Working example with v3v?

I'm trying to pass an array of vec3's for use in a palette lookup... I tried the following but no dice:

  //SHADER CODE:

  precision mediump float;

  uniform vec3 palette[1];
  varying vec2 vTextureCoord;

  void main() {

    vec3 pColor = palette[0];
    gl_FragColor.r = pColor.r;
    gl_FragColor.g = pColor.g;
    gl_FragColor.b = pColor.b;
    gl_FragColor.a = 1.0;


  }

//FILTER:

var PaletteFilter = function(initPalettes) {
      var vertexShader = $("#default-vertex-shader").text();
      var fragmentShader = $("#palette-fragment-shader").text();
      PIXI.Filter.call(this, vertexShader, fragmentShader, {
          palette: {
            type: 'v3v',
            value: initPalettes
          }
      });

  }

  PaletteFilter.prototype = Object.create(PIXI.Filter.prototype);
  PaletteFilter.prototype.constructor = PaletteFilter;
  Object.defineProperties(PaletteFilter.prototype, {

      lPalettes: {
          get: function() {
              return this.uniforms.palette;
          },
          set: function(value) {
              this.uniforms.palette = value;
          }
      },
  });

//Called like:

graphics.filters = [new RGBA_LETTERS.LettersPaletteFilter([
        {x: 0xFF, y: 0xFF, z: 0xFF}
        //tried other stuff like PIXI.utils.hex2rgb(0x00FFFF)
      ])];