BMD/BDL (File Format)

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BMD (Binary Model) and BDL (Binary Display List) are two 3D model formats used in Super Mario Galaxy and Super Mario Galaxy 2, among a few other Wii and GameCube games, such as Super Mario Sunshine.

These two formats hold the same data, except BDL contains an additional set of data which is used for faster rendering speeds.

Super Mario Galaxy & Super Mario Galaxy 2 contain J3DLoader versions 21 and 26.

File Header

Offset	Type	Description
0x00	String	The magic that tells the game which format this file is. (ASCII) J3D2bmd2 for BMD (J3DLoader V21) J3D2bmd3 for BMD (J3DLoader v26) J3D2bdl4 for BDL (J3DLoader v26)
0x08	Int32	The total size of the file
0x0C	Int32	The number of chunks present in this file. 8 for BMD 9 for BDL

Subversion Header

This part of the header is not used, and can be anything.

Offset	Type	Description
0x00	String	A 4 character value representing the Subversion. Usually SVR3 for SMG/2.
0x04	Byte[12]	Twelve bytes of padding. Usually these are 0xFF

INF1 - Scene Information

The Information section hosts a hierarchy of Joints, Materials, and Shapes, which are used to render the model.

Offset	Type	Description
0x00	String	Always INF1 (ASCII)
0x04	Int32	The total size of this chunk
0x08	Int16	J3DLoader Flags
0x0A	Int16	Padding (0xFFFF)
0x0C	Int32	Matrix Group Count
0x10	Int32	Vertex Count Always equals the number of entries in the "POSITION" data buffer

J3DLoader Flags

The J3DLoader contains several flags which affect how models are handled. There are more than what are shown here, however, those must be applied by the game itself in the code.

Value	Description
0b0000000000000000	No flags applied (TODO: Check if this defaults to basic matrix calculation)
0b0000000000000001	Use Autodesk Softimage matrix calculation
0b0000000000000010	Use Autodesk Maya matrix calculation
0b0000000000000100	Use Basic matrix calculation
0b0000000000001000	UNKNOWN
0b0000000000010000	UseImmidiateMtx (needs research)
0b0000000000100000	UsePostTexMtx (needs research)
0b0000000001000000	UNKNOWN
0b0000000010000000	UNKNOWN
0b0000000100000000	NoMatrixTransform (needs research)
0b0000001000000000	UNKNOWN
0b0000010000000000	UNKNOWN
0b0000100000000000	UNKNOWN
0b0001000000000000	UNKNOWN
0b0010000000000000	DoBdlMaterialCalc
0b0100000000000000	NoBdlMaterialPatch - If set, skips the call to J3DModelLoader::readPatchedMaterial.
0b1000000000000000	UNKNOWN

For all BMD files, the game always includes load flags Material_PE_Full, Material_UseIndirect, UseUniqueMaterials, and UNKNOWN_21.
For all BDL files, the game always includes load flags Material_UseIndirect, and UseUniqueMaterials.

> Note: Changing the load flags by changing the code doesn't seem to do much.

VTX1 - Vertex Data

The Vertex Data section contains the actual number values used for the properties of the geometry. It also includes the information on how the values are formatted.

Offset	Type	Description
0x00	String	Always VTX1 (ASCII)
0x04	Int32	The total size of this chunk
0x08	Int32	Buffer Format list offset
0x0C	Int32	"POSITION" data buffer offset 0 if not used.
0x10	Int32	"NORMAL" data buffer offset 0 if not used.
0x14	Int32	"TANGENT" data buffer offset 0 if not used.
0x18	Int32	"COLOR_0" data buffer offset 0 if not used.
0x1C	Int32	"COLOR_1" data buffer offset 0 if not used.
0x20	Int32	"TEXCOORD_0" data buffer offset 0 if not used.
0x24	Int32	"TEXCOORD_1" data buffer offset 0 if not used.
0x28	Int32	"TEXCOORD_2" data buffer offset 0 if not used.
0x2C	Int32	"TEXCOORD_3" data buffer offset 0 if not used.
0x30	Int32	"TEXCOORD_4" data buffer offset 0 if not used.
0x34	Int32	"TEXCOORD_5" data buffer offset 0 if not used.
0x38	Int32	"TEXCOORD_6" data buffer offset 0 if not used.
0x3C	Int32	"TEXCOORD_7" data buffer offset 0 if not used.

Buffer Formats

Each of the Buffers in this section have a format descriptor. This allows different types of data storage, allowing for smaller files.

Each format descriptor contains an Attribute Target, a Component Count, a Data Type, and a Mantissa shifter (to allow floats to be stored as smaller datatypes compared to FLOAT).
Only one descriptor can exist for each attribute.

The Attribute Target tells the game what this buffer is used for.

Attribute Targets

Value	Name	Description
0x00000009	POSITION	This buffer represents the positions of vertices in the model. Basically required for all visual models.
0x0000000A	NORMAL	This buffer represents vertex normals, used for the engine's vertex shading. Not needed if no material requires it.
0x0000000B	COLOR_0	This buffer is available for Vertex Colors.
0x0000000C	COLOR_1	This buffer is available for Vertex Colors.
0x0000000D	TEXCOORD_0	This buffer is available for Texture Coordinates.
0x0000000E	TEXCOORD_1	This buffer is available for Texture Coordinates.
0x0000000F	TEXCOORD_2	This buffer is available for Texture Coordinates.
0x00000010	TEXCOORD_3	This buffer is available for Texture Coordinates.
0x00000011	TEXCOORD_4	This buffer is available for Texture Coordinates.
0x00000012	TEXCOORD_5	This buffer is available for Texture Coordinates.
0x00000013	TEXCOORD_6	This buffer is available for Texture Coordinates.
0x00000014	TEXCOORD_7	This buffer is available for Texture Coordinates.
0x00000019	TANGENT	Currently unknown exactly what goes in here.
0x000000FF	List End	A buffer using this target will end the descriptor list.

The component count tells the game how many parts of the component that there are. Note that the values are considered based on the attribute target they're assigned to.

Component Count

Value	Name	Description
0x00000000	POSITION_XY	Unknown
0x00000001	POSITION_XYZ	Represents a position in 3D space with 3 values: X, Y, and Z.
0x00000000	NORMAL_XYZ	Represents a normal vector in 3D space with 3 values: X, Y, and Z.
0x00000001	NORMAL_NBT	Unknown
0x00000002	NORMAL_NBT3	Unknown
0x00000000	COLOR_RGB	Represents a color value with only Red, Green, and Blue values.
0x00000001	COLOR_RGBA	Represents a color value with Red, Green, Blue, and Alpha values.
0x00000000	TEXCOORD_S	Unknown
0x00000001	TEXCOORD_ST	Represents a UV texture coordinate with 2 values: X and Y.

The Data Type tells the game how many bytes each value is, in the sense that an Int32 is 4 bytes, a Int16 is 2 bytes, a Float is 4 bytes, etc.
Note that the Color values have a different set of options.

Data Types

Value	Name	Description
0x00000000	UInt8	1 byte per value (0 to 255)
0x00000001	Int8	1 byte per value (-128 to 127)
0x00000002	UInt16	2 bytes per value (0 to 65535)
0x00000003	Int16	2 bytes per value (-32,768 to 32,767)
0x00000004	Float	4 bytes per value
0x00000000	RGB565	2 bytes per color
0x00000001	RGB8	3 bytes per color
0x00000002	RGBX8	3 bytes per color
0x00000003	RGBA4	2 bytes per color
0x00000004	RGBA6	4 bytes per color
0x00000005	RGBA8	4 bytes per color

> Note: Both games require colors to be 4 bytes wide at all times, so changing from RGBA8 is worthless.

EVP1 - Skinning Envelopes

Offset	Type	Description
0x00	String	Always EVP1 (ASCII)
0x04	Int32	The total size of this chunk
0x08	Int16	The number of Envelopes stored.
0x0A	Int16	Padding (0xFFFF)
0x0C	Int32	"Joint Count" list offset
0x10	Int32	"'Joint Count' list index" list offset
0x14	Int32	"Joint Weight" list offset
0x18	Int32	"Inverse Bind Matrices" list offset

JNT1 - Joint Hierarchy

The Joint Hierarchy section defines the rigging skeleton of a model. There can only be one skeleton per model.

Offset	Type	Description
0x00	String	Always JNT1 (ASCII)
0x04	Int32	The total size of this chunk
0x08	Int16	The number of Joints stored.
0x0A	Int16	Padding (0xFFFF)
0x0C	Int32	Joint Data table offset
0x10	Int32	Remap table offset
0x14	Int32	Name table offset

Joint Data

Each joint includes positional data and a bounding box which is used by the game for determining rendering range automatically.

Offset	Type	Description
0x00	Int16	Matrix Type
0x01	UInt8	Parent Scale inheritance 0 = Follow parent joint's scale 1 = Ignore parent joint's scale
0x02	UInt8	Padding (0xFF)
0x04	Float	Scale X
0x08	Float	Scale Y
0x0C	Float	Scale Z
0x10	Int16	Rotation X
0x12	Int16	Rotation Y
0x14	Int16	Rotation Z
0x16	Int16	Padding (0xFFFF)
0x18	Float	Translation X
0x1C	Float	Translation Y
0x20	Float	Translation Z
0x24	Float	Bounding Sphere Should encapsulate all vertices that the joint affects
0x28	Float	Bounding Box Minimum X
0x2C	Float	Bounding Box Minimum Y
0x30	Float	Bounding Box Minimum Z
0x34	Float	Bounding Box Maximum X
0x38	Float	Bounding Box Maximum Y
0x3C	Float	Bounding Box Maximum Z

Rotation is stored between -0x7FFF and 0x7FFF, which ranges -180 degrees and 180 degrees.

SHP1 - Shape Information

The Shape Information section determines how to use the data in the VTX1 section to create shapes.

Offset	Type	Description
0x00	String	Always SHP1 (ASCII)
0x04	Int32	The total size of this chunk
0x08	Int16	The number of Shapes stored.
0x0A	Int16	Padding (0xFFFF)
0x0C	Int32	Shape Data table offset
0x10	Int32	Remap table offset
0x14	Int32	Name table offset (Generally not used, and thus set to 0)
0x18	Int32	"Vertex Attribute table" offset
0x1C	Int32	"Weight Matrix data table" offset
0x20	Int32	"GXDisplayList data buffer" offset
0x24	Int32	"Weight Matrix group table" offset (entry count must equal the entry count of the GXDisplayList group table)
0x28	Int32	"GXDisplayList group table" offset

Shape Data

Each shape denotes a Matrix Calculation type, which is used for Billboarding, as well as multi-joint skinning.
A shape also contains a group of GXDisplayList primitives, and can have multiple groups if the geometry needs to be weighted to more than 10 DRW1 matrices.

TODO: Figure out what happens in the event that more than 10 are needed. Is it just straight up not allowed?

Offset	Type	Description
0x00	UInt8	Matrix Type
0x01	UInt8	Padding (0xFF)
0x02	Int16	"GXDisplayList group" count
0x04	Int16	Vertex Attribute offset
0x06	Int16	First "Weight Matrix group table" index
0x08	Int16	First "GXDisplayList group" index
0x0A	Int16	Padding (0xFFFF)
0x0C	Float	Bounding Sphere
0x10	Float	Bounding Box Minimum X
0x14	Float	Bounding Box Minimum Y
0x18	Float	Bounding Box Minimum Z
0x1C	Float	Bounding Box Maximum X
0x20	Float	Bounding Box Maximum Y
0x24	Float	Bounding Box Maximum Z

MAT2 - Material List (Old)

Technically supported by the game, but not known to be used by any model.