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      1 /*
      2  ** Copyright 2013, The Android Open Source Project
      3  **
      4  ** Licensed under the Apache License, Version 2.0 (the "License");
      5  ** you may not use this file except in compliance with the License.
      6  ** You may obtain a copy of the License at
      7  **
      8  **     http://www.apache.org/licenses/LICENSE-2.0
      9  **
     10  ** Unless required by applicable law or agreed to in writing, software
     11  ** distributed under the License is distributed on an "AS IS" BASIS,
     12  ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  ** See the License for the specific language governing permissions and
     14  ** limitations under the License.
     15  */
     16 
     17 #define LOG_TAG "GLConsumer"
     18 
     19 #define GL_GLEXT_PROTOTYPES
     20 #define EGL_EGLEXT_PROTOTYPES
     21 
     22 #include <EGL/egl.h>
     23 #include <EGL/eglext.h>
     24 
     25 #include <utils/Log.h>
     26 #include <utils/Singleton.h>
     27 #include <utils/String8.h>
     28 
     29 #include <private/gui/SyncFeatures.h>
     30 
     31 EGLAPI const char* eglQueryStringImplementationANDROID(EGLDisplay dpy, EGLint name);
     32 
     33 namespace android {
     34 
     35 ANDROID_SINGLETON_STATIC_INSTANCE(SyncFeatures);
     36 
     37 SyncFeatures::SyncFeatures() : Singleton<SyncFeatures>(),
     38         mHasNativeFenceSync(false),
     39         mHasFenceSync(false),
     40         mHasWaitSync(false) {
     41     EGLDisplay dpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
     42     // This can only be called after EGL has been initialized; otherwise the
     43     // check below will abort.
     44     const char* exts = eglQueryStringImplementationANDROID(dpy, EGL_EXTENSIONS);
     45     LOG_ALWAYS_FATAL_IF(exts == NULL, "eglQueryStringImplementationANDROID failed");
     46     if (strstr(exts, "EGL_ANDROID_native_fence_sync")) {
     47         // This makes GLConsumer use the EGL_ANDROID_native_fence_sync
     48         // extension to create Android native fences to signal when all
     49         // GLES reads for a given buffer have completed.
     50         mHasNativeFenceSync = true;
     51     }
     52     if (strstr(exts, "EGL_KHR_fence_sync")) {
     53         mHasFenceSync = true;
     54     }
     55     if (strstr(exts, "EGL_KHR_wait_sync")) {
     56         mHasWaitSync = true;
     57     }
     58     mString.append("[using:");
     59     if (useNativeFenceSync()) {
     60         mString.append(" EGL_ANDROID_native_fence_sync");
     61     }
     62     if (useFenceSync()) {
     63         mString.append(" EGL_KHR_fence_sync");
     64     }
     65     if (useWaitSync()) {
     66         mString.append(" EGL_KHR_wait_sync");
     67     }
     68     mString.append("]");
     69 }
     70 
     71 bool SyncFeatures::useNativeFenceSync() const {
     72     // EGL_ANDROID_native_fence_sync is not compatible with using the
     73     // EGL_KHR_fence_sync extension for the same purpose.
     74     return mHasNativeFenceSync;
     75 }
     76 bool SyncFeatures::useFenceSync() const {
     77 #ifdef DONT_USE_FENCE_SYNC
     78     // on some devices it's better to not use EGL_KHR_fence_sync
     79     // even if they have it
     80     return false;
     81 #endif
     82     // currently we shall only attempt to use EGL_KHR_fence_sync if
     83     // USE_FENCE_SYNC is set in our makefile
     84     return !mHasNativeFenceSync && mHasFenceSync;
     85 }
     86 bool SyncFeatures::useWaitSync() const {
     87     return (useNativeFenceSync() || useFenceSync()) && mHasWaitSync;
     88 }
     89 
     90 String8 SyncFeatures::toString() const {
     91     return mString;
     92 }
     93 
     94 } // namespace android
     95