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RubeParser

The RubeParser creates QML items based on the description of a JSON file exported by the RUBE level editor. More...

• List of all members, including inherited members

Properties

• entitiesFolder : url

Methods

• clearLevel()
• setupLevelFromJSON(jsonPath, world, levelContainer)

Detailed Description

The RubeParser creates QML items based on the description of a JSON file exported by the RUBE level editor.

Example Usage

Add the RubeParser to your scene and call the setupLevelFromJSON function like in this example:

 import Felgo
 import QtQuick

 import "Rube"

 GameWindow {
     Scene {
         id: scene

         EntityManager {
             id: entityManager
             entityContainer: level
         }

         Item {
             id: level

             PhysicsWorld {
                 id: physicsWorld
             }
         }

         RubeParser {
             id: parser
             entitiesFolder: "entities/"

             Component.onCompleted: {
                 console.debug("load finished, start parsing")
                 parser.setupLevelFromJSON( Qt.resolvedUrl("../assets/sidescroller.json"), physicsWorld, level )
             }
         }
     }
 }

Level Creation

Just call setupLevelFromJSON().

The parameters are:

• jsonPath - a path to a .json file as string
• world - the id of your game's physics world
• levelContainer - the id of an item, the created RubeBodies will be children of this item

At first, the JSON file is read and loaded into a JSON-object in the memory by the setupLevelFromJSON() function. Then, this function calls parseJSON() passing through all the parameters. This function reads the settings from the JSON and applies them to the physics world. The parseJSON() function calls the createBodies() with a list of body objects from the JSON, the world and the levelContainer. The createBodies() function creates objects from the Rube Components. If the custom property "qmlType" is set it tries to create an object of this type. Then the signal internalInit is emitted on this new body causing it to initialize its properties from the transmitted JSON. For each created body the addFixturesToBody() function is called, which creates objects of the different fixture components and attaches them to the body. Each fixtures has its internalInit signal emitted. When all fixtures are attached to the body the fixturesFinished signal is emitted on it. Afterwards, the initialized signal is emitted on the body giving the users a chance to react to the finished object. When all bodies are finished the createImages() function is called, which does the same as the createBodies() but with images. If the image belongs to a body (as said in the JSON) it is assigned as a child to this body. The the renderOrder aka. z in Qt is applied and the image if it doesn't belong to any body or to its parent body. This is because the z property works only among siblings. Then, internalInit and initialized are emitted on the image just like the body before.

In short:

• setupLevelFromJSON()
  • parseJSON()
    • createBodies()
      • emit internalInit
      • addFixturesToBody()
      • emit fixturesFinished
      • emit initialized
    • createImages()
      • emit internalInit
      • emit initialized

Level Deletion

Just call clearLevel. All created RubeBodies with their fixtures and all RubeImages will be destroyed.

Supported RUBE Features

World Type

Following properties are read from the JSON and applied to the World given as parameter:

• autoClearForces - see World::autoClearForces
• gravity - see World::gravity
• positionIterations - see World::positionIterations
• velocityIterations - see World::velocityIterations
• stepsPerSecond - see World::timeStep

Following properties are not yet supported:

• allowSleep
• continuousPhysics
• subStepping
• warmStarting

Bodies

Following properties are read from the JSON and applied to the RubeBody instances:

• active - affected by the physics simulation, see Body::active
• angle - rotation, see Item::rotation
• angularDamping - reduction of the angular velocity over time, see Body::angularDamping
• angularVelocity - rotation per time in deg/sec, see Body::angularVelocity
• awake - not currently sleeping (performance optimization), see Body::awake
• type - says how the body should be simulated (0 = Body.Static, 1 = Body.Kinematic, 2 = Body.Dynamic), see Body::bodyType
• bullet - more accurate simulation to prevent small objects from tunneling through other objects, see Body::bullet
• fixedRotation - says whether the body should rotate or not, see Body::fixedRotation
• gravityScale - multiplier for the gravity, see Body::gravityScale
• linearDamping - reduction of the linear velocity over time, see Body::linearDamping
• linearVelocity - way per time in m/s, see Body::linearVelocity
• position - current translation of the object, see Item::x and Item::y
• allowSleep - says if the body can sleep, see Body::sleepingAllowed

The RubeBody contains a list of fixtures Body::fixtures, too.

Fixtures

Following properties are read from the JSON and applied to all the different RubeFixture instances:

• density - density * area = mass, see Fixture::density
• filter-categoryBits - see Fixture::categories
• filter-groupIndex - see Fixture::groupIndex
• filter-maskBits - see Fixture::collidesWith
• friction - see Fixture::friction
• restitution - see Fixture::restitution
• sensor - see Fixture::sensor

Following properties are read from the JSON and applied to the RubeFixtureCircle instances:

• center - see Circle::x and Circle::y
• radius - see Circle::radius

Following properties are read from the JSON and applied to the PolygonFixture instances:

• vertices - see Polygon::vertices

The RUBE fixture type "line" and "loop" are not supported at the moment.

Images

Following properties are read from the JSON and applied to the RubeImage instances:

• angle - see Item::rotation
• corners - slightly complicated calculation to get the position and size of a rectangle from four (rotated) vertices, see Item::x, Item::y, Item::height and Item::width
• file - see MultiResolutionImage::source
• flip - see MultiResolutionImage::mirrorX
• filter - see MultiResolutionImage::smooth

Joints

Joints are not yet supported

Property Documentation

Method Documentation