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Mother 3/SOB block: Difference between revisions
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{{subpage|game=Mother 3}} | |||
==Overview== | ==Overview== | ||
SOB blocks are used for storing sprite arrangement data. They're organized of tables that are two levels deep. They need to be manually associated with a valid tileset and palette group. | SOB blocks are used for storing sprite arrangement data. They're organized of tables that are two levels deep. They need to be manually associated with a valid tileset and palette group. | ||
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===Offset table=== | ===Offset table=== | ||
The offset table contains offsets for both the primary and secondary entries. The secondary entry offsets immediately succeed the primary entry offsets. Each offset is 16 bits, and is calculated relative to the start of the table (including the header). | The offset table contains offsets for both the primary and secondary entries. The secondary entry offsets immediately succeed the primary entry offsets. Each offset is 16 bits (unsigned), and is calculated relative to the start of the table (including the header). | ||
==Primary entries== | ==Primary entries== | ||
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===Primary entry format=== | ===Primary entry format=== | ||
* <tt> | * <tt>02 bytes</tt> = Preamble count; let '''x1 = (preamble count * 8)''' | ||
* <tt>02 | * <tt>x1 bytes</tt> = Preamble | ||
* <tt> | * <tt>02 bytes</tt> = Number of OAM sprites in this entry; let '''x2 = (sprite count * 8)''' | ||
* <tt>x2 bytes</tt> = OAM entries | |||
The OAM entries follow the same format as the standard [http:// | The preamble is ''usually'' not present, but the game does still check for it (e.g. $808866A when showing an OAM-based battle animation) and adjust the starting offset of the OAM data accordingly. The format of the preamble is currently unknown. | ||
The OAM entries follow the same format as the standard [http://problemkaputt.de/gbatek.htm#lcdobjoamattributes GBA OAM data]. Each entry uses 8 bytes. | |||
Typically in MOTHER 3, a picture will be composed of many sprites; for example, the NK Cyborg picture is composed of six large sprites, so its primary entry will have 6 OAM sprites. Since the OAM entries store coordinate information, one can easily piece together a full picture from the OAM data, tileset and palette data alone. | Typically in MOTHER 3, a picture will be composed of many sprites; for example, the NK Cyborg picture is composed of six large sprites, so its primary entry will have 6 OAM sprites. Since the OAM entries store coordinate information, one can easily piece together a full picture from the OAM data, tileset and palette data alone. | ||
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It is not known how secondary entries function. There are typically much fewer secondary entries than primary entries. | It is not known how secondary entries function. There are typically much fewer secondary entries than primary entries. | ||
[[Category: | ===Secondary entry format=== | ||
[[Category: | * <tt>02 bytes</tt> = Byte count; let '''x1 = Byte count''' | ||
* <tt>02 bytes</tt> = Entry count | |||
* <tt>x1 bytes</tt> = Effective secondary entries. They seem to be 4 bytes long | |||
[[Category:Mother 3 named data structures|SOB]] | |||
[[Category:Mother 3|SOB]] | |||
Latest revision as of 02:21, 20 May 2024
This is a sub-page of Mother 3.
Overview
SOB blocks are used for storing sprite arrangement data. They're organized of tables that are two levels deep. They need to be manually associated with a valid tileset and palette group.
Format
- 00-03 (04) = "sob " header
- 04-05 (02) = Number of primary entries
- 06-07 (02) = Number of secondary entries
- 08-.. (..) = Offset table
- ..-.. (..) = Primary entries
- ..-.. (..) = Secondary entries
- ..-.. (04) = "~sob" footer
Offset table
The offset table contains offsets for both the primary and secondary entries. The secondary entry offsets immediately succeed the primary entry offsets. Each offset is 16 bits (unsigned), and is calculated relative to the start of the table (including the header).
Primary entries
The primary entries contain sprite arrangement data.
Primary entry format
- 02 bytes = Preamble count; let x1 = (preamble count * 8)
- x1 bytes = Preamble
- 02 bytes = Number of OAM sprites in this entry; let x2 = (sprite count * 8)
- x2 bytes = OAM entries
The preamble is usually not present, but the game does still check for it (e.g. $808866A when showing an OAM-based battle animation) and adjust the starting offset of the OAM data accordingly. The format of the preamble is currently unknown.
The OAM entries follow the same format as the standard GBA OAM data. Each entry uses 8 bytes.
Typically in MOTHER 3, a picture will be composed of many sprites; for example, the NK Cyborg picture is composed of six large sprites, so its primary entry will have 6 OAM sprites. Since the OAM entries store coordinate information, one can easily piece together a full picture from the OAM data, tileset and palette data alone.
Secondary entries
It is not known how secondary entries function. There are typically much fewer secondary entries than primary entries.
Secondary entry format
- 02 bytes = Byte count; let x1 = Byte count
- 02 bytes = Entry count
- x1 bytes = Effective secondary entries. They seem to be 4 bytes long