Procedural texture functions

[Lisbon]

Been trying to get a better understanding of the procedural texture functions, but I don't know how some of them work.
In particular:
- Vector creation: tovec3
- Vector utilities: debump
- Stepping: mapcui, smoothstepsini
- Quantisation: All of them

Any help on any of these functions would be appreciated.
It can be a url. I don't mind.

[NotMyFault]

Let me try:

mapcui (lower, upper, runner)

• if runner<=lower: 0
• if lower<runner<upper: linear interpolation from 0 to 1
• if runner>upper: 1

See historgram

play with lower / upper slider

smoothstepsini (lower, upper, runner)

• if runner<=lower: 0
• if lower<runner<upper: sinus interpolation from 0 to 1
• if runner>upper: 1

[NotMyFault]

tovec3: I did not get this to work. Probably defunct.

[NotMyFault]

quantize (steps, smoother, runner)

steps: create 1/n steps, e.g 1/2: 2 steps, 1/3: 3 steps

smoother: 0: hard steps, 1: max soft steps, in between: linear interpolation of smoothness

example shows 3 steps (0/3, 1/3, 2/3). note that 3/3 is excluded!

same with max smoothness:

The other quantizers differ in the kind of smoothness function

[NotMyFault]

Here the test file to play / experiment with

PT filter explained.afphoto

[NotMyFault]

debump:

More info can be found here:

https://stannum.io/blog/0IwyJ-

https://www.pluralsight.com/blog/film-games/bump-normal-and-displacement-maps

•  
• bump maps
• normal maps
• displacement maps

 

Please keep in mind that Affinity seems to treat bump maps in displacement filter different than other apps. So the information given in the linksmay not apply to Affinity's special interpretation.

Bump maps are used either in lighting filter (works great) or in displacement filter (this is kind of strange according to more experienced users, incompatible with Photoshop).

 

 

 

 

[Lisbon]

Thanks a lot NotMyFault.

This is a great help.

1 hour ago, NotMyFault said:

mapcui (lower, upper, runner)

• if runner<=lower: 0
• if lower<runner<upper: linear interpolation from 0 to 1
• if runner>upper: 1

You are right.
The help file misled me: mapcui(T v, T edge0, T edge1)

1 hour ago, NotMyFault said:

smoothstepsini (lower, upper, runner)

• if runner<=lower: 0
• if lower<runner<upper: sinus interpolation from 0 to 1
• if runner>upper: 1

Maybe, but im not sure NotMyFault.
smoothstepsin (without the "i" at the end) does what you described.
On my pc, smoothstepsini doesn't do anything regardless of the values i input.
Maybe a bug, i dont know.

1 hour ago, NotMyFault said:

tovec3: I did not get this to work. Probably defunct.

The only thing i can do with tovec3 is this:
var v1=vec2(0.5); tovec3(v1) [RGB all selected]
This will make the R=0.5, G=0.5 and B=0
But im sure im using this wrong.

1 hour ago, NotMyFault said:

quantize (steps, smoother, runner)

steps: create 1/n steps, e.g 1/2: 2 steps, 1/3: 3 steps

smoother: 0: hard steps, 1: max soft steps, in between: linear interpolation of smoothness

example shows 3 steps (0/3, 1/3, 2/3). note that 3/3 is excluded!

The other quantizers differ in the kind of smoothness function

I definitely had no idea what I was doing.
That posterize effect was exactly what I was hoping to get when using this function.

1 hour ago, NotMyFault said:

debump:

More info can be found here:

https://stannum.io/blog/0IwyJ-

https://www.pluralsight.com/blog/film-games/bump-normal-and-displacement-maps

I will read that.

Again, thank you NotMyFault.

(Almost there. Only ~400 functions left)

 

[NotMyFault]

The documentation of procedural texture is really not on par with elementary quality standards. I tried multiple times to get more information, raised feature request, never get anything substantial answer from Affinity.

Essentially all trial and error. 
tovec3 lead always to non-funktional filter (showing no effect). It does not show red text (indicating syntax error), only no effect.

Today i found in CMYK that you cannot use K channel as input value, and filed a new bug report.

[Lisbon]

15 minutes ago, NotMyFault said:

Essentially all trial and error.

Exactly what I am doing.
Testing and searching the web.
It's not easy and it takes a lot of time.

15 minutes ago, NotMyFault said:

Today i found in CMYK that you cannot use K channel as input value, and filed a new bug report.

yes. I read your post this afternoon.
(No K is not OK)

[NotMyFault]

13 hours ago, Lisbon said:

Maybe, but im not sure NotMyFault.
smoothstepsin (without the "i" at the end) does what you described.
On my pc, smoothstepsini doesn't do anything regardless of the values i input.
Maybe a bug, i dont know.

Yeah a bug with smoothstepsini

The functions ending on "i" are "inverse", see example for smoothstepcr[i] below.

The white area in the middle is caused by the chosen parameters b and c which do not overlap. In case of b=c, you get the inverse as nothing is excluded.