In the previous lesson you saw an "event block" of the Class Actor, that has elements about the avatar behavior.

We can use a method of the same Class for, using a timestep loop, create another "event block" that will trigger some action when the avatar is "n" centimeters near some point in the ground. Look this sample:

isFar=true;
myLoop1 = new Object(); 
myLoop1.timestep = function(appLag, dt){
 if(Actor.dist(Vector(3000,0, -2000)) < 500 && isFar){  
  Chat.print("I am near the point 3000,0, -2000 "); 
  isFar=false;
 }
}
Application.addTimestep(myLoop1 );

TIPS: Do not use the position of an object like the vector.

The distance is really from the "camera", normally 200/300 cm. behind the avatar.

The exercice of this lesson is: when the avatar is near a character (a "bbgerian"), this character will ask a question to be answered by the player clicking one of the numeric keys of the keyboard.

But we need first to learn how to capture the press of a keyboard key. There are the Class Key.

We will not present each one of the elements of the Class but a generic sample of its use:

notPressed1=true;
notPressed2=true;
notPressed3=true;
oKeyListener = new Object();
oKeyListener.onEvent = function(){  
 if ( Key.isKeyDown( Key.KEY_1) && notPressed1  ){      
  Chat.print( "Pressed 1" );
  notPressed1=false;
 }
 if ( Key.isKeyDown( Key.KEY_2) && notPressed2  ){      
  Chat.print( "Pressed 2" );
  notPressed2=false;
 }
 if ( Key.isKeyDown( Key.KEY_3) && notPressed3  ){  
  Chat.print( "Pressed 3" );
  notPressed3=false;
 }
}
 Key.addListener(oKeyListener );

There are some values to specify a key. The complete list you find in the documentation:

KEY_1
KEY_2
KEY_3
KEY_4
.
.
KEY_A
KEY_B
KEY_C
KEY_D
.
.
KEY_UP
KEY_LEFT
KEY_RIGHT
KEY_DOWN
.
.
KEY_DELETE
.
.

Look two pictures of the exercice. Try to do it by yourself. The complete code is after the figures.

TIP: You can download all you need (included .BLEND file) for the creation of a customized "bbgerian":

// Attach the Land
oLandEntity = Scene.createEntity( "Land", "land.mesh" );
Scene.rootNode.attachObject(oLandEntity );
oLandEntity.fixed = true;
oLandEntity.collisionGeometryType = oLandEntity.COLLISION_GEOM_TRI_SOUP;
oLandEntity.createPhysicalModel();
oLandEntity.active = false;
oLandEntity.position = Vector(0, 0, 0);
  
// Create a   light
oDistantLight = Scene.createDistantLight( "light" ); 
Scene.shadowTechnique = Scene.SHADOW_STENCIL_MODULATIVE; 
Scene.shadowColor = Color (0.7, 0.7, 0.7, 0 ); 
oDistantLight.diffuseColor = Color( 1, 1, 1, 0 );
oDistantLight.specularColor = Color( 1, 1, 1, 0 );
oDistantLight.direction = Vector( -0.45, -1, -1 );
oDistantLight.castShadows = true; 

//The bbgerian
oObjEntity = Scene.createEntity( "Obj", "bbgerian.mesh" );
oObjNode = Scene.createSceneNode( "ObjNode" );
oObjNode.attachObject( oObjEntity );
oObjNode.translate(Vector(3000,0, -2000 ), oObjNode.TRANSFORM_WORLD );
oObjEntity.fixed = true;
oObjEntity.collisionGeometryType = oObjEntity.COLLISION_GEOM_TRI_SOUP;
oObjEntity.createPhysicalModel();
oObjEntity.active = true;

Chat.print("Find the bbgerian. He has a question for you.");

 //Flags
isFar=true;
notPressed1=true;
notPressed2=true;
notPressed3=true;

//Sound
oSound = SoundSystem.createSound(); 
oSound.setFileName( "aplause1.ogg" ); ////Included in the sound kit
oSound.ambient = true; 
oSound.volume = 1; 
oSound.loopCount = 1; 

//Capturing distance
myLoop1 = new Object(); 
myLoop1.timestep = function(appLag, dt){
 if(Actor.dist(Vector(3000,0, -2000)) < 500 && isFar){  
  Chat.print("What is the name of a river from China: 1 - Amazon; 2 - Nile; 3 - Yellow. \nPress the key of the correct number."); 
  isFar=false;
 }
}
Application.addTimestep(myLoop1 ); 

//Capturing key press
oKeyListener = new Object();
oKeyListener.onEvent = function(){  
 if ( Key.isKeyDown( Key.KEY_1) && notPressed1  ){      
  Chat.print( "Wrong answer.Amazon is in Brazil.Try again." );
  notPressed1=false;
 }
 if ( Key.isKeyDown( Key.KEY_2) && notPressed2  ){      
  Chat.print( "Wrong answer.Nile is in Egipt. Try again." );
  notPressed2=false;
 }
 if ( Key.isKeyDown( Key.KEY_3) && notPressed3  ){  
  oSound.play();    
  Chat.print( "Correct! Congratulation! " );
  notPressed3=false;
 }
}
Key.addListener(oKeyListener ); 

NOTE OF THE BETA VERSION: There are the methods OnChatIn() and OnChatOut() of the Class Chat tha could be used for "dialog applications". But they are not working today.

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