FlatRedBall
  • 🖥️Downloading FlatRedBall
  • 🏗️Building FlatRedBall From Source
    • Linking Games to FlatRedBall Engine Source
    • Linking FNA
  • ❓Need Help?
  • ✨FlatRedBall Features
  • 🎓Tutorials
    • Introduction To FlatRedBall
    • Quick Start Guide
    • Beefball - A Full FlatRedBall Tutorial Project
      • Creating a FlatRedBall Project
      • Creating an Entity
      • Creating a Screen
      • Controlling an Entity
      • Creating the Screen Collision
      • Advanced PlayerBall Controls
      • Creating the Puck Entity
      • Adding Multiple Players
      • Scoring and Restarting Rounds
      • Scoring Hud
      • Scoring Hud Logic
      • Adding Dashing
    • Platformer Tutorials
      • Platformer Basics
        • Creating an Entity
        • Controlling a Platformer Entity
        • Movement Values
        • Double Jump
      • Checkpoint and Level End
      • Climbing Ladders
      • Doors
      • GroundCollidedAgainst and Movement Values
      • Moving Platforms
      • Multiple Players
      • NPC Dialog
      • Breaking Blocks
        • New Project Setup
        • Creating Level1 Map
        • Creating the Block Entity
        • Block Removal
      • Dealing Damage
        • New Project Setup
        • Enemy Entity
        • Shooting Bullets
        • Damaging the Enemy
      • Enemy Movement
        • New Project Setup
        • Enemy Entity
        • Enemy Input Logic
        • Detecting Platform Edges
      • Ground Type and Water Movement
        • New Project Setup
        • Creating Level1 Map
        • Adding Ice and Water
        • Platformer Movement Values
      • Animation and Platformer Values
        • New Project Setup
        • Creating AnimationLayers
        • Modifying Platformer Values
      • Wall Sliding and Jumping
    • Damage Dealing
      • Setup
      • Team Index
      • Damage Events
      • IDamageArea Removal
      • Melee Damage
    • Entity Variants Using Inheritance
    • FlatRedBall.Forms
      • Getting Started with FlatRedBall.Forms
        • Setup
        • Working with Common Controls
        • Forms vs Gum in Code
      • Forms and Xbox360GamePad
      • Data Binding (BindingContext)
        • BindingContext Property
        • Binding FlatRedBall.Forms
        • Parent and Children Binding using BindingContext
        • ListBox Templates
      • Styling Forms
      • Defining New Forms Types
        • Adding New Types to FlatRedBall.Forms Library
      • Accessing Forms Events in Gum Runtimes
    • Top Down Games
      • Top Down Basics
        • Setup
        • Input Device
        • CurrentMovement
      • Enemy Movement
        • Enemy Pathfinding
        • Direct Enemy Control
      • GroundVelocity
      • Animation
      • Sorting
    • Post Processing
    • Rock Blaster - A Full FlatRedBall Tutorial Project
      • Introduction
      • Setup
      • Game Skeleton
      • Player Entity
      • Player Behavior
      • Rock Entity
      • Collision
      • Rock States
      • HUD
      • Multiple Players
      • Health
      • Health Part 2
      • Destroying Entities
      • Cleaning Up
    • Code-Only Projects (No Editor)
      • Creating a FlatRedBall Project
      • Adding a Circle
      • Loading Textures and Using Sprites
    • Code Tutorials
      • 3D Camera Setup
      • Adding FlatRedBall to a MonoGame/FNA Project
      • Adding WPF to an Existing Game
      • async and await
      • CLR Profiler
      • Collision Jitter
      • Culling
      • Customizing Cursor Visuals
        • Windows Desktop
        • windows-rt
      • Depth Buffer Z Fighting
      • Dictionaries and Enum Keys
      • FlatRedBall XNA in Windows Form
      • Improving Performance
        • CustomActivity Performance
        • Identifying Screen Creation Performance Issues
        • Rendering Performance
        • Manually Updated Objects
          • Introduction
          • Measuring Automatic Updates
          • Measuring Sprite Automatic Updates
          • Manual Particle Systems
      • Object Sorting
      • Pix
      • Rendering Sprites with Shaders
      • Tile-Based Movement
      • Velocity
    • Distribution
      • App Icon
      • Emptying bin Folder Using Probing Path
      • itch.io
      • Release Build
      • Steam
    • FlatRedBall and Velcro Physics
      • Using Velcro Physics with the FlatRedBall Editor
      • Code-Only Velcro Projects
    • FlatRedBall Editor Plugins
      • Introduction to FlatRedBall Plugins
      • Creating a Plugin Project
      • Creating a Plugin Class
      • Adding UI to FlatRedBall
      • Using MVVM
      • Creating a NamedObjectSave-Editing Plugin
      • Adding File Format Support
      • Adding Code Files to a Game Project
      • Errors
      • Exporting a Plugin
    • Additional FlatRedBall Editor Tutorials
      • How to Create a First Person Camera
      • How to Play Sounds
      • How to Share Reference Data Between Screens and Entities
    • Math Tutorials
      • Circle Collision
      • Determining required magnitude for trajectory
      • Introduction to Collision
      • Power of Two
      • Rectangle Collision
      • rotation
      • statistics
      • trigonometry
      • vector
      • matrix
      • interpolation
    • Overworld Tutorials
      • Spinning Mode 7
        • New Project Setup
        • Adding Camera Code
        • Fading In and Out
  • 🎞️Videos
  • 📐FlatRedBall Editor
    • Display Settings
    • Entities
      • BaseEntity
      • Constructor
      • ConvertToManuallyUpdated
      • CreatedByOtherEntities
      • CustomActivity
      • CustomDestroy
      • CustomInitialize
      • Destroying Entities
      • Entity Performance
      • Export Entity
      • Implements IClickable
      • Implements ICollidable
      • Implements IDamageArea
      • Implements IDrawableBatch
      • Implements IGumCollidable
      • Implements IVisible
      • Implements IWindow
        • SlideOnClick
      • Import Entity
      • Inheriting from FlatRedBall Types
      • LayerProvidedByContainer
      • MoveToLayer
      • PooledByFactory
      • Top Down Movement
        • TopDownSpeedMultiplier
      • Use Global Content
    • Events
      • ResolutionRrOrientationChanged
    • Factories
      • CreateNew
      • EntitySpawned
      • Initialize
      • SortAxis
    • Files
      • File Types
        • Animation Chain List (.achx)
        • Comma Separated Values (.csv)
          • Combining .csvs With Entities
          • CreatesDictionary
          • Cross Referencing CSVs
          • Instantiating Custom Types
          • OrderedList
          • SetCreatedClass
            • generate-data-class
          • uniformrowtype
        • Effect (.fx, .fxb)
        • Font (.fnt)
        • JSON (.json)
        • Model (.fbx)
        • MP3
        • Node Network (.nntx)
        • OpenDocument Spreadsheet (.ods)
        • ShapeCollections (.shcx)
        • SplineList (.splx)
        • Texture2D (.png)
        • Wave (.wav)
      • Accessing Files in Code
      • Adding File Objects to Managers
      • Destroy on Unload
      • File Build Tool
      • Folders
      • Global Content Files
      • IsDatabaseForLocalizing
      • IsManuallyUpdated
      • IncludeDirectoryRelativeToContainer
      • LoadedAtRuntime
      • LoadedOnlyWhenReferenced
      • Name
      • Platform Inclusions
      • Project Specific Files
      • RuntimeType
      • SourceFile
      • UseContentPipeline
      • Wildcard Files
    • FileVersion (.gluj)
    • Generated Code
    • Global Content Files
      • LoadAsynchronously
      • Reload
      • Setting Files At Runtime
    • Live Edit
      • Render Targets
    • Menu
      • Content
        • Additional Content
          • Using Runtime Types as Objects
          • creating-runtime-objects
          • runtime-object-charateristics
          • simple-line-of-text-tutorial
        • Introduction
        • pipeline-settings
      • File
        • New Project
      • Edit
        • Find File References
      • Plugins
        • Install Plugin
        • Manage Plugins
      • Project
        • View Projects
      • Settings
        • Camera Settings
        • File Associations
        • File Build Tools
        • Performance Settings
      • Update
        • Introduction
        • glue-reference-menu-frbdk
        • glue-reference-menu-libraries
    • Multi-Platform
      • Synced Projects
      • Changing Main Project Type
      • Android
        • Distribution
        • Setup
      • iOS
        • Certificates and Profiles
        • Copying Projects to Mac
        • Using Xamarin Build Host
      • Switch (Nintendo)
      • Web
    • Objects
      • Object Types
        • AxisAlignedRectangle
        • Camera
        • CameraControllingEntity
        • Circle
        • CollisionRelationship
        • Layer
          • DestinationRectangle
          • Is2D
        • Polygon
        • PositionedObjectList
        • RenderTarget2D
        • ShapeCollection
        • SoundEffectInstance
        • Sprite
        • Text
        • TileNodeNetwork
      • AddToManagers
      • AttachToCamera
      • AttachToContainer
      • CallActivity
      • Collidable Objects
      • EntireFile
      • ExposedInDerived
      • HasPublicProperty
      • IgnoresPausing
      • IncludeInIClickable
      • IncludeInICollidable
      • IsContainer
      • LayerOn
      • Map
      • SetByDerived
      • SourceFile
      • SourceType
    • Plugins
      • glue-gluevault-component-pages-rendertargetrenderer
      • glue-gluevault-component-pages-simple-command-console
      • glue-gluevault-component-pages-squid-gui-integration
      • kalldrexx-interactive-debugging-console
    • Profiling
    • Screens
      • AsyncLoadingState
      • BaseScreen
      • Constructor
      • Creating a New Screen
      • CustomDestroy
      • CustomInitialize
      • DefaultLayer
      • GameScreen
      • IsActivityFinished
      • IsLoadingScreen
      • LoadStaticContent
      • MoveToScreen
      • PauseAdjustedCurrentTime
      • Set as StartUp Screen
      • UnloadsContentManagerWhenDestroyed
    • States
      • InterpolateToState
      • InterpolateToState vs InterpolateBetween
      • State Categories
      • State Classes
      • States and Inheritance
      • Tunneling Category Variables
    • Variables
      • CreatesEvent
      • HasAccompanyingVelocityProperty
      • IsShared
      • Proper Variable Naming
      • SetByDerived
      • Type
      • Variable Order
    • Visual Studio Project (.csproj)
  • 🏃Animation Editor
    • Frame Time
    • Animation Shapes and Collision
  • Tiled
    • Tiled Basics
      • Introduction
      • Creating a GameScreen
      • Adding Collision
      • Colliding Entities Against TileShapeCollections
      • Working with Multiple Levels
      • Creating Entities from Tiles
      • Creating Entities from Object Layers
      • Accessing Tiled Properties
      • Working with Tiled Shapes
    • Tiled Files in Entities
    • TileEntityInstantiator
    • Using TiledObjects.Generated.xml
    • LayeredTileMap
      • Collisions
      • Destroy
      • FromTiledMapSave
      • Z
    • MapDrawableBatch
      • AddTile
      • CoordinateAdjustment
      • GetBottomLeftWorldCoordinateForOrderedTile
      • MergeOntoThis
      • NamedTileOrderedIndexes
      • PaintTile
      • PaintTileTextureCoordinates
      • ParallaxX
      • Paste
      • Properties
      • RemoveQuads
      • RenderingScale
      • SortAxis
    • TiledMapSave
    • TileShapeCollection
      • AddCollisionAtWorld
      • AddCollisionFrom
      • AddCollisionFromTilesWithProperty
      • AddMergedCollisionFromLayer
      • AddMergedCollisionFromTilesWithProperty
      • AdjustRepositionDirectionsOnAddAndRemove
      • CollideAgainst
      • CollideAgainstClosest
      • GetRectangleAtPosition
      • InsertCollidables
      • LastCollisionAxisAlignedRectangles
      • Rectangles
      • RemoveFromManagers
      • RemoveSurroundedCollision
  • 🟩Gum
    • Tutorials
      • Introduction and Setup
      • Screens in Gum
      • Gum Objects in Code
      • Events on Gum Objects
      • Events on Gum Objects Part 2
      • Exposed Variables
      • States
      • Adding Code to Gum Objects
    • Accessing Gum Screens in Code
    • Adding Components to Layers
    • Adding Gum Screens to FlatRedBall
    • Animations in Code
    • Components in FlatRedBall Entities
    • Converting Gum Coordinates
    • Creating Components in Code
    • GraphicalUiElement as IWindow
    • Gum Resolution
    • Gum Properties Tab
    • Gum Animations
      • How to Play Gum Screen Animations
      • Named Events
      • Setting Gum Animationchain Achx in Code
  • 🦴Spine
    • Setup
    • Atlas
    • Changing Spine Textures at Runtime
    • SpineDrawableBatch
      • Event
      • PlayAnimation
      • SetCollision
      • Skeleton
  • ⏸️Aseprite
    • AnimationChainList
  • 🏫API Documentation
    • FlatRedBall Engine
      • AI
        • LineOfSight
          • VisibilityGrid
        • Pathfinding
          • PositionedNode
          • Link
            • Cost
            • NodeLinkingTo
          • NodeNetwork
            • GetPath
            • UpdateShapes
            • Visible
          • TileNodeNetwork
            • AddAndLinkTiledNode
            • AddAndLinkTiledNodeWorld
            • OccupyTileWorld
            • SetCosts
      • Audio
        • AudioManager
          • AreSoundEffectsEnabled
          • CurrentlyPlayingSong
          • MasterSongVolume
          • MasterSoundVolume
          • Play
          • PlaySong
          • PlaySongs
          • StopSong
        • PositionedSound
        • Sound
      • Camera
        • AbsoluteRightXEdge
        • AbsoluteRightXEdgeAt
        • AddLayer
        • AddSpriteToBillboard
        • AspectRatio
        • AttachTo
        • BackgroundColor
        • CameraCullMode
        • ClearMinimumsAndMaximums
        • ClearsDepthBuffer
        • DestinationRectangle
        • DrawsShapes
        • DrawsToScreen
        • DrawsWorld
        • FarClipPlane
        • FieldOfView
        • FixAspectRatioYConstant
        • ForceUpdateDependencies
        • GetViewport
        • IsSpriteInView
        • KeepSpriteInScreen
        • Layer
        • Layers
        • Main
        • MaximumX
        • Orthogonal
        • OrthogonalHeight
        • OrthogonalWidth
        • PixelsPerUnitAt
        • Position
        • PositionRandomlyInView
        • RelativeXEdgeAt
        • RemoveLayer
        • RotationMatrix
        • SetBordersAtZ
        • SetLookAtRotationMatrix
        • SetSplitScreenViewport
        • UpdateViewProjectionMatrix
        • UpVector
        • UsePixelCoordinates
        • UsePixelCoordinates3D
        • View
      • Content
        • ContentLoadBatch
        • AnimationChain
          • AnimationChainListSave
        • ContentManager
          • AddUnloadMethod
          • FileAliases
          • IsAssetLoadedByName
          • Load
          • LoadFromGlobalIfExists
          • Multiple Content Managers
        • Math
          • Geometry
            • ShapeCollectionSave
        • Polygon
          • PolygonSave
        • Scene
          • CameraSave
          • SceneSave
        • SpriteEditorScene
          • Camera
      • Debugging
        • Debugger
          • CommandLineWrite
          • GetFullPerformanceInformation
          • TextBlue
          • WriteAutomaticallyUpdatedObjectInformation
      • Entities
        • CameraControllingEntity
        • IDamageable
        • IDamageArea
      • FlatRedBallServices
        • AddDisposable
        • AddManager
        • CornerGrabbingResize
        • Draw
        • ForceClientSizeUpdates
        • Game
        • GetManagerInformation
        • GlobalContentManager
        • GraphicsOptions
        • Initialize
        • IsLoaded
        • Load
        • Owner
        • Random
        • RenderAll
        • Unload
        • Update
        • WindowHandle
      • Graphics
        • Animation
          • AnimationChain
            • Clone
            • FrameToFrame
            • TotalLength
          • AnimationChainList
          • AnimationController
          • AnimationFrame
            • RelativeX
            • ShapeCollectionSave
            • Texture
          • IAnimationChainAnimatable
            • Animate
            • Animation and Timing
            • AnimationChains
            • AnimationSpeed
            • CurrentChainName
            • CurrentFrameIndex
            • JustChangedFrame
            • JustCycled
            • UseAnimationRelativePosition
        • BitmapFont
          • BMFC File
          • BitmapCharacterInfo
          • FNT File
          • Glyphs
          • LineHeightInPixels
          • RenderToTexture2D
        • BlendOperation
        • ColorOperation
          • Add
          • Color
          • ColorTextureAlpha
          • InterpolateColor
          • Modulate
          • Texture
        • GraphicsOptions
          • Filtering
          • IsFullScreen
          • ResolutionHeight
          • SetFullScreen
          • SetResolution
          • SizeOrOrientationChanged
          • TextureFilter
          • TextureLoadingColorKey
          • UseMultisampling
        • IColorable
          • Alpha
          • BlendOperation
          • Blue
          • ColorOperation
        • IDrawableBatch
          • Z
          • RenderState
        • IVisible
          • IgnoresParentVisibility
        • Layer
          • Layer Membership Details
          • LayerCameraSettings
          • Remove
          • RenderTarget
          • SortType
          • Sprites
          • UsePixelCoordinates
        • LayerCameraSettings
          • OrthogonalWidth
          • TopDestination
        • Particle
          • EmissionSettings
            • Drag
            • PixelSize
            • ScaleX
          • Emitter
        • PostProcessing
          • SwapChain
        • RenderBreak
        • Renderer
          • Draw
          • LastFrameRenderBreakList
          • RenderBreaksAllocatedThisFrame
        • Text
          • AdjustPositionForPixelPerfectDrawing
          • ColorOperation
          • DisplayText
          • GetWidth
          • Font
          • HorizontalAlignment
          • InsertNewLines
          • MaxWidth
          • MaxWidthBehavior
          • NewLineDistance
          • NumberOfLines
          • ScaleX
          • SetColor
          • SetPixelPerfectScale
          • VerticalAlignment
          • Width
        • TextManager
          • AddManuallyUpdated
          • AddText
          • AddToLayer
          • FilterTexts
          • RemoveText
        • Texture
          • RenderTargetSprite
          • ImageData
            • ApplyColorOperation
            • Fill
            • FromTexture2D
      • Gui
        • Cursor
          • Camera
          • ClickNoSlideThreshold
          • CustomUpdate
          • GetRay
          • IngnoreInputThisFrame
          • IsInWindow
          • IsOn
          • IsOn3d
          • PrimaryClick
          • PrimaryClickNoSlide
          • PrimaryPushTime
          • ScreenX
          • SecondaryClick
          • SetControllingGamepad
          • SetJoystickControl
          • TransformationMatrix
          • WindowOver
          • WidowPushed
          • WorldPosition
          • WorldX
          • WorldXAt
          • WorldYAt
          • XForUi
        • GuiManager
          • AddDominantWindow
          • BringsClickedWindowsToFront
          • BringToFront
          • GamepadsForUiControl
          • MakeRegularWindow
          • RemoveWindow
          • SortZAndLayerBased
          • Windows
        • IClickable
        • IInputReceiver
          • IWindow
            • CallClick
            • Enabled
          • ReceiveInput
      • Input
        • AnalogButton
        • AnalogStick
          • IsMaxPositionNormalized
        • DelegateBased1DInput
        • DelegateBased2DInput
        • DelegateBasedPressableInput
        • I1DInput
        • I2DInput
        • IMouseOver
        • InputDeviceBase
        • InputManager
          • ClearAllInput
          • InputReceiver
        • IPressableInput
        • Keyboard
          • Clear
          • ControlPositionedObject
          • Get2DInput
          • GetKey
          • GetStringTyped
          • IgnoreKeyForOneFrame
          • KeyDown
          • KeyPushed
        • Mouse
          • GrabbedPositionedObject
          • IsOn3D
          • ModifyMouseState
          • Restricting Mouse to Screen Bounds
          • SetScreenPosition
        • TouchScreen
          • LastFrameGestures
          • ReadsGestures
        • Windows
          • WindowsInputEventManager
        • Xbox360GamePad
          • ButtonDown
          • ButtonMap
          • ButtonPosition vs Button
          • ButtonPushed
          • ControlPositionedObject
          • CreateDefaultButtonMap
          • Deadzone
          • DeadzoneType
          • FakeIsConnected
          • GamepadLayout
          • IgnoreButtonForOneFrame
      • Instructions
        • DelegateInstruction
        • IInstructable
          • Call
          • Cnstructions
          • Set
        • Instruction
        • InstructionList
          • ExecuteAndRemoveOrCyclePassedInstructions
        • InstructionManager
          • Add
          • AddSafe
          • Instructions
          • MoveThrough
          • MoveTo
          • MoveToAccurate
          • ObjectsIgnoringPausing
          • PauseEngine
          • Pulse
          • RotateToAccurate
        • Reflection
          • LateBinder
          • PropertyCollection
        • MethodInstruction
        • StaticMethodInstruction
      • IO
        • Csv
          • CsvHeader
          • CsvFilemanager
            • Cells with Multiple Lines
            • Color
            • CsvDeserializelist
            • Rows with Lists
          • RuntimeCsvRepresentation
            • FromList
            • GenerateCsvString
        • FileManager
          • BinarySerialize
          • CloneObject
          • FromFileText
          • GetAllFilesInDirectory
          • GetUserFolder
          • InitializeUserFolder
          • RelativeDirectory
          • SaveEmbeddedResource
          • SaveText
          • Standardize
          • UserApplicationDataForThisApplication
          • XmlDeserialize
          • XmlSerialize
      • Localization
        • LocalizationManager
      • Managers
        • IManager
      • Math
        • IAttachableRemovable
        • AttachableList
          • FindByName
          • MakeOneWay
        • Collision
          • CollisionManager
            • Relationships
            • Update
        • Geometry
          • AxisAlignedCube
            • CollideAgainstBounce
          • AxisAlignedRectangle
            • Axis Alignment And Rotation
            • CollideAgainstMoveSoft
            • Color
            • GetRandomPositionInThis
            • KeepThisInsideOf
            • LastMoveCollisionReposition
            • Left
            • RepositionDirections
          • Capsule2D
          • Circle
            • CollideAgainst
            • CollideAgainstBounce
            • CollideAgainstMove
            • IsPointInside
            • LastCollisionTangent
            • LastMoveCollisionReposition
            • ProjectParentVelocityOnLastMoveCollisionTangent
            • Visible
            • Z
          • Colliding a List of Shapes Against Itself
          • FloatRectangle
          • ICollidable
          • IScalable
            • Scale
          • Line
            • Color
            • LastCollisionPoint
            • RelativePoint1
            • SetFromAbsoluteEndpoints
          • Point
          • Polygon
            • AbsolutePointPosition
            • Clone
            • CollideAgainstBounce
            • CollideAgainstMove and Attachments
            • CollideAgainstMove
            • Color
            • CreateEquilateral
            • CreateRectangle
            • ForceUpdateDependencies
            • IsPointInside
            • LastMoveCollisionReposition
            • OptimizeRadius
            • Points
            • Position
            • ProjectParentVelocityOnLastMoveCollisionTangent
            • ScaleBy
            • Thin Polygon Problem
            • VectorFrom
            • Visible
            • Z
          • Segment
            • ClosestPointTo
          • Shape
          • ShapeCollection
            • AttachTo
            • AxisAlignedRectangles
            • CollideAgainst
            • CollideAgainstBounceWithoutSnag
            • CollideAgainstMove
            • CollideAgainstMoveWithoutSnag
            • LastCollisionAxisAlignedRectangles
            • SortAscending
            • Visible
          • ShapeManager
            • AddToLayer
            • Remove
            • ShapeDrawingOrder
          • ShapeMerger
          • Shapes and 2D Collision
          • Sphere
        • IAttachable
          • Attachment Updates in the Engine
          • Detach
          • ParentRotationChangesPosition
          • ParentRotationChangesRotation
          • TopParent
        • IRotatable
          • RotationMatrix
        • MathFunctions
          • AbsoluteToWindow
          • AngleToAngle
          • AngleToVector
          • GetPointInCircle
          • GetPositionAfterTime
          • RegulatAngle
          • RotatePointAroundPoint
          • RoundFloat
          • RoundToInt
          • WidowToAbsolute
        • Paths
          • Path
        • PositionedObjectList
          • Add
          • AttachTo
          • Clear
          • GetFirstAfter
          • GetFirstAfterPosition
          • SortXInsertionAscending
        • Splines
          • Spline
            • GetPositionAtLengthAlongSpline
      • Performance
        • Measurement
          • Section
            • GetAndStartContextAndTime
            • Save
            • ToStringVerbose
      • PositionedObject
        • Acceleration
        • AttachTo
        • Children
        • Clone
        • Drag
        • ForceUpdatedependencies
        • ForceUpdatedependenciesDeep
        • Initialize
        • KeepTrackOfReal
        • LastPosition
        • Mirrored properties
        • ParentRotationChangesPosition
        • ParentRotationChangesRotation
        • Position
        • RelativePosition
        • RelativeRotationZ
        • RelativeVelocity
        • RemoveSelfFromListsBelongingTo
        • RotationZ
        • SetRelativeFromAbsolute
        • TimedActivity
        • TopParent
        • UpdateDependencies
        • Velocity
        • Z
      • Screens
        • Screen
          • ContentManagerName
          • CustomDestroy
          • IsActivityFinished
          • MoveToScreen
          • PauseThisScreen
        • ScreenManager
          • Activity
          • CurrentScreen
          • Start
      • Sprite
        • Alpha
        • AnimateSelf
        • AnimationChains
        • AnimationSpeed
        • Bottom
        • BottomTextureCoordinate
        • Changing a Sprite's Origin
        • ColorOperation
        • CurrentChainName
        • CurrentFrameIndex
        • IgnoreAnimationChainTextureFlip
        • Inheriting from the Sprite Class
        • JustCycled
        • LeftTextureCoordinate
        • PixelSize
        • Position
        • RightTextureCoordinate
        • SetAnimationChain
        • SetScaleXRatioToY
        • Sorting and Overlapping
        • Sprite vs Texture2d
        • Texture Coordinates
        • Texture
        • TextureAddressMode
        • TextureCoordinate
        • TextureFilter
        • TextureScale
        • TimeIntoAnimation
        • TopTextureCoordinate
        • UseAnimationRelativePosition
        • Vertices
        • VerticesForDrawing
        • Visible
      • SpriteList
      • SpriteManager
        • AddDrawableBatch
        • AddManagedInvisibleSprite
        • AddManualSprite
        • AddParticleSprite
        • AddPositionedObject
        • AddSprite
        • AddToLayer
        • AddZBufferedDrawableBatch
        • AddZBufferedSprite
        • AutomaticallyUpdatedSprites
        • Camera
        • ConvertToAutomaticallyUpdated
        • ConvertToManagedInvisible
        • ConvertToManuallyUpdated
        • ConvertToZBufferedSprite
        • DrawableBatches
        • ManagedPositionedObjects
        • ManualUpdate
        • MaxParticleCount
        • MoveToBack
        • OrderedSortType
          • Z
        • OrderedSprites
        • RemoveDrawableBatch
        • RemoveLayer
        • RemovePositionedObject
        • RemoveSprite
        • RemoveSpriteOneWay
        • SortTexturesSecondary
        • SortYSpritesSecondary
        • UnderAllDrawnLayer
      • TimeManager
        • Accumulating Time
        • CurrentScreenSecondsSince
        • CurrentTime
        • Profiling
        • SecondDifference
        • SecondsSince
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On this page
  • Introduction
  • Method Signature
  • Example Code
  • Reacting to CollideAgainstBounce
  • Bouncing and Velocity
  • CollideAgainstBounce for platformers

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  1. API Documentation
  2. FlatRedBall Engine
  3. Math
  4. Geometry
  5. Polygon

CollideAgainstBounce

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Last updated 1 year ago

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Introduction

The CollideAgainstBounce is a collision method which performs the following:

  • Returns true if a collision has occurred.

  • Repositions the calling Circle and/or the argument object depending on the argument masses.

  • Changes the calling Shape's Velocity and/or the argument object's Velocity depending on the argument masses.

Note: All collision methods, including CollideAgainstBounce, are methods common to all Shapes. If you came here through a link on a page beside the Circle (such as Polygon), don't worry, the code for all shapes is identical.

Method Signature

The signature for CollideAgainstBounce is as follows:

bool CollideAgainstBounce(Circle circle, float thisMass, float otherMass, float elasticity)
bool CollideAgainstBounce(Polygon polygon, float thisMass, float otherMass, float elasticity)
bool CollideAgainstBounce(AxisAlignedRectangle axisAlignedRectangle, float thisMass, float otherMass, float elasticity)

Arguments:

  • Circle circle (or other shape) - the shape to collide against. This method supports other shapes as well, and if you find a shape that you'd like to collide against which is not supported, please request this feature in the forums.

  • float thisMass - the mass of this shape. This does not have to be an absolute mass since it will only be used relative to the otherMass argument.

  • float otherMass - the mass of the argument shape. Just like thisMass, otherMass does not have to be absolute. It will be compared against thisMass.

  • float elasticity - The amount of bounce that will result. A value of 1 results in all momentum being preserved through the collision. A value of 0 results in no momentum being preserved. Negative values should not be used. Values greater than 1 introduce extra momentum. Values greater than 1 can be used to simulate "bouncing" against a wound-up spring, or to create false physics. For more information on the elasticity variable, see the Elasticity Examples section below.

Example Code

Add the following using statements:

using FlatRedBall.Input;
using FlatRedBall.Math.Geometry;
using Microsoft.Xna.Framework.Input;

Add the following at class scope:

PositionedObjectList<Circle> mPegs = new PositionedObjectList<Circle>();
PositionedObjectList<Circle> mFallingPieces = new PositionedObjectList<Circle>();

Add the following in Initialize after initializing FlatRedBall:

 for (int i = 0; i < 8; i++)
 {
     for (int j = 0; j < 7; j++)
     {
         Circle circle = ShapeManager.AddCircle();
         circle.X = -16 + 4 * i;
         circle.Y = -14 + 4 * j;

         if (j % 2 == 0)
             circle.X += 2;

         mPegs.Add(circle);
     }
 }

Add the following in Update:

 if (InputManager.Keyboard.KeyPushed(Keys.Space))
 {
     Circle circle = ShapeManager.AddCircle();
     circle.Radius = .5f;
     circle.YAcceleration = -5;
     circle.Y = 16;

     circle.X = -16 + (float)FlatRedBallServices.Random.NextDouble() * 32;

     mFallingPieces.Add(circle);
 }

 foreach (Circle fallingPiece in mFallingPieces)
 {
     foreach (Circle peg in mPegs)
     {
         // The second argument (0) is the mass of the falling piece relative to the peg.
         // The third argument (1) is the mass of the peg relative to the falling piece.
         // The 0,1 combination makes the peg of infinite mass - it will never move.
         // The last argument (.75) makes the collision slightly inelastic so it
         // looks a little more realistic.
         fallingPiece.CollideAgainstBounce(peg, 0, 1, .75f);
     }
 }

Reacting to CollideAgainstBounce

Since CollideAgainstBounce returns a bool, your code can use the return value to modify your game when a collision occurs:

bool didCollisionOccur = circle.CollideAgainstBounce(otherCircle, 0, 1, 1);
if(didCollisionOccur)
{
   // Here you can do whatever you want, like play a sound effect, add points, or even modify the velocity
   // of either of the objects
}

Bouncing and Velocity

"For bouncing to behave properly, we have to make sure that we're not controlling the involved Shapes' position or velocity"

Let's consider why this is the case. Imagine a situation where a shape (or parent of a shape) is moving toward the right. This is being done with the following code:

someShape.XVelocity = 1;

If this code is called every frame, that means that the XVelocity will be set to 1 every frame, regardless of what it was before. Imagine that "someShape" performs bounce collision against a wall. When collision occurs, the shape's XVelocity will get inverted (that is, set to -1) so that it moves to the left. However, if Velocity is set to 1 every frame, than the -1 would get changed back to 1. In other words, the setting of velocity every frame would cancel out the velocity change from CollideAgainstBounce. Let's look at another example: one where an object is moved with the mouse. In this example, the mouse is simply setting the position of an object:

someShape.X = InputManager.Mouse.WorldXAt(0);
someShape.Y = InputManager.Mouse.WorldYAt(0);

In this case, someShape will have a velocity of 0 (assuming there is no other code that sets its velocity. Therefore, even though someShape appears to be moving smoothly with the mouse, if another object bounces against it, it may not bounce at all.

Code Example

Add the following using statements:

using FlatRedBall;
using FlatRedBall.Input;
using FlatRedBall.Math;
using FlatRedBall.Math.Geometry;

Add the following at class scope:

PositionedObjectList<Circle> mCircles = new PositionedObjectList<Circle>();
Circle mControlledCircle;

Add the following in Initialize after initializing FlatRedball:

 mControlledCircle = ShapeManager.AddCircle();

 for (int i = 0; i < 30; i++)
 {
     Circle circle = ShapeManager.AddCircle();
     mCircles.Add(circle);
     SpriteManager.Camera.PositionRandomlyInView(circle, 40, 40);
 }

Add the following in Update:

 // true will result in no bouncing
 // false will result in bouncing (probably expected behavior)
 bool controlByPositionInsteadOfVelocity = false;

 if (controlByPositionInsteadOfVelocity)
 {
     mControlledCircle.X = InputManager.Mouse.WorldXAt(0);
     mControlledCircle.Y = InputManager.Mouse.WorldYAt(0);
 }
 else
 {
     // Increasing this reduces lag, but increases potential jittery
     // velocity values.
     const float coefficient = 20;

     mControlledCircle.XVelocity = coefficient * 
         (InputManager.Mouse.WorldXAt(0) - mControlledCircle.X);
     mControlledCircle.YVelocity = coefficient *
         (InputManager.Mouse.WorldYAt(0) - mControlledCircle.Y);
 }
 foreach (Circle circle in mCircles)
 {
     // Make this mass 1, the other mass 0 so that this is
     // immovable and it will bounce and push all other objects.
     mControlledCircle.CollideAgainstBounce(circle, 1, 0, 1);
 }

CollideAgainstBounce for platformers

The following code creates a board.

The mentions:

The following example shows a problem with using CollideAgainstBounce and control and how it can be corrected.

The CollideAgainstBounce method is effective for performing bouncing physics, but it can also be used in situations where you'd like collision to reset velocity, such as in platformers. It's very common to have acceleration in platformers, and the easiest way to do this is to set the player to have a negative YAcceleration. However, if the player collides with the ground using CollideAgainstMove, the YAcceleration will continue to accumulate the YVelocity value. Eventually this value will build up to be so large that the player will fall through the level. Even if this doesn't occur, the player will show weird behavior if it walks off of a ledge. To solve this, you can simply use CollideAgainstBounce instead of CollideAgainstMove. An elasticity of 0 will result in the same behavior as CollideAgainstMove, but the velocity will be modified according to the velocity to solve accumulation errors. You can try this in the demo above by setting the elasticity argument to 0.

🏫
Plinko
Collision tutorial
Mouse
Entity
CircleBounceCollision.png
CollideAgainstBouncAndVelocity.png