Difference between revisions of "AGI/Specifications/Other"

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→‎Fan-Made Extensions: -- move to separate page
m (→‎External links: update link here too :P)
(→‎Fan-Made Extensions: -- move to separate page)
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<span id="Extensions"></span>
<span id="Extensions"></span>
=Fan-Made Extensions=
==AGIPAL==
AGIPAL uses the [[AGI/Specifications/Logic#Other_commands | shake.screen]] command to call an external file which changes the palette. The range of palette files is 100-109.
<syntax type="C++">
shake.screen(101)
</syntax>
That command would use the palette in pal.101, instead of shaking the screen 101 times under the AGIPAL interpreter.
===pal.* Format===
There are always eight 24-byte chunks, so the file is always 192 bytes.
<pre>
Chunk0 Holds RGB palette data for the first 8 colors (R0, G0, B0, R1, G1, B1, R2, G2, B2, ...)
Chunk1 Same as Chunk0
Chunk2 Holds RGB palette data for the second 8 colors (R8, G8, B8, R9, G9, B9, R10, G10, B10, ...)
Chunk3 Same as Chunk2
Chunk4-Chunk7 Same as Chunk0-Chunk3
</pre>
Because VGA used 18-bit colors (i.e. 6 bits per color component) only the lowest 6 bits of each color component are actually used
(i.e. the topmost two bits of each color component byte are simply discarded).
==AGI256==
AGI256 is a hack to AGI interpreter v2.936 to add 256-color picture resource support.
The AGI256 hack was originally made by Dark Minister.
AGI256 uses the [[AGI/Specifications/Logic#Other_commands_2 | unknown170(n)]]
a.k.a. set.simple(n) command to load 256-color picture resources.
The parameter n is the variable's number that holds the picture resource's number.
Example of use:
<syntax type="C++">
v123 = 10
unknown170(v123)
</syntax>
That would load the picture resource number 10 as a 256-color picture resource.
Any variable can be used with unknown170, v123 was just chosen for this example.
===256-color picture resource format===
<pre>
Data    : Simply a raw 256-color 160x168 size picture, one byte per pixel.
Length  : Always 160*168*1 = 26880 bytes.
Palette : Isn't saved in the file. Uses the default VGA palette.
</pre>
As AGI256 was hacked to a v2.936 AGI interpreter no compression is used on
the picture resource data (Only v3 AGI interpreters use compression).
===Implementation details===
See the [[AGI/Specifications/Other/AGI256/Implementation_Details | AGI256 Implementation Details]] page.
===External links===
[http://agisci.classicgaming.gamespy.com/agi256.shtml How to use AGI256]<br>
[http://dl.fileplanet.com/dl/dl.asp?ClassicGaming/agisci/agi-256c.zip The AGI256 demo]<br>
[http://agisci.classicgaming.gamespy.com/agiutil.shtml#PictureTools AGI Picture Tools (Some support AGI256)]<br>
[http://agisci.classicgaming.gamespy.com/txt/unknown.txt An example of unknown170 command use]<br>
[http://www.agidev.com/download/#cat4 Sierra's original v2.936 AGI interpreter (Among other things)]<br>
[http://en.wikipedia.org/wiki/Video_Graphics_Array#The_VGA_color_palette The default VGA palette]
==AGI256-2==
AGI256-2 is an extension to AGI256 to further add 256-color view support.
The AGI256-2 hack was originally made by Brian Provinciano.
AGI256-2 uses a modified cel blitting routine so that it can handle view data
that isn't run length encoded and has 256 colors.
AGI256-2 uses the same palette as AGI256 i.e. the default VGA palette.
===256-color view resource format===
Like the v2 AGI [[AGI/Specifications/View#VIEW_resources | view resources]] but with the following differences:
* [[AGI/Specifications/View#View_header_.287.2B_bytes.29 | View header]] starts with bytes 0x0F, 0xF0
** Can be used for detecting 256-color view resources
* Doesn't support mirroring
** Transparency and cel mirroring byte in [[AGI/Specifications/View#Cel_header_.283_bytes.29 | cel header]] is used solely for choosing the transparent color
* Cel data is not run length encoded
** Cel data is raw 256-color data, one byte per pixel
*** NOTE though that 0x00 for a new line is still supported
===Implementation details===
See the [[AGI/Specifications/Other/AGI256-2/Implementation_Details | AGI256-2 Implementation Details]] page.
===External links===
[http://dl.fileplanet.com/dl/dl.asp?ClassicGaming/agisci/agi256-2.zip The AGI256-2 demo]<br>
[http://agisci.classicgaming.gamespy.com/agiutil.shtml#ViewTools AGI View Tools (Some support AGI256-2)]<br>
[http://en.wikipedia.org/wiki/Video_Graphics_Array#The_VGA_color_palette The default VGA palette]<br>

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