Thanks Howard, > > Downgrading for the SAM is complicated, because it has 7-bit colour. 2 > bits for each of RGB, and the Spectrum handed down its 'half-brightness' > bit.
I knew there was a reason I shouldnt go down this road! [rr][gg][bb][x] is the layout? > results can be quite nice. On the other hand, ages ago Mike AJ flicked > between diffferent palettes to fake new colours. It's not quite as > convincing, especially with large blocks of colour. I have jerry-rigged some code to try this and the results are a little sad. I dont want to just go for the cop out and have say a graduated sky ( yes you heard me Im not exactly sticking to the Atic Atac original!!! > > As for breadboarding new graphics chips, I have no idea! I think I was getting overenthusiastic. My soldering iron is at the back of the garden shed behind a kitchen cupboard that I ripped out to plumb in the dishwasher. Ive been going through my spectrum game collection this morning, working out what I want to be able to achieve with the engine before I get shot by my other half for getting back into hobbyist programming. Things I liked: Knightlore style - the Isometic discussion - with true offset blocks ) ChaseHQ - the display routines are pretty good, given decent sprites and a faster CPU the game could be quite impressive on the SAM Carrier Command - the 3d wireframe is simple. Given a fast scanline routine it could be made solid ( AKA Atari ST version ) quite simply. The Z80B seems to achieve 80% speed of the same polygon fill algorithm as the 68000. Im not pretending to have written the fastest algorithm but it gives me a good feeling that solid 3D games are possible given we restrict the number of polygons on screen - perhaps with a limited depth z-buffer algorithm? > > Momentum is the only real SAM isometric game I think Dave, and Graham > Burtenshaw probably wrote it in BASIC (doesn't mean it's not really good, > just really, really slow at swapping screens). I could simply achieve the Movie/Ninja style of 3D isometic as you suggest with the engine as it stands. As you point out the more clever projection style is much harder to achieve correctly. Ill give it some thought this weekend. > > >4) Is there a SAM Carrier Command/Elite already? > > Don't start! Long and bitter tales about this - we eventually got a > Spectrum port of Elite with patched LOAD and SAVE routines, sold at full > price. Hmmm. The spectrum version of Elite was not the best by a long shot IMHO and I was a spectrum bigot before I became a general bigot. Im not convinced that Mode 4 is particularly fast. Whilst I can create a bitmap from my 3d algorithms quickly when it comes to displaying it on screen the frame rate drops dramatically compared to the same non hardware blittered Amiga version. Perhaps Im not taking advantage of some shortcut? It isnt so noticeable on the sprite engine I have already. If I limit the projection size to 64x64 it speeds up disproportionatly to the performance figures projected by the 94x94 and 128x128 figures. If this is the case it would be easier to create a Space Hulk type game because it would run at the same speed as a 3d game in 128x128 even if we projected 4 live action views. Is this because of the way SAM handles screen memory? > > >7) Finally, is there a decent GUI project for the SAM? > > Ages ago Steve Taylor wrote a MODE 3 one, but it never caught on cos it > cost too much and was fiddly to convert existing software. And it's word > processor was apparantly too slow for real typists. This might be the same display update limitation I am hitting? I also had a few bits of software for the SAM I havent seen elsewhere: Sphera ( the Mode 2 shoot em up ) The Secretary ( excellent! ) Tasword Maybe I just havent read the right web pages yet. > You might try hacking > SAMmines by Mnemotech/Andrew Collier, and I like the GI_monitor one, though > you can't redefine windows' size and position! I looked at this on your suggestion and I have to agree. > > I've got a bunch of display routines and graphics for a system I started > for O3D. I did a nice robust priority table routine, but the button > scanning is atrocious, even when you only scan for live windows and desktop > icons. Oh, and it's in Assembler. The writers of GEM found the same thing. Thats why it started out having only one window!! :-) Thanks for your help Howard! Dave.
