1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14precision mediump float;
15uniform vec3 u_LightPos;
16uniform sampler2D u_Texture;
17varying vec3 v_Position;
18varying vec3 v_Normal;
19varying vec2 v_TexCoordinate;
20void main() {
21  // Get a lighting direction vector from the light to the vertex.
22  vec3 lightVector = normalize(u_LightPos - v_Position);
23  // Calculate the dot product of the light vector and vertex normal.
24  float diffuse = max(dot(lightVector, v_Normal), 0.0);
25  // Add ambient lighting
26  diffuse = diffuse + 0.25;
27  // Multiply the diffuse illumination and texture to get final output color.
28  gl_FragColor = (diffuse * texture2D(u_Texture, v_TexCoordinate));
29}