[splishsplash] about how to receive / display user parameters, MVC mode and genparam on GUI and JSON

principle ：splishsplash Medium MVC Patterns and GenericParameter

splishsplash Have adopted the MVC Design patterns . The biggest feature of this design pattern is to separate the user interface from the back-end data calculation , It's also known as “ front end ” and “ Back end ” Separate . actually , As long as it involves GUI Or graphics program , Are almost more or less necessary MVC Design patterns .

MVC The three letters in represent Model View Controller
Model Be responsible for data calculation ,View Responsible user IO（ That is, display the interface and receive user input ）,Controller Be responsible for the communication between the two . adopt Controller, We completely cut off the back-end and front-end . The decoupling of the system is realized .

splishsplash Medium Model Don't need to say more , Is the main body of calculation , Think of it as FluidModel And other examples of calculation data .

View It stands for GUI, At present, the default is IMGUI.

and Controller, It is GenericParamerter This third-party library . This library is splishsplash Another project developed by the project team . stay splishsplash As a third-party library . Its purpose is to manage parameters . As long as you want to Model The parameters in and the parameters of the user interface communicate with each other , It can be GenericParameter As the parent of your current class .GenericParameter Will be responsible for and IMGUI Communicate with each other . that , For our code developers , Just need to be able to use GenericParameter Of API Can be realized with GUI Communication between .

You may ask why you want to add an intermediary , Instead of going directly to Unicom IMGUI Well ？ as a result of 1）GUI There are many options for libraries ,IMGUI,TweakBar( Once the default GUI) wait . If I change GUI, Wouldn't all the code in the algorithm have to change ？ So for the sake of unity API, Adding an intermediary is beneficial .2） If there is no intermediary Controller, The code of communication between the two , Or write it in the GUI In the source file of , Or write it in the source file of the algorithm , Both of them will cause very troublesome coupling problems .3） Simplified use .IMGUI There are many functions , But we only need to manage parameters here , What is superfluous is a burden for us .

therefore , Next, we only focus on this intermediary Controller（ That is to say GenericParameters） Of API.

Explain how to use

Let's look at an example , Code from SurfaceTensionBase.cpp

SURFACE_TENSION = createNumericParameter("surfaceTension", "Surface tension coefficient", &m_surfaceTension); 
setGroup(SURFACE_TENSION, "Surface tension");
setDescription(SURFACE_TENSION, "Coefficient for the surface tension computation"); 
RealParameter* rparam = static_cast<RealParameter*>(getParameter(SURFACE_TENSION));
rparam->setMinValue(0.0);

The function of this code is ： Binding parameters m_surfaceTension To GUI Up ,GUI The parameters shown in are called surfaceTension.

We analyze it line by line ：
first line

SURFACE_TENSION = createNumericParameter("surfaceTension", "Surface tension coefficient", &m_surfaceTension); 

createNumericParameter This function is to create a numeric parameter . The name of this parameter is surfaceTension（ This name also applies to json file ）. Described as Surface tension coefficient, The bound parameter is m_surfaceTension（ Note that the pointer is passed ）. As for the integer variable returned , yes GUI Group number of . It must be a static Of （ Because static lifetime is required ）

The second line

setGroup(SURFACE_TENSION, "Surface tension"); 

For the convenience of management , Parameters are usually grouped . This is in GUI The above effect is paging . Each group is a separate page to display .

The third line

setDescription(SURFACE_TENSION, "Coefficient for the surface tension computation"); 

Description displayed when the mouse hovers .

In the fourth row

RealParameter* rparam = static_cast<RealParameter*>(getParameter(SURFACE_TENSION));

Used to set the maximum and minimum value . This is to prevent users from entering incorrectly .

The fifth row

rparam->setMinValue(0.0);

Set minimum value

Let's modify the experimental effect

I've just finished talking about the principle and usage , So let's try to change something , See if the theory conforms to practice .

Change the name, description and initial value of the test

The first line is changed to

SURFACE_TENSION = createNumericParameter("thisIsName", "This is Discription", &m_surfaceTension); 

Compile operation

We found that it was

Then whether it can pass json Change its parameters ？ At present, the default is 0.05
We're in a json Change in

"Materials": [
	{
		"id": "Fluid",
		"thisIsName": 1.11
	}
],

function

It is found that the parameters are indeed read

Test groups

The second line is changed to

setGroup(SURFACE_TENSION, "A new group");

Compile operation

When you choose any SurfaceTension New groups will appear when the algorithm

And our previous parameter has also been moved to the new page .

Please note that ： Decide whether your parameters are in the new page , Is the group of your parameters （ That is, the group number SURFACE_TENSION Determined by ）

For example, the original Boundary surface tension coeff There is no new lease “A new group”

Test group description

Different from the previous one , This is a description of each variable in the Group

setDescription(SURFACE_TENSION, "This is the group discription");

Test the maximum and minimum values

The fifth line is changed to

rparam->setMinValue(1.0);
rparam->setMaxValue(5.0);

Suppose we type 0.9, Will automatically bounce back 1.0

The maximum is the same