, name: string = "") {
+    super(engine);
+    this._name = name || "Arial";
+  }
+
+  /**
+   * @internal
+   */
+  _registerUpdateFlag(): UpdateFlag {
+    return this._updateFlagManager.register();
+  }
+
+  /**
+   * @override
+   */
+  protected _onDestroy(): void {}
+}
+