webgl2/gl.js at master · xernobyl/webgl2 · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
const DEBUG = true

export class GL {
  static #canvas
  static #gl
  static #frame = 0
  static #time = 0.0        // milliseconds
  static #timeOffset = 0.0  // milliseconds
  static #frameDuration     // milliseconds
  static #cbLoad = null
  static #cbLoop = null
  static #cbResize = null
  static #aspectRatio

  static #createCanvas() {
    GL.#canvas = document.createElement('canvas')

    Object.assign(document.body.style, {
      margin: '0',
      padding: '0',
      overflow: 'hidden',
      position: 'fixed',
      width: '100vw',
      height: '100vh'
    })

    Object.assign(GL.#canvas.style, {
      display: 'block',
      width: '100%',
      height: '100%'
    })
  }

  static #createContext() {
    GL.#gl = GL.#canvas.getContext('webgl2', { alpha: false, depth: false, stencil: false, antialias: false })
    if (GL.#gl === null) {
      throw new Error('WebGL 2.0 not supported, apparently 🤷')
    }

    const ext = GL.#gl.getExtension('EXT_color_buffer_float')
    if (!ext) {
      throw new Error('Floating-point rendering not supported! We kind of need that')
    }

    console.log(GL.#gl.getSupportedExtensions())
  }

  static #onResize() {
    const rect = GL.#canvas.getBoundingClientRect()
    const dpr = devicePixelRatio || 1
    const width = Math.floor(rect.width * dpr)
    const height = Math.floor(rect.height * dpr)

    GL.#aspectRatio = width / height

    if (GL.#canvas.width !== width || GL.#canvas.height !== height) {
      GL.#canvas.width = width
      GL.#canvas.height = height

      if (GL.#cbResize !== null) {
        GL.#cbResize()
      }
    }
  }

  static #logStats() {
    // console.log(`Frames: ${GL.#frame}`)
    // console.log(`FPS: ${10000.0 / GL.#frameDuration}`)
  }

  static #renderLoop(frameTime) {
    if (GL.#frame === 0) {
      GL.#timeOffset = frameTime
    }

    const previousTime = GL.#time
    GL.#time = frameTime - GL.#timeOffset
    GL.#frameDuration = (frameTime - previousTime)

    if (GL.#frame % 120 === 119) {
      GL.#logStats()
    }

    GL.#cbLoop()

    ++GL.#frame
    requestAnimationFrame(GL.#renderLoop)
  }

  static #onLoad() {


    GL.#createCanvas()
    GL.#createContext()

    if (GL.#cbLoad !== null) {
      GL.#cbLoad()
    }

    document.body.appendChild(GL.#canvas)

    GL.#onResize()
    addEventListener('resize', GL.#onResize)

    requestAnimationFrame(GL.#renderLoop)
  }

  static init(load, loop, resize) {
    GL.#cbLoad = load
    GL.#cbLoop = loop
    GL.#cbResize = resize
    //addEventListener('load', GL.#onLoad)
    GL.#onLoad()
  }

  static get gl() {
    return GL.#gl
  }

  static get canvas() {
    return GL.#canvas
  }

  static get frame() {
    return GL.#frame
  }

  static get time() {
    return GL.#time
  }

  static get timeOffset() {
    return GL.#timeOffset
  }

  static get aspectRatio() {
    return GL.#aspectRatio
  }
}