Also Amstrad's Video RAM was shared with the Z80 RAM. This and a cheap concept with fewer custom chips to ease the CPU could turn it into a sluggish snail if badly programmed.
Yet colourful games with few scrolling requirements, reflection games such as [[Klax (cartridge)|KLAX]]... were perhaps the easiest medium for a CPC to shine above other 8 bit computers.
Too bad too few graphically-heavy Role-Playing Games were produced.
*'''Mode 1''': '''320×200''' pixels with 4 colors (2 bpp)
*'''Mode 2''': '''640×200''' pixels with 2 colors (1 bpp)
*'''Mode 3''': '''160x200160×200''' pixels with 4 colors (2bpp) (this is not an official mode, but rather a side-effect of the hardware)
The Video modes are known to display pixels with different sizes.
Basically, the Amstrad CPC Video works like a CGA video card from a PC. But extra features like a 16 colours mode exist.
The dimensions in pixels given could be raised with clever use of FullScreen Trick (often dubbed erronuously as "[[Programming:Overscan|overscan mode]]".)
This then allows with a video memory of 24Ko 24 KB (approximately) to displays on the standard screen up to :* Full screen '''Mode 0''': '''192x272192×272''' pixels with 16 colors (4 bpp)* Full screen'''Mode 1''': '''384x272384×272''' pixels with 4 colors (2 bpp)* Full screen'''Mode 2''': '''768x272768×272''' pixels with 2 colors (1 bpp)
Also the use of scanlines to increase vertical resolution is not "easly" possible on Amstrad CPC.
When dealing with Full screen on real Hardware, the vertical limit of 256 pixels is the "safely displayed zone". As the actually displayed zone may vary depending the time your monitor ran (warmed ?) or from individual hardware to another. The same goes for horizontal diplay as we deal with old electronic.
==Colour attributes==
The Amstrad CPC is perhaps the only cheap personal computer of this generation with absolutely no such thing as (character ) colour attributes.
Speccy was awful for this, and even better computers had modes with it.
Yet the use of "Raster colour changes" can actually produce horizontal colour clashes if an animated object is to cross the 2 zones and the colours choosen badly/on purpose (or in 2 coloured mode2).
Such effect can almost be seen in the game [[Striker in the Crypts of Trogan]]/[[Stryker and the Crypts of Trogan]] when monsters cross the "rasterzones"...
Later [[Thomson ]] 8 bit computers (MO6 and TO8) used to have the same Video Modes and Palette as the Amstrad Plus and an additional Mode (320x200 and 16 colors with attribute limitation of 4096 colours palette)
[[C64 ]] and [[MSX ]] also had Colour attributes, yet also some modes without or with less limitations than Speccy, and later models (C128, MSX2+ and 3) were also designed with even better extra non-attributed modes.
As a result, an Amstrad never sees any faulty colour clashes... despite the numerous speccy ports, because it cannot unless voluntarily programmed.... This saved many speccy ports indeed.
It is Cubic, generated by "Trigits" (ternary digits)
* This palette is used by the [[CPC|Amstrad CPC]] old series only and is almost not found in any other computers (but clones of course). * The Toshiba [[PASOPIA 7]] is known to feature the same 3-level RGB palette as the Amstrad CPC, its video modes are different than Amstrad CPC's ones though.
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*To set a CPC palette on modern Graphic softwaressoftware.
*Also the official names of the colours may not be that accurate...
"Purple" is more like some kind of Magenta while "Magenta" is more like some sort of MAuve Mauve and Mauve a Purple... and so on.
"White" is actually grey while "bright white" is white...
As shown... the CPC original palette is good as it enable gradiants in Black and White + 3 shades for the 6 basic colours...
Red, Green, Blue... and Yellow, Cyan and Magenta (purlplepurple).
Added to those, there are a few special crossbreed colours such as "Mauve" (2 shades : Mauve and Pastel blue), orange (can mix with red and yellows), "Purple" (a bluer Red) and a lot of "light greeens" (turning into Cyan or yellow).
Courtesy of MacDeath.
The Amstrad's "grey " (Real name = "White"... or dark white in opposition to bright white) is used as background . It is not shown on the cubes because it is supposed to be "inside" the cubes. *How to extend the cube With a certain limit and providing the use of fine regular dithering, the RGB cube of the Amstrad CPC's greycan be stretched into bigger RGB cubes. Such cubes are also a guide to get the smooth gradiants from one CPC colours into another. [[File:R2G2B2 EGA palette on CPC. which png]] This is actually "inside" the CPC palette stretched into a R2G2B2 cube (bits, not displayedvalues)with help from dithering, hence giving 4x4x4= 64 colours. Basically the MS-DOS era IBM PC EGA as availlable on Amstrad PC1640 [[File:R5G5B5 CPC complete ditherings.png]] This is the CPC palette stretched into a R5G5B5 cube (values, not bits) with help from dithering, hence giving 5x5x5 = 125 colours. Notice how some colours can be obtained with up to 4 different combinaisons, yet with the same result. But when considering on screen pixels reactions, notably during flickering technics, some combinaison may be better than others in order to reduce the flash effect of the flickerings. Bigger RGB cubes would need the use of unpractical ditherings (other than 50%) and perhaps mix of more than 2 colours. This would simply not work properly. [[File:Mire CPC.png]] This kind of picture can be obtained on a real CPC (through mode0 and Rasters) in order to test the monitors, and also to understand at first sight how the Colours logic works. [[File:Stretched CPC palette macdeath.png]]
==='''12-bit RGB of the PLUS'''===
*More infos here : [[Programming:Amstrad CPC plus sprite format]]
==Related pagesSoftware Video modes== Some odd and obscure "software video modes" can be achieved through the use of various tricks. such modes are : *[[Mode 5]] which makes heavy use of Rasters and Split Rasters in order to enable far more colours in the normal Mode1. *[[Mode R]] which make use of the the interlace effect in order to gain. It was used in the [[Batman Forever]] demo *[[Flickering Screens Mode]] : which alternates 2 screen at 25hz each so they seem to blend together on the CRTC, this can mix different palettes (and colour swaps) or different modes to achieve colours unavailable on the normal Palette or some higher actual resolution by mixing Mode0 with Mode1 or Mode2. (also known in French as Flashouilles, or Epyleptic mode) ==See also==
*[[CRTC]]
*[[Gate Array]]
*[[ASIC]]
*[[Creating images for the Amstrad]]
*[[Mode R]]
==External Links==