object:applyForce?

Getting Started Newbie Questions
#1

How can I use the object:applyForce command to apply a force in the direction the object is already traveling, not just in the x and y direction?

#2

Do some 2D Math on the result of getLinearVelocity()

  1. Activate this plugin: https://store.coronalabs.com/plugin/math2d

  2. Put it in your build.settings file: http://roaminggamer.com/math2d/#usage

  3.  Do this (tested in head, may have typos):

    local function applyDirectionalForce( obj, magnitude ) local math2d = require “plugin.math2d” local vx,vy = obj:getLinearVelocity() vx,vy = math2d.normalize( vx, vy ) vx,vy = math2d.scale( vx, vy, magnitude * obj.mass ) obj:applyForce( vx, vy, obj.x, obj.y ) end applyDirectionalForce( bob, 10 )

#3

I wouldn’t be able to use this on a collision though would I? I want the force to be applied once has collided with a physics sensor

#4 
timer.performWithDelay(1,function() applyDirectionalForce( bob, 10 ) end )

 i.e. wait one frame.  Tip: A timer delay of 1ms is enough to force it to wait till the next frame.

#5

Cheers. Is it supposed to be “local function applyDirectionalForce” rather than “local applyDirectionalForce” And would I just have it as timer.performWithDelay(1, function(applyDirectionalForce)(bob, 10) end) ?

Also, sorry but what does bob mean, is it just an example??

#6

  1. Was missing keyword function - Fixed.

  2. The timer example was to answer your question about handling physics updates in a collision handler.  Just use a timer to delay the update.

  3. Bob, Sue, Bill, Buddy, … gotta give example objects some kind of name… :slight_smile:

#7

Do some 2D Math on the result of getLinearVelocity()

  1. Activate this plugin: https://store.coronalabs.com/plugin/math2d

  2. Put it in your build.settings file: http://roaminggamer.com/math2d/#usage

  3.  Do this (tested in head, may have typos):

    local function applyDirectionalForce( obj, magnitude ) local math2d = require “plugin.math2d” local vx,vy = obj:getLinearVelocity() vx,vy = math2d.normalize( vx, vy ) vx,vy = math2d.scale( vx, vy, magnitude * obj.mass ) obj:applyForce( vx, vy, obj.x, obj.y ) end applyDirectionalForce( bob, 10 )

#8

I wouldn’t be able to use this on a collision though would I? I want the force to be applied once has collided with a physics sensor

#9 
timer.performWithDelay(1,function() applyDirectionalForce( bob, 10 ) end )

 i.e. wait one frame.  Tip: A timer delay of 1ms is enough to force it to wait till the next frame.

#10

Cheers. Is it supposed to be “local function applyDirectionalForce” rather than “local applyDirectionalForce” And would I just have it as timer.performWithDelay(1, function(applyDirectionalForce)(bob, 10) end) ?

Also, sorry but what does bob mean, is it just an example??

#11

  1. Was missing keyword function - Fixed.

  2. The timer example was to answer your question about handling physics updates in a collision handler.  Just use a timer to delay the update.

  3. Bob, Sue, Bill, Buddy, … gotta give example objects some kind of name… :slight_smile: