[solved] How to make a dynamic object not react to gravity while still being able to detect collisions?

Getting Started Newbie Questions
#1

I have 2 objects, one stationary and one moving. The stationary object is called player and the moving object is called wall. I need both objects to not react to gravity while still detecting collisions. So I tried using the code below on player.

isBodyActive = false isAwake = true

the object doesn’t fall but it also doesn’t detect collisions. I can’t make both objects kinematic because that prevents them from detecting collisions, I can’t make them both dynamic because they’ll fall, and applying the code above doesn’t work. So I can’t think of anything! Seems like there should be an easy solution, but I’ve been trying to fix this for more than 3 hours straight, searching the internet for answers but nothing works!! Can someone with more experience pleeeaaase help! I’m seriously exhausted from searching and thinking. :frowning:

#2

Set objects gravity scale to 0

ex:

local tmp = display.newCircle( 10, 10, 10 ) physics.addBody( tmp, "dynamic" ) tmp.gravityScale = 0
#3

Also, if you want an object to not respond do collisions (i.e. no bounce or pushback), set isSensor to true.

You may need this info later.

#4

You can find out more about this kind of thing 

#5

yeah that was actually the first thing I tried haha. gravityScale = 0 doesn’t work. :frowning: any other ideas?

#6

Here, I isolated the code that I’m using:

local physics = require "physics" physics.start() local \_W, \_H, centerX, centerY = display.contentWidth, display.contentHeight, display.contentCenterX, display.contentCenterY function onLocalCollision( self, event ) if ( event.phase == "began" ) then print( "collided" ) local loseText = display.newText( "YOU LOSE", centerX, centerY, native.systemFont, 100 ) end end function move( self, event ) self.x = self.x - self.speed end player = display.newRect( centerX, centerY, 100, 100 ) wall = display.newRect( 0, 0, 100, 100 ) wall.x = \_W+wall.contentWidth/2 wall.y = \_H/2 wall.speed = 20 wall.enterFrame = move physics.addBody( player, "dynamic" ) physics.addBody( wall, "kinematic" ) player.isSensor = true player.gravityScale = 0 player.collision = onLocalCollision player:addEventListener( "collision" ) Runtime:addEventListener( "enterFrame", wall )
#7

Update: HOORAY I just solved it! It was a bug elsewhere in the code xD it finally works! thanks for the help roaminggamer!

#8

You’re welcome.

Thanks for taking the time to isolate the code for me, even though you then solved it.

I wonder, did isolating the code, lead you to think of / identify the actual culprit?  

Cheers,

Ed

#9

yes it did  :smiley:

#10

Set objects gravity scale to 0

ex:

local tmp = display.newCircle( 10, 10, 10 ) physics.addBody( tmp, "dynamic" ) tmp.gravityScale = 0
#11

Also, if you want an object to not respond do collisions (i.e. no bounce or pushback), set isSensor to true.

You may need this info later.

#12

You can find out more about this kind of thing 

#13

yeah that was actually the first thing I tried haha. gravityScale = 0 doesn’t work. :frowning: any other ideas?

#14

Here, I isolated the code that I’m using:

local physics = require "physics" physics.start() local \_W, \_H, centerX, centerY = display.contentWidth, display.contentHeight, display.contentCenterX, display.contentCenterY function onLocalCollision( self, event ) if ( event.phase == "began" ) then print( "collided" ) local loseText = display.newText( "YOU LOSE", centerX, centerY, native.systemFont, 100 ) end end function move( self, event ) self.x = self.x - self.speed end player = display.newRect( centerX, centerY, 100, 100 ) wall = display.newRect( 0, 0, 100, 100 ) wall.x = \_W+wall.contentWidth/2 wall.y = \_H/2 wall.speed = 20 wall.enterFrame = move physics.addBody( player, "dynamic" ) physics.addBody( wall, "kinematic" ) player.isSensor = true player.gravityScale = 0 player.collision = onLocalCollision player:addEventListener( "collision" ) Runtime:addEventListener( "enterFrame", wall )
#15

Update: HOORAY I just solved it! It was a bug elsewhere in the code xD it finally works! thanks for the help roaminggamer!

#16

You’re welcome.

Thanks for taking the time to isolate the code for me, even though you then solved it.

I wonder, did isolating the code, lead you to think of / identify the actual culprit?  

Cheers,

Ed

#17

yes it did  :smiley: