Palettes: Difference between revisions
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[[File:Palmap.png|thumb]] | [[File:Palmap.png|thumb|Palette organisation]] | ||
There are 2 banks of 256 palettes | There are 2 banks (one usable at a time) of 256 palettes available. Each palette has 16 entries, the first is the transparent index ("color 0"), the 15 others are real colors, made of 16bit RGB definitions. | ||
Palettes are located at $400000 in the 68k | Palettes are located at $400000 in the [[68k memory map]], they're physically stored in the [[palette RAM]]. | ||
The bank used | The bank used can be set by writing a byte to registers '''REG_PALBANK1''' ($3A000F) or '''REG_PALBANK0''' ($3A001F). | ||
[[Sprites|Sprite]] tiles can use any of the 256 palettes, while the [[Fix layer|fix]] tiles can only use the 16 firsts. | |||
The maximum number of colors on screen without [[68k interrupts|RLI]] tricks is 256*16=4096 (out of 2^16=65536). | |||
==Special colors== | |||
There are two special colors used: | |||
*The first color of the palette bank ($400000) is the '''reference color''' for the video output. It has to be $8000 (black). | |||
*The last color of the palette bank ($401FFE) is the '''backdrop color''' (the color of the backmost layer on the screen). | |||
==Color format== | |||
D | D | ||
<span style="color:red;">R0</span> | <span style="color:red;">R0</span> | ||
| Line 16: | Line 26: | ||
<span style="color:blue;">B4 B3 B2 B1</span> | <span style="color:blue;">B4 B3 B2 B1</span> | ||
{{Template:16BitRegister|[[Dark bit]]|1|R0|1|G0|1|B0|1|R4|1|R3|1|R2|1|R1|1|G4|1|G3|1|G2|1|G1|1|B4|1|B3|1|B2|1|B1|1|}} | {{Template:16BitRegister|[[Video DAC|Dark bit]]|1|R0|1|G0|1|B0|1|R4|1|R3|1|R2|1|R1|1|G4|1|G3|1|G2|1|G1|1|B4|1|B3|1|B2|1|B1|1|}} | ||
[[Category:Video system]] | [[Category:Video system]] | ||
Revision as of 13:59, 11 October 2011
There are 2 banks (one usable at a time) of 256 palettes available. Each palette has 16 entries, the first is the transparent index ("color 0"), the 15 others are real colors, made of 16bit RGB definitions. Palettes are located at $400000 in the 68k memory map, they're physically stored in the palette RAM.
The bank used can be set by writing a byte to registers REG_PALBANK1 ($3A000F) or REG_PALBANK0 ($3A001F).
Sprite tiles can use any of the 256 palettes, while the fix tiles can only use the 16 firsts.
The maximum number of colors on screen without RLI tricks is 256*16=4096 (out of 2^16=65536).
Special colors
There are two special colors used:
- The first color of the palette bank ($400000) is the reference color for the video output. It has to be $8000 (black).
- The last color of the palette bank ($401FFE) is the backdrop color (the color of the backmost layer on the screen).
Color format
D R0 G0 B0 R4 R3 R2 R1 G4 G3 G2 G1 B4 B3 B2 B1
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Def | Dark bit | R0 | G0 | B0 | R4 | R3 | R2 | R1 | G4 | G3 | G2 | G1 | B4 | B3 | B2 | B1 |