nanochess

I'll make a scan in a few days.

Yes, of course, but I was showing just the example because I didn't want to extend to the full 32 sprites. Besides there are lots of solutions that don't require sprites. By example in some labyrinth games it would be better to replace enemies by characters even with pixel offset. Not a problem with games that don't require overlap, like SHMUPS. For other games like RPG it's possible to devise a special flicker algorithm. By example, keeping player as sprite 0 and 1 so player doesn't flicker and gets priority over other sprites, and keep sprites 2-31 cycling for flicker.

In Colecovision/MSX games it's common to use an intermediate table to contain the 128 bytes of sprite table. Then in interrupt routine, the table is loaded to VDP, but each time a counter is incremented to indicate start sprite and sprites are "jumped" by an offset. By example, talking only about 8 sprites (advance one sprite per frame, 3 sprites offset): First frame: sprite0, sprite3, sprite6, sprite1, sprite4, sprite7, sprite2, sprite5 Second frame: sprite1, sprite4, sprite7, sprite2, sprite5, sprite0, sprite3, sprite6 Third frame: sprite2, sprite5, sprite8, sprite3, sprite6, sprite1, sprite4, sprite7 And so on. The algorithm will not show flicker when no more than 4 sprites are in line. The flicker will show when there are more than 4 sprites in line. Of course, some adjustment should be done per project to offset (3 in example) and increment (1 in example) You can download the Meisei MSX emulator and try the Nemesis ROM game, there is an option in the emulator that shows you the sprite table being used and you'll see the sprite cycling.

I think that the blue snake could be a printing error. This remembered me a Zaxxon cartridge Canadian version, the hues are slightly different in comparison to the three USA cartridges I have.

There is a trick to know how much time are you wasting inside vertical retrace interrrupt. At start of interrupt (after saving the register and everything) load border register with white color, and at end of interrupt reload border with black. The white color will show you how much screen time are you using inside interrupt. Typically the white color should not exceed the first 32 lines, but that depends on your game.

It could be the headphone jack, it can be stuck so it interrupts the speaker.

There is a further trick that is so overly complicated that I don't have used it, but you can define characters while the scene is scrolling. So effectively the complexity of scene would be only limited by your ROM space.

Yep, buying Colecovision cartridges from ebay one by one is not economical! By example, I got Wizmath loose for US$104, so when I see someone got the lot with it for US$125 I'm just jealous! , in reality not so much, because I got what I want So buying one in one only possible if the cartridge is rare, you're about to complete your collection, or is included with other cartridges. Anyway now I'm pretty proud of my Q*bert with silver label

Thanks, Rom Hunter!

I've bought stuff from that place, pretty dusty but everything worked fine after cleaning. I remember also seeing Air Raid loose in Atari2600.com some weeks ago for a very similar price. And this of course remembers me when I saw one for $10 USD here at Mexico (but I didn't know anything of Atari,) so at this date I'm still banging my head against the wall.

Hey Opcode!, have you received my mail? I think I'll go with the not-so-perfect nameplate, I want to get my SGM! (and Yie-Ar Kung Fu )

For the SGM you have the information here http://atariage.com/forums/topic/203851-super-game-module-technical-forum/ Pixelboy provided me information about Megacart when developing Princess Quest but he got it from Opcode, so you should send a PM to Opcode.

Well, there are tricks. The vertical scroll uses just too much characters (because the three patterns should be the same,) so you should check the speed you want to get and you can limit the scroll to 30 frames per second (at 60 fps you get blurred visuals in some TVs) and, by example, use only 4 scroll offsets (2 pixels per pass) plus careful tile revision to reduce combinations. For horizontal scroll there are is an extra trick, each of the three sections (top, middle and bottom) can have independent tilesets , this way I managed to introduce some high-res graphics in Princess Quest.

For Princess Quest and Mecha-8 as both use a lot of patterns, instead of updating the patterns (3 pattern tables and 3 color tables upto 12288 bytes!), I went the other way, I update only the tiles. Patterns (already precalculated) are preloaded before the level starts. And there is an intermediate table that gives the correspondence between tile number and real pattern for a given offset (0-7 pixels or less depending on your scroll rate) In Z80 the code for copying to screen is very simple (the following code is repeated several times): ld a,(de) ; Read tile number pointed by DE ld l,a ; Index into translation table for pixel offset (reg.H preloaded before) outi ; Send data pointed by HL to VDP port (reg.C preloaded to VDP port) inc e ; Go for next tile (aligned to not use slower INC DE)

Check this list, it can give you a heads up on prices http://www.rarityguide.com/colecovision_view.php I suppose you can start an eBay bid on half the price shown. If these games haven't been in eBay in a long time is probable you can get a good price.

I was expecting an e-mail saying at least "you're now in our files" , possibly adding "and we will be watching you"

Incredible utility!

Hi Rom Hunter, here are the promised scans. Crose Forcy (I didn't found it in Atarimania) Fishing (yellow) Pigs in Space (missing top label, there are remains of glue)

The back of my 32 in 1 v-case

Talking about that. The Pigs in Space cartridge has missing the top label.

Also it was the only one in the two big bags of cartridges. Besides it is very fun You can count with them. Also I've checked that Crose Forcy isn't listed in Atarimania Yes, it looks nice. The top says Barzack, it is just a clone of Berzerk, ironically a game where doesn't appear never a princess.

In Mexico them are relatively common. I can sell you some if you want.