P2 gravity Center ?

[Nikow]

Hi !!

 

I'm on a space game using P2, and i'm trying to create a center of gravity for the planets, to be more explicit, i want all the planets attract the spaceship bu the planet center...

 

If you don't understand or if i did too many error with my worlds, i could try to re explain better ^^!

[valueerror]

before i start fantasizing about possible solutions for your problem (because dot gravity is nothing p2 can do atm as far as i know) i need to ask more questions.

 

will there be more than one planet attracting the spaceship at a time?  

should gravity lose it's effect with more distance to the planet?

how many objects are usually affected by the planets gravity? only the spaceship?

[Nikow]

before i start fantasizing about possible solutions for your problem (because dot gravity is nothing p2 can do atm as far as i know) i need to ask more questions.

 

will there be more than one planet attracting the spaceship at a time?  

should gravity lose it's effect with more distance to the planet?

how many objects are usually affected by the planets gravity? only the spaceship?

Hi ! 

 

For now, i did that :

game.physics.p2.gravity.y = planete.body.y - fusee.body.y;game.physics.p2.gravity.x = planete.body.x - fusee.body.x;

But it's bugging a little and i'm looking for a better solution !

 

About your questions :

 

1- No

2- Yes Sure !

3- For now, only the spaceship yes

[valueerror]

it's space.. so you could stop using gravity and instead use forces....

 

you could use this function (give it your spaceship and the planet) to get the distance between 2 objects and then calculate the speed based on the returned distance 

 

function distanceBetween(spriteA,spriteB){    var dx = spriteA.body.x - spriteB.body.x;  //distance ship X to planet X    var dy = spriteA.body.y - spriteB.body.y;  //distance ship Y to planet Y    var dist = Math.sqrt(dx*dx + dy*dy);     //pythagoras ^^  (get the distance to each other)    return dist;}

define speed (force)

if (distanceBetween(ship,planet) < 300) { speed = 30;}else if (distanceBetween(ship,planet) < 600) { speed = 20;}else if (distanceBetween(ship,planet) < 900) { speed = 10;}

and then call this function to create a force  into the direction of the planet

function accelerateToObject(obj1, obj2, speed) {    if (typeof speed === 'undefined') { speed = 20; }    var angle = Math.atan2(obj2.y - obj1.y, obj2.x - obj1.x);    obj1.body.rotation = angle + game.math.degToRad(180);  // correct angle if wanted    obj1.body.force.x = Math.cos(angle) * speed;    // accelerateToObject     obj1.body.force.y = Math.sin(angle) * speed;}

[valueerror]

http://phaser.io/sandbox/edit/awDIvALb

 

phaser sandbox.. hope it works

[Nikow]

 

it's space.. so you could stop using gravity and instead use forces....

 

you could use this function (give it your spaceship and the planet) to get the distance between 2 objects and then calculate the speed based on the returned distance 

 

function distanceBetween(spriteA,spriteB){    var dx = spriteA.body.x - spriteB.body.x;  //distance ship X to planet X    var dy = spriteA.body.y - spriteB.body.y;  //distance ship Y to planet Y    var dist = Math.sqrt(dx*dx + dy*dy);     //pythagoras ^^  (get the distance to each other)    return dist;}

define speed (force)

if (distanceBetween(ship,planet) < 300) { speed = 30;}else if (distanceBetween(ship,planet) < 600) { speed = 20;}else if (distanceBetween(ship,planet) < 900) { speed = 10;}

and then call this function to create a force  into the direction of the planet

function accelerateToObject(obj1, obj2, speed) {    if (typeof speed === 'undefined') { speed = 20; }    var angle = Math.atan2(obj2.y - obj1.y, obj2.x - obj1.x);    obj1.body.rotation = angle + game.math.degToRad(180);  // correct angle if wanted    obj1.body.force.x = Math.cos(angle) * speed;    // accelerateToObject     obj1.body.force.y = Math.sin(angle) * speed;}

 

Amazing.. !

My mistakes was to use gravity instead of force ! It's so cool !

 

Thank you man !!

[tidelake]

Yes, thank you so much for this very illustrative sample