cocos creator 帧率60 不生效meta50 能刷新到90

环境：

cocos creator 2.4.3

华为meta 50

背景：

小游戏需要在update 里取帧率发现跟时间对不上

游戏设置60帧

手机上显示 90帧

cc.game.setFrameRate(30) 显示 30帧

cc.game.setFrameRate(60) 显示 90帧

结论：

对于老版本的cocos creator 如果有依赖帧率的逻辑

需要自行注意逻辑正确性

cc.game.getFrameRate() 取出来的帧率有可能并不是当前真实帧率只是逻辑帧率

源码分析：

java 复制代码

	cocos2dxRenderer.java 

	@Override
    public void onDrawFrame(final GL10 gl) {
        if (mNeedToPause)
            return;

        if (mNeedShowFPS) {
            /
            //IDEA: show FPS in Android Text control rather than outputing log.
            ++mFrameCount;
            long nowFpsTime = System.nanoTime();
            long fpsTimeInterval = nowFpsTime - mOldNanoTime;
            if (fpsTimeInterval > 1000000000L) {
                double frameRate = 1000000000.0 * mFrameCount / fpsTimeInterval;
                Cocos2dxHelper.OnGameInfoUpdatedListener listener = Cocos2dxHelper.getOnGameInfoUpdatedListener();
                if (listener != null) {
                    listener.onFPSUpdated((float) frameRate);
                }
                mFrameCount = 0;
                mOldNanoTime = System.nanoTime();
            }
            /
        }
        /*
         * No need to use algorithm in default(60 FPS) situation,
         * since onDrawFrame() was called by system 60 times per second by default.
         */
        if (sAnimationInterval <= INTERVAL_60_FPS) {
            Cocos2dxRenderer.nativeRender();
        } else {
            final long now = System.nanoTime();
            final long interval = now - this.mLastTickInNanoSeconds;

            if (interval < Cocos2dxRenderer.sAnimationInterval) {
                try {
                    Thread.sleep((Cocos2dxRenderer.sAnimationInterval - interval) / Cocos2dxRenderer.NANOSECONDSPERMICROSECOND);
                } catch (final Exception e) {
                }
            }
            /*
             * Render time MUST be counted in, or the FPS will slower than appointed.
            */
            this.mLastTickInNanoSeconds = System.nanoTime();
            Cocos2dxRenderer.nativeRender();
        }
    }

分析上述代码

java 复制代码

if (sAnimationInterval <= INTERVAL_60_FPS) {
            Cocos2dxRenderer.nativeRender();
}

说明 >= 60帧的设置。没有处理刷新帧率走的系统是高刷

所以会导致 dt 并不是 60帧的dt