我试图通过openGL过滤器运行来自相机硬件的流来过滤它，然后在GLSurfaceView中显示它。当 openGL 去渲染帧时，LogCat 反复吐出一个错误：
[unnamed-3314-0] updateTexImage：清除 GL 错误：0x502
0x502 是一个通用的 openGL 错误，并不能真正帮助我找出问题所在。这是代码如何工作的序列（或者至少应该像我想象的那样工作），我已经在下面复制了我的代码。我希望其他人可以看到我的问题是什么。
- 创建新的 MyGLSurfaceView。这也在内部创建了新的 MyGL20Renderer 对象。这个 MyGLSurfaceView 被设置为内容视图。
- 一旦 MyGLSurfaceView 完成膨胀/初始化，此完成事件会触发渲染器创建 DirectVideo 绘制对象，该对象编译/链接定义的着色器并将它们添加到 openGL 程序。然后它会创建一个新的 openGL 纹理对象，然后使用纹理对象 ID 回调 MainActivity。
- 当从渲染器调用 MainActivity 方法时，它会使用传递的 openGL 纹理对象创建一个新的 SurfaceTexture 对象。然后它将自己设置为表面的 onFrameListener。然后它创建/打开相机对象，将创建的 SurfaceTexture 设置为视频流的目标，并启动相机源。
- 当提要中的帧可用时，onFrameAvailable 会向渲染器发送渲染请求。这是在 openGL 线程上获取的，该线程调用 SurfaceTexture 的 updateTexImage()，它将帧内存加载到 openGL 纹理中。然后它调用 DirectVideo 的绘图对象，并运行 openGL 程序序列。如果我注释掉这个 .draw() 行，上面提到的错误就会消失，所以问题似乎出在此处的某个地方，但我不排除它是由不正确的链接/创建的纹理引起的。
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);
}
}