What is double buferring in computer graphics

Double buffering

Functional welding

The framebuffer of the graphics card memory was in the front and back buffer sections. While the RAMDAC of the front buffer is read out and displayed on the screen, the GPU is the next image in the back buffer. After completing this calculation, the execution is completeSwap this is the swap where the memory addresses of the front and back buffers (- commandTurn the page ) - depending on VSync.

  • If VSync is deactivated, the exchange is carried out immediately, as is the RAMDAC with the image display from the front buffer. This is where the image construction began. But not from the beginning - there’s good luck, Buffertausch’s big hat belongs to us. You are welcome to look at the pictures and look at the pictures. This effect is calledTear .
  • With activistem VSync, swapping is waited for until the RAMDAC has finished displaying the current image from the front buffer. This is indicated with the VSync signal. In the meantime, there is no way to find image computation that should be the place in the city buffer. This reduces the performance of the graphics card. This problem occurs with triple buffering (Triple buffering ) compensated by introducing an additional back buffer.

After executing theSwap Command (the exchange of front and back buffers) the whole cycle starts again from the beginning.

Before and from double buffering

advantages

  • fluid and judder-free image build-up
  • Lower latency than Beer Triple Quadruple buffering

disadvantage

  • disabled VSync FeedsTear However, especially when the refresh rate of the monitors is low, the graphics type reaches a high frame rate
  • Activated VSync sometimes leads to a high loss of performance
  • Double frame buffer size compared to single buffering

Areas of application

Microsoft Windows

If the Windows Aero skin was selected in Microsoft Windows, where Desktop Window Manager uses double buffering by default to prevent tearing.[1] [2]

Change buffer technology

In other areas (for the first time in real-time applications) double buffering has been referred to as the alternating buffer technique. A change buffer is a ring buffer with two places (producer-consumer problem).

Individual evidence

  1. Jump up ↑ This Windows Aero feature uses double buffering to draw on the screen.
  2. Jump up ↑ http://blogs.msdn.com/b/greg_schechter/archive/2006/03/19/555087.aspx The DWM avoids tearing windows during the update