pub/vector_math/lib/src/vector_math_geometry/filters/color_filter.dart

// Copyright (c) 2015, Google Inc. Please see the AUTHORS file for details.
// All rights reserved. Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

part of vector_math_geometry;

class ColorFilter extends GeometryFilter {
  Vector4 color;

  ColorFilter(this.color);

  @override
  List<VertexAttrib> get generates =>
      <VertexAttrib>[new VertexAttrib('COLOR', 4, 'float')];

  @override
  MeshGeometry filter(MeshGeometry mesh) {
    MeshGeometry output;
    if (mesh.getAttrib('COLOR') == null) {
      final List<VertexAttrib> attributes = <VertexAttrib>[]
        ..addAll(mesh.attribs)
        ..add(new VertexAttrib('COLOR', 4, 'float'));
      output = new MeshGeometry.resetAttribs(mesh, attributes);
    } else {
      output = new MeshGeometry.copy(mesh);
    }

    final VectorList<Vector> colors = output.getViewForAttrib('COLOR');
    if (colors is Vector4List) {
      for (int i = 0; i < colors.length; ++i) {
        colors[i] = color;
      }
      return output;
    } else {
      return null;
    }
  }
}