Record frames displayed on TextureView to mp4

Question

I managed to write a demo displaying a 3D model on TextureView and the model can move according to the sensors of the phone. The 3D engine is wrote by C++ and what I need to do is giving the SurfaceTexture of TextureView to the 3D engine. The engine calls the function ANativeWindow_fromSurface to retrieve a native window and draw 3D model on it. 3D engine is not the key point I want to talk about in this question.

Now I want to record the moving 3d model to a video. One way is using GL_TEXTURE_EXTERNAL_OES texture just like grafika, make 3D engine draw frames to the oes texture and draw the texture content to screen after every call of updateTexImage().But for some restrictions, I am not allowed to use this way.

I plan to use the SurfaceTexture of TextureView directly. I think functions such as attachToGLContext() and detachFromGLContext() will be useful for my work.

Could anyone give me some advices?

Answer 1

Grafika's "record GL app" has three different modes of operation:

1. Draw everything twice.
2. Render to an offscreen pbuffer, then blit that twice.
3. Draw once, then copy between framebuffers (requires GLES 3).

If you can configure the EGL surface that is rendered to, approaches 2 and 3 will work. For approach #3, bear in mind that the pixels don't go to the Surface (that's the Android Surface, not the EGL surface) until you call eglSwapBuffers() .

If the engine code is managing the EGL surface and calling eglSwapBuffers() for you, then things are a bit more annoying. The SurfaceTexture attach/detach calls will let you access the GLES texture with the output from a different EGL context, but the render thread needs that when rendering the View UI. I'm not entirely sure how that's going to work out.