JPA (File Format)

JPA stands for JPArticle, and is part of Nintendo's JSystem. The version of JPA documented here is JPAC2-10.

This page is a work in progress.

JPA Header

The file starts with this Header

Offset	Type	Description
0x00	String	JPAC2-10 in ASCII
0x08	UInt16	Particle Count
0x0A	UInt16	Image Count
0x0C	UInt32	Offset to the TEX1 section
0x10	UInt32	Unknown
0x14	UInt32	Unknown

BEM1

This section is the Base Emitter, which contains settings for the emitter object.
This chunk is required for every particle

Offset	Type	Description
0x00	String	BEM1 in ASCII
0x04	UInt32	Section Length
0x08	UInt32	Flags. VolumeType = (flags >> 8) & 0x07. See the Volume Type Table
0x0C	UInt32	Unknown
0x10	Single	Emitter Scale X
0x14	Single	Emitter Scale Y
0x18	Single	Emitter Scale Z
0x1C	Single	Emitter Translation X
0x20	Single	Emitter Translation Y
0x24	Single	Emitter Translation Z
0x28	Single	Emitter Direction X
0x2C	Single	Emitter Direction Y
0x30	Single	Emitter Direction Z
0x34	Single	Initial Velocity Omni-Directional (?)
0x38	Single	Initial Velocity Axis
0x3C	Single	Initial Velocity Random
0x40	Single	Initial Velocity Direction
0x44	Single	Spread
0x48	Single	Initial Velocity Ratio
0x4C	Single	Rate
0x50	Single	Rate Random
0x54	Single	Lifetime Random
0x58	Single	Volume Sweep
0x5C	Single	Volume Minimum Radius
0x60	Single	Air Resistance
0x64	Single	Moment Random
0x68	Int16	Emitter Rotation X in Degrees
0x6A	Int16	Emitter Rotation Y in Degrees
0x6C	Int16	Emitter Rotation Z in Degrees
0x6E	Int16	Max Frame
0x70	Int16	Start Frame
0x72	Int16	Lifetime
0x74	Int16	Volume Size
0x76	Int16	Division Number
0x78	UInt8	Rate Step
0x79	UInt8[3]	Padding

BSP1

This section is the Basic Shape, which contains settings on how to draw the particle.
This chunk is required for every particle

Offset	Type	Description
0x00	String	BSP1 in ASCII
0x04	UInt32	Section Length
0x08	UInt32	Flags: ShapeType = flags & 0x0F. See the Shape Type Table DirectionType = (flags >> 0x04) & 0x07. See the Direction Type Table RotationType = (flags >> 0x07) & 0x07. See the Rotation Type Table PlaneType = (flags >> 0x0A) & 0x01. See the Plane Type Table. (If the ShapeType is DIRECTIONCROSS or ROTATIONCROSS, the PlaneType is always X) ColourInSelect = (flags >> 0x0F) & 0x07 AlphaInSelect = (flags >> 0x12) & 0x01 TlingS = if !((flags >> 0x19) & 0x01), set to 2.0, otherwise, use 1.0 TlingT = if !((flags >> 0x1A) & 0x01), set to 2.0, otherwise, use 1.0 bool IsGlobalColourAnimation = !(flags & 0x00001000) bool IsGlobalTextureAnimation = !(flags & 0x00004000) bool IsEnableProjection = !(flags & 0x00100000) bool IsDrawForwardAhead = !(flags & 0x00200000) bool IsDrawPrintAhead = !(flags & 0x00400000) bool IsEnableTextureScrollAnimation = !(flags & 0x01000000) bool IsNoDrawParent = !(flags & 0x08000000) bool IsNoDrawChild = !(flags & 0x10000000)
0x0C	UInt16	Primary Colour Data Offset. ColourFlags & 0x02 must equal 0
0x0E	UInt16	Environment Colour Data Offset. ColourFlags & 0x08 must equal 0
0x10	Single	BaseSizeX
0x14	Single	BaseSizeY
0x18	UInt16	Blend Mode Flags
0x1A	UInt8	Alpha Compare Flags
0x1B	UInt8	Alpha Reference 0
0x1C	UInt8	Alpha Reference 0
0x1D	UInt8	Z Mode Flags
0x1E	UInt8	Texture Flags: Texture Calculate Index Type = (TextureFlags >> 2) & 0x07. See the Calculate Index Type Table bool IsEnableTextureAnimation = !(TextureFlags & 0x01)
0x1F	UInt8	Texture Index Animation Count TexIDAnimCount
0x20	UInt8	TextureIndex
0x21	UInt8	Colour Flags: Colour Calculate Index Type = (ColourFlags >> 0x04) & 0x07
0x22	UInt8	Primary Colour Animation Data Count. ColourFlags & 0x02 must equal 0
0x23	UInt8	Environment Colour Animation Data Count. ColourFlags & 0x08 must equal 0
0x24	UInt16	Colour Animation Max Frame
0x26	Colour RGBA UInt8[4]	Primary Colour
0x2A	Colour RGBA UInt8[4]	Environment Colour
0x2E	UInt8	Animation Random
0x2F	UInt8	Colour Loop Offset Mask
0x30	UInt8	Texture Index Loop Offset Mask
0x34	UInt8[3]	Padding

Extra BSP1 Data

This extra data exists if IsEnableTextureScrollAnimation is TRUE

Offset	Type	Description
0x00	Single	Texture Init Translation X
0x04	Single	Texture Init Translation Y
0x08	Single	Texture Init Scale X
0x0C	Single	Texture Init Scale Y
0x10	Single	Texture Init Rotation
0x14	Single	Texture Increment Translation X
0x18	Single	Texture Increment Translation Y
0x1C	Single	Texture Increment Scale X
0x20	Single	Texture Increment Scale Y
0x24	Single	Texture Increment Rotation
0x28	UInt8[TexIDAnimCount]	A list of bytes representing texture IDs

ESP1

Extra settings for how to draw the particle. This chunk is optional.

Offset	Type	Description
0x00	String	ESP1 in ASCII
0x04	UInt32	Section Length
0x08	UInt32	Flags. bool IsEnableScale = !(flags & 0x01) bool IsDifferentXY = !(flags & 0x02) ScaleAnimTypeX = (flags >> 0x08) & 0x03. See the Calculate Scale Animation Type Table ScaleAnimTypeY = (flags >> 0x0A) & 0x03. See the Calculate Scale Animation Type Table PivotX = (flags >> 0x0C) & 0x03 PivotY = (flags >> 0x0E) & 0x04 bool IsEnableAlpha = !(flags & 0x0010000) bool IsEnableSinWave = !(flags & 0x0020000) bool IsEnableRotate = !(flags & 01000000)
0x0C	Single	Scale In Timing
0x10	Single	Scale Out Timing
0x14	Single	Scale In Value X
0x18	Single	Scale Out Value X
0x1C	Single	Scale In Value Y
0x20	Single	Scale Out Value Y
0x24	Single	Scale Out Random
0x28	UInt16	Scale Animation X Max Frame
0x2A	UInt16	Scale Animation Y Max Frame
0x2C	Single	Alpha In Timing
0x30	Single	Alpha Out Timing
0x34	Single	Alpha In Value
0x38	Single	Alpha Base Value
0x3C	Single	Alpha Out Value
0x40	Single	Alpha Wave Frequency
0x44	Single	Alpha Wave Random
0x48	Single	Alpha Wave Amplitude
0x4C	Single	Rotate Angle
0x50	Single	Rotate Angle Random
0x54	Single	Rotate Speed
0x58	Single	Rotate Speed Random
0x5C	Single	Rotate Direction

SSP1

Settings for child particles that are spawned from the parent particle

Offset	Type	Description
0x00	String	SSP1 in ASCII
0x04	UInt32	Section Length
0x08	UInt32	Flags: ShapeType = flags & 0x0F. See the Shape Type Table DirectionType = (flags >> 0x04) & 0x07. See the Direction Type Table RotationType = (flags >> 0x07) & 0x07. See the Rotation Type Table PlaneType = (flags >> 0x0A) & 0x01. See the Plane Type Table. (If the ShapeType is DIRECTIONCROSS or ROTATIONCROSS, the PlaneType is always X) bool IsInheritedScale = !(flags & 0x0001000) bool IsInheritedAlpha = !(flags & 0x0002000) bool IsInheritedRGB = !(flags & 0x0004000) bool IsEnableField = !(flags & 0x0020000) bool IsEnableScaleOut = !(flags & 0x0040000) bool IsEnableAlphaOut = !(flags & 0x0080000) bool IsEnableRotate = !(flags & 0x0100000)
0x0C	Single	Position Random
0x10	Single	Base Velocity
0x14	Single	Base Velocity Random
0x18	Single	Velocity Inf Rate
0x1C	Single	Gravity
0x20	Single	Global Scale 2D X
0x24	Single	Global Scale 2D Y
0x28	Single	Inherit Scale
0x2C	Single	Inherit Alpha
0x30	Single	Inherit RGB
0x34	Colour RGBA UInt8[4]	Primary Colour
0x38	Colour RGBA UInt8[4]	Environment Colour
0x3C	Single	Timing
0x40	UInt16	Life
0x42	UInt16	Rate
0x44	UInt8	Step
0x45	UInt8	Texture Index
0x46	UInt16	Rotate Speed

ETX1

Settings for configuring two or three textures on a particle

Offset	Type	Description
0x00	String	ETX1 in ASCII
0x04	UInt32	Section length
0x08	UInt32	Flags: IndirectTextureMode = flags & 0x01. See the Indirect Texture Mode Table
0x0C	Single	Indirect Texture Matrix. Item00
0x10	Single	Indirect Texture Matrix. Item01
0x14	Single	Indirect Texture Matrix. Item02
0x18	Single	Indirect Texture Matrix. Item10
0x1C	Single	Indirect Texture Matrix. Item11
0x20	Single	Indirect Texture Matrix. Item12
0x24	Int8	Matrix Scale
0x25	UInt8	Indirect Texture Index
0x26	UInt8	Second Texture Index. Set to -1 if (flags & 0x00000100) is true
0x27	UInt8[2]	Padding

KFA1

Contains curve animation tracks that can affect various properties of the emitter over time

Offset	Type	Description
0x00	String	KFA1 in ASCII
0x04	UInt32	Section length
0x08	UInt8	Key Type. See the JPA Key Types Table
0x09	UInt8	Key Count
0x0A	UInt8	Padding
0x0B	bool	Loop
0x0C	J3DKeyframe[]	Keyframes

J3D Keyframe

Offset	Type	Description
0x00	Single	Time
0x04	Single	Value
0x08	Single	Tangent In
0x0C	Single	Tangent Out

FLD1

Defines different physics simulation fields that affect the particles

Offset	Type	Description
0x00	String	FLD1 in ASCII
0x04	UInt32	Section length
0x08	UInt32	Flags: Type = flags & 0x0F. See the Field Type Table VelocityType = (flags >> 0x08) & 0x03. See the Field Add Type Table STTFlag = (flags >> 0x10)
0x0C	Single	Position X
0x10	Single	Position Y
0x14	Single	Position Z
0x18	Single	Direction X
0x1C	Single	Direction Y
0x20	Single	Direction Z
0x24	Single	Param 1
0x28	Single	Param 2
0x2C	Single	Param 3
0x30	Single	Fade In
0x34	Single	Fade Out
0x38	Single	Enter Time (?)
0x3C	Single	Distance Time
0x40	UInt8	Cycle
0x41	UInt8[3]	Padding

TDB1

This "chunk" stores a mapping of particle texture indices to the JPAC texture indices.
This chunk is required for every particle

Offset	Type	Description
0x00	String	TDB1 in ASCII
0x04	UInt32	Section length - 0x08
0x08	UInt16[]	JPAC Texture Indices

Type Lists

Volume Types

Value	Type
0x00	CUBE
0x01	SPHERE
0x02	CYLINDER
0x03	TORUS
0x04	POINT
0x05	CIRCLE
0x06	LINE

Shape Types

Value	Type
0x00	POINT
0x01	LINE
0x02	BILLBOARD
0x03	DIRECTION
0x04	DIRECTIONCROSS
0x05	STRIPE
0x06	STRIPECROSS
0x07	ROTATION
0x08	ROTATIONCROSS
0x09	DIRBILLBOARD
0x0A	YBILLBOARD

Direction Types

Value	Type
0x00	VELOCITY
0x01	POSITION
0x02	POSITIONINVERSE
0x03	EMITTERDIRECTION
0x04	PREVIOUSPARTICLE

Rotation Types

Value	Type
0x00	X
0x01	Y
0x02	Z
0x03	XYZ
0x04	YJIGGLE

Plane Types

Value	Type
0x00	XY
0x01	YZ
0x02	X

Calculate Index Types

Value	Type
0x00	NORMAL
0x01	REPEAT
0x02	REVERSE
0x03	MERGE
0x04	RANDOM

Calculate Scale Animation Types

Value	Type
0x00	NORMAL
0x01	REPEAT
0x02	REVERSE

Calculate Alpha Wave Types

Value	Type
0xFF	NONE
0x00	NORMALSIN
0x01	ADDSIN
0x02	MULTIPLYSIN

Indirect Texture Mode

Value	Mode
0x00	OFF
0x01	NORMAL
0x02	SUBTRACT

Field Types

Value	Type
0x00	GRAVITY
0x01	AIR
0x02	MAGNET
0x03	NEWTON
0x04	VORTEX
0x05	RANDOM
0x06	DRAG
0x07	CONVECTION
0x08	SPIN

Field Add Types

Value	Type
0x00	FIELDACCELERATION
0x01	BASEVELOCITY
0x02	FIELDVELOCITY

JPA Key Types

Value	Type
0x00	RATE
0x01	VOLUMESIZE
0x02	VOLUMESWEEP
0x03	VOLUMEMINIMUMRADIUS
0x04	LIVETIME
0x05	MOMENT
0x06	INITIALVELOCITYOMNIDIRECTIONAL (?)
0x07	INITIALVELOCITYAXIS
0x08	INITIALVELOCIRTDIRECTION
0x09	SPREAD
0x0A	SCALE

(Source: noclip.website source code)