[OpenGL]从零开始写一个Android平台下的全景视频播放器——2.2 使用GLSurfaceView和MediaPlayer播放一个平面视频（中）

Posted 2022-11-28 Red风信子

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更新着色器代码

因为使用了，需要更新着色器代码
fragment_shader.glsl

#extension GL_OES_EGL_image_external : require
precision mediump float;
varying vec2 vTexCoord;
uniform samplerExternalOES sTexture;
void main() 
    gl_FragColor=texture2D(sTexture, vTexCoord);

precision mediump float;
varying vec2 vTexCoord;
uniform samplerExternalOES sTexture;
void main() 
    gl_FragColor=texture2D(sTexture, vTexCoord);

在这里，我们使用samplerExternalOES代替之前的sampler2D,需要注意的是第一行的注解是必须加上的
这个samplerExternalOES有什么用呢？其实就是之前说的和surfaceTexture配合进行纹理更新和格式转换，具体的可以直接看OpenGL ES的官方文档,我截了一段供大家参考(估计也没什么人看。。):

vertex_shader.glsl

attribute vec4 aPosition;
attribute vec4 aTexCoord;
varying vec2 vTexCoord;
uniform mat4 uMatrix;
uniform mat4 uSTMatrix;
void main() 
    vTexCoord = (uSTMatrix * aTexCoord).xy;
    gl_Position = uMatrix*aPosition;
 vec4 aPosition;
attribute vec4 aTexCoord;
varying vec2 vTexCoord;
uniform mat4 uMatrix;
uniform mat4 uSTMatrix;
void main() 
    vTexCoord = (uSTMatrix * aTexCoord).xy;
    gl_Position = uMatrix*aPosition;

在顶点着色器中，需要加入对应的uSTMatrix，并且aTexCoord要改成长度为4的向量，以便于做乘法操作。

更新GLRenderer

在GLRenderer中，用类似的方法获取uSTMMatrixHandle

uSTMMatrixHandle = GLES20.glGetUniformLocation(programId, "uSTMatrix");GLES20.glGetUniformLocation(programId, "uSTMatrix");

每次绘制的时候，将mSTMatrix用类似的方法传给OpenGL：

GLES20.glUniformMatrix4fv(uSTMMatrixHandle, 1, false, mSTMatrix, 0);1, false, mSTMatrix, 0);

因为用了扩展纹理，所以我们绑定的纹理类型也要做修改：

GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,textureId);

我们刚才只是设定了一个boolean来表示可以更新纹理了，却没有具体操作，所以在onDrawFrame最开始加入如下代码

synchronized (this)
    if (updateSurface)
        surfaceTexture.updateTexImage();
        surfaceTexture.getTransformMatrix(mSTMatrix);
        updateSurface = false;
    
 (this)
    if (updateSurface)
        surfaceTexture.updateTexImage();
        surfaceTexture.getTransformMatrix(mSTMatrix);
        updateSurface = false;

为了后续操作方便，我将绘制三角形的方式换成了绘制三角形带。

因为目前写的代码已经比较长了，我会在最后直接贴出GLRenderer的代码，如果遇到了什么问题，可以对照着看一下。

那我们来试一下吧，直接指定一个视频源，看看能不能正常显示（别忘了声明权限哦）：

glSurfaceView.setRenderer(new GLRenderer(this, Environment.getExternalStorageDirectory().getPath()+"/360Video/video.mp4"));new GLRenderer(this, Environment.getExternalStorageDirectory().getPath()+"/360Video/video.mp4"));

这是一个2:1的全景视频，可以看到全景视频被压扁了，而且画面也是倒过来的，如果按一下HOME键，会发现视频并不会自己停止播放，我们会在下一节来解决屏幕尺寸适应和播放器生命周期的问题。

GLRenderer.java

package com.martin.ads.panoramaopengltutorial;

import android.content.Context;
import android.graphics.SurfaceTexture;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.opengl.GLES11Ext;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.opengl.Matrix;
import android.util.Log;
import android.view.Surface;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

/** * Created by Ads on 2016/11/13. */
public class GLRenderer implements GLSurfaceView.Renderer, SurfaceTexture.OnFrameAvailableListener 

    private static final String TAG = "GLRenderer";
    private Context context;
    private int aPositionHandle;
    private int programId;
    private FloatBuffer vertexBuffer;
    private final float[] vertexData = 
            1f,1f,0f,
            -1f,1f,0f,
            1f,-1f,0f,
            -1f,-1f,0f
    ;

    private final float[] projectionMatrix=new float[16];
    private int uMatrixHandle;

    private final float[] textureVertexData = 
            1f,0f,
            0f,0f,
            1f,1f,
            0f,1f
    ;
    private FloatBuffer textureVertexBuffer;
    private int uTextureSamplerHandle;
    private int aTextureCoordHandle;
    private int textureId;

    private SurfaceTexture surfaceTexture;
    private MediaPlayer mediaPlayer;
    private float[] mSTMatrix = new float[16];
    private int uSTMMatrixHandle;

    private boolean updateSurface;
    private boolean playerPrepared;
    private int screenWidth,screenHeight;
    public GLRenderer(Context context,String videoPath) 
        this.context = context;
        playerPrepared=false;
        synchronized(this) 
            updateSurface = false;
        
        vertexBuffer = ByteBuffer.allocateDirect(vertexData.length * 4)
                .order(ByteOrder.nativeOrder())
                .asFloatBuffer()
                .put(vertexData);
        vertexBuffer.position(0);

        textureVertexBuffer = ByteBuffer.allocateDirect(textureVertexData.length * 4)
                .order(ByteOrder.nativeOrder())
                .asFloatBuffer()
                .put(textureVertexData);
        textureVertexBuffer.position(0);

        mediaPlayer=new MediaPlayer();
        try
            mediaPlayer.setDataSource(context, Uri.parse(videoPath));
        catch (IOException e)
            e.printStackTrace();
        
        mediaPlayer.setAudiostreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setLooping(true);
    

    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) 
        String vertexShader = ShaderUtils.readRawTextFile(context, R.raw.vertex_shader);
        String fragmentShader= ShaderUtils.readRawTextFile(context, R.raw.fragment_shader);
        programId=ShaderUtils.createProgram(vertexShader,fragmentShader);
        aPositionHandle= GLES20.glGetAttribLocation(programId,"aPosition");

        uMatrixHandle=GLES20.glGetUniformLocation(programId,"uMatrix");
        uSTMMatrixHandle = GLES20.glGetUniformLocation(programId, "uSTMatrix");
        uTextureSamplerHandle=GLES20.glGetUniformLocation(programId,"sTexture");
        aTextureCoordHandle=GLES20.glGetAttribLocation(programId,"aTexCoord");


        int[] textures = new int[1];
        GLES20.glGenTextures(1, textures, 0);

        textureId = textures[0];
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureId);
        ShaderUtils.checkGlError("glBindTexture mTextureID");

        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER,
                GLES20.GL_NEAREST);
        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER,
                GLES20.GL_LINEAR);

        surfaceTexture = new SurfaceTexture(textureId);
        surfaceTexture.setOnFrameAvailableListener(this);

        Surface surface = new Surface(surfaceTexture);
        mediaPlayer.setSurface(surface);
        surface.release();

        if (!playerPrepared)
            try 
                mediaPlayer.prepare();
                playerPrepared=true;
             catch (IOException t) 
                Log.e(TAG, "media player prepare failed");
            
            mediaPlayer.start();
            playerPrepared=true;
        
    

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) 
        screenWidth=width; screenHeight=height;
        float ratio=width>height?
                (float)width/height:
                (float)height/width;
        if (width>height)
            Matrix.orthoM(projectionMatrix,0,-ratio,ratio,-1f,1f,-1f,1f);
        else Matrix.orthoM(projectionMatrix,0,-1f,1f,-ratio,ratio,-1f,1f);
    

    @Override
    public void onDrawFrame(GL10 gl) 
        GLES20.glClear( GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
        synchronized (this)
            if (updateSurface)
                surfaceTexture.updateTexImage();
                surfaceTexture.getTransformMatrix(mSTMatrix);
                updateSurface = false;
            
        
        GLES20.glUseProgram(programId);
        GLES20.glUniformMatrix4fv(uMatrixHandle,1,false,projectionMatrix,0);
        GLES20.glUniformMatrix4fv(uSTMMatrixHandle, 1, false, mSTMatrix, 0);

        vertexBuffer.position(0);
        GLES20.glEnableVertexAttribArray(aPositionHandle);
        GLES20.glVertexAttribPointer(aPositionHandle, 3, GLES20.GL_FLOAT, false,
                12, vertexBuffer);

        textureVertexBuffer.position(0);
        GLES20.glEnableVertexAttribArray(aTextureCoordHandle);
        GLES20.glVertexAttribPointer(aTextureCoordHandle,2,GLES20.GL_FLOAT,false,8,textureVertexBuffer);

        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,textureId);

        GLES20.glUniform1i(uTextureSamplerHandle,0);
        GLES20.glViewport(0,0,screenWidth,screenHeight);
        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
    

    @Override
    synchronized public void onFrameAvailable(SurfaceTexture surface) 
        updateSurface = true;
    

 com.martin.ads.panoramaopengltutorial;

import android.content.Context;
import android.graphics.SurfaceTexture;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.opengl.GLES11Ext;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.opengl.Matrix;
import android.util.Log;
import android.view.Surface;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

/** * Created by Ads on 2016/11/13. */
public class GLRenderer implements GLSurfaceView.Renderer, SurfaceTexture.OnFrameAvailableListener 

    private static final String TAG = "GLRenderer";
    private Context context;
    private int aPositionHandle;
    private int programId;
    private FloatBuffer vertexBuffer;
    private final float[] vertexData = 
            1f,1f,0f,
            -1f,1f,0f,
            1f,-1f,0f,
            -1f,-1f,0f
    ;

    private final float[] projectionMatrix=new float[16];
    private int uMatrixHandle;

    private final float[] textureVertexData = 
            1f,0f,
            0f,0f,
            1f,1f,
            0f,1f
    ;
    private FloatBuffer textureVertexBuffer;
    private int uTextureSamplerHandle;
    private int aTextureCoordHandle;
    private int textureId;

    private SurfaceTexture surfaceTexture;
    private MediaPlayer mediaPlayer;
    private float[] mSTMatrix = new float[16];
    private int uSTMMatrixHandle;

    private boolean updateSurface;
    private boolean playerPrepared;
    private int screenWidth,screenHeight;
    public GLRenderer(Context context,String videoPath) 
        this.context = context;
        playerPrepared=false;
        synchronized(this) 
            updateSurface = false;
        
        vertexBuffer = ByteBuffer.allocateDirect(vertexData.length * 4)
                .order(ByteOrder.nativeOrder())
                .asFloatBuffer()
                .put(vertexData);
        vertexBuffer.position(0);

        textureVertexBuffer = ByteBuffer.allocateDirect(textureVertexData.length * 4)
                .order(ByteOrder.nativeOrder())
                .asFloatBuffer()
                .put(textureVertexData);
        textureVertexBuffer.position(0);

        mediaPlayer=new MediaPlayer();
        try
            mediaPlayer.setDataSource(context, Uri.parse(videoPath));
        catch (IOException e)
            e.printStackTrace();
        
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mediaPlayer.setLooping(true);
    

    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) 
        String vertexShader = ShaderUtils.readRawTextFile(context, R.raw.vertex_shader);
        String fragmentShader= ShaderUtils.readRawTextFile(context, R.raw.fragment_shader);
        programId=ShaderUtils.createProgram(vertexShader,fragmentShader);
        aPositionHandle= GLES20.glGetAttribLocation(programId,"aPosition");

        uMatrixHandle=GLES20.glGetUniformLocation(programId,"uMatrix");
        uSTMMatrixHandle = GLES20.glGetUniformLocation(programId, "uSTMatrix");
        uTextureSamplerHandle=GLES20.glGetUniformLocation(programId,"sTexture");
        aTextureCoordHandle=GLES20.glGetAttribLocation(programId,"aTexCoord");


        int[] textures = new int[1];
        GLES20.glGenTextures(1, textures, 0);

        textureId = textures[0];
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureId);
        ShaderUtils.checkGlError("glBindTexture mTextureID");

        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER,
                GLES20.GL_NEAREST);
        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER,
                GLES20.GL_LINEAR);

        surfaceTexture = new SurfaceTexture(textureId);
        surfaceTexture.setOnFrameAvailableListener(this);

        Surface surface = new Surface(surfaceTexture);
        mediaPlayer.setSurface(surface);
        surface.release();

        if (!playerPrepared)
            try 
                mediaPlayer.prepare();
                playerPrepared=true;
             catch (IOException t) 
                Log.e(TAG, "media player prepare failed");
            
            mediaPlayer.start();
            playerPrepared=true;
        
    

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) 
        screenWidth=width; screenHeight=height;
        float ratio=width>height?
                (float)width/height:
                (float)height/width;
        if (width>height)
            Matrix.orthoM(projectionMatrix,0,-ratio,ratio,-1f,1f,-1f,1f);
        else Matrix.orthoM(projectionMatrix,0,-1f,1f,-ratio,ratio,-1f,1f);
    

    @Override
    public void onDrawFrame(GL10 gl) 
        GLES20.glClear( GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
        synchronized (this)
            if (updateSurface)
                surfaceTexture.updateTexImage();
                surfaceTexture.getTransformMatrix(mSTMatrix);
                updateSurface = false;
            
        
        GLES20.glUseProgram(programId);
        GLES20.glUniformMatrix4fv(uMatrixHandle,1,false,projectionMatrix,0);
        GLES20.glUniformMatrix4fv(uSTMMatrixHandle, 1, false, mSTMatrix, 0);

        vertexBuffer.position(0);
        GLES20.glEnableVertexAttribArray(aPositionHandle);
        GLES20.glVertexAttribPointer(aPositionHandle, 3, GLES20.GL_FLOAT, false,
                12, vertexBuffer);

        textureVertexBuffer.position(0);
        GLES20.glEnableVertexAttribArray(aTextureCoordHandle);
        GLES20.glVertexAttribPointer(aTextureCoordHandle,2,GLES20.GL_FLOAT,false,8,textureVertexBuffer);

        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,textureId);

        GLES20.glUniform1i(uTextureSamplerHandle,0);
        GLES20.glViewport(0,0,screenWidth,screenHeight);
        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
    

    @Override
    synchronized public void onFrameAvailable(SurfaceTexture surface) 
        updateSurface = true;

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