Update 'Analog Clock'

Analog-Clock.md

@@ -486,3 +486,51 @@ It all looks like this:
 <a href="https://pgetinker.com/s/SnIkSOJ7Vk" title="Click to try it out!" target="_blank">[***Try it out!***]</a>
 
 <a href="https://pgetinker.com/s/SnIkSOJ7Vk" title="Click to try it out!" target="_blank"><img src="https://pit.pgetinker.com/S2ySVCFsMKgw.png" width="256" height="240"></a>
+
+## "Ticking" Jump Back Motion
+When the second hand jumps forward, it has a slight jump back as it locks into place. It's very subtle but also a feature in analog clocks that I like. Let's try to recreate that subtle detail.
+
+Start by adding a new variable to track the amount of time it takes before the second hand "jumps back". We'll make it 0.02 seconds for now (very subtle). We also need a variable tracking what the amount of seconds that have passed was the previous frame. If it ever differs, we set the `secondHandBounceTimer` to `0.02` and it starts decreasing by `GetElapsedTime()` (the amount of time in seconds that have passed for this rendering frame). 
+
+One way we would be able to trigger the "tick back" motion is by modifying the `DrawHand()` lambda inside `DrawClockHands()` to have a float parameter passed in with an "additional rotation" amount.
+
+First update the `DrawHand()` lambda with the new parameter and angle offset:
+```cpp
+        const auto DrawHand=[&](const float handLength,const float secondsPerRevolution,const olc::Pixel col,const float angleOffset=0.f){
+            using namespace std::numbers;
+            const float angle{float(2*pi*fmod(totalTime,secondsPerRevolution)/secondsPerRevolution+angleOffset)};
+            olc::vf2d handVec{handLength,float(angle-pi/2)};
+            DrawLine(GetScreenSize()/2,GetScreenSize()/2+handVec.cart(),col);
+        };
+```
+Add two new variables into the game class:
+```cpp
+public:
+    bool OnUserCreate() override
+    {
+        return true;
+    }
+
+    float secondHandBounceTimer{0.f};
+    size_t lastSecond{};
+```
+Update the last second value and the bounce timer if it changes.
+```cpp
+        if(lastSecond!=localTime->tm_sec){
+            secondHandBounceTimer=0.02f;
+            lastSecond=localTime->tm_sec;
+        }
+```
+In `OnUserUpdate()` we have to tick down the bounce timer. We use `std::max` as it's equivalent to `if(secondHandBounceTimer>0)secondHandBounceTimer-=fElapsedTime; secondHandBounceTimer=std::max(secondHandBounceTimer,0.f);`
+```cpp
+        secondHandBounceTimer=std::max(secondHandBounceTimer-fElapsedTime,0.f);
+```
+Finally, apply the bounce timer to the `DrawHand()` call for the second hand.
+```cpp
+        DrawHand(85,60,olc::RED,secondHandBounceTimer);
+```
+Screenshots don't do it justice, but look at the results for yourself and it is a pretty convincing behavior!
+
+<a href="https://pgetinker.com/s/k2GF-BTk2tQ" title="Click to try it out!" target="_blank">[***Try it out!***]</a>
+
+<a href="https://pgetinker.com/s/k2GF-BTk2tQ" title="Click to try it out!" target="_blank"><img src="https://pit.pgetinker.com/W4tqHfCm4TXo.png" width="256" height="240"></a>