Add Scalar

Add Scalar

Overview

The Add family of nodes allow you to add the colour/scalar/vector coming into the Main Input with the colour/scalar/vector coming into Input 2.

The Add Scalar node adds two scalars together. It wants the incoming data to be scalars, but it will convert colours and vectors to scalars if necessary.

• When the source of the incoming data is colour data, the Add Scalar node converts the data to scalar based on the luminance of the colour. The math for this is: 0.2125 * r + 0.7152 *g + 0.0724 * b.

• When the source of the incoming data is vector data, the Add Scalar node converts the data to scalar based on the length of the vector. The math for this is: square_root(x*x + y*y + z*z).

Settings:

• Name: This setting allows you to apply a descriptive name to the node, which can be helpful when using multiple Add Scalar nodes in a project.
• Enable: When checked, the node is active and the Main Input value is added with the Input 2 value. When unchecked, only the Main Input value is passed through the node.
• Input 2: The values from the shader or function nodes assigned to this setting are added to the values of the Main Input.

Fun with Add Scalar

The Add scalar node requires scalar data. Here the colour output from the red nodes is converted to scalar data via the Luminous to scalar nodes.

Add scalar combines the Main Input and Input 2 component values, discarding displacement data, and outputting scalar data.

When Input 2 is unassigned, data from the Main Input is passed through as scalar data.

When the Main Input is unassigned, nothing is passed through.

When colour values are used as the source for the Main Input and Input 2, their component’s luminance values are used.

When vector values are used as the source, the scalar values are based on the length of the vector from a zero origin.

Vector and colour values can be used simultaneously as inputs to the Add Scalar node. Their component values are converted as necessary and output as scalar data.

A scalar is a single number. 1, 200.45, -45, -0.2 are all examples of scalar values.

A vector is a set of three scalars, normally representing X, Y and Z coordinates. It also commonly represents rotation, where the values are pitch, heading and bank.

A single object or device in the node network which generates or modifies data and may accept input data or create output data or both, depending on its function. Nodes usually have their own settings which control the data they create or how they modify data passing through them. Nodes are connected together in a network to perform work in a network-based user interface. In Terragen 2 nodes are connected together to describe a scene.

This is essentially the brightness of the colour. Terragen converts RGB colours to greyscale by taking the luminance of the colour.

A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.

Literally, to change the position of something. In graphics terminology to displace a surface is to modify its geometric (3D) structure using reference data of some kind. For example, a grayscale image might be taken as input, with black areas indicating no displacement of the surface, and white indicating maximum displacement. In Terragen 2 displacement is used to create all terrain by taking heightfield or procedural data as input and using it to displace the normally flat sphere of the planet.