Commit 0250eb3c4f5cd2b353d7496da37cee620a69f3bf
2016-10-01T14:16:04
Fixed bug 3134 - CalculateXRandRRefreshRate() returns incorrect refresh rate due to floating point truncation. Michael In SDL_x11modes.c the CalculateXRandRRefreshRate() function performs integer math on values that may return fractional results. This causes a value that would be calculated as 59.99972... to be returned as 59. In Linux the xrandr command returns 60Hz for this particular display mode yet SDL returns 59Hz. I suggest this function be updated to correctly round the result of the calculation instead of truncating the result.
diff --git a/src/video/x11/SDL_x11modes.c b/src/video/x11/SDL_x11modes.c
index e3f8497..ba28001 100644
--- a/src/video/x11/SDL_x11modes.c
+++ b/src/video/x11/SDL_x11modes.c
@@ -264,8 +264,8 @@ CheckXRandR(Display * display, int *major, int *minor)
static int
CalculateXRandRRefreshRate(const XRRModeInfo *info)
{
- return (info->hTotal
- && info->vTotal) ? (info->dotClock / (info->hTotal * info->vTotal)) : 0;
+ return (info->hTotal && info->vTotal) ?
+ round(((double)info->dotClock / (double)(info->hTotal * info->vTotal))) : 0;
}
static SDL_bool