Fix texture format handling for Nvidia driver

src/wayland/drmclientbuffer.cpp

@@ -36,12 +36,16 @@ DrmClientBuffer::DrmClientBuffer(wl_resource *resource, DrmClientBufferIntegrati
     Q_D(DrmClientBuffer);
 
     EGLDisplay eglDisplay = integration->display()->eglDisplay();
-    eglQueryWaylandBufferWL(eglDisplay, resource, EGL_TEXTURE_FORMAT, &d->textureFormat);
+    if (!eglQueryWaylandBufferWL(eglDisplay, resource, EGL_TEXTURE_FORMAT, &d->textureFormat)) {
+        // The proprietary Nvidia driver doesn't support querying the EGL_TEXTURE_FORMAT.
+        // We must assume that the buffer has an alpha channel for transparency to work.
+        d->textureFormat = EGL_TEXTURE_RGBA;
+    }
+
     eglQueryWaylandBufferWL(eglDisplay, resource, EGL_WIDTH, &d->width);
     eglQueryWaylandBufferWL(eglDisplay, resource, EGL_HEIGHT, &d->height);
 
-    bool ok = eglQueryWaylandBufferWL(eglDisplay, resource, EGL_WAYLAND_Y_INVERTED_WL, &d->yInverted);
-    if (!ok) {
+    if (!eglQueryWaylandBufferWL(eglDisplay, resource, EGL_WAYLAND_Y_INVERTED_WL, &d->yInverted)) {
         // If EGL_WAYLAND_Y_INVERTED_WL is unsupported, we must assume that the buffer is inverted.
         d->yInverted = true;
     }