Opened 8 years ago

Last modified 12 months ago

#4388 new defect

AGI: Incorrect CGA palette

Reported by: SF/charliix Owned by: sev-
Priority: normal Component: Engine: AGI
Keywords: Cc:


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:
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...

Ticket imported from: #2818883. Ticket imported from: bugs/4388.

Change History (5)

comment:1 Changed 8 years ago by sev-

Raising priority. This bug is nice to get fixed before the release.

comment:2 Changed 8 years ago by sev-

Owner: set to sev-
Priority: normalhigh

comment:3 Changed 8 years ago by sev-

Priority: highnormal

comment:4 Changed 8 years ago by sev-

Implementing this would be really nice, but glimpse into original showed that there is too much work to for making it before the release. Lowering priority.

comment:5 Changed 12 months ago by wjp

Component: Engine: AGI
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