Add label and temp functions to ShaderNode

[LeviPesin]

Related issue: - (mentioned in #23534)

Description

This PR adds the label and temp functions to the ShaderNode.

[sunag]

@LeviPesin do you think we got another name for it? Maybe setvar?

[LeviPesin]

I actually think that makeVar is better, because it should be mainly used to create a new variable from a value to stop it from recalculating in further calculations (e.g. something like const four = makeVar(add(2, 2)); const eight = add(four, four)). setVar could be a good name for assign, but I like its current name too.

[sunag]

I think that temp to define a variable and label to define a variable name?
It's just that for me the variable concept in ShaderNode should be the JS const or let.

About add( 2, 2 ) I think that this should be optimized by the NodeBuilder compiler and the variable should be created automatically if used more than once? At least it was supposed to work that way.

// 1. force variable creation
const four = temp( add( 2, 2 ) );

// 2.  define a var name in NodeBuilder -> GLSL or WGSL
label( four, 'FOUR' ); 

// 3. create a named variable
const four = label( add( 2, 2 ), 'FOUR' );

[LeviPesin]

I think that temp to define a variable and label to define a variable name?

I like this approach!

I think that this should be optimized by the NodeBuilder compiler and the variable should be created automatically if used more than once? At least it was supposed to work that way.

Here is an example:
https://jsfiddle.net/aopLv2cx/
There is a duplicate calculation of dot(nodeVar2, nodeVar3). If you comment line 61 and uncomment 60, it will work properly.

[sunag]

@LeviPesin It seems that exist some conflicts in this PR.

[sunag]

There is a duplicate calculation of dot(nodeVar2, nodeVar3). If you comment line 61 and uncomment 60, it will work properly.

This shouldn't happen, I will investigate.
Thanks for the example.

[LeviPesin]

@sunag I think I resolved the conflicts.

[sunag]

Thanks! :)

[LeviPesin]

@sunag Is there any progress on fixing this example? Should I make a new issue for it?

[LeviPesin]

#23728