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Video modes

5 bytes added, 20:34, 24 October 2009
The standard [[video modes]] or '''Screen Modes'''.
As a Colour Personnal Personal Computer, perhaps the Amstrad CPC best argument (beside being cheap, fully equipped and well rounded) was his it's video capability. Yet this was also heavier more demanding for the Z80 to handle compared to other lighter diplayers players such as ZX Spectrum.
Also Amstrad's Video RAM was shared on with the Z80 RAM. This and a cheap conception concept with the fewer specific chip custom chips to ease the CPU could turn it into a sluggish snails snail if badly programmed.
Yet colourfull colourful games with few scrollings requirementscrolling requirements, reflexion reflection games such as KLAX... were perhaps the easiest medium for a CPC to shine above other 8 bit computers.
Too bad too few graphicalygraphically-heavy RolePlayingGames Role-Playing Games were produced.
==Specifications==
Those These are :
*'''Mode 0''': '''160×200''' pixels with 16 colors (4 bpp)
The Video modes are known to display pixels with different sizes.
Basically, the Amstrad CPC Video work 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 Mode.
* Full screen'''Mode 2''': '''768x272''' pixels with 2 colors (1 bpp)
Also the use of canline scanline may increase vertical resolution.
==Colours Colour attributes==
The Amstrad CPC is perhaps the only cheap personnal personal computer of his this generation with absolutly absolutely no such thing as character's colour attributes.
Speccy was awfull awful for this, and even better computers had modes with it.
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 from of 4096 colours palette)
C64 and MSX also had Colours 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 see sees any faulty colour clashes... despite the numerous speccy ports, because it cannot unless voluntarily programmed.... This saved many speccy ports indeed.
Is this better ?
Well colours attribute system allow a good resolution with more than 4 colours displayed on screen with few effortslittle effort.
So this would be interesting to display...colourfull colourful texts.
Yet fine graphics with a really colourfull colourful feeling become harder to get, so are nice metallic or graphical effect letter fonts with 4 colors...
==Colours==
The 3-level (not '''bits''') RGB uses three level for every red, green and blue color components, resulting in a 3<sup>3</sup> = 27 colours palette.
A notabble specificity notable specification of the Amstrad CPC palette is that it offers only one "Grey".
Compared to the C64 with...er...only greys..? (Humor inside)
This explains why in some games rocks and stone are coloured in other shades to get a good colour layer with more than 3 shades (black, grey and white).
*Exemples Examples : [[Defender of the Crown]] with Purple rocks and stone walls... Also [[Barbarian]].
It is also notable that this palette has a "lot" of Blue and Green variations... It is possible to use a mode 0 screen with almost only 16 pseudo Green and Blue colours (yet a bit purple for some of them).
Many graphists graphic programmers used mostly coloured flashy bold colours as it was often reproached by other 8bit fans (C64...).
But a clever choice in said colours could also give good results too in Pastel shades.
http://upload.wikimedia.org/wikipedia/commons/3/3b/Screen_color_test_AmstradCPC_16colors.png
Courtesy from of Wikipedia.
Yet the good high amount of colours allows to the use AntiAliasing technics of Anti-Aliasing techniques to soften the shapes.
It is the mode that made CPC a '''Colour''' Personnal Personal computer.
Ditherings are Dithering is sometimes used in this mode, yet the good high number of colours allows better colour layers.
Dithering more offers a good "texture" or feel effect than real "new colours".
==Mode 1 graphics==
The pixels are square, but the only 4 colours a per bit... few.
http://upload.wikimedia.org/wikipedia/commons/3/3b/Screen_color_test_AmstradCPC_4colors.png
Courtesy from of Wikipedia.
Yet a massive amount of horizontal "split rasters" allows you to multiply the number of colours displayed on the screen.
It's like using the colour attribute specificity specification (as on [[ZX Spectrum]]) but with horizontal limitations.
Basically a CGA standard PC video display.
Pictures and graphic material have to make good use of [[Dithering|ditheringsdithering]] in order to get a realistic look, yet the square pixels allow smooth ditheringsdithering.
==Mode 2 graphics==
The pixels are 1x2, extremly extremely slim.
http://upload.wikimedia.org/wikipedia/commons/4/48/Screen_color_test_AmstradCPC_2colors.png
Courtesy from of Wikipedia.
This mode is difficult to use in a coloured way.
Better used as a Text Mode, yet it can be included in a splitted split screen (games).
Because of this Mode, the Amstrad CPC was perhaps one of the 8 bit computer able to display the highest screen resolution in Full Screen (the so called "overscan")...
==Border==
The border allows 1 another additionnal additional colour to be displayed on the screen with no tricks.
==Amstrad Plus==
This means 32 colours per screen with no tricks (including Border).
Also it is worth noting that the resolution of those these Sprites (16x16 pixels) can be displayed through "magnification".
The basic x1/x1 pixel is like a Mode2 Pixel (a x=1 and y=2 ratio...or X= 0.5 and Y=1).
==External Links==
[http://www.en.wikipedia.org/wiki/List_of_8-bit_computer_hardware_palettes Wikipedia's pageon page on the different 8 Bit systems Hardware Palettes and Modes] including amstrad CPC of course...
[http://en.wikipedia.org/wiki/List_of_monochrome_and_RGB_palettes#18-bit_RGB Wikipedia's page on RGB palette] including Amstrad CPC specific one
[http://sylvestre.grimware.org/cpc/ Les Sucres en Morceaux] the French site from supersly, shows many exemples examples and technics techniques to use the different Video mode of the amstrad CPC.
[[Category:Graphic]][[Category:Programming]]
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