E/OpenGLRenderer: Unable to match the desired swap behavior

rfresh737 · March 25, 2023, 3:44pm

I get this log message when I run my Android Studio app. How do I fix this problem?

Thank you…

Remi-Coulom · August 19, 2023, 5:37pm

Hi. I have the same problem. Did you find any solution? Thanks.

Dark_Photon · August 19, 2023, 9:55pm

If you check:

you’ll see there’s a Surface option that can be set via eglSurfaceAttrib() called:

EGL_SWAP_BEHAVIOR

which has the following possible values:

EGL_BUFFER_PRESERVED - indicates that color buffer contents are unaffected, while
EGL_BUFFER_DESTROYED - indicates that color buffer contents may be destroyed or changed by the operation.

This setting pertains to the COLOR buffer of an EGL surface such as a window.

You’re apparently running an application that’s requesting a specific swap buffers behavior for a surface (probably EGL_BUFFER_PRESERVED) that the graphics driver, in its current configuration at least, does not support. So it’s telling you that.

If this was your application, the fix is don’t depend on this swap behavior, because in some circumstances you won’t get it. Better to render to an offscreen FBO backed by textures and/or renderbuffers, where you have control of the contents of these FBO buffers from frame-to-frame.

Again if this was your application, prior to creating your EGL surface, you could look for an EGLConfig which supports the EGL_SWAP_BEHAVIOR == EGL_BUFFER_PRESERVED behavior. You do this by specifying EGL_SWAP_BEHAVIOR_PRESERVED_BIT in the EGL_SURFACE_TYPE value when choosing the desired EGLConfig. That said, if you don’t find one, you can’t get EGL_BUFFER_PRESERVED behavior via an EGL surface on that graphics driver. Again, the solution is to just render to an FBO where you have full control of frame-to-frame content persistence and not depend on the persistence behavior of the system framebuffer.

Remi-Coulom · August 19, 2023, 11:04pm

Thanks for your reply. It is my application. But it is a very plain application, with no EGL at all. I searched the whole source code for the “EGL” string and it is not present at all.

It seems all other applications on my phone (Pixel 5) produce the same error, so I guess it is not my fault.

I will stop trying to fix this, since my app is working anyway.

Dark_Photon · August 20, 2023, 12:25am

Google Pixel 5 runs Google Android (11 or 13).
Android uses EGL as a windowing system interface with OpenGL ES and Vulkan being exposed graphics APIs.

So while your app may not be directly using EGL, it is most likely using it indirectly through whatever libraries and layers you are using to provide window and graphics rendering capability for your application.

Dark_Photon · August 20, 2023, 12:55am

Ah! Here you go:

The error message:
E/OpenGLRenderer: Unable to match the desired swap behavior
OpenGLRenderer Configuration
- https://source.android.com/docs/core/graphics/renderer
OpenGLRenderer (libhwui) properties
libhwui source code:
- https://cs.android.com/android/platform/superproject/+/master:frameworks/base/libs/hwui/

frameworks/base/libs/hwui/SwapBehavior.h

enum class SwapBehavior {
    kSwap_default,
    kSwap_discardBuffer,
};

frameworks/base/libs/hwui/pipeline/skia/SkiaOpenGLPipeline.cpp

    if (mEglSurface != EGL_NO_SURFACE) {
        const bool preserveBuffer = (swapBehavior != SwapBehavior::kSwap_discardBuffer);
        const bool isPreserved = mEglManager.setPreserveBuffer(mEglSurface, preserveBuffer);
        ALOGE_IF(preserveBuffer != isPreserved, "Unable to match the desired swap behavior.");
        return true;
    }

Notice the error message in that last code fragment. Look familiar?:

"Unable to match the desired swap behavior."

Assuming this is the source of your message, you can observe a few things:

This uses EGL
It also uses OpenGL ES

My guess is you’re using EGL / OpenGL ES via Skia, either directly or indirectly.

Skia: