From 88e6768a305ac5e4a44ea518bd2dd08e7517a4d0 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 16 Jul 2018 04:36:47 +0900
Subject: [PATCH] Use the term 'TPS' ticks per second

---
 internal/clock/clock.go | 10 +++++-----
 run.go                  | 14 +++++++++-----
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/internal/clock/clock.go b/internal/clock/clock.go
index 742c77c8c..10f5a3dc2 100644
--- a/internal/clock/clock.go
+++ b/internal/clock/clock.go
@@ -64,7 +64,7 @@ func updateFPS(now int64) {
 
 // Update updates the inner clock state and returns an integer value
 // indicating how many game frames the game should update.
-func Update(logicFPS int) int {
+func Update(tps int) int {
 	m.Lock()
 	defer m.Unlock()
 
@@ -95,15 +95,15 @@ func Update(logicFPS int) int {
 		// Let's force to sync the game time with the system clock.
 		syncWithSystemClock = true
 	} else {
-		count = int(diff * int64(logicFPS) / int64(time.Second))
+		count = int(diff * int64(tps) / int64(time.Second))
 	}
 
 	// Stabilize FPS.
 	// Without this adjustment, count can be unstable like 0, 2, 0, 2, ...
-	if count == 0 && (int64(time.Second)/int64(logicFPS)/2) < diff {
+	if count == 0 && (int64(time.Second)/int64(tps)/2) < diff {
 		count = 1
 	}
-	if count == 2 && (int64(time.Second)/int64(logicFPS)*3/2) > diff {
+	if count == 2 && (int64(time.Second)/int64(tps)*3/2) > diff {
 		count = 1
 	}
 
@@ -111,7 +111,7 @@ func Update(logicFPS int) int {
 	if syncWithSystemClock {
 		lastSystemTime = n
 	} else {
-		lastSystemTime += int64(count) * int64(time.Second) / int64(logicFPS)
+		lastSystemTime += int64(count) * int64(time.Second) / int64(tps)
 	}
 
 	updateFPS(n)
diff --git a/run.go b/run.go
index d5b704546..fc2c2489e 100644
--- a/run.go
+++ b/run.go
@@ -30,13 +30,15 @@ import (
 )
 
 // FPS represents how many times game updating happens in a second (60).
+//
+// BUG: This actually represents TPS, not FPS.
 const FPS = 60
 
 // CurrentFPS returns the current number of frames per second of rendering.
 //
-// The returned value represents how many times rendering happens in a second and
-// NOT how many times logical game updating (a passed function to Run) happens.
-// Note that logical game updating is assured to happen 60 times in a second.
+// The returned value FPS (frames per second) that represents how many times rendering happens in a
+// second and NOT TPS (ticks per second) that represents how many times logical game updating (a
+// passed function to Run) happens in a second.
 //
 // CurrentFPS is concurrent-safe.
 func CurrentFPS() float64 {
@@ -250,8 +252,10 @@ func (i *imageDumper) update(screen *Image) error {
 // Run must be called from the OS main thread.
 // Note that Ebiten bounds the main goroutine to the main OS thread by runtime.LockOSThread.
 //
-// The given function f is guaranteed to be called 60 times a second
-// even if a rendering frame is skipped.
+// Ebiten tries to call f 60 times a second. In other words,
+// TPS (ticks per second) is 60.
+// This is not related to framerate (display's frashrate).
+//
 // f is not called when the window is in background by default.
 // This setting is configurable with SetRunnableInBackground.
 //