Relationship between Game Frame Number and Display Refresh Rate

Generally speaking, because the frame number generation time is not uniform

While that refresh rate of the display is fix.

Therefore, even if the 60-frame and 60-Hz display are refreshed, there is no way to completely synchronize, and there will still be lost frames, which will cause the picture to get stuck. So the higher the number of frames, the better.

Sometimes the number of frames is much larger than the refresh rate of the display, which will also cause the picture to tear. The reason is that it takes some time for the screen to refresh from top to bottom. If a new frame number comes at this time, the first half is still the previous frame, and the second half is the new frame number. So you need to turn on vertical synchronization.

References:

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On triple buffering

When the frame rate is much higher than the refresh rate of the display, in order to keep the refresh time of the display and the time for the graphics card to write pictures into the buffer, it is necessary to artificially increase the delay to delay the output of "too fast pictures" to the display. Therefore, in competitive games, the feel after turning on vertical synchronization will be greatly reduced.

Since the delay of vertical synchronization is because the graphics card can't respond to the latest operation of the mouse and keyboard after outputting an image, why don't we let the graphics card work all the time? So you can respond to the latest input operation at any time? Triple buffer is designed based on this idea. On the basis of double buffers, a frame buffer is added to form the specifications of a front buffer and two rear buffers. The program writes the image back and forth to two background buffers, and each time the display is refreshed, the foreground buffer will be exchanged with the background buffer that has recently been written. It can be seen that even if one buffer is controlled by traffic lights, the other two buffers can still write images back and forth, and there is no need to artificially increase the picture delay.

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