Constant Nodes
In the Shader Designer, constant nodes represent literal values and interpolated vertex attributes in pixelshader calculations. Because vertex attributes are interpolated—and so, are different for each pixel—each pixelshader instance receives a different version of the constant. This gives each pixel a unique appearance.
The image of a 3D scene in a game or app is made by mathematically transforming a number of objects—which are defined by vertices, vertex attributes, and primitive definitions—into onscreen pixels. All of the information that's required to give a pixel its unique appearance is supplied through vertex attributes, which are blended together according to the pixel's proximity to the different vertices that make up its primitive. A primitive is a basic rendering element; that is, a simple shape such as a point, a line, or a triangle. A pixel that's very close to just one of the vertices receives constants that are nearly identical to that vertex, but a pixel that's evenly spaced between all the vertices of a primitive receives constants that are the average of those vertices. In graphics programming, the constants that the pixels receive are said to be interpolated. Providing constant data to pixels in this way produces very good visual quality and at the same time reduces memory footprint and bandwidth requirements.
Although each pixelshader instance receives only one set of constant values and cannot change these values, different pixelshader instances receive different sets of constant data. This design enables a shader program to produce a different color output for each pixel in the primitive.
Node 
Details 
Properties 

Camera Vector 
The vector that extends from the current pixel to the camera in world space. You can use this to calculate reflections in world space. Output 
None 
Color Constant 
A constant color value. Output 

Constant 
A constant scalar value. Output 

2D Constant 
A twocomponent vector constant. Output 

3D Constant 
A threecomponent vector constant. Output 

4D Constant 
A fourcomponent vector constant. Output 

Normalized Position 
The position of the current pixel, expressed in normalized device coordinates. The xcoordinate and ycoordinate have values in the range of [1, 1], the zcoordinate has a value in the range of [0, 1], and the w component contains the point depth value in view space; w is not normalized. Output 
None 
Point Color 
The diffuse color of the current pixel, which is a combination of the material diffuse color and vertex color attributes. Output 
None 
Point Depth 
The depth of the current pixel in view space. Output 
None 
Normalized Point Depth 
The depth of the current pixel, expressed in normalized device coordinates. The result has a value in the range of [0, 1]. Output 
None 
Screen Position 
The position of the current pixel, expressed in screen coordinates. The screen coordinates are based on the current viewport. The x and y components contain the screen coordinates, the z component contains the depth normalized to a range of [0, 1], and the w component contains the depth value in view space. Output 
None 
Surface Normal 
The surface normal of the current pixel in object space. You can use this to calculate lighting contributions and reflections in object space. Output 
None 
Tangent Space Camera Vector 
The vector that extends from the current pixel to the camera in tangent space. You can use this to calculate reflections in tangent space. Output 
None 
Tangent Space Light Direction 
The vector that defines the direction in which light is cast from a light source in the tangent space of the current pixel. You can use this to calculate lighting and specular contributions in tangent space. Output: 
None 
World Normal 
The surface normal of the current pixel in world space. You can use this to calculate lighting contributions and reflections in world space. Output 
None 
World Position 
The position of the current pixel in world space. Output 
None 