(This is the legacy documentation for SDL2, the previous stable version; SDL3 is the current stable version.)

SDL_GL_SetSwapInterval

Set the swap interval for the current OpenGL context.

Header File

Syntax

int SDL_GL_SetSwapInterval(int interval);

Function Parameters

int

interval

0 for immediate updates, 1 for updates synchronized with the vertical retrace, -1 for adaptive vsync.

Return Value

(int) Returns 0 on success or -1 if setting the swap interval is not supported; call SDL_GetError() for more information.

Remarks

Some systems allow specifying -1 for the interval, to enable adaptive vsync. Adaptive vsync works the same as vsync, but if you've already missed the vertical retrace for a given frame, it swaps buffers immediately, which might be less jarring for the user during occasional framerate drops. If an application requests adaptive vsync and the system does not support it, this function will fail and return -1. In such a case, you should probably retry the call with 1 for the interval.

Adaptive vsync is implemented for some glX drivers with GLX_EXT_swap_control_tear, and for some Windows drivers with WGL_EXT_swap_control_tear.

Read more on the Khronos wiki: https://www.khronos.org/opengl/wiki/Swap_Interval#Adaptive_Vsync

Version

This function is available since SDL 2.0.0.