pathfinder/demo/client/src/text-demo.ts

// pathfinder/client/src/text-demo.ts
//
// Copyright © 2017 The Pathfinder Project Developers.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

import {Font} from 'opentype.js';
import * as _ from 'lodash';
import * as base64js from 'base64-js';
import * as glmatrix from 'gl-matrix';
import * as opentype from 'opentype.js';

import {AntialiasingStrategy, AntialiasingStrategyName, NoAAStrategy} from './aa-strategy';
import {DemoAppController} from './app-controller';
import {ECAAMonochromeStrategy, ECAAStrategy} from './ecaa-strategy';
import {createFramebuffer, createFramebufferColorTexture} from './gl-utils';
import {createFramebufferDepthTexture, QUAD_ELEMENTS, setTextureParameters} from './gl-utils';
import {UniformMap} from './gl-utils';
import {PathfinderMeshBuffers, PathfinderMeshData} from './meshes';
import {PathfinderShaderProgram, ShaderMap, ShaderProgramSource} from './shader-loader';
import {BUILTIN_FONT_URI, PathfinderGlyph, TextLayout} from "./text";
import {PathfinderError, assert, expectNotNull, UINT32_SIZE, unwrapNull, panic} from './utils';
import {MonochromePathfinderView, Timings} from './view';
import PathfinderBufferTexture from './buffer-texture';
import SSAAStrategy from './ssaa-strategy';

const DEFAULT_TEXT: string =
`’Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.

“Beware the Jabberwock, my son!
The jaws that bite, the claws that catch!
Beware the Jubjub bird, and shun
The frumious Bandersnatch!”

He took his vorpal sword in hand:
Long time the manxome foe he sought—
So rested he by the Tumtum tree,
And stood awhile in thought.

And as in uffish thought he stood,
The Jabberwock, with eyes of flame,
Came whiffling through the tulgey wood,
And burbled as it came!

One, two! One, two! And through and through
The vorpal blade went snicker-snack!
He left it dead, and with its head
He went galumphing back.

“And hast thou slain the Jabberwock?
Come to my arms, my beamish boy!
O frabjous day! Callooh! Callay!”
He chortled in his joy.

’Twas brillig, and the slithy toves
Did gyre and gimble in the wabe;
All mimsy were the borogoves,
And the mome raths outgrabe.`;

const INITIAL_FONT_SIZE: number = 72.0;

const PARTITION_FONT_ENDPOINT_URL: string = "/partition-font";

const DEFAULT_FONT: string = 'open-sans';

const B_POSITION_SIZE: number = 8;

const B_PATH_INDEX_SIZE: number = 2;

const ATLAS_SIZE: glmatrix.vec2 = glmatrix.vec2.fromValues(3072, 3072);

declare global {
    interface Window {
        jQuery(element: HTMLElement): JQuerySubset;
    }
}

interface JQuerySubset {
    modal(options?: any): void;
}

type Matrix4D = Float32Array;

type Rect = glmatrix.vec4;

interface Point2D {
    x: number;
    y: number;
}

type Size2D = glmatrix.vec2;

type ShaderType = number;

// `opentype.js` monkey patches

declare module 'opentype.js' {
    interface Font {
        isSupported(): boolean;
    }
    interface Glyph {
        getIndex(): number;
    }
}

/// The separating axis theorem.
function rectsIntersect(a: glmatrix.vec4, b: glmatrix.vec4): boolean {
    return a[2] > b[0] && a[3] > b[1] && a[0] < b[2] && a[1] < b[3];
}

class TextDemoController extends DemoAppController<TextDemoView> {
    constructor() {
        super();
        this.text = DEFAULT_TEXT;
        this._atlas = new Atlas;
    }

    start() {
        super.start();

        this._fontSize = INITIAL_FONT_SIZE;

        this.fpsLabel = unwrapNull(document.getElementById('pf-fps-label'));
        this.editTextModal = unwrapNull(document.getElementById('pf-edit-text-modal'));
        this.editTextArea = unwrapNull(document.getElementById('pf-edit-text-area')) as
            HTMLTextAreaElement;

        const editTextOkButton = unwrapNull(document.getElementById('pf-edit-text-ok-button'));
        editTextOkButton.addEventListener('click', () => this.updateText(), false);

        this.loadInitialFile();
    }

    showTextEditor() {
        this.editTextArea.value = this.text;

        window.jQuery(this.editTextModal).modal();
    }

    private updateText() {
        this.text = this.editTextArea.value;
        this.recreateLayout();

        window.jQuery(this.editTextModal).modal('hide');
    }

    protected createView() {
        return new TextDemoView(this,
                                this.canvas,
                                unwrapNull(this.commonShaderSource),
                                unwrapNull(this.shaderSources));
    }

    protected fileLoaded() {
        this.recreateLayout();
    }

    private recreateLayout() {
        this.layout = new TextLayout(this.fileData, this.text, glyph => new GlyphInstance(glyph));
        this.layout.partition().then((meshes: PathfinderMeshData) => {
            this.meshes = meshes;
            this.view.then(view => {
                view.attachText();
                view.uploadPathMetadata(this.layout.uniqueGlyphs.length);
                view.attachMeshes(this.meshes);
            });
        });
    }

    updateTimings(newTimes: Timings) {
        this.fpsLabel.innerHTML =
            `${newTimes.atlasRendering} ms atlas, ${newTimes.compositing} ms compositing`;
    }

    get atlas(): Atlas {
        return this._atlas;
    }

    /// The font size in pixels per em.
    get fontSize(): number {
        return this._fontSize;
    }

    /// The font size in pixels per em.
    set fontSize(newFontSize: number) {
        this._fontSize = newFontSize;
        this.view.then(view => view.attachText());
    }

    get pixelsPerUnit(): number {
        return this._fontSize / this.layout.font.unitsPerEm;
    }

    protected get builtinFileURI(): string {
        return BUILTIN_FONT_URI;
    }

    protected get defaultFile(): string {
        return DEFAULT_FONT;
    }

    private fpsLabel: HTMLElement;
    private editTextModal: HTMLElement;
    private editTextArea: HTMLTextAreaElement;

    private _atlas: Atlas;
    atlasGlyphs: AtlasGlyph[];

    private meshes: PathfinderMeshData;

    private _fontSize: number;

    private text: string;

    layout: TextLayout<GlyphInstance>;
}

class TextDemoView extends MonochromePathfinderView {
    constructor(appController: TextDemoController,
                canvas: HTMLCanvasElement,
                commonShaderSource: string,
                shaderSources: ShaderMap<ShaderProgramSource>) {
        super(canvas, commonShaderSource, shaderSources);

        this.appController = appController;

        this.canvas.addEventListener('dblclick', () => this.appController.showTextEditor(), false);
    }

    protected initContext() {
        super.initContext();
    }

    uploadPathMetadata(pathCount: number) {
        const pathColors = new Uint8Array(4 * (pathCount + 1));
        for (let pathIndex = 0; pathIndex < pathCount; pathIndex++) {
            for (let channel = 0; channel < 3; channel++)
                pathColors[(pathIndex + 1) * 4 + channel] = 0x00; // RGB
            pathColors[(pathIndex + 1) * 4 + 3] = 0xff;           // alpha
        }

        this.pathColorsBufferTexture.upload(this.gl, pathColors);
    }

    /// Lays out glyphs on the canvas.
    private layoutGlyphs() {
        this.appController.layout.layoutText();

        const textGlyphs = this.appController.layout.textGlyphs;
        const glyphPositions = new Float32Array(textGlyphs.length * 8);
        const glyphIndices = new Uint32Array(textGlyphs.length * 6);

        for (let glyphIndex = 0; glyphIndex < textGlyphs.length; glyphIndex++) {
            const textGlyph = textGlyphs[glyphIndex];
            const rect = textGlyph.getRect(this.appController.pixelsPerUnit);
            glyphPositions.set([
                rect[0], rect[3],
                rect[2], rect[3],
                rect[0], rect[1],
                rect[2], rect[1],
            ], glyphIndex * 8);
            glyphIndices.set(Array.from(QUAD_ELEMENTS).map(index => index + 4 * glyphIndex),
                             glyphIndex * 6);
        }

        this.glyphPositionsBuffer = unwrapNull(this.gl.createBuffer());
        this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.glyphPositionsBuffer);
        this.gl.bufferData(this.gl.ARRAY_BUFFER, glyphPositions, this.gl.STATIC_DRAW);
        this.glyphElementsBuffer = unwrapNull(this.gl.createBuffer());
        this.gl.bindBuffer(this.gl.ELEMENT_ARRAY_BUFFER, this.glyphElementsBuffer);
        this.gl.bufferData(this.gl.ELEMENT_ARRAY_BUFFER, glyphIndices, this.gl.STATIC_DRAW);
    }

    private buildAtlasGlyphs() {
        const textGlyphs = this.appController.layout.textGlyphs;
        const pixelsPerUnit = this.appController.pixelsPerUnit;

        // Only build glyphs in view.
        const canvasRect = glmatrix.vec4.fromValues(-this.translation[0],
                                                    -this.translation[1],
                                                    -this.translation[0] + this.canvas.width,
                                                    -this.translation[1] + this.canvas.height);

        let atlasGlyphs =
            textGlyphs.filter(glyph => rectsIntersect(glyph.getRect(pixelsPerUnit), canvasRect))
                      .map(textGlyph => new AtlasGlyph(textGlyph.opentypeGlyph));
        atlasGlyphs.sort((a, b) => a.index - b.index);
        atlasGlyphs = _.sortedUniqBy(atlasGlyphs, glyph => glyph.index);
        this.appController.atlasGlyphs = atlasGlyphs;

        this.appController.atlas.layoutGlyphs(atlasGlyphs, pixelsPerUnit);

        const uniqueGlyphs = this.appController.layout.uniqueGlyphs;
        const uniqueGlyphIndices = uniqueGlyphs.map(glyph => glyph.index);
        uniqueGlyphIndices.sort((a, b) => a - b);

        // TODO(pcwalton): Regenerate the IBOs to include only the glyphs we care about.
        const transforms = new Float32Array((uniqueGlyphs.length + 1) * 4);

        for (let glyphIndex = 0; glyphIndex < atlasGlyphs.length; glyphIndex++) {
            const glyph = atlasGlyphs[glyphIndex];

            let pathID = _.sortedIndexOf(uniqueGlyphIndices, glyph.index);
            assert(pathID >= 0, "No path ID!");
            pathID++;

            const atlasLocation = glyph.getRect(pixelsPerUnit);
            const metrics = glyph.metrics;
            const left = metrics.xMin * pixelsPerUnit;
            const bottom = metrics.yMin * pixelsPerUnit;

            transforms[pathID * 4 + 0] = pixelsPerUnit;
            transforms[pathID * 4 + 1] = pixelsPerUnit;
            transforms[pathID * 4 + 2] = atlasLocation[0] - left;
            transforms[pathID * 4 + 3] = atlasLocation[1] - bottom;
        }

        this.pathTransformBufferTexture.upload(this.gl, transforms);
    }

    private createAtlasFramebuffer() {
        const atlasColorTexture = this.appController.atlas.ensureTexture(this.gl);
        this.atlasDepthTexture = createFramebufferDepthTexture(this.gl, ATLAS_SIZE);
        this.atlasFramebuffer = createFramebuffer(this.gl,
                                                    this.drawBuffersExt,
                                                    [atlasColorTexture],
                                                    this.atlasDepthTexture);

        // Allow the antialiasing strategy to set up framebuffers as necessary.
        this.antialiasingStrategy.setFramebufferSize(this);
    }

    private setGlyphTexCoords() {
        const textGlyphs = this.appController.layout.textGlyphs;
        const atlasGlyphs = this.appController.atlasGlyphs;

        const atlasGlyphIndices = atlasGlyphs.map(atlasGlyph => atlasGlyph.index);

        const glyphTexCoords = new Float32Array(textGlyphs.length * 8);

        const currentPosition = glmatrix.vec2.create();

        for (let textGlyphIndex = 0; textGlyphIndex < textGlyphs.length; textGlyphIndex++) {
            const textGlyph = textGlyphs[textGlyphIndex];
            const textGlyphMetrics = textGlyph.metrics;

            let atlasGlyphIndex = _.sortedIndexOf(atlasGlyphIndices, textGlyph.index);
            if (atlasGlyphIndex < 0)
                continue;

            // Set texture coordinates.
            const atlasGlyph = atlasGlyphs[atlasGlyphIndex];
            const atlasGlyphRect = atlasGlyph.getRect(this.appController.pixelsPerUnit);
            const atlasGlyphBL = atlasGlyphRect.slice(0, 2) as glmatrix.vec2;
            const atlasGlyphTR = atlasGlyphRect.slice(2, 4) as glmatrix.vec2;
            glmatrix.vec2.div(atlasGlyphBL, atlasGlyphBL, ATLAS_SIZE);
            glmatrix.vec2.div(atlasGlyphTR, atlasGlyphTR, ATLAS_SIZE);

            glyphTexCoords.set([
                atlasGlyphBL[0], atlasGlyphTR[1],
                atlasGlyphTR[0], atlasGlyphTR[1],
                atlasGlyphBL[0], atlasGlyphBL[1],
                atlasGlyphTR[0], atlasGlyphBL[1],
            ], textGlyphIndex * 8);
        }

        this.glyphTexCoordsBuffer = unwrapNull(this.gl.createBuffer());
        this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.glyphTexCoordsBuffer);
        this.gl.bufferData(this.gl.ARRAY_BUFFER, glyphTexCoords, this.gl.STATIC_DRAW);
    }

    attachText() {
        if (this.atlasFramebuffer == null)
            this.createAtlasFramebuffer();
        this.layoutGlyphs();

        this.rebuildAtlasIfNecessary();
    }

    private rebuildAtlasIfNecessary() {
        this.buildAtlasGlyphs();
        this.setGlyphTexCoords();
        this.setDirty();
    }

    protected panned() {
        this.rebuildAtlasIfNecessary();
    }

    private setIdentityTexScaleUniform(uniforms: UniformMap) {
        this.gl.uniform2f(uniforms.uTexScale, 1.0, 1.0);
    }

    protected get usedSizeFactor(): glmatrix.vec2 {
        const usedSize = glmatrix.vec2.create();
        glmatrix.vec2.div(usedSize, this.appController.atlas.usedSize, ATLAS_SIZE);
        return usedSize;
    }

    protected compositeIfNecessary() {
        // Set up composite state.
        this.gl.bindFramebuffer(this.gl.FRAMEBUFFER, null);
        this.gl.viewport(0, 0, this.canvas.width, this.canvas.height);
        this.gl.disable(this.gl.DEPTH_TEST);
        this.gl.disable(this.gl.BLEND);
        this.gl.disable(this.gl.SCISSOR_TEST);

        // Clear.
        this.gl.clearColor(1.0, 1.0, 1.0, 1.0);
        this.gl.clear(this.gl.COLOR_BUFFER_BIT);

        // Set up the composite VAO.
        const blitProgram = this.shaderPrograms.blit;
        const attributes = blitProgram.attributes;
        this.gl.useProgram(blitProgram.program);
        this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.glyphPositionsBuffer);
        this.gl.vertexAttribPointer(attributes.aPosition, 2, this.gl.FLOAT, false, 0, 0);
        this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.glyphTexCoordsBuffer);
        this.gl.vertexAttribPointer(attributes.aTexCoord, 2, this.gl.FLOAT, false, 0, 0);
        this.gl.enableVertexAttribArray(attributes.aPosition);
        this.gl.enableVertexAttribArray(attributes.aTexCoord);
        this.gl.bindBuffer(this.gl.ELEMENT_ARRAY_BUFFER, this.glyphElementsBuffer);

        // Create the transform.
        const transform = glmatrix.mat4.create();
        glmatrix.mat4.fromTranslation(transform, [-1.0, -1.0, 0.0]);
        glmatrix.mat4.scale(transform,
                            transform,
                            [2.0 / this.canvas.width, 2.0 / this.canvas.height, 1.0]);
        glmatrix.mat4.translate(transform,
                                transform,
                                [this.translation[0], this.translation[1], 0.0]);

        // Blit.
        this.gl.uniformMatrix4fv(blitProgram.uniforms.uTransform, false, transform);
        this.gl.activeTexture(this.gl.TEXTURE0);
        this.gl.bindTexture(this.gl.TEXTURE_2D, this.appController.atlas.ensureTexture(this.gl));
        this.gl.uniform1i(blitProgram.uniforms.uSource, 0);
        this.setIdentityTexScaleUniform(blitProgram.uniforms);
        this.gl.drawElements(this.gl.TRIANGLES,
                             this.appController.layout.textGlyphs.length * 6,
                             this.gl.UNSIGNED_INT,
                             0);
    }

    get bgColor(): glmatrix.vec4 {
        return glmatrix.vec4.fromValues(1.0, 1.0, 1.0, 1.0);
    }

    get fgColor(): glmatrix.vec4 {
        return glmatrix.vec4.fromValues(0.0, 0.0, 0.0, 1.0);
    }

    get destFramebuffer(): WebGLFramebuffer {
        return this.atlasFramebuffer;
    }

    get destAllocatedSize(): glmatrix.vec2 {
        return ATLAS_SIZE;
    }

    get destUsedSize(): glmatrix.vec2 {
        return this.appController.atlas.usedSize;
    }

    protected get scale(): number {
        return this.appController.fontSize;
    }

    protected set scale(newScale: number) {
        this.appController.fontSize = newScale;
    }

    protected createAAStrategy(aaType: AntialiasingStrategyName, aaLevel: number):
                               AntialiasingStrategy {
        return new (ANTIALIASING_STRATEGIES[aaType])(aaLevel);
    }

    protected updateTimings(timings: Timings) {
        this.appController.updateTimings(timings);
    }

    protected get worldTransform() {
        return glmatrix.mat4.create();
    }

    atlasFramebuffer: WebGLFramebuffer;
    atlasDepthTexture: WebGLTexture;

    glyphPositionsBuffer: WebGLBuffer;
    glyphTexCoordsBuffer: WebGLBuffer;
    glyphElementsBuffer: WebGLBuffer;

    appController: TextDemoController;
}

interface AntialiasingStrategyTable {
    none: typeof NoAAStrategy;
    ssaa: typeof SSAAStrategy;
    ecaa: typeof ECAAStrategy;
}

class Atlas {
    constructor() {
        this._texture = null;
        this._usedSize = glmatrix.vec2.create();
    }

    layoutGlyphs(glyphs: AtlasGlyph[], pixelsPerUnit: number) {
        let nextOrigin = glmatrix.vec2.create();
        let shelfBottom = 0.0;

        for (const glyph of glyphs) {
            // Place the glyph, and advance the origin.
            glyph.setPixelPosition(nextOrigin, pixelsPerUnit);
            nextOrigin[0] = glyph.getRect(pixelsPerUnit)[2];

            // If the glyph overflowed the shelf, make a new one and reposition the glyph.
            if (nextOrigin[0] > ATLAS_SIZE[0]) {
                nextOrigin = glmatrix.vec2.fromValues(0.0, shelfBottom);
                glyph.setPixelPosition(nextOrigin, pixelsPerUnit);
                nextOrigin[0] = glyph.getRect(pixelsPerUnit)[2];
            }

            // Grow the shelf as necessary.
            shelfBottom = Math.max(shelfBottom, glyph.getRect(pixelsPerUnit)[3]);
        }

        // FIXME(pcwalton): Could be more precise if we don't have a full row.
        this._usedSize = glmatrix.vec2.fromValues(ATLAS_SIZE[0], shelfBottom);
    }

    ensureTexture(gl: WebGLRenderingContext): WebGLTexture {
        if (this._texture != null)
            return this._texture;

        const texture = unwrapNull(gl.createTexture());
        this._texture = texture;
        gl.bindTexture(gl.TEXTURE_2D, texture);
        gl.texImage2D(gl.TEXTURE_2D,
                      0,
                      gl.RGBA,
                      ATLAS_SIZE[0],
                      ATLAS_SIZE[1],
                      0,
                      gl.RGBA,
                      gl.UNSIGNED_BYTE,
                      null);
        setTextureParameters(gl, gl.NEAREST);

        return texture;
    }

    get usedSize(): glmatrix.vec2 {
        return this._usedSize;
    }

    private _texture: WebGLTexture | null;
    private _usedSize: Size2D;
}

class AtlasGlyph extends PathfinderGlyph {
    constructor(glyph: opentype.Glyph) {
        super(glyph);
    }

    getRect(pixelsPerUnit: number): glmatrix.vec4 {
        const glyphSize = glmatrix.vec2.fromValues(this.metrics.xMax - this.metrics.xMin,
                                                   this.metrics.yMax - this.metrics.yMin);
        glmatrix.vec2.scale(glyphSize, glyphSize, pixelsPerUnit);
        glmatrix.vec2.ceil(glyphSize, glyphSize);

        const glyphBL = glmatrix.vec2.create(), glyphTR = glmatrix.vec2.create();
        glmatrix.vec2.scale(glyphBL, this.position, pixelsPerUnit);
        glmatrix.vec2.add(glyphBL, glyphBL, [1.0, 1.0]);
        glmatrix.vec2.add(glyphTR, glyphBL, glyphSize);
        glmatrix.vec2.add(glyphTR, glyphTR, [1.0, 1.0]);

        return glmatrix.vec4.fromValues(glyphBL[0], glyphBL[1], glyphTR[0], glyphTR[1]);
    }
}

class GlyphInstance extends PathfinderGlyph {
    constructor(glyph: opentype.Glyph) {
        super(glyph);
    }

    getRect(pixelsPerUnit: number): glmatrix.vec4 {
        // Determine the atlas size.
        const atlasSize = glmatrix.vec2.fromValues(this.metrics.xMax - this.metrics.xMin,
                                                   this.metrics.yMax - this.metrics.yMin);
        glmatrix.vec2.scale(atlasSize, atlasSize, pixelsPerUnit);
        glmatrix.vec2.ceil(atlasSize, atlasSize);

        // Set positions.
        const textGlyphBL = glmatrix.vec2.create(), textGlyphTR = glmatrix.vec2.create();
        const offset = glmatrix.vec2.fromValues(this.metrics.leftSideBearing,
                                                this.metrics.yMin);
        glmatrix.vec2.add(textGlyphBL, this.position, offset);
        glmatrix.vec2.scale(textGlyphBL, textGlyphBL, pixelsPerUnit);
        glmatrix.vec2.round(textGlyphBL, textGlyphBL);
        glmatrix.vec2.add(textGlyphTR, textGlyphBL, atlasSize);

        return glmatrix.vec4.fromValues(textGlyphBL[0], textGlyphBL[1],
                                        textGlyphTR[0], textGlyphTR[1]);
    }
}

const ANTIALIASING_STRATEGIES: AntialiasingStrategyTable = {
    none: NoAAStrategy,
    ssaa: SSAAStrategy,
    ecaa: ECAAMonochromeStrategy,
};

function main() {
    const controller = new TextDemoController;
    window.addEventListener('load', () => controller.start(), false);
}

main();