dri2ConfigQueryf,
};
-/**
- * Calculate amount of swap interval used between GLX buffer swaps.
- *
- * The usage value, on the range [0,max], is the fraction of total swap
- * interval time used between GLX buffer swaps is calculated.
- *
- * \f$p = t_d / (i * t_r)\f$
- *
- * Where \f$t_d\f$ is the time since the last GLX buffer swap, \f$i\f$ is the
- * swap interval (as set by \c glXSwapIntervalSGI), and \f$t_r\f$ time
- * required for a single vertical refresh period (as returned by \c
- * glXGetMscRateOML).
- *
- * See the documentation for the GLX_MESA_swap_frame_usage extension for more
- * details.
- *
- * \param dPriv Pointer to the private drawable structure.
- * \return If less than a single swap interval time period was required
- * between GLX buffer swaps, a number greater than 0 and less than
- * 1.0 is returned. If exactly one swap interval time period is
- * required, 1.0 is returned, and if more than one is required then
- * a number greater than 1.0 will be returned.
- *
- * \sa glXSwapIntervalSGI glXGetMscRateOML
- *
- * \todo Instead of caching the \c glXGetMscRateOML function pointer, would it
- * be possible to cache the sync rate?
- */
-float
-driCalculateSwapUsage( __DRIdrawable *dPriv, int64_t last_swap_ust,
- int64_t current_ust )
-{
- int32_t n;
- int32_t d;
- int interval;
- float usage = 1.0;
- __DRIscreen *psp = dPriv->driScreenPriv;
-
- if ( (*psp->systemTime->getMSCRate)(dPriv, &n, &d, dPriv->loaderPrivate) ) {
- interval = (dPriv->swap_interval != 0) ? dPriv->swap_interval : 1;
-
-
- /* We want to calculate
- * (current_UST - last_swap_UST) / (interval * us_per_refresh). We get
- * current_UST by calling __glXGetUST. last_swap_UST is stored in
- * dPriv->swap_ust. interval has already been calculated.
- *
- * The only tricky part is us_per_refresh. us_per_refresh is
- * 1000000 / MSC_rate. We know the MSC_rate is n / d. We can flip it
- * around and say us_per_refresh = 1000000 * d / n. Since this goes in
- * the denominator of the final calculation, we calculate
- * (interval * 1000000 * d) and move n into the numerator.
- */
-
- usage = (current_ust - last_swap_ust);
- usage *= n;
- usage /= (interval * d);
- usage /= 1000000.0;
- }
-
- return usage;
-}
-
void
dri2InvalidateDrawable(__DRIdrawable *drawable)
{