Nodes

Nodes are the main elements used to build diagrams representing functions.

To insert a node in the workspace, simply drag and drop it from the toolbox. You can also find them in the insert menu.

To connect a node to another, simply drag a socket of the node and drop it on the other one. Note : to cannot connect a node to an output node or to itself.

To delete a connection between two nodes, right-click on the node and chose disconnect from the menu.

Here are all the available and how to use them :

• X and Y :

These nodes return a real number between 0 and 1 depending on the position of each pixel.

For X, 0 corresponds to the left-most column of pixels in the output image and 1 corresponds to the right. Same for Y but vertically (top to bottom).

For now, you can have at most only one of each of these nodes.

• Real numbers :

The real number node returns a constant number chosen by the user. It can be positive or negative and can only have 3 digits after the coma.

• Math operations :

These nodes represent basic math operations that can be done to implement complex formulas. They work for real and complex numbers.

The order of the parameters is from top to bottom. Don't try to divide by 0.

• Output :

The output node is a special node. It does not return any value. It converts the value it receives for each pixel into a color, which makes an image! Real numbers are converted to a gradient of colors between black and white, corresponding to [0-1]. Complex numbers are converted to colors depending on their angle and magnitude.

• Width/Height Ratio :

Returns the width/height ratio of the output image.

• Color :

The color node returns a constant color chosen by the user.

• LUT (Look-Up Table) :

This node takes one parameter and return a color. The received parameter is converted to a real number (if needed). If this number is greater than 1, the node returns the color corresponding to the highest value (1). If the number is less than 0, the node returns the color corresponding to the lowest value (0).

• Comparison :

These nodes take 2 parameters, convert them into real numbers, compare them and return a Boolean depending on the result. Same as the math nodes : the order of the parameters is from top to bottom.

• Logic :

Logic nodes, logic gates!

• Linear interpolation :

The linear interpolation node takes 3 parameters : the 3rd one is the minimum value, the first one is the maximum value and the one in the middle is a number between 0 and 1.

Like the LUT node, if this number is greater than 1, the node returns the number corresponding to the highest value (1). If the number is less than 0, the node returns the number corresponding to the lowest value (0).

• Clamp :

Clamp node is quite the opposite of the linear interpolation gate. It takes 3 parameters and returns a number between 0 and 1 depending on how close the 2nd parameter is to the 1st and 3rd ones.

• Condition :

As it's indicated on the node, this node returns the 1st (then) parameter if the second (if) is true, and it returns the 3rd (else) in any other case.

There is no condition on the types of the 1st and 3rd parameter.

• RGB and HSV :

These nodes take 3 parameters which are converted to real numbers between 0 and 1. Each corresponding to the Red, Green and Blue values or Hue, Saturation and Value depending on the node. The resulting color is returned.

• Complex numbers :

The complex number node takes exactly 2 parameters and return a complex number. These parameters are preferred to be real numbers.

In Emergence, complex numbers are converted to colors using their angle and magnitude. The angle [-pi; pi] is interpolated to [0; 1] and used as Hue. The magnitude is clamped between 0 and 1 and used as Value. This idea was inspired by a 3blue1brown video.

• Image :

This node takes two parameters and return the color of the corresponding pixel of a bitmap image chosen by the user.