Amiga Halfbrite mode

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File:32 vs Ehb64.png

File:Ehb64.png

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Extra Half Brite (also referred to as Extra-Half-Brite, Extra-Halfbrite, or EHB),{{Cite book |last=Mortimore |first=Eugene P. |url=https://books.google.com/books?id=dXsZAQAAIAAJ&q=%22Extra+Half-Brite%22+-wikipedia |title=Amiga Programmer's Handbook |date=1986 |publisher=SYBEX |isbn=978-0-89588-343-8 |language=en}}{{Cite book |last=Maher |first=Jimmy |url=https://books.google.com/books?id=Gr74DwAAQBAJ&dq=%22Extra+Half-Brite%22+-wikipedia&pg=PA56 |title=The Future Was Here: The Commodore Amiga |date=January 26, 2018 |publisher=MIT Press |isbn=978-0-262-53569-4 |language=en}} is a planar display mode of the Amiga computer.

This mode uses six bit planes (six bits per pixel).{{Cite web |title=Amiga Hardware Reference Manual: Color Selection in Extra Half Brite (EHB) Mode |url=http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0098.html |access-date=November 19, 2022 |website=Amiga Developer Docs}}{{Cite web |title=The Atari ST and Amiga computing evolution! |url=https://www.retroshowcase.gr/index.php?p=article&artid=6 |access-date=November 19, 2022 |website=Retroshowcase: oldschool game reference!}}{{Cite web |last=Peddie |first=Jon |title=Amiga (1988) |url=https://www.computer.org/publications/tech-news/chasing-pixels/amiga-1988/ |access-date=November 19, 2022 |website=IEEE Computer Society |date=June 8, 2022 |language=en-US}} The first five bit planes index 32 colors selected from a 12-bit color space of 4096 possible colors. If the bit on the sixth bit plane is set, the display hardware halves the brightness of the corresponding color component.{{Cite book |last=Maher |first=Jimmy |url=https://books.google.com/books?id=Gr74DwAAQBAJ&dq=Amiga+extra+Half-brite+mode+-wiki&pg=PA57 |title=The Future Was Here: The Commodore Amiga |date=January 26, 2018 |publisher=MIT Press |isbn=978-0-262-53569-4 |language=en}} This way 64 simultaneous colors are possible (32 arbitrary colors plus 32 half-bright components) while using only 32 color registers.{{Cite book |last= |first= |url=https://books.google.com/books?id=GdBQAAAAMAAJ&q=%22Extra+Half-Brite%22+-wikipedia |title=Amiga ROM Kernel Reference Manual: Libraries |date=1992 |publisher=Addison-Wesley |isbn=978-0-201-56774-8 |language=en}} The number of color registers is a hardware limitation of pre-AGA chipsets in Amiga computers.

Some contemporary games (Fusion, Defender of the Crown,{{Cite web |title=Defender of the Crown - Castle Norman - Amiga Graphics Archive |url=https://amiga.lychesis.net/colors/EHB/DefenderOfTheCrown_CastleNorman.html |access-date=April 12, 2023 |website=amiga.lychesis.net |language=en}} Agony,{{Cite web |title=Agony - Loader 1 - Amiga Graphics Archive |url=https://amiga.lychesis.net/colors/EHB/Agony_Loader1.html |access-date=April 12, 2023 |website=amiga.lychesis.net |language=en}} Lotus II,{{Cite web |title=Lotus 2 - Level 1 - Forest - Amiga Graphics Archive |url=https://amiga.lychesis.net/colors/EHB/Lotus2_Level1_Forest.html |access-date=April 12, 2023 |website=amiga.lychesis.net |language=en}} or Unreal{{Cite web |title=Unreal - Amiga Graphics Archive |url=https://amiga.lychesis.net/colors/EHB/Unreal.html |access-date=April 12, 2023 |website=amiga.lychesis.net |language=en}}) and animations (HalfBrite Hill) use EHB mode as a hardware-assisted means to display shadows or silhouettes.{{Cite web |title=Extra Half Bright (EHB) |url=https://amiga.lychesis.net/knowledge/EHB.html |access-date=November 19, 2022 |website=Amiga Graphics Archive}}{{Cite web |title=Enhanced Graphics - Extra Half-Brite (EHB) Mode |url=http://hol.abime.net/hol_search.php?N_ref_genre_quickmatch=80 |access-date=April 12, 2023 |website=Hall Of Light - The database of Amiga games}} EHB is often used as general-purpose 64 color mode with its own restrictions.{{cite web |title=EHB images |url=http://amiga.lychesis.net/colors/EHB/index.html |accessdate=September 19, 2011 |publisher=Amiga Graphics Archive}}{{Cite book |url=https://books.google.com/books?id=RZQoAAAAMAAJ&q=%22Extra+Half-Brite%22+-wikipedia |title=Compute |date=1989 |publisher=Small System Services |volume=11 |pages=44,53 |language=en}}{{Cite web |last=Kroah |date=2020 |title=The Bard's Tale serie - Bard's Tale Construction Set |url=http://bringerp.free.fr/RE/BardsTale/bard4.php5 |access-date=November 19, 2022 |website=Kroah's Game Reverse Engineering Page}}

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.{{Cite web |last=Sullivan |first=Kevin |date=1987 |title=HalfBrite Hill |url=https://www.randelshofer.ch/animations/anims/blair_sullivan/HBriteHill.html |access-date=November 19, 2022 |website=Amiga Animations |publisher=Blair-Sullivan Computer Graphics & Animation}}