ofxPhysicsEditorBox2D

OpenFrameworks addon for loading fixtures generated by Physics Editor(https://www.codeandweb.com/physicseditor).

Features

• Attach polygons and circles
• Debug draw facility of all fixtures

Dependencies

• ofxBox2d

Output

The following image shows the Physics Editor file with all the fixtures. The annotated image is concerned with the following:

• 1 - Shape name: Corresponds to a Box2D Body. May conatain many fixtures.
• 2 - Anchor Point: This relative position is taken into account while initializing the positions of the bodies.
• 3 - Fixtures: Polygons and Circles.
• 4 - PTM Ratio: Pixel-To-Meters ratio. This addon works best with PTM = 30.
• 5 - Export Format: This addon works with Box2D Generic (PLIST).

The following screenshot was taken from iPAD Mini Retina.

Usage

• Init Box2D

  box2d.init();
  box2d.setGravity(0, 10);
  box2d.setFPS(60.0);

• Create a Body

  b2BodyDef bodydef;
  bodydef.type = b2_staticBody; //could be static, dynamic or kinematic
  gameArea = box2d.getWorld()->CreateBody(&bodydef);

• Load fixture file

  NSString *file = [[NSString alloc] initWithCString:"images/bgFixture.plist"
                                              encoding:NSUTF8StringEncoding];
  [[GB2ShapeCache sharedShapeCache]
  		            //the file exported by Physics Editor
                  addShapesWithFile:file       
                  
                  //With default anchor point, we need to flip the y-coordinate  
                  screenHeight:ofGetHeight()  
                  
                  //Scale Factor
                  //1 means the normal size as designed on the editor
                  //< 1 means the fixtures are shrunk
                  //> 1 means the fixtures are enlarged
                  scaleFactor:1];             
                                   
                       
  [[GB2ShapeCache sharedShapeCache] 
                  addFixturesToBody:gameArea 
                  forShapeName:@"gameArea"];
  

• Debug Draw Fixtures

  void ofApp::draw() {
      ofPushStyle();
      ofSetLineWidth(3);
      [[GB2ShapeCache sharedShapeCache] drawFixtures];
      ofPopStyle();
  }

See Example for more details.

To-Do

• Debug Draw support for multiple bodies

About

Follow me on twitter: @hemantasapkota and don't forget to star this project.