Ich versuche, EGL_KHR_image_base in einem nativen Android-Prozess zu verwenden, um glReadPixels zu ersetzen, da es zu langsam ist (220 ms für 1280 x 800 RGBA).

Dies ist, was ich bisher habe, aber mein es erzeugt einen leeren Puffer (nur Nullen)

uint8_t *ptr;
GLuint mTexture;
status_t error;

GraphicBufferAlloc* mGraphicBufferAlloc  = new GraphicBufferAlloc();    
sp<GraphicBuffer> window = mGraphicBufferAlloc->createGraphicBuffer(width, height, PIXEL_FORMAT_RGBA_8888, GraphicBuffer::USAGE_SW_READ_OFTEN | GraphicBuffer::USAGE_HW_TEXTURE,&error);
EGLClientBuffer buffer = (EGLClientBuffer)window->getNativeBuffer();
EGLint eglImageAttributes[] = {EGL_WIDTH, width, EGL_HEIGHT, height, EGL_MATCH_FORMAT_KHR,  EGL_FORMAT_RGBA_8888_KHR, EGL_IMAGE_PRESERVED_KHR, EGL_TRUE, EGL_NONE};
EGLImageKHR image = eglCreateImageKHR(eglGetCurrentDisplay(), EGL_NO_CONTEXT, EGL_NATIVE_BUFFER_ANDROID,buffer, eglImageAttributes);

glGenTextures(1, &mTexture);    
glBindTexture(GL_TEXTURE_2D, mTexture);
glEGLImageTargetTexture2DOES(GL_TEXTURE_2D, image);
window->lock(GraphicBuffer::USAGE_SW_READ_OFTEN, (void**)&ptr); 
memcpy(texture, ptr, width * height * 4);
window->unlock();

Was mache ich falsch ?