clock: Bug fix: Syncing with the system clock happens more often than expected

When the specified TPS is too big (e.g., 300), the time threshold
to determine whether the clock should be synchronized with the
system clock can be too small, and the decision can be wrong too
often. To fix this, prepare another time assuming the TPS was 60
and use the bigger one.

Fixes #1443

internal/clock/clock.go

@@ -57,6 +57,13 @@ func CurrentTPS() float64 {
 	return v
 }
 
+func max(a, b int64) int64 {
+	if a < b {
+		return b
+	}
+	return a
+}
+
 func calcCountFromTPS(tps int64, now int64) int {
 	if tps == 0 {
 		return 0
@@ -73,7 +80,10 @@ func calcCountFromTPS(tps int64, now int64) int {
 	count := 0
 	syncWithSystemClock := false
 
-	if diff > int64(time.Second)*5/int64(tps) {
+	// When TPS is big (e.g. 300), the time gap can be small and diff might always exceeds the gap.
+	// To avoid this, prepare another gap assuming TPS was 60 and use the bigger one (#1443).
+	tooBigGap := max(int64(time.Second)*5/int64(tps), int64(time.Second)*5/60)
+	if diff > tooBigGap {
 		// The previous time is too old.
 		// Let's force to sync the game time with the system clock.
 		syncWithSystemClock = true