khronos_api 3.1.0

The Khronos XML API Registry, exposed as byte string constants.
Documentation 
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

<?xml version="1.0" encoding="UTF-8"?>
<!-- vi:set sw=2 ts=4: -->
<?xml-stylesheet href="../../extension.xsl" type="text/xsl"?>
<draft href="KHR_parallel_shader_compile/">
  <name>KHR_parallel_shader_compile</name>

  <contact> <a href="https://www.khronos.org/webgl/public-mailing-list/">WebGL
  working group</a> (public_webgl 'at' khronos.org) </contact>

  <contributors>
    <contributor>Jie Chen, (jie.a.chen 'at' intel.com)</contributor>
    <contributor>Geoff Lang, (geofflang 'at' google.com)</contributor>
    <contributor>Members of the WebGL working group</contributor>
  </contributors>

  <number>37</number>

  <depends>
    <api version="1.0"/>
  </depends>

  <overview>
    <mirrors href="https://www.khronos.org/registry/OpenGL/extensions/KHR/KHR_parallel_shader_compile.txt"
             name="KHR_parallel_shader_compile">
    </mirrors>

    <features>
      <feature>
        Shader compilation and program linking may be performed in a separate CPU thread. This extension provides a mechanism for the application to provide a hint to limit the number of threads it wants to be used to compile shaders, as well as a query to determine if the compilation process is complete.
      </feature>
    </features>
  </overview>

  <idl xml:space="preserve">
    [NoInterfaceObject]
    interface KHR_parallel_shader_compile {
      const GLenum MAX_SHADER_COMPILER_THREADS_KHR      = 0x91B0;
      const GLenum COMPLETION_STATUS_KHR                = 0x91B1;

      void maxShaderCompilerThreadsKHR(GLuint count);
    };
  </idl>

  <samplecode xml:space="preserve">
    <pre>
    var canvas = document.createElement("canvas");
    var gl = canvas.getContext("webgl");
    var ext = gl.getExtension('KHR_parallel_shader_compile');
    if (ext) {
      // Just for demo of API usage. Generally it's not needed unless you really
      // want to override the implementation-specific maximum.
      var threads = gl.getParameter(ext.MAX_SHADER_COMPILER_THREADS_KHR);
      ext.maxShaderCompilerThreadsKHR(Math.max(2, threads));
    }

    var vSource = "attribute vec2 position; void main() { gl_Position = vec4(position, 0, 1); }";
    var fSource = "precision mediump float; void main() { gl_FragColor = vec4(1,0,0,1); }";

    var vShader = gl.createShader(gl.VERTEX_SHADER);
    gl.shaderSource(vShader, vSource);
    gl.compileShader(vShader);

    var fShader = gl.createShader(gl.FRAGMENT_SHADER);
    gl.shaderSource(fShader, fSource);
    gl.compileShader(fShader);

    var program = gl.createProgram();
    gl.attachShader(program, vShader);
    gl.attachShader(program, fShader);
    gl.linkProgram(program);

    function checkToUseProgram() {
      if (gl.getProgramParameter(program, gl.LINK_STATUS) == true) {
        gl.useProgram(program);
      } else {
        // error check.
      }
    }

    if (ext) {
      function checkCompletion() {
        if (gl.getProgramParameter(program, ext.COMPLETION_STATUS_KHR) == true) {
          checkToUseProgram();
        } else {
          requestAnimationFrame(checkCompletion);
        }
      }
      requestAnimationFrame(checkCompletion);
    } else {
      checkToUseProgram();
    }
    </pre>
  </samplecode>

  <history>
    <revision date="2018/08/07">
      <change>Initial revision.</change>
    </revision>
    <revision date="2018/09/14">
      <change>Moved to draft status.</change>
    </revision>
  </history>
</draft>