ibisum wrote:I'm not sure the color-clash can be exploited this way on ZX Spectrum attribs, or am I totally wrong?
Its not possible on Spectrum by default.
The Spectrum attribute system allows 1 foreground (ink) and 1 background (paper) colour for every 8x8 pixel block of the screen.
There are 7 colours in the palette plus black.
For each 8x8 pixel block, there is also a 'bright' and 'flash' attribute. The bright attribute will affect both foreground and background colours with the exception of black which only has one shade (there's not a 'bright black' to give grey), so there are effectively 14 colours plus black to play with. As the bright attribute affects the whole 8x8 pixels, you can't have a bright foreground colour and a 'normal' background colour.
The big benefit of the Spectrum attribute system over the Oric's is that you don't need to reserve a whole byte in advance for a colour change - you can contain graphic pixel data as well as a colour change. On the Oric, changing colours prevents any graphic pixel data for the 6 pixels in that cell (unless you're inverting colours, which in itself is tricky since it inverts both foreground and background colours).
Oric does have the advantage of being able to change colours on every line, where the Speccy can only have one colour for every 8 lines. Some clever programming trickery can get round this limitation, as seen in games like Buzzsaw:
http://www.worldofspectrum.org/infoseek ... loadpics=3
Personally I prefer the Spectrum attribute system, but the Oric does at least treat it's screen memory in a linear fashion. The Spectrum has 3 (iirc) chunks of screen that are stored in a rather odd fashion. You can see this on any Spectrum game that shows its loading screen build up as it loads, with the lines not filling in from top to bottom but instead doing a one line for each character block of its memory section, then the next line, then when that's complete it moves down to the next section of screen. Very odd, but I'm sure there was a reason for it being done that way.