An Analog Clock

Clocks show up everywhere in HMIs, and happen to be simple to create in Incari.

Load up the 'AnalogClock' project file from Incari Hub. The included Scenes are a version with a ticking animation and a basic one.

Basic Version	Ticking Version

1. The Basic Version

Open the 'AnalogClock' project from the Incari Hub Remote Projects tab. In the Project Outliner look for 'Basic' and make sure its visibility toggle is active. You can press Run (Ctrl+R) to preview how the Scene looks.

The Project Outliner with an active visibility toggle for the 'Basic Scene'.

Now we can dive into how it works. In the top Menu bar, go to View -> Logic Editor if it isn't already visible. Double click 'Basic' in the Project Outliner to load up the Scene Logic. Make sure the 'Basic' tab is selected in the Logic Editor module- the Project Logic is explained later.

All Logic from the 'Basic' tab in the Logic Editor.

You'll see two major groups of Nodes, which don't appear to be connected. The left side handles the data gathering part of our Scene. The right side takes this data and updates the User Interface (the clock face).

It's always a good practice to try and separate the view Logic (changing the interface) from the model Logic (changing the data) as much as possible. It makes things much easier to reason about in the long run!

Let's look a bit closer at how we've done this.

Model Logic

Model Logic from the 'Basic' tab.

When the Scene is displayed, we trigger a Start Interval Node. This takes a single Pulse (►) Input and creates a recurring Pulse Output triggering the next Node at a set time interval. This will let us get the current time on an ongoing basis.

In this case, we have set Start Interval to retrigger System Time every 0.1 seconds (see the Timeout Attribute).

Start Interval Node and Attributes

The System Time Node outputs hour, minute, second, and millisecond values separately in a variety of formats. By default, it will just give the current time in whole-number values. We have chosen the built-in degree values in this case, which will handily convert the time value to a rotation value that we can use to drive the interface.

System Time Node and Attributes

Every time it is triggered, it will update the values stored in its Outputs (square green Sockets). We read these values sequentially and store them in separate Variables using three Variable Setter Nodes, one for each clock hand.

Setting the time Variables.

By storing into these Variables, we can achieve the decoupling between data and interface mentioned earlier.

View Logic

Using an On Change Event Node for each Variable will allow us to trigger an update on each clock hand only when needed.

Finally, we pass the Variable value and the trigger from the On Change Nodes to three Set Rotation Nodes configured to point to each clock hand image layer.

That's it for how the basic example works under the hood.

Save and run the project to see the basic clock!

2. The Ticking Version

But what if we want our second hand to “tick” like an analog clock? By adding a little more complexity, we can allow for the visual look to be tweaked to our needs. In order to manage this complexity, we'll also introduce the concept of Functions in Incari.

From the Project Outliner, double click the Scene named ‘Ticking Animation'.

This Scene is split across two tabs on the Logic Editor: The ‘Project’ tab and the ‘Ticking Animation’ tab.

'Project' tab Logic

Logic in the 'Project' tab

The Logic in here is shared across the whole Project, as you might expect from the name. We didn't use anything here in the basic example. But in a real app, here is where you would set Variables like the current time, as you would expect to need to tell the time across many different Scenes.

The chain starts with the On Initialize Event which fires when the Incari Project is run. Two functions are pulsed here: 'updateTimeVariables' and 'initializeTime'.

'updateTimeVariables' Function

This Function gets the current time and sets the time Variables to the current system time. The seconds are saved as Integer values, while the minutes and hours are saved as Float values.

updateTimeVariables Function.

We also check the option to output the values for the hours and minutes as smooth Float values. This is because the hours and minutes will be positioned in between the positions on the clockface, as they do on a real clock.

'initializeTime' Function

The 'initializeTime' Function checks to see if the time has been initialized and sets the 'timeInitialized' Boolean value to true.

'Ticking Animation' Logic

The 'Ticking Animation' Logic is divided into several parts. The Logic updates the time Variables every 1s, creates the second hand ticking movement, converts time value to a rotation value for all hands, and then finally rotates the clock hand images. We will go into detail about how each of these parts works.

All logic in the ‘Ticking Animation’ tab.

Update Time Variables

This part of the Logic runs only when the time has first been initialized. Then, a Start Interval Node is triggered. Every 1 second, the Function 'updateTimeVariables' will run, which will update the current 'Second', 'Minute', and 'Hour' Variables.

Create Second Hand Ticking Movement

Whenever the 'currentSecond' Variable changes, that new value is used to calculate the starting and ending position of the second hand when it ticks. The starting position of the hand is the current time, and the ending position is the current time + 1. The Interpolate Node is used to output a smooth transition from one number to the next across a period of time. This is what will animate the hand to make it “tick".

The Interpolate Node has a few different Attributes that we can tweak to achieve a certain look:

• Duration - how long the interpolation takes.

• Interval Time - how long each sub-unit of time is. For example, if we have a duration of 10 seconds and an interval time of 1 second, then Interpolate will output 10 values across 10 seconds:

  1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

  Half the interval time outputs twice as many numbers in the same duration:

  1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0.

• From - the value we start from. In this case the current second - 1 (the previous second).

• To - the value we end at (the current time).

• There is also the Interpolation Type, which will give you the option for non-linear easing. For example you might want the hand to start slow and speed up. The best way to understand the difference is to experiment with the settings.

Convert Time Value to a Rotation Value for all Hands

For each, the seconds, minutes, and hours, the time value is remapped to a rotation value (degrees) using a custom 'convertTimeToRotation' Function. This Function takes the time value, remaps the value using a Range Mapper Node, and converts those values to a Vector3 value.

convertTimetoRotation Function.

The Range Mapper Node needs a maximum value of the time, meaning the number that equals one full revolution around the clockface. (seconds = 60; minutes = 60; hours = 12). It then uses that maximum and remaps the value to a new maximum of 360 (for 360 degrees in a circle). This gives the degree of rotation for the current time.

Rotates the Clock Hand Images

Now that the time values have been converted to rotation values, we can use those values to set the rotation of each clock hand image using a Set Rotation Node.

Save and run the Project to see the ticking clock!