Function webglNodeProgram

src/WebGL/webglNodeProgram.js:15–163

* Defines simple UI for nodes in webgl renderer. Each node is rendered as square. Color and size can be changed.

()

 * Defines simple UI for nodes in webgl renderer. Each node is rendered as square. Color and size can be changed.
 */
function webglNodeProgram() {
  var ATTRIBUTES_PER_PRIMITIVE = 4; // Primitive is point, x, y, size, color
  // x, y, z - floats, color = uint.
  var BYTES_PER_NODE = 3 * Float32Array.BYTES_PER_ELEMENT + Uint32Array.BYTES_PER_ELEMENT;
  var nodesFS = [
    'precision mediump float;',
    'varying vec4 color;',

    'void main(void) {',
    '   gl_FragColor = color;',
    '}'
  ].join('\n');
  var nodesVS = [
    'attribute vec3 a_vertexPos;',
    'attribute vec4 a_color;',
    'uniform vec2 u_screenSize;',
    'uniform mat4 u_transform;',
    'varying vec4 color;',

    'void main(void) {',
    '   gl_Position = u_transform * vec4(a_vertexPos.xy/u_screenSize, 0, 1);',
    '   gl_PointSize = a_vertexPos.z * u_transform[0][0];',
    '   color = a_color.abgr;',
    '}'
  ].join('\n');

  var program;
  var gl;
  var buffer;
  var locations;
  var utils;
  var storage = new ArrayBuffer(16 * BYTES_PER_NODE);
  var positions = new Float32Array(storage);
  var colors = new Uint32Array(storage);
  var nodesCount = 0;
  var width;
  var height;
  var transform;
  var sizeDirty;

  return {
    load: load,

    /**
     * Updates position of node in the buffer of nodes.
     *
     * @param idx - index of current node.
     * @param pos - new position of the node.
     */
    position: position,

    updateTransform: updateTransform,

    updateSize: updateSize,

    removeNode: removeNode,

    createNode: createNode,