Explanation regarding collisions - CodeandWeb Physics editor

ivan888 · July 7, 2016, 1:29pm

Hi guys,

I have one question :rolleyes:

I am using CodeAndWeb Physics editor.

When you look at collision boundaries in physics “debug” mode (please see attached jpg), you will see the inner circle (which is basically collision shape loaded/created by Physics editor - smaller in size than actual PNG I am loading).

And you will also see outer Rectangle shape (whole PNG basically).

My problem is: Collisions are registered even when outer Rectangle shape is collided with another dynamic object. This should not happen, collisions should be registered only when dynamic object hits inner circle ?

So this is the case where static object (above mentioned PNG) is collided with dynamic object.

Waiting your reply.

Many thanks!

Ivan

nick_sherman · July 7, 2016, 1:55pm

Need to see the code really to see what’s going wrong…

ivan888 · July 7, 2016, 5:17pm

Hi Nick,

Here is the chunk that regulates collision.

display.setStatusBar(display.HiddenStatusBar) -- most commonly used screen coordinates local centerX = display.contentCenterX local centerY = display.contentCenterY local screenLeft = display.screenOriginX local screenWidth = display.viewableContentWidth - screenLeft \* 2 local screenRight = screenLeft + screenWidth local screenTop = display.screenOriginY local screenHeight = display.viewableContentHeight - screenTop \* 2 local screenBottom = screenTop + screenHeight local physics = require("physics") physics.start() physics.setDrawMode( "debug" ) physics.setGravity( 0, 0 ) local spriteObstacles = require "spriteObstacles" --- TABLE THAT CONTAINS MULTIPLE OBSTACLE OBJECTS local randomObstacle = spriteObstacles[math.random(#spriteObstacles)] local physicsData = randomObstacle.image\_sheet.physicsData() --- SUBTABLE THAT CONTAINS PHYSICS DATA local function playersCollision(event) print("COLLIDED") end local &nbsp;obstacle = display.newImageRect(randomObstacle.img, randomObstacle.wi, randomObstacle.he) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.x = centerX &nbsp; &nbsp; &nbsp; &nbsp;obstacle.y = math.random(screenHeight\*0.1, screenHeight\*0.9) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.typ = "obstacle" --- .nam is just a string like "obstacle24", used to identify specific obstacle &nbsp; &nbsp; &nbsp; physics.addBody(obstacle, "static", physicsData:get(randomObstacle.nam), {density=1.0, friction=0.2, bounce=0 }) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.collision = playersCollision &nbsp; &nbsp; &nbsp; &nbsp;obstacle:addEventListener( "collision", obstacle )&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; local ball = display.newCircle( screenLeft, (obstacle.y+obstacle.height\*0.65), 30 ) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ball:setFillColor(0, 1, 0) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; physics.addBody ( ball, "dynamic", {density=1.0, friction=0.2, bounce=0 }) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ball:setLinearVelocity(100, 0)

Ball does not even enter Obstacle area, it does not penetrate inside the smaller area where collision should occur.

Ball immediately gets bounced off the outside Obstacle boundaries…

roaminggamer · July 7, 2016, 5:17pm

Nope. if that is debug mode, (you should really use hybrid), the issue is that you have two bodies attached to the object. That is what I’m seeing in the picture.

I think this call:

physicsData:get(randomObstacle.nam)

is returning a multi-part body. You should check it out in you editor. You should also check out the file “spriteObstacles” to see if any multi-part bodies are defined.

ivan888 · July 7, 2016, 5:27pm

Hi Ed,

I got that code ( physicsData:get(randomObstacle.nam) ) from official tutorial:

https://www.codeandweb.com/texturepacker/tutorials/example-with-coronasdk-using-physicseditor-texturepacker

— .nam is just a string like “obstacle24”, used to identify specific obstacle

No multipart bodies are defined in file “spriteObstacles”

Check out one obstacle example that I am loading (attached).

It was created by Physics Editor tool.

I had to change spike1.lua to spike1.doc in order to upload it here…

roaminggamer · July 7, 2016, 6:00pm

Sorry don’t know what to tell you then. I’ll let someone who also uses this tool chime in. I’m afraid I do all my collisions using basic bodies or manually.

ivan888 · July 7, 2016, 9:11pm

OK Ed.

I hope somebody will take a look at this for me? :blink:

***UPDATE***

I found one solution.

I apply neutral newFilter to obstacle like this:

local newFilter = {categoryBits = 8, maskBits = 4} physics.addBody(obstacle, "static", physicsData:get(randomObstacle.nam), {density=1.0, friction=0.2, bounce=0, filter =&nbsp;newFilter&nbsp;})

This takes care that ball does not collide with obstacle, i.e ball only collides with inner circle (because newFilter apparently does not apply to inner circle).

I would still like to know what is going on here (despite this solution) !

andreas.loew · July 8, 2016, 6:54am

You are currently not creating a “inner circle”:

local ball = display.newCircle( screenLeft, (obstacle.y+obstacle.height*0.65), 30 )

ball:setFillColor(0, 1, 0)
physics.addBody ( ball, “dynamic”, {density=1.0, friction=0.2, bounce=0 })
ball:setLinearVelocity(100, 0)

You are creating a circle shape and set the colors.

After that you create a physics body for this shape - but you are not specifying any shape at all. Corona now uses the shape’s bounding box. https://docs.coronalabs.com/api/library/physics/addBody.html - see “Examples -> Rectangular Body”.

You can either create the ball’s outlines in PhysicsEditor - or specify it manually by adding the radius parameter:

physics.addBody( ball, { density=1.0, friction=0.3, bounce=0.2, radius=30 } )

ivan888 · July 8, 2016, 9:28am

Hi Andreas,

Thanks for your input.

I think you misunderstood me.

Ball is the dynamic object that collides with the obstacle (static object).

I am using Physics Editor only for the obstacle (not for the ball).

I am initializing physics shape created by Physics Editor for the obstacle - please see my first post in this thread.

Like this:

local &nbsp;obstacle = display.newImageRect(randomObstacle.img, randomObstacle.wi, randomObstacle.he) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.x = centerX &nbsp; &nbsp; &nbsp; &nbsp;obstacle.y = math.random(screenHeight\*0.1, screenHeight\*0.9) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.typ = "obstacle" --- .nam is just a string like "obstacle24", used to identify specific obstacle &nbsp; &nbsp; &nbsp; physics.addBody(obstacle, "static", physicsData:get(randomObstacle.nam), {density=1.0, friction=0.2, bounce=0 })&nbsp;

nick_sherman · July 8, 2016, 9:49am

I think I have it.

When you call physics.addBody, you pull in the data for randomObstacle.nam. This includes radius, density, friction, bounce etc which are set the editor. So this creates the ‘inner circle’ physics object.

[lua]

physics.addBody(obstacle, “static”, physicsData:get(randomObstacle.nam)

– CIRCLE PHYSICS OBJECT CREATED

[/lua]

You then added this code:

[lua]

, {density=1.0, friction=0.2, bounce=0 }

– RECTANGLE PHYSICS OBJECT CREATED

[/lua]

Which creates another rectangular physics object the size of the obstacle image.

So I think the code should just be:

[lua]

physics.addBody(obstacle, “static”, physicsData:get(randomObstacle.nam))

[/lua]

ivan888 · July 8, 2016, 10:48am

I am such an idiot!

Thanks Nick!

ivan888 · July 8, 2016, 10:53am

One last question please.

How to change precreated filter bits on the fly (later on)?

-- This file is for use with Corona(R) SDK -- -- This file is automatically generated with PhysicsEdtior (http://physicseditor.de). Do not edit -- -- Usage example: --&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; local scaleFactor = 1.0 --&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; local physicsData = (require "shapedefs").physicsData(scaleFactor) --&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; local shape = display.newImage("objectname.png") --&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; physics.addBody( shape, physicsData:get("objectname") ) -- -- copy needed functions to local scope local unpack = unpack local pairs = pairs local ipairs = ipairs local M = {} function M.physicsData(scale) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; local physics = { data = &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; { &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ["spike1"] = { &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; { &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; pe\_fixture\_id = "", density = 2, friction = 0.30000000000000004, bounce = 0.20000000000000001, &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; filter = { categoryBits = 1, maskBits = 65535, groupIndex = 0 }, &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; radius = 17.000 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; } } &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -- apply scale factor &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; local s = scale or 1.0 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; for bi,body in pairs(physics.data) do &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; for fi,fixture in ipairs(body) do &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if(fixture.shape) then &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; for ci,coordinate in ipairs(fixture.shape) do &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;fixture.shape[ci] = s \* coordinate &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; else &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; fixture.radius = s \* fixture.radius &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; function physics:get(name) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return unpack(self.data[name]) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; function physics:getFixtureId(name, index) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return self.data[name][index].pe\_fixture\_id &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; end &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return physics; end return M

I am aiming at this line:

filter = { categoryBits = 1, maskBits = 65535, groupIndex = 0 },

nick_sherman · July 8, 2016, 11:32am

You could create a table that holds over-ride parameters.

[lua]

local override = {{spike1 = {categoryBits = 2, maskBits = 12345, groupIndex = 1}}}

[/lua]

Then check this table before you add the physics body.

[lua]

local data = physicsData:get(randomObstacle.nam)

if override[randomObstacle.nam] ~= nil then

data.filter = override[randomObstacle.nam]

end

physics.addBody(obstacle, “static”, data)

[/lua]

If you need to do this to an already created obstacle, you’ll need to removeBody and then immediately addBody again.

nick_sherman · July 7, 2016, 1:55pm

Need to see the code really to see what’s going wrong…

ivan888 · July 7, 2016, 5:17pm

Hi Nick,

Here is the chunk that regulates collision.

display.setStatusBar(display.HiddenStatusBar) -- most commonly used screen coordinates local centerX = display.contentCenterX local centerY = display.contentCenterY local screenLeft = display.screenOriginX local screenWidth = display.viewableContentWidth - screenLeft \* 2 local screenRight = screenLeft + screenWidth local screenTop = display.screenOriginY local screenHeight = display.viewableContentHeight - screenTop \* 2 local screenBottom = screenTop + screenHeight local physics = require("physics") physics.start() physics.setDrawMode( "debug" ) physics.setGravity( 0, 0 ) local spriteObstacles = require "spriteObstacles" --- TABLE THAT CONTAINS MULTIPLE OBSTACLE OBJECTS local randomObstacle = spriteObstacles[math.random(#spriteObstacles)] local physicsData = randomObstacle.image\_sheet.physicsData() --- SUBTABLE THAT CONTAINS PHYSICS DATA local function playersCollision(event) print("COLLIDED") end local &nbsp;obstacle = display.newImageRect(randomObstacle.img, randomObstacle.wi, randomObstacle.he) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.x = centerX &nbsp; &nbsp; &nbsp; &nbsp;obstacle.y = math.random(screenHeight\*0.1, screenHeight\*0.9) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.typ = "obstacle" --- .nam is just a string like "obstacle24", used to identify specific obstacle &nbsp; &nbsp; &nbsp; physics.addBody(obstacle, "static", physicsData:get(randomObstacle.nam), {density=1.0, friction=0.2, bounce=0 }) &nbsp; &nbsp; &nbsp; &nbsp;obstacle.collision = playersCollision &nbsp; &nbsp; &nbsp; &nbsp;obstacle:addEventListener( "collision", obstacle )&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; local ball = display.newCircle( screenLeft, (obstacle.y+obstacle.height\*0.65), 30 ) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ball:setFillColor(0, 1, 0) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; physics.addBody ( ball, "dynamic", {density=1.0, friction=0.2, bounce=0 }) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ball:setLinearVelocity(100, 0)

Ball does not even enter Obstacle area, it does not penetrate inside the smaller area where collision should occur.

Ball immediately gets bounced off the outside Obstacle boundaries…

roaminggamer · July 7, 2016, 5:17pm

Nope. if that is debug mode, (you should really use hybrid), the issue is that you have two bodies attached to the object. That is what I’m seeing in the picture.

I think this call:

physicsData:get(randomObstacle.nam)

is returning a multi-part body. You should check it out in you editor. You should also check out the file “spriteObstacles” to see if any multi-part bodies are defined.

ivan888 · July 7, 2016, 5:27pm

Hi Ed,

I got that code ( physicsData:get(randomObstacle.nam) ) from official tutorial:

https://www.codeandweb.com/texturepacker/tutorials/example-with-coronasdk-using-physicseditor-texturepacker

— .nam is just a string like “obstacle24”, used to identify specific obstacle

No multipart bodies are defined in file “spriteObstacles”

Check out one obstacle example that I am loading (attached).

It was created by Physics Editor tool.

I had to change spike1.lua to spike1.doc in order to upload it here…

roaminggamer · July 7, 2016, 6:00pm

Sorry don’t know what to tell you then. I’ll let someone who also uses this tool chime in. I’m afraid I do all my collisions using basic bodies or manually.

ivan888 · July 7, 2016, 9:11pm

OK Ed.

I hope somebody will take a look at this for me? :blink:

***UPDATE***

I found one solution.

I apply neutral newFilter to obstacle like this:

local newFilter = {categoryBits = 8, maskBits = 4} physics.addBody(obstacle, "static", physicsData:get(randomObstacle.nam), {density=1.0, friction=0.2, bounce=0, filter =&nbsp;newFilter&nbsp;})

This takes care that ball does not collide with obstacle, i.e ball only collides with inner circle (because newFilter apparently does not apply to inner circle).

I would still like to know what is going on here (despite this solution) !

andreas.loew · July 8, 2016, 6:54am

You are currently not creating a “inner circle”:

local ball = display.newCircle( screenLeft, (obstacle.y+obstacle.height*0.65), 30 )

ball:setFillColor(0, 1, 0)
physics.addBody ( ball, “dynamic”, {density=1.0, friction=0.2, bounce=0 })
ball:setLinearVelocity(100, 0)

You are creating a circle shape and set the colors.

After that you create a physics body for this shape - but you are not specifying any shape at all. Corona now uses the shape’s bounding box. https://docs.coronalabs.com/api/library/physics/addBody.html - see “Examples -> Rectangular Body”.

You can either create the ball’s outlines in PhysicsEditor - or specify it manually by adding the radius parameter:

physics.addBody( ball, { density=1.0, friction=0.3, bounce=0.2, radius=30 } )