/*
 * Copyright (c) 2012 Adobe Systems Incorporated. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

precision mediump float;

// Uniforms passed in from CSS

uniform float amount;

// Varyings

varying float v_lighting;
varying float xpos;

// Main

void main()
{
  float alpha = abs(xpos) <= (amount * 0.5) ? 0.0 : 1.0;

  /* Remove any perspective artifacts */
  if (amount == 1.0) alpha = 0.0;

  css_ColorMatrix = mat4(
       vec4(v_lighting, 0.0, 0.0, 0.0),
        vec4(0.0, v_lighting, 0.0, 0.0),
        vec4(0.0, 0.0, v_lighting, 0.0),
        vec4(0.0, 0.0, 0.0, alpha)
    );
}