Egret P2 pit encountered by physical engine (1)

• Direct will pythsic Bag to libs Directory and modify egretPropertis.json file

TypeError [ERR_INVALID_ARG_TYPE]: The "to" argument must be of type string. Received type object
    at validateString (internal/validators.js:125:11)
    at Object.relative (path.js:493:5)
    at C:\Users\mi\AppData\Roaming\EgretLauncher\download\EgretCompiler\@egret\egret-webpack-bundler\lib\egretproject\data.js:149:34
    at Array.map (<anonymous>)
    at EgretProjectData.getModulesConfig (C:\Users\mi\AppData\Roaming\EgretLauncher\download\EgretCompiler\@egret\egret-webpack-bundler\lib\egretproject\data.js:145:51)     
    at Object.getLibsFileList (C:\Users\mi\AppData\Roaming\EgretLauncher\download\EgretCompiler\@egret\egret-webpack-bundler\lib\egretproject\index.js:8:24)
    at EgretWebpackBundler.startDevServer (C:\Users\mi\AppData\Roaming\EgretLauncher\download\EgretCompiler\@egret\egret-webpack-bundler\lib\index.js:47:38)
    at C:\Users\mi\Documents\EgretProjects\keli_go\scripts\plugins\webpack-plugin.ts:59:21
    at new Promise (<anonymous>)

Cause analysis ：

Generally, there is a problem with the path , Not configured correctly p2 Specific file path of the package **,to Input parameters receive object parameters

Solution ：

Need to be in egretProperties.json The file configuration is specific path route , As follows ： take physics.d.ts/physics.js/physics.min.js Put it in root directory /../physics Under the table of contents

And then egretProperties.json Add configuration item

{
      "name":"physics",
      "path":"../physics"
    }

• After modifying the configuration file and address, the compiler will not report an error , But in the browser create p2 Objects will still not be found p2 The problem with this object

  Main.ts:89 Uncaught (in promise) ReferenceError: p2 is not defined
      at HelloWorld../src/Main.ts.HelloWorld.createWorld (Main.ts:89:22)
      at HelloWorld.<anonymous> (Main.ts:24:10)
      at step (main.js:80:19)
      at Object.next (main.js:61:49)
      at fulfilled (main.js:51:54)
  

  Solution ：

   Need to use `egret` Self contained `wing` The editor finds   plug-in unit -Egret Project tools - Build engine 
  
   Click to compile , After the compilation , Open the project again 
  
  [ Failed to transfer the external chain picture , The origin station may have anti-theft chain mechanism , It is suggested to save the pictures and upload them directly (img-psPeBIZO-1644245149474)(9e3c157f63630e22e7e4397976151e41.png)]
  ![ Please add a picture description ](https://img-blog.csdnimg.cn/aad4d49d4c514a17b757c44412ec9856.png)
  
  

  Or use code egret build -e Try manual compilation

  The symbol of successful compilation is [ Failed to transfer the external chain picture , The origin station may have anti-theft chain mechanism , It is suggested to save the pictures and upload them directly (img-PhCjBywC-1644245149480)(5bbf974a7f99351d79a4eff9391377c4.png)]
  

  stay libs/modules/ There are compiled under the path physics Library file directory

  
  

• wrold,plane（ Horizon ), Objects have been set up and added to world in , But it doesn't show the pattern

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  Possible causes ： No maps are bound to the objects in the relevant physics engine , Bind map through ,p2.Body Object's displays Property to bind , Example

  this.display =  new egret.Shape()
      this.display.x = 100
      this.display.graphics.beginFill(0xff0000,1)
      this.display.graphics.drawCircle(0,0,(<p2.Box>boxShape).width)
      this.display.graphics.endFill()
      // this.display.width = (<p2.Box>bfoxShape).width
      // this.display.height = (<p2.Box>boxShape).height
      boxBody.displays = [this.display]
  

  After binding the map , You can see... In the physics engine body Rigid body objects also have corresponding maps

• The rigid body sets the material to STATIC, The collision of objects can still pass through the surface of objects

  [ Failed to transfer the external chain picture , The origin station may have anti-theft chain mechanism , It is suggested to save the pictures and upload them directly (img-DtOAIhqq-1644245149491)(89c0654d2e24bef4011e2aeeac1d8528.gif)]
  

  
  

The properties of the ground rigid body initialization are as follows

new p2.Body({
      type:p2.Body.STATIC,
      position:[0,stageHeight -100]
    })

The properties of sphere rigid body initialization are as follows

new p2.Body({ mass: 1, position: [200, 200], angularVelocity: 1})

Here the rigid body type There are three types ：

Dynamic ： dynamic , Dynamic Type rigid bodies can interact with any type of rigid body , Can be moved .

STATIC： static state ,Static Type rigid bodies cannot be moved , But it can be done with dynamic Type rigid body interaction .

Kinematic： Dynamic rigid bodies ,Kinematic Type rigid bodies control by setting the speed , Others are similar to Static Rigid bodies are the same .

To be reasonable, here we set up STATIC It should not be worn out when it collides with objects

1. The first question is whether the sphere has no rigid body , Put the sphere's type Also set to STATIC Have a try

   ....emmm Find yourself mentally retarded , I just said STATIC Type cannot be moved , Here's the picture , Not at all

   [ Failed to transfer the external chain picture , The origin station may have anti-theft chain mechanism , It is suggested to save the pictures and upload them directly (img-WUd416oh-1644245149496)(e0c3c8afe4ec9ea01301f333d5355e0c.png)]
   

2. Doubt the sphere shape There is a problem with the shape , The current setup is like this

   var boxShape:p2.Shape =  new p2.Box({width:20,height:20})
   

    Not solved yet , It's a little late today , Ready for a break 
   

• world and Horizon , The balls are all set , Or how to make the physics engine move

  [ Failed to transfer the external chain picture , The origin station may have anti-theft chain mechanism , It is suggested to save the pictures and upload them directly (img-UtgJ15jf-1644245149500)(332c851fec7c82243b9fe45404bb6046.png)]
  

There are several possible situations

1. Set the... Of the rigid body type Types are static , A static rigid body cannot have displacement
2. There is no tone world.step() Step function , Make the physical world follow the formula track , Use timer , Or in egret Frame refresh event binding step function , And refresh in the function egret View location

   // Frame event , Step function 
     private update() {
       this.world.step(1);
       var l = this.world.bodies.length;
       for (var i:number = 0; i < l; i++) {
           var boxBody:p2.Body = this.world.bodies[i];
           var box:egret.DisplayObject = boxBody.displays[0];
           if (box) {
               // Assign the coordinates and angles of the rigid body to the display object 
               box.x = boxBody.position[0];
               box.y = boxBody.position[1];
               // If the current state of the rigid body is sleep , The picture alpha Set to 0.5, Otherwise 1
               if (boxBody.sleepState == p2.Body.SLEEPING) {
                   box.alpha = 0.5;
               }
               else {
                   box.alpha = 1;
               }
           }
       }
     }
     
     
     
      Main function , Monitoring events 
     this.addEventListener(egret.Event.ENTER_FRAME,this.update,this);
   

3. The object is not set mass Weight attribute , Or there is a problem with the view binding