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使用SurfaceTexture和OpenGL修改相机输出

androidopengl-esopengl-es-2.0
42
我试图通过将相机硬件流经过openGL滤镜进行过滤，然后在GLSurfaceView中显示它。当openGL渲染帧时，LogCat会反复输出错误信息：

[unnamed-3314-0] updateTexImage: clearing GL error: 0x502

0x502是一个通用的openGL错误，对于我追踪问题并没有太大帮助。这是代码如何工作的序列（至少在我头脑中应该是这样的），下面是我的代码。我希望其他人能够看出我的问题所在。MainActivity.java
public class MainActivity extends Activity implements SurfaceTexture.OnFrameAvailableListener
{
    private Camera mCamera;
    private MyGLSurfaceView glSurfaceView;
    private SurfaceTexture surface;
    MyGL20Renderer renderer;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        glSurfaceView = new MyGLSurfaceView(this);
        renderer = glSurfaceView.getRenderer();
        setContentView(glSurfaceView);
    }

    public void startCamera(int texture)
    {
        surface = new SurfaceTexture(texture);
        surface.setOnFrameAvailableListener(this);
        renderer.setSurface(surface);

        mCamera = Camera.open();

        try
        {
            mCamera.setPreviewTexture(surface);
            mCamera.startPreview();
        }
        catch (IOException ioe)
        {
            Log.w("MainActivity","CAM LAUNCH FAILED");
        }
    }

    public void onFrameAvailable(SurfaceTexture surfaceTexture)
    {
        glSurfaceView.requestRender();
    }

    @Override
    public void onPause()
    {
        mCamera.stopPreview();
        mCamera.release();
        System.exit(0);
    }

MyGLSurfaceView.java

class MyGLSurfaceView extends GLSurfaceView
{
    MyGL20Renderer renderer;
    public MyGLSurfaceView(Context context)
    {
        super(context);

        setEGLContextClientVersion(2);

        renderer = new MyGL20Renderer((MainActivity)context);
        setRenderer(renderer);
        setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);

    }
    public MyGL20Renderer getRenderer()
    {
        return renderer;
    }
}

MyGL20Renderer.java

public class MyGL20Renderer implements GLSurfaceView.Renderer
{

    DirectVideo mDirectVideo;
    int texture;
    private SurfaceTexture surface;
    MainActivity delegate;

    public MyGL20Renderer(MainActivity _delegate)
    {
        delegate = _delegate;
    }

    public void onSurfaceCreated(GL10 unused, EGLConfig config)
    {
        mDirectVideo = new DirectVideo(texture);
        texture = createTexture();
        GLES20.glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
        delegate.startCamera(texture);
    }

    public void onDrawFrame(GL10 unused)
    {
            float[] mtx = new float[16];
            GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);
            surface.updateTexImage();
            surface.getTransformMatrix(mtx); 

            mDirectVideo.draw();
    }

    public void onSurfaceChanged(GL10 unused, int width, int height)
    {
        GLES20.glViewport(0, 0, width, height);
    }

    static public int loadShader(int type, String shaderCode)
    {
        int shader = GLES20.glCreateShader(type);

        GLES20.glShaderSource(shader, shaderCode);
        GLES20.glCompileShader(shader);

        return shader;
    }

    static private int createTexture()
    {
        int[] texture = new int[1];

        GLES20.glGenTextures(1,texture, 0);
        GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture[0]);
        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
             GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_LINEAR);        
        GLES20.glTexParameterf(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
             GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
     GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
             GL10.GL_TEXTURE_WRAP_S, GL10.GL_CLAMP_TO_EDGE);
     GLES20.glTexParameteri(GLES11Ext.GL_TEXTURE_EXTERNAL_OES,
             GL10.GL_TEXTURE_WRAP_T, GL10.GL_CLAMP_TO_EDGE);

        return texture[0];
    }

    public void setSurface(SurfaceTexture _surface)
    {
        surface = _surface;
    }
}

DirectVideo.java

public class DirectVideo {


    private final String vertexShaderCode =
            "#extension GL_OES_EGL_image_external : require\n"+
            "attribute vec4 position;" +
            "attribute vec4 inputTextureCoordinate;" +
            "varying vec2 textureCoordinate;" +
            "void main()" +
            "{"+
                "gl_Position = position;"+
                "textureCoordinate = inputTextureCoordinate.xy;" +
            "}";

        private final String fragmentShaderCode =
            "#extension GL_OES_EGL_image_external : require\n"+
            "precision mediump float;" +
            "uniform vec4 vColor;" +
            "void main() {" +
            "  gl_FragColor = vColor;" +
            "}";

        private FloatBuffer vertexBuffer, textureVerticesBuffer;
        private ShortBuffer drawListBuffer;
         private final int mProgram;
            private int mPositionHandle;
            private int mColorHandle;
            private int mTextureCoordHandle;


    // number of coordinates per vertex in this array
    static final int COORDS_PER_VERTEX = 2;
    static float squareVertices[] = { // in counterclockwise order:
         -1.0f,  1.0f,
         -1.0f,  -1.0f,
         1.0f,  -1.0f,
         1.0f,  1.0f
    };

    private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices

    static float textureVertices[] = { // in counterclockwise order:
        1.0f,  1.0f,
        1.0f,  0.0f,
        0.0f,  1.0f,
        0.0f,  0.0f
   };

    private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex

    private int texture;

    public DirectVideo(int _texture)
    {
        texture = _texture;

        ByteBuffer bb = ByteBuffer.allocateDirect(squareVertices.length * 4);
        bb.order(ByteOrder.nativeOrder());
        vertexBuffer = bb.asFloatBuffer();
        vertexBuffer.put(squareVertices);
        vertexBuffer.position(0);

        ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2);
        dlb.order(ByteOrder.nativeOrder());
        drawListBuffer = dlb.asShortBuffer();
        drawListBuffer.put(drawOrder);
        drawListBuffer.position(0);

        ByteBuffer bb2 = ByteBuffer.allocateDirect(textureVertices.length * 4);
        bb2.order(ByteOrder.nativeOrder());
        textureVerticesBuffer = bb2.asFloatBuffer();
        textureVerticesBuffer.put(textureVertices);
        textureVerticesBuffer.position(0);

        int vertexShader = MyGL20Renderer.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
        int fragmentShader = MyGL20Renderer.loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);

        mProgram = GLES20.glCreateProgram();             // create empty OpenGL ES Program
        GLES20.glAttachShader(mProgram, vertexShader);   // add the vertex shader to program
        GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
        GLES20.glLinkProgram(mProgram);          
    }

    public void draw()
    {
        GLES20.glUseProgram(mProgram);

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

        mPositionHandle = GLES20.glGetAttribLocation(mProgram, "position");
        GLES20.glEnableVertexAttribArray(mPositionHandle);
        GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false,vertexStride, vertexBuffer);

        mTextureCoordHandle = GLES20.glGetAttribLocation(mProgram, "inputTextureCoordinate");
        GLES20.glEnableVertexAttribArray(mTextureCoordHandle);
        GLES20.glVertexAttribPointer(mTextureCoordHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false,vertexStride, textureVerticesBuffer);

        mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");

        GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length,
        GLES20.GL_UNSIGNED_SHORT, drawListBuffer);

        // Disable vertex array
        GLES20.glDisableVertexAttribArray(mPositionHandle);
        GLES20.glDisableVertexAttribArray(mTextureCoordHandle);
    }
}
1
502 是 GL_INVALID_OPERATION。在调用 updateTexImage 之前，您可以尝试显式检查错误吗？Assert.assertTrue(GLES20.glGetError() == 0); 可能是您所做的某些事情导致了错误，并且直到 updateTexImage 调用它时才被查询。从该错误消息中无法确定该错误是由 updateTexImage 引起的，还是来自之前的挂起错误。 - Tim
确实，你是正确的。在初始化期间，绘制函数运行良好，但在第一个onFrameAvailable发出渲染请求时进行第一次draw()调用时，ASSERT失败了。 - Dan Collins
3
你需要在绘制函数中添加assert语句，直到找到导致OpenGL错误的那个调用。 - Tim
好的，我会尝试并查看结果。谢谢！ - Dan Collins
所以我发现需要 #extension require，因为 GL_TEXTURE_EXTERNAL_OES 应该在片段着色器中而不是顶点着色器中。一旦我修复了这个问题，错误就消失了。虽然视频还没有显示在屏幕上，但我已经更接近成功了，这解决了原始问题中发布的错误。再次感谢！ - Dan Collins
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1个回答
36
mDirectVideo = new DirectVideo(texture);
texture = createTexture();
应该是这样的。
texture = createTexture();
mDirectVideo = new DirectVideo(texture);

着色器

private final String vertexShaderCode =
        "attribute vec4 position;" +
        "attribute vec2 inputTextureCoordinate;" +
        "varying vec2 textureCoordinate;" +
        "void main()" +
        "{"+
            "gl_Position = position;"+
            "textureCoordinate = inputTextureCoordinate;" +
        "}";

    private final String fragmentShaderCode =
        "#extension GL_OES_EGL_image_external : require\n"+
        "precision mediump float;" +
        "varying vec2 textureCoordinate;                            \n" +
        "uniform samplerExternalOES s_texture;               \n" +
        "void main() {" +
        "  gl_FragColor = texture2D( s_texture, textureCoordinate );\n" +
        "}";

mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");

应该为：

mColorHandle = GLES20.glGetAttribLocation(mProgram, "s_texture");

将DirectVideo绘制中的初始化内容（如glVertexAttribPointer等）移除，并将其放入某个初始化函数中。

public void draw()
{
    GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture);
    GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length,
            GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
}
1
我相信这确实解决了问题。谢谢！（并已接受；迟到总比不来好）。 - Dan Collins
嗯... @DanCollins 我按照所有步骤操作了，但只得到了一个灰色的屏幕... 有什么建议吗？ - Brad Moore
6
坐标也不正确，三角形看起来很奇怪。如果是原生手机使用，请使用以下内容：static float squareVertices[] = { -1.0f, 1.0f, -1.0f, -1.0f, 1.0f, -1.0f, 1.0f, 1.0f }; static float textureVertices[] = { 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, }; - Joel Teply
2
我已经按照您的建议尝试了该项目，并创建了一个GitHub存储库以展示结果：链接。为了使其正常工作，我将GLES20.glVertexAttribPointer(mTextureCoordHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, textureVerticesBuffer);方法调用移动到了DirectVideo中。显示的图像仍然是镜像反转的。欢迎提出任何修复建议。 - Chau Thai
2
为了去除镜像反转，请将 { 0.0f，0.0f，1.0f，0.0f，1.0f，1.0f，0.0f，1.0f，} 替换为 { 0.0f，1.0f，1.0f，1.0f，1.0f，0.0f，0.0f，0.0f，}。 - RobotRock
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