“Coding Druid” series is my horizontal programming practice notes, each part around a topic like mathematical, physics, electronic, graphics, sound, etc., implemented in several programming languages.


Coding Druid
Part: Math
Chapter: Trigonometric Function
Section: Unity3D

In the previous three sections, I visualized Trigonometric function (Sine and unit circle) by MaxMSP, JavaScript (React), and Python:

trig-max-visualization.gif

Trigonometric function visualization using MaxMSP

sine-js-croped.gif

Sine function visualization using JavaScript (React)

sine python effect

Sine function visualization using Python

This time I use Unity3D to implement it.

In the previous Python version, the data visualization Library Matplotlib was used. With Unity I just draw it according to the trigonometric function algorithm.

Firstly, Let a point move with the Sine function curve.

Put a Sphere in the scene, and let its position.x increase at a constant speed, then position.y = sin(position.x).

Vector3 posSine = sphere.localPosition;
posSine.x += speed;
posSine.y = Mathf.Sin(posSine.x);
sphere.localPosition = posSine;

sine-unity-sineball

Next, draw a path of the sphere moving along the unit circle.

Note that here, set the radius of the unit circle to 1, and set the period length of Sine to 2Pi. That is as shown in the previous sections, the unit circle shares a coordinate system with Sine.

Formula to drawing a circle:

x = cos(t);
y = sin(t);

The param t here, in fact is the position.x of the Sine in previous step.

Then move the center of the circle to the left, to make the rotating starting point of the unit circle consistent with the starting point of Sine.

Vector3 posCircle = posSine;
posCircle.x = Mathf.Cos(posSine.x) – 1f;
posCircle.y = Mathf.Sin(posSine.x);
circleDot.localPosition = posCircle;

sine-unity-circleball

Combine the Sine and unit circle:

sine-unity-sinecircleball

In the previous articles, I drew the path of the curve to make it more clearly, such as Python:

sine python effect

I plan to be lazy with Unity.
Add the Trail Renderer directly to the two spheres, and let them draw path trail effect themselves.

sine-unity-trail0

Well, The default trail is a bit strong…

OK let’s change it. After searching trail in the Unity Assets Store I find a free good track effect

unity-trail

After installation the asset there are a lot of effects. Then pick a material by liking:

sine-unity-trail-material

Attach the material to the Trail Renderer.

Final Effect:

sine-unity-croped

In the released source code, I added Trail Renderer to an empty GameObject and moved with the sphere. I didn’t add the track directly to the sphere. There is no special reason, just practice of Unity newbie.

Reference article: Building a Graph Visualizing Math


Talk is cheap. Show me the code!

This demo and the “Coding Druid” series is open source here:
https://github.com/avantcontra/coding-druid

You can find more resources in my site floatbug.com.
Or you may buy me a coffee in my Patreon. Your encouragement is my driving energy!
https://www.patreon.com/avantcontra

Cheers~

Contra

Fb/Tw/Ins/Github: @avantcontra
Website: floatbug.com

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