[ scummvm-Bugs-2818883 ] AGI: Incorrect CGA palette

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Bugs item #2818883, was opened at 2009-07-09 09:37
Message generated for change (Tracker Item Submitted) made by charliix
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Category: Graphics
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Charlii (charliix)
Assigned to: Nobody/Anonymous (nobody)
Summary: AGI: Incorrect CGA palette

Initial Comment:
Most AGI games (KQ1-3 and Larry 1 for sure) used two different sets of CGA graphics that could be switched during runtime. The first was a composite mode, 640*200 monochrome, made for computers with a composite NTSC monitor. The black and white pattern was mistaken for color information by the monitor, enabling the use of 16 colors even though standard CGA-cards only supported 4 colors to be used at any given time. The second mode was the RGB-mode, 320*200 4-colors, for people with RGB monitors. In this mode extra dithering was applied to simulate more colors. 
These palettes, and how they looked on different monitors, can be seen here: http://en.wikipedia.org/wiki/File:KQ_CompVsRGB.png
When selecting the CGA render mode in ScummVM, the game is started in composite-mode but rendered as 320*160 4-color using CGA palette 1. This results in graphics that would never have been seen on any computer back when the game was launched. My suggestion is that you force the game to switch to RGB graphics (and change the palette accordingly) which would give a correct representation of one of the modes with very little work. It would of course be awesome if you could implement composite monitor simulation and runtime switching of the graphic modes, but I guess that would be overdoing it slightly. DOSbox is better for that kind of tinkering anyway...

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