WebGL renderer!

js/term/font_cache.js

@@ -0,0 +1,59 @@
+module.exports = class GLFontCache {
+  constructor (gl) {
+    this.gl = gl
+
+    // cache: string => WebGLTexture
+    this.cache = new Map()
+    this.dp = 1
+    this.cellSize = { width: 0, height: 0 }
+
+    this.canvas = document.createElement('canvas')
+    this.ctx = this.canvas.getContext('2d')
+  }
+
+  clearCache () {
+    for (let texture of this.cache.values()) this.gl.deleteTexture(texture)
+    this.cache = new Map()
+  }
+
+  getChar (font, character) {
+    let name = `${font}@${this.dp}x:${character}`
+
+    if (!this.cache.has(name)) {
+      this.cache.set(name, this.render(font, character))
+    }
+    return this.cache.get(name)
+  }
+
+  render (font, character) {
+    const { gl, ctx, dp, cellSize } = this
+
+    let width = dp * cellSize.width * 3
+    let height = dp * cellSize.height * 3
+    if (this.canvas.width !== width) this.canvas.width = width
+    if (this.canvas.height !== height) this.canvas.height = height
+
+    ctx.setTransform(1, 0, 0, 1, 0, 0)
+    ctx.clearRect(0, 0, width, height)
+    ctx.scale(dp, dp)
+
+    if (ctx.font !== font) ctx.font = font
+
+    ctx.textAlign = 'center'
+    ctx.textBaseline = 'middle'
+    ctx.fillStyle = 'white'
+    ctx.fillText(character, cellSize.width * 1.5, cellSize.height * 1.5)
+
+    let imageData = ctx.getImageData(0, 0, width, height)
+
+    let texture = gl.createTexture()
+    gl.bindTexture(gl.TEXTURE_2D, texture)
+    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, imageData)
+
+    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
+    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
+    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
+
+    return texture
+  }
+}

js/term/screen_layout.js

@@ -1,5 +1,6 @@
 const EventEmitter = require('events')
-const CanvasRenderer = require('./screen_renderer')
+const CanvasRenderer = require('./canvas_renderer')
+const WebGLRenderer = require('./webgl_renderer')
 
 /**
  * Manages terminal screen layout and sizing
@@ -9,7 +10,11 @@ module.exports = class ScreenLayout extends EventEmitter {
     super()
 
     this.canvas = document.createElement('canvas')
+    try {
+      this.renderer = new WebGLRenderer(this.canvas)
+    } catch (err) {
       this.renderer = new CanvasRenderer(this.canvas)
+    }
 
     this._window = {
       width: 0,
@@ -243,7 +248,7 @@ module.exports = class ScreenLayout extends EventEmitter {
       this.canvas.style.height = `${realHeight}px`
 
       // the screen has been cleared (by changing canvas width)
-      this.renderer.resetDrawn()
+      this.renderer.resetDrawn(this.canvas.width, this.canvas.height)
 
       this.renderer.render('update-size', this.serializeRenderData())
 

js/term/webgl_renderer.js

@@ -0,0 +1,409 @@
+const EventEmitter = require('events')
+const FontCache = require('./font_cache')
+const { themes, getColor } = require('./themes')
+const {
+  ATTR_FG,
+  ATTR_BG,
+  ATTR_BOLD,
+  ATTR_UNDERLINE,
+  ATTR_INVERSE,
+  ATTR_BLINK,
+  ATTR_ITALIC,
+  ATTR_STRIKE,
+  ATTR_OVERLINE,
+  ATTR_FAINT,
+  ATTR_FRAKTUR
+} = require('./screen_attr_bits')
+
+module.exports = class WebGLRenderer extends EventEmitter {
+  constructor (canvas) {
+    super()
+
+    this.canvas = canvas
+    this.gl = this.canvas.getContext('webgl') || this.canvas.getContext('experimental-webgl')
+    if (!this.gl) throw new Error('No WebGL context')
+
+    this.fontCache = new FontCache(this.gl)
+
+    this._palette = null
+    this.defaultBG = 0
+    this.defaultFG = 7
+
+    this._debug = null
+
+    // screen data, considered immutable
+    this.width = 0
+    this.height = 0
+    this.padding = 0
+    this.charSize = { width: 0, height: 0 }
+    this.cellSize = { width: 0, height: 0 }
+    this.fonts = ['', '', '', ''] // normal, bold, italic, bold-italic
+    this.screen = []
+    this.screenFG = []
+    this.screenBG = []
+    this.screenAttrs = []
+    this.screenSelection = []
+    this.cursor = {}
+    this.hasBlinkingCells = false
+    this.statusScreen = null
+
+    this.blinkStyleOn = false
+    this.blinkInterval = null
+    this.cursorBlinkOn = false
+    this.cursorBlinkInterval = null
+
+    this.resetDrawn(100, 100)
+
+    // start blink timers
+    this.resetBlink()
+    this.resetCursorBlink()
+
+    this.init()
+  }
+
+  render (reason, data) {
+    if ('hasBlinkingCells' in data && data.hasBlinkingCells !== this.hasBlinkingCells) {
+      if (data.hasBlinkingCells) this.resetBlink()
+      else clearInterval(this.blinkInterval)
+    }
+
+    Object.assign(this, data)
+    this.scheduleDraw(reason)
+  }
+
+  resetDrawn (width, height) {
+    this.gl.clearColor(0, 0, 0, 1)
+    this.gl.viewport(0, 0, width, height)
+    this.gl.enable(this.gl.BLEND)
+    this.gl.blendFunc(this.gl.SRC_ALPHA, this.gl.ONE_MINUS_SRC_ALPHA)
+  }
+
+  /**
+   * The color palette. Should define 16 colors in an array.
+   * @type {string[]}
+   */
+  get palette () {
+    return this._palette || themes[0]
+  }
+
+  /** @type {string[]} */
+  set palette (palette) {
+    if (this._palette !== palette) {
+      this._palette = palette
+      this.emit('palette-update', palette)
+      this.scheduleDraw('palette')
+    }
+  }
+
+  getCharWidthFor (font) {
+    this.fontCache.ctx.font = font
+    return Math.floor(this.fontCache.ctx.measureText(' ').width)
+  }
+
+  loadTheme (i) {
+    if (i in themes) this.palette = themes[i]
+  }
+
+  setDefaultColors (fg, bg) {
+    if (fg !== this.defaultFG || bg !== this.defaultBG) {
+      this.defaultFG = fg
+      this.defaultBG = bg
+      this.scheduleDraw('default-colors')
+
+      // full bg with default color (goes behind the image)
+      this.canvas.style.backgroundColor = this.getColor(bg)
+    }
+  }
+
+  /**
+   * Schedule a draw in the next millisecond
+   * @param {string} why - the reason why the draw occured (for debugging)
+   * @param {number} [aggregateTime] - time to wait for more scheduleDraw calls
+   *   to occur. 1 ms by default.
+   */
+  scheduleDraw (why, aggregateTime = 1) {
+    clearTimeout(this._scheduledDraw)
+    this._scheduledDraw = setTimeout(() => this.draw(why), aggregateTime)
+  }
+
+  /**
+   * Returns the specified color. If `i` is in the palette, it will return the
+   * palette color. If `i` is between 16 and 255, it will return the 256color
+   * value. If `i` is larger than 255, it will return an RGB color value. If `i`
+   * is -1 (foreground) or -2 (background), it will return the selection colors.
+   * @param {number} i - the color
+   * @returns {string} the CSS color
+   */
+  getColor (i) {
+    return WebGLRenderer.colorToRGBA(getColor(i, this.palette))
+  }
+
+  /**
+   * Resets the cursor blink to on and restarts the timer
+   */
+  resetCursorBlink () {
+    this.cursorBlinkOn = true
+    clearInterval(this.cursorBlinkInterval)
+    this.cursorBlinkInterval = setInterval(() => {
+      this.cursorBlinkOn = this.cursor.blinking ? !this.cursorBlinkOn : true
+      if (this.cursor.blinking) this.scheduleDraw('cursor-blink')
+    }, 500)
+  }
+
+  /**
+   * Resets the blink style to on and restarts the timer
+   */
+  resetBlink () {
+    this.blinkStyleOn = true
+    clearInterval(this.blinkInterval)
+    let intervals = 0
+    this.blinkInterval = setInterval(() => {
+      if (this.blinkingCellCount <= 0) return
+
+      intervals++
+      if (intervals >= 4 && this.blinkStyleOn) {
+        this.blinkStyleOn = false
+        intervals = 0
+        this.scheduleDraw('blink-style')
+      } else if (intervals >= 1 && !this.blinkStyleOn) {
+        this.blinkStyleOn = true
+        intervals = 0
+        this.scheduleDraw('blink-style')
+      }
+    }, 200)
+  }
+
+  compileShader (vertex, fragment) {
+    const { gl } = this
+    let vert = gl.createShader(gl.VERTEX_SHADER)
+    gl.shaderSource(vert, vertex)
+    gl.compileShader(vert)
+    let frag = gl.createShader(gl.FRAGMENT_SHADER)
+    gl.shaderSource(frag, fragment)
+    gl.compileShader(frag)
+    if (!gl.getShaderParameter(vert, gl.COMPILE_STATUS) || !gl.getShaderParameter(frag, gl.COMPILE_STATUS)) {
+      console.error(gl.getShaderInfoLog(vert), gl.getShaderInfoLog(frag))
+      gl.deleteShader(vert)
+      gl.deleteShader(frag)
+      throw new Error('Shader compile error')
+    }
+
+    let shader = gl.createProgram()
+    gl.attachShader(shader, vert)
+    gl.attachShader(shader, frag)
+    gl.linkProgram(shader)
+
+    if (!gl.getProgramParameter(shader, gl.LINK_STATUS)) {
+      console.error(gl.getProgramInfoLog(shader))
+      throw new Error('Shader link error')
+    }
+
+    return shader
+  }
+
+  init () {
+    const { gl } = this
+
+    let bgShader = this.compileShader(`
+precision mediump float;
+attribute vec2 position;
+uniform mat4 projection;
+uniform vec2 char_pos;
+void main() {
+  gl_Position = projection * vec4(char_pos + position, 0.0, 1.0);
+}
+    `, `
+precision highp float;
+uniform vec4 color;
+void main() {
+  gl_FragColor = color;
+}
+    `)
+
+    let charShader = this.compileShader(`
+precision mediump float;
+attribute vec2 position;
+uniform mat4 projection;
+uniform vec2 char_pos;
+varying highp vec2 tex_coord;
+void main() {
+  gl_Position = projection * vec4(char_pos - vec2(1.0, 1.0) + 3.0 * position, 0.0, 1.0);
+  tex_coord = position;
+}
+    `, `
+precision highp float;
+uniform vec4 color;
+uniform sampler2D texture;
+varying highp vec2 tex_coord;
+void main() {
+  gl_FragColor = texture2D(texture, tex_coord) * color;
+}
+    `)
+
+    this.bgShader = {
+      shader: bgShader,
+      attributes: {
+        position: gl.getAttribLocation(bgShader, 'position')
+      },
+      uniforms: {
+        projection: gl.getUniformLocation(bgShader, 'projection'),
+        charPos: gl.getUniformLocation(bgShader, 'char_pos'),
+        color: gl.getUniformLocation(bgShader, 'color')
+      }
+    }
+
+    this.charShader = {
+      shader: charShader,
+      attributes: {
+        position: gl.getAttribLocation(charShader, 'position')
+      },
+      uniforms: {
+        projection: gl.getUniformLocation(charShader, 'projection'),
+        charPos: gl.getUniformLocation(charShader, 'char_pos'),
+        color: gl.getUniformLocation(charShader, 'color'),
+        texture: gl.getUniformLocation(charShader, 'texture')
+      }
+    }
+
+    let buffer = gl.createBuffer()
+    gl.bindBuffer(gl.ARRAY_BUFFER, buffer)
+    gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
+      1, 1,
+      0, 1,
+      1, 0,
+      0, 0
+    ]), gl.STATIC_DRAW)
+    this.squareBuffer = buffer
+    this.useShader = (shader, projection) => {
+      gl.vertexAttribPointer(shader.attributes.position, 2, gl.FLOAT, false, 0, 0)
+      gl.enableVertexAttribArray(shader.attributes.position)
+      gl.useProgram(shader.shader)
+
+      gl.uniformMatrix4fv(shader.uniforms.projection, false, projection)
+    }
+    this.drawSquare = () => {
+      gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4)
+    }
+  }
+
+  draw (reason) {
+    const { gl, width, height, padding, devicePixelRatio } = this
+
+    if (this.debug && this._debug) this._debug.drawStart(reason)
+
+    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
+    this.fontCache.cellSize = this.cellSize
+    this.fontCache.dp = devicePixelRatio
+
+    let paddingX = padding / this.cellSize.width
+    let paddingY = padding / this.cellSize.height
+
+    let projection = new Float32Array([
+      2 / (width + 2 * paddingX), 0, 0, 0,
+      0, -2 / (height + 2 * paddingY), 0, 0,
+      0, 0, 1, 0,
+      -1 + 2 * paddingX / width, 1 - 2 * paddingY / height, 0, 1
+    ])
+
+    // draw background
+    this.useShader(this.bgShader, projection)
+
+    let textCells = {}
+
+    for (let cell = 0; cell < width * height; cell++) {
+      let x = cell % width
+      let y = Math.floor(cell / width)
+      let isCursor = this.cursorBlinkOn &&
+        this.cursor.x === x &&
+        this.cursor.y === y &&
+        this.cursor.visible
+
+      let text = this.screen[cell]
+      let fg = this.screenFG[cell] | 0
+      let bg = this.screenBG[cell] | 0
+      let attrs = this.screenAttrs[cell] | 0
+      let inSelection = this.screenSelection[cell]
+
+      // let isDefaultBG = false
+
+      if (!(attrs & ATTR_FG)) fg = this.defaultFG
+      if (!(attrs & ATTR_BG)) {
+        bg = this.defaultBG
+        // isDefaultBG = true
+      }
+
+      if (attrs & ATTR_INVERSE) [fg, bg] = [bg, fg] // swap - reversed character colors
+      if (this.screen.reverseVideo) [fg, bg] = [bg, fg] // swap - reversed all screen
+
+      if (attrs & ATTR_BLINK && !this.blinkStyleOn) {
+        // blinking is enabled and blink style is off
+        // set text to nothing so drawCharacter only draws decoration
+        text = ' '
+      }
+
+      if (inSelection) {
+        fg = -1
+        bg = -2
+      }
+
+      // TODO: actual cursor
+      if (isCursor) [fg, bg] = [bg, fg]
+
+      gl.uniform2f(this.bgShader.uniforms.charPos, x, y)
+      gl.uniform4f(this.bgShader.uniforms.color, ...this.getColor(bg))
+
+      this.drawSquare()
+
+      if (text.trim()) {
+        let fontIndex = 0
+        if (attrs & ATTR_BOLD) fontIndex |= 1
+        if (attrs & ATTR_ITALIC) fontIndex |= 2
+        let font = this.fonts[fontIndex]
+        let type = font + text
+
+        if (!textCells[type]) textCells[type] = []
+        textCells[type].push({ x, y, text, font, fg })
+      }
+    }
+
+    this.useShader(this.charShader, projection)
+    gl.activeTexture(gl.TEXTURE0)
+
+    for (let key in textCells) {
+      let { font, text } = textCells[key][0]
+      let texture = this.fontCache.getChar(font, text)
+      gl.bindTexture(gl.TEXTURE_2D, texture)
+      gl.uniform1i(this.charShader.uniforms.texture, 0)
+
+      for (let cell of textCells[key]) {
+        let { x, y, fg } = cell
+
+        gl.uniform2f(this.charShader.uniforms.charPos, x, y)
+        gl.uniform4f(this.charShader.uniforms.color, ...this.getColor(fg))
+
+        this.drawSquare()
+      }
+    }
+
+    if (this.debug && this._debug) this._debug.drawEnd()
+  }
+
+  static colorToRGBA (color) {
+    color = color.substr(1)
+    if (color.length === 3) {
+      return [
+        parseInt(color[0], 16) * 0x11 / 0xff,
+        parseInt(color[1], 16) * 0x11 / 0xff,
+        parseInt(color[2], 16) * 0x11 / 0xff,
+        1
+      ]
+    } else {
+      return [
+        parseInt(color.substr(0, 2), 16) / 0xff,
+        parseInt(color.substr(2, 2), 16) / 0xff,
+        parseInt(color.substr(4, 2), 16) / 0xff,
+        1
+      ]
+    }
+  }
+}