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User:Buddha^/GSoC2007-ProjectDiary (view source)
Revision as of 23:37, 13 June 2007
, 23:37, 13 June 2007Added info on 2007-06-13's work.
(Added more info on 2007-06-12's work.) |
(Added info on 2007-06-13's work.) |
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After this I started looking into AGI256 & AGI256-2 related stuff because | After this I started looking into AGI256 & AGI256-2 related stuff because | ||
that's what's next! | that's what's next! | ||
== 2007-06-13 (Wednesday) - Started looking into AGI256 == | |||
Read some AGI specifications on the ScummVM wiki. Read some of the ScummVM's AGI engine code. | |||
Now I know that in the ScummVM's AGI engine the priorities ("Sort of a Z-buffer") are saved | |||
in the same buffer as the picture data (Each pixel's lower 4 bits give the picture data and | |||
upper 4 bits give the priority data). So that'll make it a bit more of an effort to support | |||
256 color images in the AGI engine. | |||
Also found that Ctrl-D brings up the debug console and that first 16 colors are for the | |||
EGA/Amigaish-palette and the next 16 colors are for the console's transparency | |||
(So you can still see the underlying game with the console window on top). We'll see | |||
what's to be done with those console transparency colors when we need to use the whole | |||
256 colors for the images' palette. Maybe map them through a table lookup to the static | |||
AGI256 256 color palette? | |||
Looked at the AGI 256 pictures' static palette with GIMP. There's a pattern in it. | |||
Here's my current theory on the subject: | |||
* AGI256 pictures' palette's structure: | |||
** First 16 colors are the default EGA palette. | |||
** Next 16 colors are greyscale colors from black to white. | |||
** Next 72 colors are probably a HSL/HSI (Or something like that) color sweep with full saturation and brightness. | |||
** Then the same color sweep as before but with less saturation and/or brightness. | |||
** And again the same color sweep as before but with even less saturation and/or brightness. | |||
** Last 8 colors are greyscale colors from low intensity grey to almost black. | |||
Also looked at differences in AGI.EXE between the original Sierra On-Line's | |||
AGI interpreter version 2.936 and the hacked AGI256 AGI.EXE. Used [http://hte.sourceforge.net/ HT editor] for that. | |||
Didn't learn much with that approach though. But then I took [http://en.wikipedia.org/wiki/Interactive_Disassembler Interactive Disassembler] | |||
Freeware v4.3 and started looking at AGI256's AGIGRAF.OVL file. | |||
Using IDA I got some info out of the AGIGRAF.OVL. Commented some of the functions in it. | |||
But without understanding what the functions are that are called from outside I can't understand it fully (AGIGRAF.OVL is like a DOS age DLL so it references functions that aren't in AGIGRAF.OVL | |||
but should be in memory when it's loaded into memory). | |||
* Some guesses for the function names from AGI256's AGIGRAF.OVL (*HIGHLY* preliminary and subject to change): | |||
** setVideoMode (320x200x256c) | |||
** setTextMode (40x25x16c) | |||
** showAgi256Pic? | |||
** calcHeightLUT | |||
*** Calculates table of y*320 values in range 0 <= y < 200 | |||
** setPalette? | |||
** readNextAgi256Pic? | |||
** readAgi256Pic? | |||
** setClrCurrPixel | |||
** setWhiteMenuBar | |||