Box2d Screen for Diddy
Monkey Forums/Monkey Code/Box2d Screen for Diddy
| ||
| A screen class for using Box2d with Diddy. Creating bodies, Collision detection. [Edit] Added a demo for acceleration controller and gravitycontroller. Uncomment the line in Method Start() to view this.
Strict
Import diddy
Import box2d.collision
Import box2d.collision.shapes
Import box2d.collision.shapes
Import box2d.dynamics.joints
Import box2d.common.math
Import box2d.dynamics.contacts
Import box2d.dynamics
Import box2d.flash.flashtypes
Import box2d.common.math.b2vec2
Import box2d.dynamics.controllers
Global gameScreen:Screen
Function Main:Int()
game=New MyGame()
Return 0
End Function
Class MyGame Extends DiddyApp
Method OnCreate:Int()
Super.OnCreate()
game.FPS=60 ' set the update rate for Diddy. 60 is standard. Just here for demonstration.
gameScreen = new Box2dscreen
gameScreen.PreStart()
Return 0
End
End
Class Box2dscreen extends Screen
'
Field world:b2World
Field contactlistener:ContactListener
'
Field m_velocityIterations:int = 10
Field m_positionIterations:int = 10
Field m_timeStep:Float = 1.0/60 ' set this to your SetUpdateRate()
Field m_physScale:Float = 1' 30 ' Not in use, but you should not use pixels as your units, an object of length 200 pixels would be seen by Box2D as the size of a 45 story building.
Field m_debugdrawscale:Float=1 ' set this to m_physScale if you are scaling your world.
Method New()
Local doSleep:Bool = True
self.world = New b2World(New b2Vec2(0,0), doSleep) ' no need for AABB in newer versions of box2d, the world is infinite
Self.SetGravity(0.0,10) '
world.SetWarmStarting(True)
'
'
'// set debug draw
Local dbgDraw :b2DebugDraw = New b2DebugDraw()
dbgDraw.SetDrawScale(m_debugdrawscale) ' was 30
dbgDraw.SetFillAlpha(0.3)
dbgDraw.SetLineThickness(1.0)
dbgDraw.SetFlags(b2DebugDraw.e_shapeBit | b2DebugDraw.e_jointBit)'| b2DebugDraw.e_pairBit)
world.SetDebugDraw(dbgDraw)
Self.contactlistener=New ContactListener()
world.SetContactListener(Self.contactlistener)' for collision detection, if you need information which objects collide
End Method
Method Start:Void()
game.screenFade.Start(50, False) ' just a fading effect
Self.CreateDemo()
' Self.CreateControllerDemo() ' uncomment this for a demo of controllers
End
Method Render:Void()
Cls
self.world.DrawDebugData()
End
Method Update:Void()
world.TimeStep(m_timeStep, m_velocityIterations, m_positionIterations)
world.ClearForces()
End Method
Method SetGravity:Void(x:Float,y:Float)
Self.world.SetGravity(New b2Vec2(x,y))
End Method
Method CreateControllerDemo:Void()
' uncomment the line 'Self.CreateControllerDemo()' in Method Start() to see this running.
'
' accelration controllers are good to simulate wind, or if some bodies shall fall faster then others.
local accelcontroller:b2ConstantAccelController=new b2ConstantAccelController ' create an acceleration controller
accelcontroller.A=New b2Vec2(0,50) ' Set force. Every body added to Controller will be accelerated by this vector (box2d does this, just fire and forget).
world.AddController(accelcontroller) ' add controller to world
' add a body to controller. This body will fall faster then all others, because he is accelerated on the y-axis.
Local box:b2Body=self.CreateBox(600,100,20,20,false)
accelcontroller.AddBody(box)
'
' a gravitycontroller, good to simulate gravity between objects or magnetism.
local gravitycontroller:b2GravityController=new b2GravityController
gravitycontroller.G=15 ' the force with which the bodies attract each other.
world.AddController(gravitycontroller)
Local anotherbox:b2Body=self.CreateBox(510,100,30,10,false) ' add two bodies.
Local lastbox:b2Body=self.CreateBox(410,100,30,10,false) ' This bodies will attract each other like 'planets', they have their own gravity.
gravitycontroller.AddBody(anotherbox) ' add bodies to controller
gravitycontroller.AddBody(lastbox) 'call controller.RemoveBody() to stop a controller affecting a body.
End Method
Method CreateDemo:Void()
Local b:b2Body
' a box for ground
b=Self.CreateBox(340,420,480,30,true)
b.SetUserData(New StringObject("ground")) ' give object a name for collision detection in contactlistener
' a sphere
b=Self.CreateSphere(350,220,40)
b.SetUserData(New StringObject("sphere"))
' create a polygon from an array of b2d Vectors
Local tri:b2Vec2[]= [New b2Vec2(0, 0), New b2Vec2(0, -100), New b2Vec2(200 ,0)]
b=Self.CreatePolybody(200,20,tri)
b.SetUserData(New StringObject("triangle1"))
' ' create a polygon from an array with floats
Local triangle:Float[]=[0.000000000,-49.000000,99.000000,59.0000000,-77.000000,79.0000000]
b=Self.CreatePolybody(200,100,Self.ArrayToVectorarray(triangle))
b.SetUserData(New StringObject("triangle2"))
End Method
Method CreateBox:b2Body (xpos:Float,ypos:Float,width:Float,height:Float,static:Bool=true)
Local fd :b2FixtureDef = New b2FixtureDef()
Local sd :b2PolygonShape = New b2PolygonShape()
Local bd :b2BodyDef = New b2BodyDef()
if static=true
bd.type = b2Body.b2_staticBody
else
bd.type = b2Body.b2_Body
endif
fd.density = 1.0
fd.friction = 0.5
fd.restitution = 0.1
fd.shape = sd
sd.SetAsBox(width,height)
bd.position.Set(xpos,ypos)
Local b :b2Body
b = self.world.CreateBody(bd)
' Recall that shapes don’t know about bodies and may be used independently of the physics simulation. Therefore Box2D provides the b2Fixture class to attach shapes to bodies.
b.CreateFixture(fd)
'
Return b
End Method
Method CreateSphere:b2Body (xpos:Float,ypos:Float,radius:Float,static:Bool=false)
Local fd :b2FixtureDef = New b2FixtureDef()
Local bd :b2BodyDef = New b2BodyDef()
Local cd :b2CircleShape = New b2CircleShape()
'
cd.m_radius = radius
fd.density = 2
fd.restitution = 0.2
fd.friction = 0.5
fd.shape=cd
if static=true
bd.type = b2Body.b2_staticBody ' a static body
else
bd.type = b2Body.b2_Body 'a dynamic body
endif
bd.position.Set(xpos,ypos)
Local b :b2Body
b=Self.world.CreateBody(bd)
b.CreateFixture(fd)
Return b
End Method
Method CreatePolybody:b2Body(xpos:Float,ypos:Float,verts:b2Vec2[],static:Bool=false,bullet:Bool=false)
' polys must be defined vertices from left to right or their collision will not work. They must be convex.
' A polygon is convex when all line segments connecting two points in the interior do not cross any edge
' of the polygon.
' Polygons are solid and never hollow. A polygon must have 3 or more vertices.
Local b :b2Body
Local fd :b2FixtureDef = New b2FixtureDef()
Local sd :b2PolygonShape = New b2PolygonShape()
Local bd :b2BodyDef = New b2BodyDef()
'
sd.SetAsArray(verts,verts.Length)
fd.shape=sd
bd.type = b2Body.b2_Body
'
bd.position.Set(xpos,ypos)
bd.bullet=bullet
b=Self.world.CreateBody(bd)
'
fd.density = 1.0
fd.friction = 0.5
fd.restitution = 0.1
b.CreateFixture(fd)
'
Return b
End Method
Method ArrayToVectorarray:b2Vec2[](arr:Float[])
' converts a normal array with floats to an array of b2Vec2
Local vecs:b2Vec2[1]
vecs=vecs.Resize(arr.Length/2)
Local count:int
For Local f:Float=0 to arr.Length-2 step 2
vecs[count]=new b2Vec2(arr[f],arr[f+1])
count+=1
Next
Return vecs
End Method
Method Cleanup:Void()
' When a world leaves scope or is deleted by calling delete on a pointer, all the memory reserved for bodies, fixtures, and joints is freed.
' This is done to improve performance and make your life easier. However, you will need to nullify any body, fixture, or joint pointers you have because they will become invalid.
End Method
End Class
Class ContactListener Extends b2ContactListener
' to gather information about collided objects.
' http://www.box2dflash.org/docs/2.1a/reference/Box2D/Dynamics/b2ContactListener.html
' You cannot create/destroy Box2D entities inside these callbacks.
Method New()
Super.New()
End
Method PreSolve : void (contact:b2Contact, oldManifold:b2Manifold)
End
Method BeginContact:void(contact:b2Contact)
' Print "objects did collide.."
'
' get the fixtures involved in collision
Local fixA:b2Fixture=contact.GetFixtureA()' Instead of telling you which b2Body collided, the b2Contact tells you which fixture collided.
Local fixB:b2Fixture=contact.GetFixtureB()' To know which b2Body was involved in the collision you can retrieve a reference to the fixture.
Local userdata1:Object=Object(fixA.GetBody().GetUserData())
Local userdata2:Object=Object(fixB.GetBody().GetUserData())
if userdata1<>NULL
Local name:String=StringObject(userdata1).ToString()
' Print "involved in collision:"+ name
EndIf
if userdata2<>NULL
Local name:String=StringObject(userdata2).ToString()
' Print "involved in collision:"+ name
EndIf
End Method
End
|
| ||
| Nice example Volker! Can I suggest a couple of things: 1. With Diddy you dont need to set the update rate yourself, it happens within the super.OnCreate and is set to 60 by default - if you want to change it alter the game.FPS in the Main function: Function Main:Int() game=New MyGame() game.FPS = 30 ' sets the update rate to 30 Return 0 End 2. Add a fade in and fade out: Method Start:Void() game.screenFade.Start(50, False) Self.CreateDemo() End Method Update:Void() world.TimeStep(m_timeStep, m_velocityIterations, m_positionIterations) world.ClearForces() If KeyHit(KEY_ESCAPE) game.screenFade.Start(50, True) game.nextScreen = game.exitScreen End End Method 3. Maybe increase the falling speed, as someone doesnt know how things fall - ROFL! |
| ||
| :O Yea do that please |
| ||
| I was joking with number 3... maybe ask God to do it ;) |
| ||
| All is under control :) ----signed: major tom---- |
| ||
| Update: Acceleration and gravity controller demo. Fading added, just for Steve ;-) |
| ||
| Great stuff, this comes in handy! |
| ||
| Corrected double creation of body in method CreateSphere(). |
| ||
An updated version for latest Diddy and with some physics scaling.
Strict
Import diddy
Import box2d.collision
Import box2d.collision.shapes
Import box2d.collision.shapes
Import box2d.dynamics.joints
Import box2d.common.math
Import box2d.dynamics.contacts
Import box2d.dynamics
Import box2d.flash.flashtypes
Import box2d.common.math.b2vec2
Import box2d.dynamics.controllers
Global gameScreen:Screen
Const FRAMERATE:= 60
Const PHYSICS_SCALE_PIXELS_PER_METER:= 64
Function Main:Int()
New MyGame()
Return 0
End Function
Class MyGame Extends DiddyApp
Method OnCreate:Int()
Super.OnCreate()
' default is 60 already, no need to change this
diddyGame.FPS = FRAMERATE ' set the update rate for Diddy. 60 is standard. Just here for demonstration.
gameScreen = new Box2dscreen
gameScreen.PreStart()
Return 0
End
End
Class Box2dscreen extends Screen
'
Field world:b2World
Field contactlistener:ContactListener
'
Field m_velocityIterations:int = 6
Field m_positionIterations:int = 2
'Physics simulation timestep. If the code can't match the speed, we'll see slow motion.
Field m_timeStep:Float = 1.0 / FRAMERATE ' set this to your SetUpdateRate()
Field m_physScale:Float = PHYSICS_SCALE_PIXELS_PER_METER ' Not in use, but you should not use pixels as your units,
' an object of length 200 pixels would be seen by Box2D as the size of
' a 45 story building.
Field m_debugdrawscale:Float = PHYSICS_SCALE_PIXELS_PER_METER ' set this to m_physScale if you are scaling your world.
Method New()
Local doSleep:Bool = True
Self.world = New b2World(New b2Vec2(0, 0), doSleep) ' no need for AABB in newer versions of box2d, the world is infinite
Self.SetGravity(0.0,10) '
world.SetWarmStarting(True)
'
'
'// set debug draw
Local dbgDraw :b2DebugDraw = New b2DebugDraw()
dbgDraw.SetDrawScale(m_debugdrawscale)
dbgDraw.SetFillAlpha(0.3)
dbgDraw.SetLineThickness(1.0)
dbgDraw.SetFlags(b2DebugDraw.e_shapeBit | b2DebugDraw.e_jointBit)'| b2DebugDraw.e_pairBit)
world.SetDebugDraw(dbgDraw)
Self.contactlistener=New ContactListener()
world.SetContactListener(Self.contactlistener)' for collision detection, if you need information which objects collide
End Method
Method Start:Void()
diddyGame.screenFade.Start(50, False) ' just a fading effect
Self.CreateDemo()
' Self.CreateControllerDemo() ' uncomment this for a demo of controllers
End
Method Render:Void()
Cls
self.world.DrawDebugData()
End
Method Update:Void()
world.TimeStep(m_timeStep, m_velocityIterations, m_positionIterations)
world.ClearForces()
If KeyHit(KEY_ESCAPE)
game.screenFade.Start(50, True)
game.nextScreen = game.exitScreen
End
End Method
Method SetGravity:Void(x:Float,y:Float)
Self.world.SetGravity(New b2Vec2(x,y))
End Method
Method CreateControllerDemo:Void()
' uncomment the line 'Self.CreateControllerDemo()' in Method Start() to see this running.
'
' accelration controllers are good to simulate wind, or if some bodies shall fall faster then others.
local accelcontroller:b2ConstantAccelController=new b2ConstantAccelController ' create an acceleration controller
accelcontroller.A=New b2Vec2(0,50) ' Set force. Every body added to Controller will be accelerated by this vector (box2d does this, just fire and forget).
world.AddController(accelcontroller) ' add controller to world
' add a body to controller. This body will fall faster then all others, because he is accelerated on the y-axis.
Local box:b2Body=self.CreateBox(600,100,20,20,false)
accelcontroller.AddBody(box)
'
' a gravitycontroller, good to simulate gravity between objects or magnetism.
local gravitycontroller:b2GravityController=new b2GravityController
gravitycontroller.G=15 ' the force with which the bodies attract each other.
world.AddController(gravitycontroller)
Local anotherbox:b2Body=self.CreateBox(510,100,30,10,false) ' add two bodies.
Local lastbox:b2Body=self.CreateBox(410,100,30,10,false) ' This bodies will attract each other like 'planets', they have their own gravity.
gravitycontroller.AddBody(anotherbox) ' add bodies to controller
gravitycontroller.AddBody(lastbox) 'call controller.RemoveBody() to stop a controller affecting a body.
End Method
Method CreateDemo:Void()
Local b:b2Body
' a box for ground
b=Self.CreateBox(340,420,480,30,true)
b.SetUserData(New StringObject("ground")) ' give object a name for collision detection in contactlistener
' a sphere
b=Self.CreateSphere(350,220,40)
b.SetUserData(New StringObject("sphere"))
' create a polygon from an array of b2d Vectors
Local tri:b2Vec2[]= [New b2Vec2(0, 0), New b2Vec2(0, -100), New b2Vec2(200 ,0)]
b=Self.CreatePolybody(200,20,tri)
b.SetUserData(New StringObject("triangle1"))
' ' create a polygon from an array with floats
Local triangle:Float[]=[0.000000000,-49.000000,99.000000,59.0000000,-77.000000,79.0000000]
b=Self.CreatePolybody(200,100,Self.ArrayToVectorarray(triangle))
b.SetUserData(New StringObject("triangle2"))
End Method
Method CreateBox:b2Body (xpos:Float,ypos:Float,width:Float,height:Float,static:Bool=true)
Local fd :b2FixtureDef = New b2FixtureDef()
Local sd :b2PolygonShape = New b2PolygonShape()
Local bd :b2BodyDef = New b2BodyDef()
if static=true
bd.type = b2Body.b2_staticBody
else
bd.type = b2Body.b2_Body
endif
fd.density = 2.0
fd.friction = 0.5
fd.restitution = 0.4
fd.shape = sd
sd.SetAsBox(width / m_physScale, height / m_physScale)
bd.position.Set(xpos / m_physScale, ypos / m_physScale)
Local b :b2Body
b = self.world.CreateBody(bd)
' Recall that shapes don?t know about bodies and may be used independently of the physics simulation. Therefore Box2D provides the b2Fixture class to attach shapes to bodies.
b.CreateFixture(fd)
'
Return b
End Method
Method CreateSphere:b2Body (xpos:Float,ypos:Float,radius:Float,static:Bool=false)
Local fd :b2FixtureDef = New b2FixtureDef()
Local bd :b2BodyDef = New b2BodyDef()
Local cd :b2CircleShape = New b2CircleShape()
'
cd.m_radius = radius / m_physScale
fd.density = 2
fd.restitution = 0.2
fd.friction = 0.5
fd.shape=cd
if static=true
bd.type = b2Body.b2_staticBody ' a static body
else
bd.type = b2Body.b2_Body 'a dynamic body
endif
bd.position.Set(xpos / m_physScale, ypos / m_physScale)
Local b :b2Body
b=Self.world.CreateBody(bd)
b.CreateFixture(fd)
Return b
End Method
Method CreatePolybody:b2Body(xpos:Float,ypos:Float,verts:b2Vec2[],static:Bool=false,bullet:Bool=false)
' polys must be defined vertices from left to right or their collision will not work. They must be convex.
' A polygon is convex when all line segments connecting two points in the interior do not cross any edge
' of the polygon.
' Polygons are solid and never hollow. A polygon must have 3 or more vertices.
Local b :b2Body
Local fd :b2FixtureDef = New b2FixtureDef()
Local sd :b2PolygonShape = New b2PolygonShape()
Local bd:b2BodyDef = New b2BodyDef()
For Local v:= EachIn verts
v.Multiply(1.0 / m_physScale)
Next
sd.SetAsArray(verts,verts.Length)
fd.shape=sd
bd.type = b2Body.b2_Body
bd.position.Set(xpos / m_physScale, ypos / m_physScale)
bd.bullet=bullet
b=Self.world.CreateBody(bd)
fd.density = 1.0
fd.friction = 0.5
fd.restitution = 0.1
b.CreateFixture(fd)
Return b
End Method
Method ArrayToVectorarray:b2Vec2[](arr:Float[])
' converts a normal array with floats to an array of b2Vec2
Local vecs:b2Vec2[1]
vecs=vecs.Resize(arr.Length/2)
Local count:int
For Local f:Float=0 to arr.Length-2 step 2
vecs[count]=new b2Vec2(arr[f],arr[f+1])
count+=1
Next
Return vecs
End Method
Method Cleanup:Void()
' When a world leaves scope or is deleted by calling delete on a pointer, all the memory reserved for bodies, fixtures, and joints is freed.
' This is done to improve performance and make your life easier. However, you will need to nullify any body, fixture, or joint pointers you have because they will become invalid.
End Method
End Class
Class ContactListener Extends b2ContactListener
' to gather information about collided objects.
' http://www.box2dflash.org/docs/2.1a/reference/Box2D/Dynamics/b2ContactListener.html
' You cannot create/destroy Box2D entities inside these callbacks.
Method New()
Super.New()
End
Method PreSolve : void (contact:b2Contact, oldManifold:b2Manifold)
End
Method BeginContact:void(contact:b2Contact)
' Print "objects did collide.."
'
' get the fixtures involved in collision
Local fixA:b2Fixture=contact.GetFixtureA()' Instead of telling you which b2Body collided, the b2Contact tells you which fixture collided.
Local fixB:b2Fixture=contact.GetFixtureB()' To know which b2Body was involved in the collision you can retrieve a reference to the fixture.
Local userdata1:Object=Object(fixA.GetBody().GetUserData())
Local userdata2:Object=Object(fixB.GetBody().GetUserData())
if userdata1<>NULL
Local name:String=StringObject(userdata1).ToString()
' Print "involved in collision:"+ name
EndIf
if userdata2<>NULL
Local name:String=StringObject(userdata2).ToString()
' Print "involved in collision:"+ name
EndIf
End Method
End
|
   |