services/surfaceflinger/tests/vsync/vsync.cpp

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <android/looper.h>
#include <gui/DisplayEventReceiver.h>
#include <utils/Looper.h>

using namespace android;

int receiver(int /*fd*/, int /*events*/, void* data)
{
    DisplayEventReceiver* q = (DisplayEventReceiver*)data;

    ssize_t n;
    DisplayEventReceiver::Event buffer[1];

    static nsecs_t oldTimeStamp = 0;

    while ((n = q->getEvents(buffer, 1)) > 0) {
        for (int i=0 ; i<n ; i++) {
            if (buffer[i].header.type == DisplayEventReceiver::DISPLAY_EVENT_VSYNC) {
                printf("event vsync: count=%d\t", buffer[i].vsync.count);
            }
            if (oldTimeStamp) {
                float t = float(buffer[i].header.timestamp - oldTimeStamp) / s2ns(1);
                printf("%f ms (%f Hz)\n", t*1000, 1.0/t);
            }
            oldTimeStamp = buffer[i].header.timestamp;
        }
    }
    if (n<0) {
        printf("error reading events (%s)\n", strerror(-n));
    }
    return 1;
}

int main(int /*argc*/, char** /*argv*/)
{
    DisplayEventReceiver myDisplayEvent;


    sp<Looper> loop = new Looper(false);
    loop->addFd(myDisplayEvent.getFd(), 0, ALOOPER_EVENT_INPUT, receiver,
            &myDisplayEvent);

    myDisplayEvent.setVsyncRate(1);

    do {
        //printf("about to poll...\n");
        int32_t ret = loop->pollOnce(-1);
        switch (ret) {
            case ALOOPER_POLL_WAKE:
                //("ALOOPER_POLL_WAKE\n");
                break;
            case ALOOPER_POLL_CALLBACK:
                //("ALOOPER_POLL_CALLBACK\n");
                break;
            case ALOOPER_POLL_TIMEOUT:
                printf("ALOOPER_POLL_TIMEOUT\n");
                break;
            case ALOOPER_POLL_ERROR:
                printf("ALOOPER_POLL_TIMEOUT\n");
                break;
            default:
                printf("ugh? poll returned %d\n", ret);
                break;
        }
    } while (1);

    return 0;
}