Amiga Halfbrite mode
Extra Half Brite (also referred to as Extra-Half-Brite, Extra-Halfbrite, or EHB),[1][2][3][4] is a planar display mode of the Amiga computer.
This mode uses six bitplanes (six bits per pixel).[3][5][6] The first five bitplanes index 32 colors selected from a 12-bit color space of 4096 possible colors. If the bit on the sixth bitplane is set, the display hardware halves the brightness of the corresponding color component.[7] This way 64 simultaneous colors are possible (32 arbitrary colors plus 32 half-bright components) while only using 32 color registers.[8] The number of color registers is a hardware limitation of pre-AGA chipsets used in Amiga computers.
Some contemporary games (Fusion,[9] Defender of the Crown,[10] Agony,[11] Lotus II,[12] or Unreal[13]) and animations (HalfBrite Hill[4]) use EHB mode as a hardware-assisted means to display shadows or silhouettes.[9][14] EHB is often used as general-purpose 64 color mode with the aforementioned restrictions.[9][15][16][17]
Some early versions of the first Amiga, the Amiga 1000, sold in the United States , lack the EHB video mode, which is present in all later Amiga models.[4][2]
See also
References
- ↑ Mortimore, Eugene P. (1986) (in en). Amiga Programmer's Handbook. SYBEX. ISBN 978-0-89588-343-8. https://books.google.com/books?id=dXsZAQAAIAAJ&q=%22Extra+Half-Brite%22+-wikipedia.
- ↑ 2.0 2.1 Maher, Jimmy (2018-01-26) (in en). The Future Was Here: The Commodore Amiga. MIT Press. ISBN 978-0-262-53569-4. https://books.google.com/books?id=Gr74DwAAQBAJ&dq=%22Extra+Half-Brite%22+-wikipedia&pg=PA56.
- ↑ 3.0 3.1 "Amiga Hardware Reference Manual: Color Selection in Extra Half Brite (EHB) Mode". http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0098.html.
- ↑ 4.0 4.1 4.2 Sullivan, Kevin (1987). "HalfBrite Hill". Blair-Sullivan Computer Graphics & Animation. https://www.randelshofer.ch/animations/anims/blair_sullivan/HBriteHill.html.
- ↑ "The Atari ST and Amiga computing evolution!". https://www.retroshowcase.gr/index.php?p=article&artid=6.
- ↑ Peddie, Jon (8 June 2022). "Amiga (1988)" (in en-US). https://www.computer.org/publications/tech-news/chasing-pixels/amiga-1988/.
- ↑ Maher, Jimmy (2018-01-26) (in en). The Future Was Here: The Commodore Amiga. MIT Press. ISBN 978-0-262-53569-4. https://books.google.com/books?id=Gr74DwAAQBAJ&dq=Amiga+extra+Half-brite+mode+-wiki&pg=PA57.
- ↑ (in en) Amiga ROM Kernel Reference Manual: Libraries. Addison-Wesley. 1992. ISBN 978-0-201-56774-8. https://books.google.com/books?id=GdBQAAAAMAAJ&q=%22Extra+Half-Brite%22+-wikipedia.
- ↑ 9.0 9.1 9.2 "Extra Half Bright (EHB)". https://amiga.lychesis.net/knowledge/EHB.html.
- ↑ "Defender of the Crown - Castle Norman - Amiga Graphics Archive" (in en). https://amiga.lychesis.net/colors/EHB/DefenderOfTheCrown_CastleNorman.html.
- ↑ "Agony - Loader 1 - Amiga Graphics Archive" (in en). https://amiga.lychesis.net/colors/EHB/Agony_Loader1.html.
- ↑ "Lotus 2 - Level 1 - Forest - Amiga Graphics Archive" (in en). https://amiga.lychesis.net/colors/EHB/Lotus2_Level1_Forest.html.
- ↑ "Unreal - Amiga Graphics Archive" (in en). https://amiga.lychesis.net/colors/EHB/Unreal.html.
- ↑ "Enhanced Graphics - Extra Half-Brite (EHB) Mode". http://hol.abime.net/hol_search.php?N_ref_genre_quickmatch=80.
- ↑ "EHB images". Amiga Graphics Archive. http://amiga.lychesis.net/colors/EHB/index.html. Retrieved 19 September 2011.
- ↑ (in en) Compute. 11. Small System Services. 1989. pp. 44,53. https://books.google.com/books?id=RZQoAAAAMAAJ&q=%22Extra+Half-Brite%22+-wikipedia.
- ↑ Kroah (2020). "The Bard's Tale serie - Bard's Tale Construction Set". http://bringerp.free.fr/RE/BardsTale/bard4.php5.
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