Turrican for MSX new WIP

[thegeps]

I finally implemented the sprite slot system. The MSX1 can have up to 32 sprites on screen at the same time but all in monochrome. There is a special area of ??the VRAM which contains the data of these sprites. Four bytes for each sprite indicating its Y,X, aspect and color (the early clock bit management must also be added to the color, which determines whether the sprite will appear or disappear pixel by pixel at the left edge of the screen).
Now imagine that you want to group a few sprites together to create bigger and/or more colorful sprites. You'll have to deal with them somehow so you have to build your system on paper first and then report it as assembly code...
Turrican's sprite alone uses 8 sprites. 4 other sprites are engaged (invisible) on the edge of the lower panel so as to make the sprites that cross the scoreboard line before being definitively canceled (making them so disappear, where necessary, pixel by pixel)
So 12 sprites are already out of the game. There would be 20 left, but I wanted to reserve 6 for enemy bullets (which are monochrome so there can be up to 6 of them on screen at the same time).
So, for enemies and other items (like lives, for example) only 14 sprites are left. It complicates things a bit by the fact that I don't accept that the sprites, once "pushed" off the screen, disappear forever, as happens in the original Turrican (at least on C64 and Amiga, which are the versions I know). So we need a system that keeps track of the enemies' HP and from how many and which sprites these are composed of and the location in RAM where this information is kept so that it can be changed if necessary.
These 14 remaining sprites, if managed anarchically, risk being insufficient to manage the multitude of enemies that made Turrican's fortune!
So they are managed by the code as multipurpose slots. They can be dynamically used as slots for monochromatic sprites (such as walkers and lives), as slots for two-color sprites (or as objects formed by two sprites side by side, such as snakes), as slots for objects formed by 4 sprites (the spaceships of the first level) and finally for objects formed by 6 sprites (the robots of the first level). All these types of slots are managed simultaneously, searching for which ones are in use and reserving consecutive slots for objects made up of multiple sprites, any single slots left free between already reserved slots can be used by single sprite objects. When the object is removed from the screen (therefore NOT killed) the relative "validity" byte in RAM is not touched, while the "on screen" flag is reset so as to be able to put the sprite back into play when returning to the its spawn area (and, from this moment, also respawn).
Enjoy the video, as usual set YT to 720p50 to avoid skipping frames which would distort the real behavior of the game.
And, if you want, you can support me simply by subscribing to the YT channel.

[ Show youtube player ]

[Thorham]

Good job, movement also looks accurate

[saimon69]

This is looking very good! I said it already but now is to the next level

[eXeler0]

Never seen smooth scrolling like this on MSX ;-)

[Factor5]

We really like your great work on this ancient piece of hardware. Congratulations from the team!
Impressive.

W.Baecker / Factor 5

[thegeps]

Originally Posted by Factor5

We really like your great work on this ancient piece of hardware. Congratulations from the team!
Impressive.

W.Baecker / Factor 5

Your words make me really happy. I promise to do my best to make sure the MSX version is up to par too <3

[Anubis]

Originally Posted by Factor5

We really like your great work on this ancient piece of hardware. Congratulations from the team!
Impressive.

W.Baecker / Factor 5

Originally Posted by thegeps

Your words make me really happy. I promise to do my best to make sure the MSX version is up to par too <3

Thank you both for making this retro hobby more exciting!!

[arcam]

Very impressive :!

[thegeps]

New update!
I know I should have started implementing the animations and movements of the enemy sprites, but my friend Davide Bottino, editor of "Zzap! Italia" and gfx artist currently working on the graphic remake of Toki on C64, literally gave me a hand and I was eager to show it to you!
For this reason I added the level change code, implemented the level 1-2 map and finally added him. Gauntlet, the mechanical fist, Turrican's first and iconic boss!
As always, to best enjoy the video, set the YouTube quality to 720p50 (native resolution/framerate of the video grabbed from OpenMSX)

[ Show youtube player ]

[thegeps]

New update, new step forward for my Turrican on MSX. This time I added collisions with all the bullets. From now on, enemies hit (and ONLY those hit, no missing due to be "pushed" out from the screen) will no longer appear on the game map.

[ Show youtube player ]

[DisasterIncarna]

looking good

[thegeps]

Try it online

https://www.file-hunter.com/Homebrew/?id=turrican

[thegeps]

After the long break that began in mid-November to collaborate on the development of Puzzle Mania (game by my friend Arnaud/File Hunter) for the MSX GOTO40, continued to participate in GOTO40 itself, and extended to eat a lot during the holidays, here I am working again on my Turrican for MSX.
In the last 15 days, in the usual few time available, I've added some things (which you will soon be able to try personally on the File Hunter website, probably within a few hours).
I finally added the sprites' animations (even if there are still no movement/attack patterns so the enemies still remain stationary in their place). Enemies now have the right amount of HP before dying so some of them need to be hit repeatedly. The following modification is also linked to this: I implemented the scoring, using the same values as the C64 version. So each enemy will give us a different amount of points. We will also score points by collecting gems. Finally I also made sure that the enemies that previously disappeared in the dark now change color to remain visible.
As always I recommend setting the video on YT at 720p50 to avoid lose any of the 50 frames per second of the MSX1 PAL version (with which this video was recorded)

[ Show youtube player ]

[saimon69]

Is getting along really good! Do someone is already porting the other levels maps?

[thegeps]

Second level map (level 1-2 tbh) is already ported and ready to use in the current tech demo (only the map, without enemies). I implemented it when I added the first boss (Gauntlet). But until the code will be complete I won't add any other map. When the code will be complete (enemies attack/move patterns, phaser weapon, special weapons, rotating laser collisions, explosions, hidden blocks) then I'll add the first jetpac level. So the code will be really complete. Then I'll talk with Factor5 to ask the permission to publish the game for MSX and, if possible, also for Colecovision (almost same hardware and easy to port on Colecovision+sgm). Only if I'll get the permission I'll port the rest of the data...

[Thorham]

Very awesome. Great effort

[kremiso]

every system on Earth deserve a Turrican port

great work so far!

[thegeps]

I know, I made you wait a long time. But I'm finally ready to show you some progress in making my Turrican for MSX.
In addition to having fixed some bugs (and probably introduced new ones, but this is the curse of us programmers) I started working on the movements of enemies and objects. I implemented "physics" on the extra lives (now they will fall downwards until they find something solid to support them) and the movements of the walkers and the flying eyes. But I didn't just make them move. When they move their position is updated and saved, so if you don't kill them and retrace your steps you will find them in the position where you left them. Since when an enemy leaves the screen I cannot control what is on the map at that point, the enemy disappears momentarily, but once you move away and return it will be there again (this especially happens if an enemy "falls" out of the screen so it is possible to recover it perhaps arriving from another position if this is impossible from the one we are in). I think it's still better than enemies that disappear forever once you leave the game area.
Another notable addition is enemy collision detection with the rotating laser. In short, little by little it's taking on the look of a real game (and it's becoming more and more like my favorite game of all time).
As always I recommend setting the video on YT at 720p50 so as not to lose any of the 50 frames per second of the MSX1 PAL version (with which this video was recorded)

[ Show youtube player ]

[roondar]

It's great to see this evolve into more and more of the game, nice work!

[DanyPPC]

A good port which uses very well MSX1 features.