Circular Motion & Gravity

[GideonSam]

Hi All,

 

I have implemented planatary gravity using the below link

 

http://www.emanueleferonato.com/2015/06/19/simulate-planet-gravity-with-phaser-box2d-as-seen-on-angry-birds-space/

 

Now i need the object just move over the planet with gravity .

 

How to do it kindly help please ?????????????

[samid737]

If you want your body to move along the surface of the planet, you can add force in the local x direction of the block:

if(distance<p.width/2+p.gravityRadius/2){
					
// calculating angle between the planet and the crate
					
	var angle = Phaser.Math.angleBetween(c.x,c.y,p.x,p.y);
				     
//add force in the local x direction by pressing D key
	if (game.input.keyboard.isDown(Phaser.Keyboard.D)){
	   c.body.applyForce(-10*Math.cos(angle+90),-10*Math.sin(angle+90));
	} 
// add gravity force to the crate in the direction of planet center
  
 c.body.applyForce(p.gravityForce*Math.cos(angle)*forceReducer,p.gravityForce*Math.sin(angle)*forceReducer);
}

 

Edited August 8, 2017 by samid737
corrected applyforce

[GideonSam]

Thanks Samid  for you reply it works fine but what i want to replicate is 

Crate should move in a circle by default with gravity

On key press it should jump

Is it possible to achieve.

Kindly help

 

 

 

 

[samid737]

you can do this in two ways:

function addCrate(e){	
	var crateSprite = game.add.sprite(e.x, e.y, "crate");
	crateGroup.add(crateSprite);
	game.physics.box2d.enable(crateSprite);
	//crateSprite.body.velocity.x=200;  //without force
	for(i=0;i<4;i++){crateSprite.body.applyForce(10,0);}; //short impulse
}

when adding the crate, you either set the velocity or you apply the force for a very short amount of time(impulse). 
To jump vertically up on the planet, you do the same as gravity but opposite direction (minus sign):

if (game.input.keyboard.isDown(Phaser.Keyboard.D)){
	c.body.applyForce(-10*Math.cos(angle),-10*Math.sin(angle));
} 

 

[GideonSam]

Thanks samid the jump works great but the movement stops after some time 

Is it due to friction and can i lock rotation of the crate

[GideonSam]

I have changed the frixtion and now it moves smoothly 

 

is there a way to lock rotation while jumping

 

setFixedRotation(false) is not working

[samid737]

you can try angularDamping, won't fully lock it, but gets pretty close:

crateSprite.body.angularDamping=1000000000;