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Halfbrite Mode
Extra Half-Brite, usually abbreviated as EHB, is a planar display mode of the Amiga computer. This mode uses six bitplanes (six bits/pixel). The first five bitplanes index 32 colors selected from a 12-bit color space (4096 possible colors). If the bit on the sixth bitplane is set, the display hardware halves the brightness of the corresponding color component. This way 64 simultaneous colors are possible (32 arbitrary colors plus 32 half-bright components) while only using 32 color registers. The number of color registers is a hardware limitation of pre-AGA chipsets used in Amiga computers. Some contemporary game titles and animations used EHB mode as a hardware-assisted means to display shadows or silhouettes. EHB was also often used as general-purpose 64 color mode with the aforementioned restrictions. 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. See also * Original Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planar (computer Graphics)
In computer graphics, planar is the method of arranging pixel data into several ''bitplanes'' of RAM. Each bit in a bitplane is related to one pixel on the screen. Unlike packed, high color, or true color graphics, the whole dataset for an individual pixel isn't in one specific location in RAM, but spread across the bitplanes that make up the display. Planar arrangement determines how pixel data is laid out in memory, not how the data for a pixel is interpreted; pixel data in a planar arrangement could encode either indexed or direct color. This scheme originated in the early days of computer graphics. The memory chips of this era can not supply data fast enough on their own to generate a picture on a TV screen or monitor from a large framebuffer. By splitting the data up into multiple planes, each plane can be stored on a separate memory chip. These chips can then be read in parallel at a slower rate, allowing graphical display on modest hardware, like game consoles of the third ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amiga
Amiga is a family of personal computers introduced by Commodore in 1985. The original model is one of a number of mid-1980s computers with 16- or 32-bit processors, 256 KB or more of RAM, mouse-based GUIs, and significantly improved graphics and audio compared to previous 8-bit systems. This includes the Atari ST—released earlier the same year—as well as the Macintosh and Acorn Archimedes. Based on the Motorola 68000 microprocessor, the Amiga differs from its contemporaries through the inclusion of custom hardware to accelerate graphics and sound, including sprite (computer graphics), sprites and a blitter, and a pre-emptive multitasking operating system called AmigaOS. The Amiga 1000 was released in July 1985, but production problems kept it from becoming widely available until early 1986. The best-selling model, the Amiga 500, was introduced in 1987 along with the more expandable Amiga 2000. The Amiga 3000 was introduced in 1990, followed by the Amiga 500 Plus, and Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Depth
Color depth or colour depth (see spelling differences), also known as bit depth, is either the number of bits used to indicate the color of a single pixel, or the number of bits used for each color component of a single pixel. When referring to a pixel, the concept can be defined as bits per pixel (bpp). When referring to a color component, the concept can be defined as bits per component, bits per channel, bits per color (all three abbreviated bpc), and also bits per pixel component, bits per color channel or bits per sample (bps). Modern standards tend to use bits per component, but historical lower-depth systems used bits per pixel more often. Color depth is only one aspect of color representation, expressing the precision with which the amount of each primary can be expressed; the other aspect is how broad a range of colors can be expressed (the gamut). The definition of both color precision and gamut is accomplished with a color encoding specification which assigns a digita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGB Color Model
The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue. The main purpose of the RGB color model is for the sensing, representation, and display of images in electronic systems, such as televisions and computers, though it has also been used in conventional photography. Before the electronic age, the RGB color model already had a solid theory behind it, based in human perception of colors. RGB is a ''device-dependent'' color model: different devices detect or reproduce a given RGB value differently, since the color elements (such as phosphors or dyes) and their response to the individual red, green, and blue levels vary from manufacturer to manufacturer, or even in the same device over time. Thus an RGB value does not define the same ''color'' across d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Graphics Architecture
Amiga Advanced Graphics Architecture (AGA) is the third-generation Amiga graphic chipset, first used in the Amiga 4000 in 1992. Before release AGA was codenamed Pandora by Commodore International. AGA was originally called AA for Advanced Architecture in the United States. The name was later changed to AGA for the European market to reflect that it largely improved the graphical subsystem, and to avoid trademark issues. AGA is able to display graphics modes with a depth of up to s per pixel. This allows for in indexed display modes and (18-bit) in Hold-And-Modify (HAM-8) modes. The palette for the AGA chipset has 256 entries from (24-bit), whereas previous chipsets, the Original Chip Set (OCS) and Enhanced Chip Set (ECS), only allow out of 4096 or 64 colors in Amiga Extra Half-Brite (EHB mode). Other features added to AGA over ECS are super-hi-res smooth scrolling and 32-bit fast page memory fetches to supply the graphics data bandwidth for 8 bitplane graphics modes and wide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amiga 1000
The Commodore Amiga 1000, also known as the A1000, is the first personal computer released by Commodore International in the Amiga line. It combines the 16/32-bit Motorola 68000 CPU which was powerful by 1985 standards with one of the most advanced graphics and sound systems in its class. It runs a preemptive multitasking operating system that fits into of read-only memory and was shipped with 256 KB of RAM. The primary memory can be expanded internally with a manufacturer-supplied 256 KB module for a total of 512 KB of RAM. Using the external slot the primary memory can be expanded up to Design The A1000 has a number of characteristics that distinguish it from later Amiga models: It is the only model to feature the short-lived Amiga check-mark logo on its case, the majority of the case is elevated slightly to give a storage area for the keyboard when not in use (a "keyboard garage"), and the inside of the case is engraved with the signatures of the Amiga de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Original Chip Set
The Original Chip Set (OCS) is a chipset used in the earliest Commodore Amiga computers and defined the Amiga's graphics and sound capabilities. It was succeeded by the slightly improved Enhanced Chip Set (ECS) and greatly improved Advanced Graphics Architecture (AGA). The original chipset appeared in Amiga models built between 1985 and 1990: the Amiga 1000, Amiga 2000, Amiga CDTV, and Amiga 500. Overview of chips The chipset which gave the Amiga its unique graphics features consists of three main "custom" chips; ''Agnus'', ''Denise'', and ''Paula''. Both the original chipset and the enhanced chipset were manufactured using NMOS logic technology by Commodore's chip manufacturing subsidiary, MOS Technology. According to Jay Miner, the OCS chipset was fabricated in 5 µm manufacturing process while AGA Lisa was implemented in 1.5 µm process. All three custom chips were originally packaged in 48-pin DIPs; later versions of Agnus, known as Fat Ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hold-And-Modify
Hold-And-Modify, usually abbreviated as HAM, is a display mode of the Commodore Amiga computer. It uses a highly unusual technique to express the color of pixels, allowing many more colors to appear on screen than would otherwise be possible. HAM mode was commonly used to display digitized photographs or video frames, bitmap art and occasionally animation. At the time of the Amiga's launch in 1985, this near-photorealistic display was unprecedented for a home computer and it was widely used to demonstrate the Amiga's graphical capability. However, HAM has significant technical limitations which prevent it from being used as a general purpose display mode. Background The original Amiga chipset uses a planar display with a 12-bit RGB color space that produces 4096 possible colors. The bitmap of the playfield was held in a section of main memory known as ''chip RAM'', which was shared between the display system and the main CPU. The display system usually used an indexed colo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Platform
Java is a set of computer software and specifications developed by James Gosling at Sun Microsystems, which was later acquired by the Oracle Corporation, that provides a system for developing application software and deploying it in a cross-platform computing environment. Java is used in a wide variety of computing platforms from embedded devices and mobile phones to enterprise servers and supercomputers. Java applets, which are less common than standalone Java applications, were commonly run in secure, sandboxed environments to provide many features of native applications through being embedded in HTML pages. Writing in the Java programming language is the primary way to produce code that will be deployed as byte code in a Java virtual machine (JVM); byte code compilers are also available for other languages, including Ada, JavaScript, Python, and Ruby. In addition, several languages have been designed to run natively on the JVM, including Clojure, Groovy, and Scala. J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Display Standards
Computer display standards are a combination of aspect ratio, display size, display resolution, color depth, and refresh rate. They are associated with specific expansion cards, video connectors and monitors. History Various computer display standards or display modes have been used in the history of the personal computer. They are often a combination of aspect ratio (specified as width-to-height ratio), display resolution (specified as the width and height in pixels), color depth (measured in bits per pixel), and refresh rate (expressed in hertz). Associated with the screen resolution and refresh rate is a display adapter. Earlier display adapters were simple frame-buffers, but later display standards also specified a more extensive set of display functions and software controlled interface. Beyond display modes, the VESA industry organization has defined several standards related to power management and device identification, while ergonomics standards are set by the TCO. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
