BAM file format
Applies to:
BG1EE, BG2EE
General Description
This file format describes animated graphics. Such files are used for animations (both creature animations, item and spell animations) and interactive GUI elements (e.g. buttons) and for logical collections of images (e.g. fonts). BAM files can contain multiple sequences of animations, up to a limit of 255.
NB. While the BAM format allows the dimensions of a frame to be very large, the engine will only show frames up to a certain size. This maximum size varies with the version of the engine:
Cycles may share the frames, which is accomplished by using a layer of indirection. Instead of specifying which frames belong to a given cycle, each cycle has a list of frame indices.
These entries refer to a range of indices in the frame entries table.
NB. While the BAM format allows the dimensions of a frame to be very large, the engine will only show frames up to a certain size. This maximum size varies with the version of the engine:
BG1: Unknown
BG2: 256*256
PST: Unknown (greater than 256*256)
IWD1: Unknown
IWD2: Unknown
BG2: 256*256
PST: Unknown (greater than 256*256)
IWD1: Unknown
IWD2: Unknown
Detailed Description
| Offset | Size (data type) | Description |
|---|---|---|
| 0x0000 | 4 (char array) | Signature ('BAM ') |
| 0x0004 | 4 (char array) | Version ('V2 ') |
| 0x0008 | 4 (dword) | Count of frame entries |
| 0x000c | 4 (dword) | Count of cycle entries |
| 0x0010 | 4 (dword) | Count of data blocks |
| 0x0014 | 4 (dword) | Offset (from start of file) to frame entries |
| 0x0018 | 4 (dword) | Offset (from start of file) to cycle entries |
| 0x001c | 4 (dword) | Offset (from start of file) to data blocks |
Cycles may share the frames, which is accomplished by using a layer of indirection. Instead of specifying which frames belong to a given cycle, each cycle has a list of frame indices.
| Offset | Size (data type) | Description |
|---|---|---|
| 0x0000 | 2 (word) | Frame width |
| 0x0002 | 2 (word) | Frame height |
| 0x0004 | 2 (signed word) | Frame center X coordinate |
| 0x0006 | 2 (signed word) | Frame center Y coordinate |
| 0x0008 | 2 (word) | Start index of data blocks |
| 0x000a | 2 (word) | Count of data blocks |
These entries refer to a range of indices in the frame entries table.
| Offset | Size (data type) | Description |
|---|---|---|
| 0x0000 | 2 (word) | Count of frame entries in this cycle |
| 0x0002 | 2 (word) | Start index of frame entries in this cycle |
| Offset | Size (data type) | Description |
|---|---|---|
| 0x0000 | 4 (dword) | PVRZ page Refers to MOSxxxx.PVRZ files, where xxxx is a zero-padded four-digits decimal number. |
| 0x0004 | 4 (dword) | Source x coordinate |
| 0x0008 | 4 (dword) | Source y coordinate |
| 0x000c | 4 (dword) | Width |
| 0x0010 | 4 (dword) | Height |
| 0x0014 | 4 (dword) | Target x coordinate |
| 0x0018 | 4 (dword) | Target y coordinate |