ml
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Palettes
The engine uses a graphic mode with 256 colors per pixel. The graphic resources (images and videos) use bitmaps together with palette information to resolve a pixel value (1 byte) to the corresponding RGB value (3x1 byte).
Depending on the game-state, different palettes are in use. The splash screens at the beginning are created using a
Private Palette (see the bitmap format). Cutscenes have their own palette(s) and during the game,
one specific palette is used throughout. This game palette is stored in gamepal.res.
Format
Palettes always have a size of 768 bytes, for 256 colors with 1 byte for each of the three colour channels.
Palette (768 bytes)
0000 [256*3]byte RGB values
Transparency
Palette index 0 is used as a marker for fully transparent pixel. For instance, various decoration or critter sprites need to have transparent areas in order to lose the rectangular shape.
Pixel Animation / Palette Looping
During the game various textures can be observed with small animations. Most typically seen with LED-like blinking effects. Instead of implementing this with multiple frames, the engine simply loops through the colors within a few groups.
The following groups (palette index values) are looped:
0x03 - 0x07: Changed every ~1200 msec
0x0B - 0x0F: Changed every ~700 msec
0x10 - 0x14: Changed every ~360 msec
0x15 - 0x17: Changed every ~1800 msec
0x18 - 0x1A: Changed every ~1430 msec
0x1B - 0x1F: Changed every ~1080 msec
These groups are looped even while the game is paused.
Above switching times have been determined by counting frames of a video recording from dosbox, running within a VM. Exact values may be different.