FSCN (File Format)

Under Construction

This article is not finished. Help improve it by adding accurate information or correcting grammar and spelling.

The FSCN (caFe SCeNe animation) subfile stores scene animations controlling fog, light and camera settings. It appears as a subfile of a BFRES file in the 10th index group. Unless otherwise noted, all offsets in the file are relative to themselves.

Format

An FSCN file begins with an FSCN header. This is then followed by a number of sections pointed to by the header, many of which can occur multiple times. The purpose of these sections is described in the table below.

FSCN shares many similarities with the FSKA, FSHU, FTXP, FVIS and FSHA subfiles, which mostly only differ in the structure describing what is changed by animations over time, but reusing the same animation curve and key structures, and even headers being very similar to one another.

Header (FSCN)

Every FSCN begins with an 0x24 byte FSCN header. Beyond the general subfile fields it stores the entry number and location of Camera, Fog and Light Animation index groups.

Offset	Size	Type	Description
0x00	4	Char[4]	"FSCN" file identifier, ASCII string.
0x04	4	Int32	File name offset (without file extension).
0x08	4	Int32	File path offset, the path of the file this data was originally created from. Stripped in Mario Kart 8 files, always pointing to an empty string at the end of the BFRES string table.
0x0C	2	UInt16	User Data entry count.
0x0E	2	UInt16	Camera Animation count, the number of elements in the Camera Animation index group.
0x10	2	UInt16	Light Animation count, the number of elements in the Light Animation index group.
0x12	2	UInt16	Fog Animation count, the number of elements in the Fog Animation index group
0x14	4	Int32	Camera Animation index group offset.
0x18	4	Int32	Light Animation index group offset.
0x1C	4	Int32	Fog Animation index group offset.
0x20	4	Int32	User Data index group offset.
0x24	End of FSCN header

Camera Animation (FCAM)

A Camera Animation can modify visual parameters which control the cameera parameters like the field of view, aspect ratio, position, rotation or clipping planes. The header is of 0x24 bytes size.

Offset	Size	Type	Description
0x00	4	Char[4]	"FCAM" section identifier, ASCII string.
0x04	2	UInt16	Flags. Set of bits packed as xxxxxPxR xxxxxLxB, controlling how to play the animation and what data is stored. The following flags are possible: B determines whether curve data is baked; baked if set. L determines whether the animation is looping; looping if set. R determines whether an Euler ZXY rotation (bit set) is stored or an aim direction (bit unset). P determines whether a perspective projection (bit set) or orthographic projection is used (bit unset).
0x06	2	—	Padding.
0x08	4	Int32	Frame count.
0x0C	1	Byte	Curve count, the number of elements in the Curve array.
0x0D	1	—	Padding.
0x0E	2	UInt16	User Data entry count (for this section).
0x10	4	UInt32	Baked length.
0x14	4	Int32	Name offset of this animation.
0x18	4	Int32	Curve array offset.
0x1C	4	Int32	Base Value offset.
0x20	4	Int32	User Data index group offset (for this section).
0x24	End of Camera Animation (FCAM)

Base Value (Camera Animation Result)

The Camera Animation header points to a Camera Animation Result structure of 0x2C bytes size. It apparently stores the initial state of the camera.

Offset	Size	Type	Description
0x00	4	Single	Near clipping plane distance. Polygons closer to the camera than this distance are not drawn.
0x04	4	Single	Far clipping plane distance. Polygons further away to the camera than this distance are not drawn.
0x08	4	Single	Aspect ratio of the projected world.
0x0C	4	Single	Height offset of the camera or Field of View angle.
0x10	12	Single[3]	Position of the camera.
0x1C	12	Single[3]	Rotation (aim direction) of the camera.
0x28	4	Single	Twist of the camera.
0x2C	End of Base Value (Camera Animation Result)

Light Animation (FLIT)

A Light Animation can modify light parameters like light type, intensity or attenuation. The header is of 0x30 bytes size.

Offset	Size	Type	Description
0x00	4	Char[4]	"FLIT" section identifier, ASCII string.
0x04	2	UInt16	Flags. Set of bits packed as PPPPPPPC xxxxxLxB, controlling how to play the animation and what data is stored. The following flags are possible: B determines whether curve data is baked; baked if set. L determines whether the animation is looping; looping if set. C determines whether the curve is enabled. PPPPPPP are combinable flags with following meaning: Value Description 1 Enable Light 2 Position 4 Rotation / Direction 8 Distance Attenuation 16 Angle Attenuation 32 First Color 64 Second Color
0x06	2	UInt16	User Data entry count (for this section).
0x08	4	Int32	Frame count.
0x0C	1	Byte	Curve count, the number of elements in the Curve array.
0x0D	1	SByte	Light type, determining what kind of light source is simulated.
0x0E	1	SByte	Distance Attenuation function index.
0x0F	1	SByte	Angle Attenuation function index.
0x10	4	UInt32	Baked length.
0x14	4	Int32	Name offset of this animation.
0x18	4	Int32	Light type name offset.
0x1C	4	Int32	Distance Attenuation function name offset.
0x20	4	Int32	Angle Attenuation function name offset.
0x24	4	Int32	Curve array offset.
0x28	4	Int32	Base Value offset.
0x2C	4	Int32	User Data index group offset (for this section).
0x30	End of Light Animation (FLIT)

Base Value (Light Animation Result)

The Light Animation header points to a Light Animation Result structure of max. 0x44 bytes size. Only the elements appearing in the Flags are stored, in the order as follows. It apparently stores the initial state of the light.

Size	Type	Description
4	Int32	Enable the light or disable it.
12	Single[3]	Position of the light.
12	Single[3]	Rotation (aim direction) of the light.
8	Single[2]	Distance Attenuation.
8	Single[2]	Angle Attenuation.
12	Single[3]	First color, stored as an RGB floating point vector.
12	Single[3]	Second color, stored as an RGB floating point vector.
End of Base Value (Light Animation Result)

Fog Animation (FFOG)

A Fog Animation can modify fog parameters like distance or color. The header is of 0x30 bytes size.

Offset	Size	Type	Description
0x00	4	Char[4]	"FFOG" section identifier, ASCII string.
0x04	2	UInt16	Flags. Set of bits packed as xxxxxxxx xxxxxLxB, controlling how to play the animation and what data is stored. The following flags are possible: B determines whether curve data is baked; baked if set. L determines whether the animation is looping; looping if set.
0x06	2	—	Padding.
0x08	4	Int32	Frame count.
0x0C	1	Byte	Curve count, the number of elements in the Curve array.
0x0D	1	Byte	Distance Attenuation function index.
0x0E	2	UInt16	User Data entry count (for this section).
0x10	4	UInt32	Baked length.
0x14	4	Int32	Name offset of this animation.
0x18	4	Int32	Distance Attenuation function name offset.
0x24	4	Int32	Curve array offset.
0x28	4	Int32	Base Value offset.
0x2C	4	Int32	User Data index group offset (for this section).
0x30	End of Fog Animation (FFOG)

Base Value (Fog Animation Result)

The Fog Animation header points to a Fog Animation Result structure of 0x14 bytes size. It apparently stores the initial state of the fog.

Offset	Size	Type	Description
0x00	8	Single[2]	Distance Attenuation.
0x08	12	Single[3]	Color of the fog.
0x14	End of Base Value (Fog Animation Result)

Curve

Curves store how animations are performed over time and store the required keys and values for this. They appear in multiple animation subfiles, and their header is of 0x24 bytes size (for BFRES versions earlier than 3.4.0.0, they are of 0x20 bytes size).

Offset	Size	Type	Description
0x00	2	UInt16	Flags. Sets of bits packed as xxxxxxxx xCCCKKFF. FF determines the data type of frames in the Frame array. Value Size Type 0 4 Single 1 2 16-bit fixed point value (1 bit sign, 10 bits integral and 5 bits fractional). To convert to Single, use Float(x) / (1 << 5). To retrieve from Single, use Round(x * (1 << 5)) 2 1 Byte KK determines the data type of keys in the Key array. Value Size Type 0 4 Single 1 2 Int16 2 1 SByte CCC determines what kind of curve data is stored, resulting in a different number of elements stored per Key. They are used to set the key values and control the interpolation from one key to the next. Value Description Elements per Key 0 Cubic Single 4 (hermite interpolation) 1 Linear Single 2 (linear interpolation) 2 Baked Single 1 (no interpolation) 4 Step Integer 1 (no interpolation) 5 Baked Integer 1 (no interpolation) 6 Step Boolean 1 (no interpolation) 7 Baked Boolean 1 (no interpolation)
0x02	2	UInt16	Key count.
0x04	4	UInt32	Target Offset, an offset in bytes into the corresponding Animation Data structure to animate the field at that relative address.
0x08	4	Single	Start frame, the first frame at which a key is placed.
0x0C	4	Single	End frame, the last frame at which a key is placed.
0x10	4	Int32 / Single	Data scale, multiplier to the raw key values to get the final result. Together with Data offset, it is chosen carefully to consider an optimal granularity between the stored values.
0x14	4	Single	Data offset, added to the raw values (after multiplying them with Data scale) to get the final key value.
if BFRES version >= 3.4.0.0
0x18	4	Single	Data delta, stores the difference between the first and last key value.
0x1C	4	Int32	Frame array offset.
0x20	4	Int32	Key array offset.
0x24	End of Curve
else
0x18	4	Int32	Frame array offset.
0x1C	4	Int32	Key array offset.
0x20	End of Curve

Frames

The Curve header points to a Frame array which stores values controlling at which frame a Key from the Key array is placed. Thus, the array has as many elements as specified in Key count. The data type of the frames is given in the Curve's Flags.

The end of the array is aligned to 4 bytes.

Keys

The Curve header points to a Key array which stores the key values and additional values to interpolate the curve from one point to the next. Thus, the array has as many elements as specified in Key count, multiplied by the number of elements stored per key (depending upon the CCC Curve Type bits in the Curve Flags as described above). The data type of each element is given by the KK Key Type bits in the Curve Flags.

The end of the array is aligned to 4 bytes.

Step Curves

The elements apparently represent the key values directly.

Linear Curves

For linearly interpolated curves, 2 elements are stored per key:

1. Value at which the key is set. To get the final value, scale and then offset it.
2. Delta to value at next frame to which the curve linearly runs. To get the final value, scale it. If there is no next frame, this is always 0.

A key can be discarded by the next key if that one is stored at the same frame. In that case, only the value of the next key is stored, and the delta of the previous key is adjusted to run to the value of the now discarded key.

This example curve's keys are stored as SByte elements. The curve scale was computed as 2, the offset as 200 and the curve delta (if available in the BFRES version) as 300. Due to the lower key in frame 20 being discarded in favor of the higher key, only 3 keys are stored in 6 elements as follows.

Point	Array Index	Raw Value	*2 (Scale)	+200 (Offset)	Notes
0,0	0	-100	-200	0	Initial key with value 0.
(20,254)	1	127	254	-	Delta to end value of initial key at next frame.
20,254	-	-	-	-	This key is discarded in favor of the next.
20,400	2	100	200	400	Overrides previous key.
(30,300)	3	-50	-100	-	End value of overriding key at next frame.
30,300	4	50	100	300	Value of fourth (but third stored) key.
(end)	5	0	0	-	Since no frame follows, always 0.

Hermite Curves

For hermite curves, 4 elements are stored for each key. It is unclear how to exactly interprete them to form the curve out of it.

Target

The Curve targets which control what exactly is animated over time are not yet known.