OpenGL ES渲染YUV纹理

OpenGL中是不能直接渲染YUV数据的，但是我们可以用3个纹理来

分别获得Y、U和V的值，然后按照公式：

r = y + 1.403 * v;

g = y - 0.344 * u - 0.714 * v;

b = y + 1.770 * u;

转为rgb颜色格式显示出来。这个转化过程是在GPU中完成的万能播放器java版，计算

效率比在CPU中计算高很多倍！

vertex_shader.glsl

attribute ve av_Position;
attribute vec2 af_Position;
varying vec2 v_texPosition;
void main() {
    v_texPosition = af_Position;
    gl_Position = av_Position;
}

注： attribute 只能在vertex中使用

varying 用于vertex和fragment之间传递值

fragment_shader.glsl

precision mediump float;
varying vec2 v_texPosition;
uniform sampler2D sampler_y;
uniform sampler2D sampler_u;
uniform sampler2D sampler_v;
void main() {
    float y,u,v;
    y = texture2D(sampler_y,v_texPosition).r;
    u = texture2D(sampler_u,v_texPosition).r- 0.5;
    v = texture2D(sampler_v,v_texPosition).r- 0.5;
    vec3 rgb;
    rgb.r = y + 1.403 * v;
    rgb.g = y - 0.344 * u - 0.714 * v;
    rgb.b = y + 1.770 * u;
    gl_FragColor = ve(rgb,1);
}

注： uniform 用于在application中向vertex和fragment中释放值。

实现OpenGL ES的工具类-JfShaderUtil.java

package com.example.myplayer.opengl;
import android.content.Context;
import android.opengl.GLES20;
import com.example.myplayer.log.JfLog;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
public class JfShaderUtil {
    public static String readRawTxt(Context context, int rawId) {
        InputStream inputStream = context.getResources().openRawResource(rawId);
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        StringBuffer sb = new StringBuffer();
        String line;
        try
        {
            while((line = reader.readLine()) != null)
            {
                sb.append(line).append("\n");
            }
            reader.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        return sb.toString();
    }
    public static int loadShader(int shaderType, String source)
    {
        int shader = GLES20.glCreateShader(shaderType);
        if(shader != 0)
        {
            GLES20.glShaderSource(shader, source);
            GLES20.glCompileShader(shader);
            int[] compile = new int[1];
            GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compile, 0);
            if(compile[0] != GLES20.GL_TRUE)
            {
                JfLog.e("shader compile error");
                GLES20.glDeleteShader(shader);
                shader = 0;
            }
        }
        return shader;
    }
    public static int createProgram(String vertexSource, String fragmentSource)
    {
        int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
        if(vertexShader == 0)
        {
            return 0;
        }
        int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
        if(fragmentShader == 0)
        {
            return 0;
        }
        int program = GLES20.glCreateProgram();
        if(program != 0)
        {
            GLES20.glAttachShader(program, vertexShader);
            GLES20.glAttachShader(program, fragmentShader);
            GLES20.glLinkProgram(program);
            int[] linsStatus = new int[1];
            GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, linsStatus, 0);
            if(linsStatus[0] != GLES20.GL_TRUE)
            {
                JfLog.e( "link program error");
                GLES20.glDeleteProgram(program);
                program = 0;
            }
        }
        return  program;
    }
}

实现JfRender

package com.example.myplayer.opengl;
import android.content.Context;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import com.example.myplayer.R;
import com.example.myplayer.log.JfLog;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
public class JfRender implements GLSurfaceView.Renderer {
    private Context context;
    private final float[] vertexData ={//顶点坐标
            -1f, -1f,
            1f, -1f,
            -1f, 1f,
            1f, 1f
    };
    private final float[] textureData ={//纹理坐标
            0f,1f,
            1f, 1f,
            0f, 0f,
            1f, 0f
    };
    private FloatBuffer vertexBuffer;
    private FloatBuffer textureBuffer;
    private int program_yuv;
    private int avPosition_yuv;
    private int afPosition_yuv;
    private int sampler_y;
    private int sampler_u;
    private int sampler_v;
    private int[] textureId_yuv;
    //渲染用
    private int width_yuv;
    private int height_yuv;
    private ByteBuffer y;
    private ByteBuffer u;
    private ByteBuffer v;
    public JfRender(Context context){
        this.context = context;
        //存储顶点坐标数据
        vertexBuffer = ByteBuffer.allocateDirect(vertexData.length * 4)
                .order(ByteOrder.nativeOrder())
                .asFloatBuffer()
                .put(vertexData);
        vertexBuffer.position(0);
        //存储纹理坐标
        textureBuffer = ByteBuffer.allocateDirect(textureData.length * 4)
                .order(ByteOrder.nativeOrder())
                .asFloatBuffer()
                .put(textureData);
        textureBuffer.position(0);
    }
    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
        initRenderYUV();
    }
    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) {
        GLES20.glViewport(0, 0, width, height);
    }
    @Override
    public void onDrawFrame(GL10 gl) {
        //用黑色清屏
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        renderYUV();
    }
    /**
     * 初始化
     */
    private void initRenderYUV(){
        String vertexSource = JfShaderUtil.readRawTxt(context, R.raw.vertex_shader);
        String fragmentSource = JfShaderUtil.readRawTxt(context,R.raw.fragment_shader);
        //创建一个渲染程序
        program_yuv = JfShaderUtil.createProgram(vertexSource,fragmentSource);
        //得到着色器中的属性
        avPosition_yuv = GLES20.glGetAttribLocation(program_yuv,"av_Position");
        afPosition_yuv = GLES20.glGetAttribLocation(program_yuv,"af_Position");
        sampler_y = GLES20.glGetUniformLocation(program_yuv, "sampler_y");
        sampler_u = GLES20.glGetUniformLocation(program_yuv, "sampler_u");
        sampler_v = GLES20.glGetUniformLocation(program_yuv, "sampler_v");
        //创建纹理
        textureId_yuv = new int[3];
        GLES20.glGenTextures(3, textureId_yuv, 0);
        for(int i = 0; i < 3; i++)
        {
            //绑定纹理
            GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId_yuv[i]);
            //设置环绕和过滤方式
            GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_REPEAT);
            GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_REPEAT);
            GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
            GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
        }
        JfLog.d("initRenderYUV");
    }
    public void setYUVRenderData(int width, int height, byte[] y, byte[] u, byte[] v)
    {
        this.width_yuv = width;
        this.height_yuv = height;
        this.y = ByteBuffer.wrap(y);
        this.u = ByteBuffer.wrap(u);
        this.v = ByteBuffer.wrap(v);
    }
    /**
     * 渲染
     */
    private void renderYUV(){
        JfLog.d("渲染中");
        if(width_yuv > 0 && height_yuv > 0 && y != null && u != null && v != null){
            GLES20.glUseProgram(program_yuv);//使用源程序
            GLES20.glEnableVertexAttribArray(avPosition_yuv);//使顶点属性数组有效
            GLES20.glVertexAttribPointer(avPosition_yuv, 2, GLES20.GL_FLOAT, false, 8, vertexBuffer);//为顶点属性赋值
            GLES20.glEnableVertexAttribArray(afPosition_yuv);
            GLES20.glVertexAttribPointer(afPosition_yuv, 2, GLES20.GL_FLOAT, false, 8, textureBuffer);
            GLES20.glActiveTexture(GLES20.GL_TEXTURE0);//激活纹理
            GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId_yuv[0]);//绑定纹理
            GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, width_yuv, height_yuv, 0, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, y);//
            GLES20.glActiveTexture(GLES20.GL_TEXTURE1);
            GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId_yuv[1]);
            GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, width_yuv / 2, height_yuv / 2, 0, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, u);
            GLES20.glActiveTexture(GLES20.GL_TEXTURE2);
            GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId_yuv[2]);
            GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, width_yuv / 2, height_yuv / 2, 0, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, v);
            GLES20.glUniform1i(sampler_y, 0);
            GLES20.glUniform1i(sampler_u, 1);
            GLES20.glUniform1i(sampler_v, 2);
            y.clear();
            u.clear();
            v.clear();
            y = null;
            u = null;
            v = null;
            GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
        }
    }
}

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