The Commodore 64 (C64) demos are demonstrations of what can be done to push the limits of the Commodore 64 computer, made by programmers, musicians and artists.
Though it was not unusual to find demos that displayed a single picture, only music tracks or a programming skill, groups were formed that consisted of members who were skilled in composing music, drawing graphics and programming. Full disk demos were produced, some of which would play music as the next file loaded, without any delay in the sound.
Borders - screen shot of the intro to the "Bobby Border" part of the "Camel Park" demo. Notice the borders in black.All borders removed - screen shot of one of the main effects in the "Bobby Border" part of "Camel Park". Notice how the sprites move into the borders. Also an example of the DXYCP (sprite-scroller) effect.
Various effects are achieved in demos, most of them due to undocumented side-effects pertaining to the MOS Technology VIC-II chip. Some examples are:
Sprite scrollers were placed in the border. By tricking the hardware not to draw the border around the screen, sprites could be moved into this area and displayed.
Sprites were multiplexed across vertical raster lines (over 8 sprites, sometimes up to 120 sprites). A common perception is that no more than 8 sprites could appear at once on the screen, but assigning new Y coordinates once it has started being drawn made it reappear further down the screen.
FLD (flexible line distance) moved bitmap or character rows an arbitrary number of vertical raster lines apart, making it possible to arbitrarily move any 8 pixel high graphic block smoothly up and down across the screen. Adding sine curves to this positioning provided a wavy effect.
FLI, or Flexible Line Interpretation, can be used to increase the number of unique colors which can appear in an 8×8 or 8×4 block on the screen. This mode is occasionally extended further with sprites and/or interlacing two bitmaps together (as in SHIFLI or UIFLI). These modes usually cause the left-most 24 pixels of the display to become unusable.
FPP (Flexible Pixel Positioning), basically a variation of the FLI mode, allows the placement of any line of a character-based graphic at any one y-position, allowing for effects like x-rotating logos, barrel-like effects or smooth stretching and waving over the whole screen.
Tec-Tec (also Tech-Tech or Tic Tac) assigns a new x-position to any line of a graphic. By using animated sine waves you could for example wave a logo horizontally over the screen.
VSP (Variable Screen Positioning), also known as HSP, allows arbitrary x-placement of a bitmap, with the bitmap wrapping around at the border.
A Linecruncher allows the user to scroll a bitmap larger than one screen vertically without having to move all the bitmap data manually.
AGSP (Any Given Screen Position) is the combination of VSP and Linecruncher, for example making possible games with colorful bitmap graphics that scrolled, such as Hannes Sommer's "Fred's Back" series.
Followers of the C64 would see the growth of the demo scene. Gone were the single file demos with one scrolling text and no music. Full disk demos were produced, some of which would play music as the next file loaded, without any delay in the sound.
Hidden parts were included as was the occasional game implemented into a demo.
When the Commodore Amiga appeared, many former C64 demo programmers switched platforms and continued to make demos for the Amiga (see Amiga demos). The Atari demos were also heavily influenced by C64 demos. In the United Kingdom, the main alternative demo scene was the one of ZX Spectrum demos.
The C64 was popular in a time when local BBSes were also popular and used to communicate with other people. Software trading via mail was also common. Some C64 enthusiasts lament the loss of the social interaction that locally centered computer activities provided.
Commodore Scene Database, A scene database where you can get in touch with the sceners themselves or get info about one scener or release or event. Structured, including information (hidden parts), downloads, screenshots, forum.
C64 PortalC64 demo scene related news, about new releases, parties and other scene related news
Intros.C64.OrgLarge online archive of crack intros, the first demoscene productions.
Driven OnlineDriven Online - Covering the North American demo scene
The Commodore 64, also known as the C64, is an 8-bit home computer introduced in January 1982 by Commodore International. It has been listed in the Guinness World Records as the highest-selling single computer model of all time, with independent estimates placing the number sold between 12.5 and 17 million units. Volume production started in early 1982, marketing in August for US$595. Preceded by the VIC-20 and Commodore PET, the C64 took its name from its 64 kilobytes(65,536 bytes) of RAM. With support for multicolor sprites and a custom chip for waveform generation, the C64 could create superior visuals and audio compared to systems without such custom hardware.
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 the greatly improved Advanced Graphics Architecture (AGA).
Parallax scrolling is a technique in computer graphics where background images move past the camera more slowly than foreground images, creating an illusion of depth in a 2D scene of distance. The technique grew out of the multiplane camera technique used in traditional animation since the 1930s.
A crack intro, also known as a cracktro, loader, or just intro, is a small introduction sequence added to cracked software. It aims to inform the user which "cracking crew" or individual cracker removed the software's copy protection and distributed the crack.
Bit blit is a data operation commonly used in computer graphics in which several bitmaps are combined into one using a boolean function.
The demoscene is an international computer art subculture focused on producing demos: self-contained, sometimes extremely small, computer programs that produce audiovisual presentations. The purpose of a demo is to show off programming, visual art, and musical skills. Demos and other demoscene productions are shared at festivals known as demoparties, voted on by those who attend and released online.
The VIC-II, specifically known as the MOS Technology 6567/6566/8562/8564, 6569/8565/8566 (PAL), is the microchip tasked with generating Y/C video signals and DRAM refresh signals in the Commodore 64 and Commodore 128 home computers.
Pixel art is a form of digital art drawn with graphical software where images are built using pixels as the only building block. It is widely associated with the low-resolution graphics from 8-bit and 16-bit era computers and arcade video game consoles, in addition to other limited systems such as LED displays and graphing calculators, which have a limited number of pixels and colors available. The art form is still employed to this day by pixel artists and game studios, even though the technological limitations have since been surpassed.
Thalamus Ltd was a British computer game developer that published titles for a number of 8-bit and 16-bit platforms during the late 1980s and early 1990s.
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.
The raster bar is an effect used in demos and older video games that displays animated bars of colour, usually horizontal, which additionally might extend into the border, a.k.a. the otherwise unalterable area of the display. Raster bar-style effects were common on the Atari 2600 and Atari 8-bit family and then later in demos for the Commodore 64, Amiga, Atari ST, and Amstrad CPC.
A display list is a series of graphics commands that define an output image. The image is created (rendered) by executing the commands to combine various primitives. This activity is most often performed by specialized display or processing hardware partly or completely independent of the system's CPU for the purpose of freeing the CPU from the overhead of maintaining the display, and may provide output features or speed beyond the CPU's capability.
Simons' BASIC is an extension to BASIC 2.0 for the Commodore 64 home computer. Written by British programmer David Simons in 1983, who was 16 years old at the time, it was distributed by Commodore as a cartridge.
A raster interrupt is an interrupt signal in a legacy computer system which is used for display timing. It is usually, though not always, generated by a system's graphics chip as the scan lines of a frame are being readied to send to the monitor for display. The most basic implementation of a raster interrupt is the vertical blank interrupt.
Demo effect is computer-based real-time visual effects found in demos created by the demoscene.
The Judges was a Dutch Commodore 64 group from Roosendaal known for being one of the earliest dedicated demogroups. The Judges released several demos for the Commodore 64 home computer between the years 1986 - 1988. Groups such as The Judges are regarded as early pioneers of what came to be known as the demoscene.
The Super Expander 64 was a cartridge-based extension to the built in BASIC V2 interpreter of the then immensely popular Commodore 64 home computer: Since the 64 was developed in a hurry, Commodore simply adapted the BASIC V2 from the PET line of computers and the VIC 20 for their new machine, with no support for the advanced sound and graphics capabilities of the 64. To make use of the advanced hardware, BASIC programmers needed to memorize hardware addresses and "POKE" commands directly to the memory-mapped devices. Later 8-bit systems from Commodore had BASIC interpreters enhanced to support the special hardware, and with the Super Expander 64 cartridge, Commodore 64 users could "retrofit" their machine with a BASIC to match the hardware capabilities.
GrafX2 is a bitmap graphics editor inspired by the Amiga programs Deluxe Paint and Brilliance. It is free software and distributed under the GPL-2.0-only license.
The Real Ghostbusters is a 1987 shoot 'em up arcade game developed and published by Data East in the United States. It is loosely based on the animated series of the same name. In Japan, Data East released it as a non-Ghostbusters arcade game under the title Meikyuu Hunter G. In 1989, Activision published The Real Ghostbusters for Amiga, Amstrad CPC, Atari ST, Commodore 64, and ZX Spectrum.
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