better fix for calls to eglMakeCurrent

turns out that KHR_surfaceless_context is implied for ES3.0 when 
KHR_create_context is present. However, Adreno 306 fails even if
it advertises it. So, we now reset the value of KHR_surfaceless_context
based on actually calling eglMakeCurrent(EGL_NO_SURFACE).

filament/backend/src/opengl/platforms/PlatformEGL.cpp

@@ -115,10 +115,14 @@ Driver* PlatformEGL::createDriver(void* sharedContext, const Platform::DriverCon
 
     auto extensions = GLUtils::split(eglQueryString(mEGLDisplay, EGL_EXTENSIONS));
     ext.egl.ANDROID_recordable = extensions.has("EGL_ANDROID_recordable");
-    ext.egl.KHR_create_context = extensions.has("EGL_KHR_create_context");
     ext.egl.KHR_gl_colorspace = extensions.has("EGL_KHR_gl_colorspace");
+    ext.egl.KHR_create_context = extensions.has("EGL_KHR_create_context");
     ext.egl.KHR_no_config_context = extensions.has("EGL_KHR_no_config_context");
     ext.egl.KHR_surfaceless_context = extensions.has("KHR_surfaceless_context");
+    if (ext.egl.KHR_create_context) {
+        // KHR_create_context implies KHR_surfaceless_context for ES3.x contexts
+        ext.egl.KHR_surfaceless_context = true;
+    }
 
     eglCreateSyncKHR = (PFNEGLCREATESYNCKHRPROC) eglGetProcAddress("eglCreateSyncKHR");
     eglDestroySyncKHR = (PFNEGLDESTROYSYNCKHRPROC) eglGetProcAddress("eglDestroySyncKHR");
@@ -182,15 +186,6 @@ Driver* PlatformEGL::createDriver(void* sharedContext, const Platform::DriverCon
         eglConfig = mEGLConfig;
     }
 
-    if (UTILS_UNLIKELY(!ext.egl.KHR_surfaceless_context)) {
-        // create the dummy surface, just for being able to make the context current.
-        mEGLDummySurface = eglCreatePbufferSurface(mEGLDisplay, mEGLConfig, pbufferAttribs);
-        if (UTILS_UNLIKELY(mEGLDummySurface == EGL_NO_SURFACE)) {
-            logEglError("eglCreatePbufferSurface");
-            goto error;
-        }
-    }
-
     for (size_t tries = 0; tries < 3; tries++) {
         mEGLContext = eglCreateContext(mEGLDisplay, eglConfig,
                 (EGLContext)sharedContext, contextAttribs.data());
@@ -223,6 +218,26 @@ Driver* PlatformEGL::createDriver(void* sharedContext, const Platform::DriverCon
         goto error;
     }
 
+    if (ext.egl.KHR_surfaceless_context) {
+        // Adreno 306 driver advertises KHR_create_context but doesn't support passing
+        // EGL_NO_SURFACE to eglMakeCurrent with a 3.0 context.
+        if (UTILS_UNLIKELY(!eglMakeCurrent(mEGLDisplay,
+                EGL_NO_SURFACE, EGL_NO_SURFACE, mEGLContext))) {
+            if (eglGetError() == EGL_BAD_MATCH) {
+                ext.egl.KHR_surfaceless_context = false;
+            }
+        }
+    }
+
+    if (UTILS_UNLIKELY(!ext.egl.KHR_surfaceless_context)) {
+        // create the dummy surface, just for being able to make the context current.
+        mEGLDummySurface = eglCreatePbufferSurface(mEGLDisplay, mEGLConfig, pbufferAttribs);
+        if (UTILS_UNLIKELY(mEGLDummySurface == EGL_NO_SURFACE)) {
+            logEglError("eglCreatePbufferSurface");
+            goto error;
+        }
+    }
+
     if (UTILS_UNLIKELY(!makeCurrent(mEGLDummySurface, mEGLDummySurface))) {
         // eglMakeCurrent failed
         logEglError("eglMakeCurrent");