Pagoda of Fogong Temple

 
 
 

2D Transformation

Transformation is relative simple

Use coordinates to add a transformation vector to get new coordinates.

2D Rotation

2D Rotation is a bit more complicated.

Using trigonometric function we get the relationship from two coordinates to the center of the grid.

I found a youtube video that explains it well

If you find it confusing, please come back to see the graph. I add more labels to help you understand it more comfortably.

 
 

"Blend" Function can easily explained by graph

 

Blend curve

See color match between the curve and math

simple Cross osl

 

Smooth-Step Function is a useful function that used both on OSL and HLSL

 

Smooth-Step Function

It is a function to control the step smoothness

see the graph on left

Use an upper and lower limit to control the clamp

Definition

 

A good example would be :

using the smooth-step function to control the cosine wave

notice multiple “S“ after “cos(5s)” would achieve the control effects

 

Use number and multiply factor can control the clamps further

 

Therefore, the udn function in bombing represents this variation of the smooth-step function

 

OSL code

Now, we can step into the OSL function

The main function were explained beautifully by Blender Sushi

The link is here：Click me for the redirect

The main logic here is the same as ST pattern. It add variation for each dots’ pivot points and use for loop to overlay layers that has different size of dots

User can use for loop in the function to create as many variation as they like such as radius and color. However, each dot are still limited to move in certain area.

So be careful about variation size.

One place to notice is that each render engine use OSL slightly different

For example, Radarman use S&T while Arnold use UV directly

So be careful about definition at the very beginning