Android的OpenGL ES的过程YUV preVIEW为RGBA

我想使用OpenGL从摄像头，格式是NV21 Android平台处理数据。

I want to use OpenGL to process the data from camera which format is NV21 on Android platform.

我的code是如下：

顶点着色器：

attribute vec4 position;
attribute vec2 inputTextureCoordinate;
varying vec2 v_texCoord;
void main()
{
   gl_Position = position;
   v_texCoord = inputTextureCoordinate;
}

片段着色器：

precision mediump float;
varying vec2 v_texCoord;
uniform sampler2D yTexture; 
uniform sampler2D uvTexture;
const mat3 yuv2rgb = mat3(
                        1, 0, 1.2802,
                        1, -0.214821, -0.380589,
                        1, 2.127982, 0
                        );

void main() {    
    vec3 yuv = vec3(
                1.1643 * (texture2D(yTexture, v_texCoord).r - 0.0627),
                texture2D(uvTexture, v_texCoord).a - 0.5,
                texture2D(uvTexture, v_texCoord).r - 0.5
                );
    vec3 rgb = yuv * yuv2rgb;
    gl_FragColor = vec4(rgb, 1.0);
}

我送yTexture：

I send yTexture:

GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, w, h, 0,                  GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE,                           ByteBuffer.wrap(data));

，其中数据是相机preVIEW的NV21格式字节数组
我送uvTexture：

where data was the nv21 format byte array of camera preview And I send uvTexture:

byte[] luminanceAlpha = new byte[w * h / 2];
System.arraycopy(data, w * h, luminanceAlpha, 0, w * h / 2);
GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0,            GLES20.GL_LUMINANCE_ALPHA, w / 2, h / 2, 0,                             GLES20.GL_LUMINANCE_ALPHA,                              GLES20.GL_UNSIGNED_BYTE, ByteBuffer.wrap(luminanceAlpha));

这就是所有的code我认为是非常重要的。但是，当我运行程序时，我发现结果GLSurfaceView看起来更蓝。有什么毛病我code。我很烦恼。

That's all the code which I thought was important. But when I run the program, I found the result in GLSurfaceView looks more bluer. Is there any wrong with my code. I was very trouble.