<!-- Tell the system this app requires OpenGL ES 2.0. -->
<uses-feature android:glEsVersion="0x00020000" android:required="true" />

 attribute vec4 vPosition;
 void main() {
  gl_Position = vPosition;
 }

 precision mediump float;
 uniform vec4 vColor;
 void main() {
  gl_FragColor = vColor;
 }

float triangleCoords[] = {
   0.5f, 0.5f, 0.0f, // top
   -0.5f, -0.5f, 0.0f, // bottom left
   0.5f, -0.5f, 0.0f // bottom right
 };

float color[] = { 1.0f, 1.0f, 1.0f, 1.0f }; //白色

 //将背景设置为灰色
 GLES20.glClearColor(0.5f,0.5f,0.5f,1.0f); 
 //申请底层空间
 ByteBuffer bb = ByteBuffer.allocateDirect(
    triangleCoords.length * 4);
 bb.order(ByteOrder.nativeOrder());
 //将坐标数据转换为FloatBuffer，用以传入给OpenGL ES程序
 vertexBuffer = bb.asFloatBuffer();
 vertexBuffer.put(triangleCoords);
 vertexBuffer.position(0); 
 int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER,
    vertexShaderCode);
 int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER,
    fragmentShaderCode);

 //创建一个空的OpenGLES程序
 mProgram = GLES20.glCreateProgram();
 //将顶点着色器加入到程序
 GLES20.glAttachShader(mProgram, vertexShader);
 //将片元着色器加入到程序中
 GLES20.glAttachShader(mProgram, fragmentShader);
 //连接到着色器程序
 GLES20.glLinkProgram(mProgram);

GLES20.glViewport(0,0,width,height);

 //将程序加入到OpenGLES2.0环境
 GLES20.glUseProgram(mProgram);

 //获取顶点着色器的vPosition成员句柄
 mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
 //启用三角形顶点的句柄
 GLES20.glEnableVertexAttribArray(mPositionHandle);
 //准备三角形的坐标数据
 GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
   GLES20.GL_FLOAT, false,
   vertexStride, vertexBuffer);
 //获取片元着色器的vColor成员的句柄
 mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
 //设置绘制三角形的颜色
 GLES20.glUniform4fv(mColorHandle, 1, color, 0);
 //绘制三角形
 GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);
 //禁止顶点数组的句柄
 GLES20.glDisableVertexAttribArray(mPositionHandle);