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