Cant move collision position

[marek.radimersky]

Hello, I am using Tiled to create maps for Corona and when I center the map to center of screen with this piece of code

map.x,map.y = display.contentCenterX - map.designedWidth/2, display.contentCenterY - map.designedHeight/2

then objects collision area stays on its original position as shown on images.

Here is my code.

----------------------------------------------------------------------------------------- -- -- main.lua -- ----------------------------------------------------------------------------------------- local tiled = require "com.ponywolf.ponytiled" local physics = require "physics" physics.setDrawMode("hybrid") physics.start() physics.setGravity( 0, 0 ) local json = require "json" -- Hide the status bar display.setStatusBar( display.HiddenStatusBar ) local strokes = 5 local strokesText local ballSize = 12 -- Set up display groups local ballGroup = display.newGroup() local backGroup = display.newGroup() local mainGroup = display.newGroup() local uiGroup = display.newGroup() --Load background local background = display.newImageRect( backGroup, "texture/background/background.jpg", 1080 , 1920 ) background.x = display.contentCenterX background.y = display.contentCenterY local mapData = json.decodeFile(system.pathForFile("map.json", system.ResourceDirectory)) -- load from json export --Load map local map = tiled.new(mapData) map.x,map.y = display.contentCenterX - map.designedWidth/2, display.contentCenterY - map.designedHeight/2 --Get array of wall objects local walls\_vert = map:listTypes( "wall\_vert" ) --Add ball local ball = display.newCircle(ballGroup, display.contentCenterX, display.contentCenterY, ballSize ) ballGroup:toFront() --Add ball to physics physics.addBody( ball, "dynamic", { radius=ballSize, isSensor=false, bounce=0.6, density = 10 } ) ball.myName = "ball" ball.linearDamping = 1 --Add walls to physics -- Display strokes left strokesText = display.newText( uiGroup, "Strokes: " .. strokes, display.contentCenterX, 80, native.systemFont, 36 ) --Function that moves ball depending on touch start and release local begX local begY local endX local endY local finX local finY local function stroke(event) if ( event.phase == "began" ) then print( "Touch event began on: " .. event.x .. " " .. event.y ) begX = event.x begY = event.y elseif event.phase == "moved" then --print( "Touch event moved on: " .. event.x .. " " .. event.y ) elseif event.phase == "ended" then endX = event.x endY = event.y finX = begX - endX finY = begY - endY ball:applyLinearImpulse( finX \* 0.5, finY \* 0.5, ball.x, ball.y ) print( "Touch event ended on: " .. event.x .. " " .. event.y ) end --transition.to( ball, { linearDamping = 0.7, time = 250 } ) end backGroup:addEventListener( "touch", stroke )

Any suggestions how to fix this issue?

Thank you in advance

[ldurniat]

Hi Marek,

This should solve problem

map:insert( ballGroup)

From Moving a display group wont move the physics?

@horacebury: What you should do is place all objects to be used as physics objects into the same display group OR make sure that you keep the parent display groups of physics objects at the same location relative to each other.

From Corona documentation

Display objects with physical bodies can, of course, be placed in different display groups for z-index layering purposes. However, if you need to detect collisions between objects in different groups, you should not move, scale, or rotate entire display groups independently of each other because of underlying Box2D functionality.

It is valid to move, scale, or rotate a series of groups in unison or lock-step as long as these groups maintain the same coordinate origin, angle, and scale. However, if groups are moved, scaled, or rotated independently of each other, the Box2D collision system will consider the physics bodies to be in their original state, not as they appear as a result of transforming the group.

This also applies to the physics.setDrawMode() “hybrid” and “debug” modes — even though these draw modes will suggest that the bodies have changed as a result of modifying the group, the collision system will still consider them to be in their original state.

ldurniat

[roaminggamer]

@marek,

Hi.  While you can directly assign the <x,y> position of objects with bodies and you can use transtion.* functions on objects with bodies, the physics system is not meant to be used that way.

1. If you move an object that has a static body after you create it and add the body(), the body probably won’t move.

2. Likewise, if a ‘kinematic’ or ‘dynamic’ body has slept, changing the <x,y> values probably won’t move the body.

You can solve this issue by setting the body’s isSleepingAllowed flag to false.

Better however is to move bodies with forces and velocities: https://docs.coronalabs.com/api/library/physics/index.html#functions

3. You can get a clearer picture of where bodies are by rendering them:

https://docs.coronalabs.com/api/library/physics/setDrawMode.html

physics.setDrawMode( "hybrid" )

[marek.radimersky]

Hi Idurniat and roaminggamer,

Thank you very much for so fulfilling answers. 

map:insert( ballGroup)

solved the problem.

[ldurniat]

Hi Marek,

This should solve problem

map:insert( ballGroup)

From Moving a display group wont move the physics?

@horacebury: What you should do is place all objects to be used as physics objects into the same display group OR make sure that you keep the parent display groups of physics objects at the same location relative to each other.

From Corona documentation

Display objects with physical bodies can, of course, be placed in different display groups for z-index layering purposes. However, if you need to detect collisions between objects in different groups, you should not move, scale, or rotate entire display groups independently of each other because of underlying Box2D functionality.

It is valid to move, scale, or rotate a series of groups in unison or lock-step as long as these groups maintain the same coordinate origin, angle, and scale. However, if groups are moved, scaled, or rotated independently of each other, the Box2D collision system will consider the physics bodies to be in their original state, not as they appear as a result of transforming the group.

This also applies to the physics.setDrawMode() “hybrid” and “debug” modes — even though these draw modes will suggest that the bodies have changed as a result of modifying the group, the collision system will still consider them to be in their original state.

ldurniat

[roaminggamer]

@marek,

Hi.  While you can directly assign the <x,y> position of objects with bodies and you can use transtion.* functions on objects with bodies, the physics system is not meant to be used that way.

1. If you move an object that has a static body after you create it and add the body(), the body probably won’t move.

2. Likewise, if a ‘kinematic’ or ‘dynamic’ body has slept, changing the <x,y> values probably won’t move the body.

You can solve this issue by setting the body’s isSleepingAllowed flag to false.

Better however is to move bodies with forces and velocities: https://docs.coronalabs.com/api/library/physics/index.html#functions

3. You can get a clearer picture of where bodies are by rendering them:

https://docs.coronalabs.com/api/library/physics/setDrawMode.html

physics.setDrawMode( "hybrid" )

[marek.radimersky]

Hi Idurniat and roaminggamer,

Thank you very much for so fulfilling answers. 

map:insert( ballGroup)

solved the problem.