Difference between revisions of "Sonic Jam/Textures"
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Texture Definitions start at $250A4 in MUSEUM.MUS. | Texture Definitions start at $250A4 in MUSEUM.MUS. | ||
| − | These are basically a set of data, each 8 bytes long, that defines a texture. Here's its format: | + | These are basically a set of data, each 8 bytes long, that defines a texture. Pattern Addresses and Color Lookup Table addresses are in VDP1 Memory. |
| + | |||
| + | Here's its format: | ||
{|class="prettytable" style="width:auto;" | {|class="prettytable" style="width:auto;" | ||
! Description||Size | ! Description||Size | ||
|- | |- | ||
| − | | | + | | Pattern Address / 8 || word |
|- | |- | ||
| Width / 8 || byte | | Width / 8 || byte | ||
| Line 15: | Line 17: | ||
| Height || byte | | Height || byte | ||
|- | |- | ||
| − | | | + | | Color Lookup Table Address / 8 || word |
|- | |- | ||
| − | | | + | | Pattern Address / 8 (again?) || word |
|} | |} | ||
| + | |||
| + | For any who are savvy in VDP1 commands, this lines up with part of a Texture Draw command; the first word is CMDSRCA, the second is CMDSIZE, and the third is CMDCOLR. | ||
==Texture Patterns== | ==Texture Patterns== | ||
| Line 34: | Line 38: | ||
This part needs some serious work; I'm not very sure about how this stuff works yet. | This part needs some serious work; I'm not very sure about how this stuff works yet. | ||
| − | If bit $8000 is set, the color seems to be defined in RGB mode. Bits $4000-$0400 are blue, bits $0200-20 are green, and bits $10-$1 are red. | + | If bit $8000 is set, the color seems to be defined in RGB mode. Bits $4000-$0400 are blue, bits $0200-$20 are green, and bits $10-$1 are red. |
If bit $8000 is not set, then something else seems to happen. | If bit $8000 is not set, then something else seems to happen. | ||
Latest revision as of 09:32, 19 February 2021
| SCHG: Sonic Jam |
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| Main Article |
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Texture Definitions
Texture Definitions start at $250A4 in MUSEUM.MUS.
These are basically a set of data, each 8 bytes long, that defines a texture. Pattern Addresses and Color Lookup Table addresses are in VDP1 Memory.
Here's its format:
| Description | Size |
|---|---|
| Pattern Address / 8 | word |
| Width / 8 | byte |
| Height | byte |
| Color Lookup Table Address / 8 | word |
| Pattern Address / 8 (again?) | word |
For any who are savvy in VDP1 commands, this lines up with part of a Texture Draw command; the first word is CMDSRCA, the second is CMDSIZE, and the third is CMDCOLR.
Texture Patterns
Texture Pattern Data starts at $1AFC0 in SPRDATA.MUS.
Texture patterns are a string of data, wherein every 4 bits is one pixel. This of course means that you are limited to the 16 colors defined in this texture's color lookup table. The value of the 4 bits determines which color is used, with a value of $0 meaning the first color in the table is used, and a value of $F meaning the last color in the table is used.
The Saturn is capable of having different pattern modes; There's an 8 bits per-pixel mode, and a 16 bits per-pixel mode; It's yet to be confirmed if any of these textures use that.
Color Lookup Tables
Color Lookup Table Data starts at $0AFC0 in SPRDATA.MUS.
Each table is 32 bytes. Every word defines a single color.
This part needs some serious work; I'm not very sure about how this stuff works yet.
If bit $8000 is set, the color seems to be defined in RGB mode. Bits $4000-$0400 are blue, bits $0200-$20 are green, and bits $10-$1 are red.
If bit $8000 is not set, then something else seems to happen.