Category Archives: DevLogs

Jetboard Joust Devlog #102 – It’s the Little Things…

So… following on from my last post about bugs, here’s everything that was on that Trello TODO list that’s more of an ‘improvement’ than a bug (though of course, fixing bugs is always an improvement)!

1. Different Damage Types
I’ve added different damage types – physical, fire, plasma and jetboard and given enemies the ability to be resistant (or vulnerable) to certain type of attack. Some weapons deal out a combination of damage attacks. I’ve also added armour upgrades that increase the player’s resistance to these various damage types.

2. Object Pooling
I’ve added object pooling as described here to the flamethrower and antimatter gun, both of which were spitting out a ton of new objects per frame which was causing some slowdown if a bunch of enemies appeared armed with the same weapon type.

3. Destructible Buildings / Enemy Bones
I’ve massively improved the animations for destructible buildings and also added rubble which interacts (to an extent) with the player. Buildings now take damage from explosive weapons as well as the jetboard attack, adding to the immersive destruction. Enemy bones and rubble now spin in the air when disturbed with great force – this can look pretty cool under certain scenarios, totally pointless in terms of gameplay but cool!

I’ve also been through and designed skulls for every enemy and added shrapnel as well as bones as that seemed more appropriate for seom enemies.

4. Improved Explosions
I’ve added a bunch more visual ‘snap and crackle’ to the explosions. Spent way to long on this for something that only last a few frames and ended up going down a complete rabbit-hole writing a custom shader based on Voroni patterns (to give the ‘crackle’ effect) which still doesn’t work quite the way I wanted but I think will get the job done. I spent time doing some frame-by-frame analysis of a bunch of pixelart explosions I liked – one thing that surprised me is that the initial ‘whiteout’ flash in many explosions is often preceded by a ‘blackout’ frame. Of course I had to add one!

5. Improved Camera
One of my many arch-nemesises (or should that arch-nemesi?) throughout this project has been the bloody camera. Been back and re-worked it yet again, radically simplifying the code and ending up with a result that’s much better for it. Still little work to do but I think it’s finally almost there. Whereas before I was positioning the camera based on speed/time moving in one direction and enemy position I now rely solely on enemy position and only use speed/time moving in one direction if there aren’t any enemies nearby. I also take difficulty into account when calculating the ‘weighting’ of enemies.

6. Improved Jetboard Attack Visuals
I felt this needed more ‘punch’. It was one of the first things I designed and, as a result, was looking somewhat lacklustre compared to the rest of the visuals. I’ve added particle trails to the jetboard, a subtle shader effect that approximates the attack area, camera shake and a camera jolt. I think the result has miles more ‘oomph’ than it did before.

Oh yeah, I also made the jetboard attack quench fire if the player is alight and safely detonate any ‘stuck’ explosives (cluster bombs or limpet mines).

7. Improved Bomber Enemy
I didn’t like the way these guys pretty much ignored the player as they were attacked, just soaking up bullets until they exploded. I’ve made them get much more aggro when they take damage now which gives them a load more personality.

8. Improved Mother Enemy
This enemy was a bit too much of a ‘bullet sponge’ as well. I revisited the art for this one as I felt it looked a little flat, then I reworked the enemies it gives birth to, making them much more aggressive so it feels more akin to the ‘swarmer’ enemy in Defender that inspired it. I also changed the ‘bullets’ it fires, replacing them with little ‘space invader’ type characters that have far more personality and are far less annoying (though no less difficult).

9. Improved Squocket Enemy
As mentioned in the last post, the AI for this enemy was buggy so I rewrote it. The bullets it fired were also pretty lame and quite annoying so I’ve replaced them with these little ‘baby squocket’ dudes which (can you see a theme here?) have far more personality and are harder but somehow less annoying and more ‘fair’ at the same time! The screen capture software I use went a bit glitchy when capturing the video for these so apologies for that!

10. Improved Baiter Enemy
More of the above here! The enemy itself I was happy with but it’s bullets were really annoying so I’ve replaced them with another little mini invader.

11. Re-routed Treasure Chambers
I had placed these deliberately sporadically throughout the game world so that it would take tons of plays through to get to all of them but in retrospect I think that would have been too annoying. Consequently I’ve reworked things so that you should be able to get all the key treasure from any particular world in three ‘passes’ (or less using teleports). This has meant there’s not much treasure at the outer reaches of the game ‘pyramid’ so I might have to add a few bonus treasure chambers in those outlying reasons to give players a reason to go there other than sheer completionism.

There’s been loads of other minor improvements too but those have been the major ones. Next step I think I need to finalise the main game palettes and then start thinking about a ‘final’ (?) demo movie! The end is almost in sight people…

Dev Time: 7 days (ish)
Total Dev Time: approx 282 days

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Unlocking Plasma Armour

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Destroying Buildings And Playing Amongst The Rubble

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Explosions With More Snap & Crackle

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Bombers Are No Longer Bullet Sponges

Gratuitous Showing Off of the New Jetboard Visuals


The Improved ‘Mother’ Enemy, (Defender Swarmer)


The Improved ‘Squocket’ Enemy and It’s Offspring

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Re-routing the Treasure Chambers
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Jetboard Joust Devlog #101 – Bug Days

Yup, it’s been a while (again). I’ve really had my head down trawling through a list of bugs and small(ish) improvements that I’ve been noting down in Trello over the past few weeks. Desperately trying to keep the motivation up. Have also had a bit of contract work on (which is welcome given the current state of the BitBull coffers) which isn’t over yet either.

So I’m just gonna bore you with a long list of these bugs as this shit is all part of the joy of gamedev. The improvements, which I’ll cover in the next post, are rather more interesting. As well as these there’s been a ton of other minor fixes and a lot of just going through and checking stuff over.

1. Max Out Weapon Damage
Weapons that dealt out damage for more than one frame were often inflicting more damage than they should if they came into contact with an enemy over the course of several frames. This was particularly apparent on bosses which often have a large vulnerable area and multiple ‘proxy’ parts that do damage to the main character. I now keep a ‘damage record’ for these weapons over the course of their lifespan to ensure they don’t exceed the maximum damage to any particular enemy.

2. Fake Frame Rate Judder
Sometime it could appear that the frame rate was juddering if multiple enemies were destroyed in quick succession. This is because I deliberately drop a frame with each explosion to add to the jolt effect. I’ve now implemented something so that this ‘drop frame’ can’t happen too much in quick succession.

3. Palette Fixes
There were multiple issues with things being drawn in the correct palette – particularly with weapons that should be drawn in the same palette as the enemy that fired them. These issues were exacerbated by the fact that I’ve now added three possible palettes for different enemy types. Been through and fixed all these.

4. Bones and Rubble Not Wrapping
Enemy bones and the rubble from destroyed buildings weren’t wrapping with the rest of the world in relation to the player. This had me scratching my head a bit at first – there are a ton of these sprites so I don’t want to check them for wrapping every frame. In the end I figured I could get away with just checking one per frame (the wrapping doesn’t have to be accurate as it always happens way outside the player’s view). This works fine and has zero performance impact!

5. Check Level Up Rate and Damage Scaling for All Enemies
Some of these were wrong so I’ve been through the laborious process of checking all the scaling parameters =for every enemy.

6. Splitting Crawlers
Under some scenarios the ‘crawler’ enemies were doing weird shit, splitting in two and stuff. I think I’ve fixed this (it was to do with the algorithm that positioned them sometime positioning them out of the player’s ‘wrap zone’) but it was such a hard bug to replicate I can’t be sure so I’ve also added some code to ‘paint over’ the bug should it happen again (I hope)!

7. Levels Completing Too Early
This could happen with enemies that split into multiple offspring when destroyed. Had to write something toi account for this in teh code that checks for level completion.

8. Parallax Scrolling Glitches
Keen observers may have noticed this on some of the GIFs – elements of the parallax scrolling kept moving when they shouldn’t and, on very rare occasions, could completely glitch out. This was a real pain in the arse to fix for something that should really be pretty simple – in the end I re-wrote pretty much all the parallax scrolling code from scratch.

9. RPG Anim Playing Constantly Post-Mutation
RPG weapon would glitch out if the enemy that was armed with it mutated. This was another one that was a real pain in the arse to fix (hard to replicate). In the end I figured out it was to do with object pooling.

10. Flamethrower Not Working On Egg Sacks
Easy fix

11. Jetsuit Pickup Not Wrapping
…and doing other weird shit like disappearing. I’d implemented this in a rather hacky way for some reason so went back and wrote it as a ‘proper’ pickup.

12. Invaders Getting Stuck
Blocks of invader enemies could get wedged between a high building and the top of the screen and end up not moving. Fairly straightforward fix.

13. Title Screen Glitch
Title screen could get weirdly offset if the player exited the game whilst in a treasure chamber(!). Fixed this along with a few other game over / exit issues.

14. Treasure Chamber Escape
Player’s could jump out of a treasure chamber using the jetboard attack and end up falling endlessly through the void beneath! Fixed.

15. Buggy Bombers / Gravity Hammer
Bomber enemies were glitching out sometimes when struck by the gravity hammer. Fixed this and have also gone through and checked a bunch of other enemies against the gravity hammer (which has probably ended up being the most PITA of all the weapons).

16. Player Jump Anim Constantly Playing
This could happen sometimes after a jetboard attack. Was surprisingly difficult to fix, largely because I haven’t touched that part of the code for something like three years now!

17. Teleports Skipping Levels
Fixed various bugs to do with the selection of levels when teleporting.

18. Teleports Blocking Chamber Entrances
Sometimes teleports and warp gates could appear over the treasure chamber entrance making it impossible to enter the chamber. Easy fix.

19. Disappearing HUD
Sometimes the HUD wouldn’t appear correctly on the upgrades screen meaning the user had no idea how much cash they had to spend. Fixed.

20. Enemies Appearing ‘Inside’ Buildings
Problems with some of the algorithms that position enemies as they teleport in. Fixed.

21. Scanner Rendering Of Destroyed Buildings
The scanner rendering of destroyed buildings was glitching out if the building was destroyed after it had wrapped relative to the player. Fixed, with some difficulty. At least this one was easy to replicate!

22. Explosive Raycasting Issues
There were some issues relating to the removal/blocking of enemies in the raycasting checks that are carried out for explosive weapons. Fixed these and also tweaked the raycasting code for much better damage distribution, plus made all explosive items inherit from the same class and got rid of a load of dodgy ‘cut and paste’ code.

23. Squockets Getting Stuck On Buildings
Sometimes the ‘Squocket’ enemies could get wedged somewhere and just keep banging their heads against a brick wall. I wasn’t entirely happy with the tracking code for this enemy anyway so re-wrote the bulk of it.

24. Limpet Mines and Collision Proxies
Limpet mines were sticking to collision proxies that weren’t transferring damage in their current state, rendering them pointless. Does that mean anything to you? Probably not, but it was an easy fix.

Dev Time: 7 days (very approximately)
Total Dev Time: approx 275 days

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The Joy of a TODO List That’s Now DONE

Bug Day!

Jetboard Joust Devlog #100 – Die and Try Again!

This blog should really have been Configuring Things Out pt. 2 but I thought ‘Die and Try Again’ was more appropriate really.

Now all the enemies and weapons are finally done I’ve been going back over the game worlds, playtesting and (re)adjusting all the various character/weapon stats and levelling rates. The only way of balancing the weapons is to simply play the game a lot, and if I feel I’m either avoiding particular weapon because it’s too weak, or that I’m constantly gravitating towards a particular weapon because it’s too overpowered, I tweak the stats as appropriate. It’s been a very time consuming process and I have to say I’ve been at something of a low ebb whilst doing it.

Unlike fixing a bug, you don’t ever get to the point where you think something is ‘done’, and I know I’m going to have to go through this whole process again at least one more time to refine things further before the game is complete. It’s really getting to me now.

The thing that’s made this phase so much tougher than the first configuration ‘pass’ is that I’ve been through every single boss and mini-boss fight in the first four worlds and attempted to adjust the difficulty for each. There are over fifty of these and, by nature, they are supposed to be tough, so this entails a *lot* of failure both in terms of dying in-game and in terms of setting the difficulty level either too easy or too hard.

Most of these challenges are mini-boss battles featuring the Guardian enemy and a new weapon unlock or upgrade. To maintain a certain amount of narrative ‘flow’ (and to stop me being lazy) I’m having the enemies guarding the unlocks armed with the same weapon they are protecting. The strength of the enemy is heavily dependent on the strength of the weapon, therefore a tweak to the stats of said weapon (because I think it’s too weak or too strong in-game) has a knock-on effect in every single battle that features it. It’s a cyclical process and one that I’m starting to think could go on forever, like painting the Forth Bridge. On a good day though I see it more as a kind of gradual ‘whittling down’ with every pass getting me nearer to the ideal balance.

It also makes a difference what weapons are available to the player during these battles. I was choosing these weapons completely randomly (but based on a consistent seed) though towards the end of the process I realised this wasn’t working and I needed a better balance of weapon choices. Consequently I’ve divided the weapons into four categories – long range, short range, wide range and explosive, and I make sure a balance of weapons from each category is chosen. I think I may ditch the consistent seed as well so each time you enter a level the weapon choice is a lottery, albeit a balanced one.

There’s also been a myriad of bugs and other gameplay tweaks I’ve made along the way though at this stage I’m trying to restrict myself to fixing bugs/tweaks that actually affect the balance of gameplay and noting everything else down on Trello cards for later attention. There’s currently around fifty of the Trello cards (groan) and there’s at least another ten things I haven’t noted down yet!

I’ve also been back through the first four major boss fights and made a proper attempt to balance the difficulty of these with the (rough) stats the player should have achieved by that point in-game. If you’ve been following this blog you’ll remember how much time I’ve spent on these boss fights already, so it’s been doubly demotivating having to go back to them, debug them again, run through the fight procedure again and again AND again whilst discovering yet more bugs and issues that need fixing. On a positive note though, it’s been nice to revisit them in different colour palettes.

Lastly, and I know this is going to sound like archetypal first-world moaning, I’ve been surprised how physically exhausting this process has been. Basically playing (often ludicrously difficult) boss fights for eight hours a day for eight or nine days straight takes its toll. I try to be as careful as I can be about posture but my shoulders ache, my wrists and elbow joints ache, and my back is fucked. Yes, I know it’s not exactly working down a mine, but being physically in pain doesn’t do wonders for one’s motivation. I can’t wait to finish this game and take a break from this shit.

Oh yeah – one thing that’s kept me going through this process is the fact that I can just turn the game sound off and listen to music. I’ve finally succumbed to subscribing to Spotify and have been listening to a lot of Tangerine Dream. Strange coincidence – I finally got round to watching Netflix’s enjoyable Bandersnatch interactive movie at the same time and what does that feature? A ZX Spectrum game developer slowly going insane trying to finish a game whilst listening to lots of Tangerine Dream! Weird…

Right, on to those Trello cards…

Dev Time: 8.5 days
Total Dev Time: approx 268 days

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The ‘Spinner’ Boss In Colour

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The ‘Squirmer’ Boss In Colour

R.P.G. Guardians. Die and Try Again – and Again, and Again…

Jetboard Joust Devlog #99 – Weapons of Mass Destruction

One of the things that’s struck me whilst going through and actually playing Jetboard Joust (rather than working on individual parts in isolation) is that one of the most satisfying aspects of the game is when you get to take out loads of enemies in one go with a really destructive weapon such as the R.P.G. or Grenade Launcher.

So I decided to emphasise this side of the gameplay a little more before I finally drew a line under enemies and weapon types. I wanted to add some more ‘swarm’ type enemies and another super-destructive weapon to assist in taking them out.

Rather than work on new enemies from scratch (I really need to get this game done!!) I thought I’d re-engineer some of the ancillary enemies I’d created for the boss fights. There’s three of these, and they all fit together pretty well as a kind of ‘set’ of weird alien invertebrates – jellyfish, squid, and a kind of carnivorous worm!

Given the nature of these enemies, and that fact that they’re only going to exist in fairly large batches, I thought it would be nice to have them born from some kind of egg sack rather than teleporting into the game individually like everything else. I spent a fair bit of time working on a nice, pulsating egg sack(!) and think the end result works pretty well. The egg sack is the same for each time of enemy but I quite like the idea that you’re not quite sure what you’ll be in store for when you burst it open!

Then, just because I wanted to, I also added another enemy that’s like a really tiny version of the baiter-inspired enemy that acts as the game’s time cop. As it looks like a tiny UFO it’s also a reference to the big and little UFOs in Asteroids. These don’t spawn from egg sacks though!

The new weapon is something I’d been thinking about for some time (and even unsuccessfully experimented with a bit) but only became a solid idea after seeing the scene where Rico takes out the tanker bug in Starship Troopers (again, sorry to keep going on about that film).

I’m calling it the ‘Cluster Bomb’ – it fires a single explosive charge which splits into several smaller charges when it explodes, these smaller charges then repeat the procedure. Each charge is sticky, which means it will become attached to any enemy that comes into contact with it. The charges only detonate after a certain time period, not on impact.

As you can imagine, this weapon rapidly creates full-on mayhem. Originally I had each charge leaving a smoke trail when it explodes but, unfortunately, this was causing the refresh rate to drop when tons of charges were fired at once (by the player and enemies) so I think I’m going to have to stick to just using particles for most of the explosions. Shame, as it looked really cool with all the smoke, but I guess running all those individual custom shaders at once is asking too much. In later versions I’ve added a very slight randomness to the time the charges deonate so everything’s not quite so symmetrical, I think I prefer it like this.

I’ve also been working on a couple of new palettes. One using the (now slightly #indiedev cliché) red and black ‘Downwell’ style palette and another based on the colours available on the Commodore 64. I really like the C64 one. As I was always a Spectrum guy I’m realising the genius of whoever picked those 16 colours 35 years too late! I like the Downwell palette too but I couldn’t get it to work with visually with the background parallax so I decided to lose the background and stick with the three colours. It is retro after all…

Dev Time: 4 days
Total Dev Time: approx 259.5 days

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Taking Out a Batch of Mini-Squockets with the Cluster Bomb

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Cluster Bomb vs Jellyfish

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Mass Destruction of Mini-Squirmers

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I Call These Enemies the ‘Little Bastards’!

Jetboard Joust Devlog #98 – Not *That* Kind of Bug!

Onto the last of the ‘classic videogame’ enemies now, this one draws its inspiration mainly from the wonderful ‘Space Invaders’ style shooter ‘Galaxian‘ and, to a lesser extent, its sequel ‘Galaga’. It’s also heavily inspired by my recent re-watching of Paul Verhoven’s marvellously cheesy Sci-Fi gorefest ‘Starship Troopers’. I’m calling it the ‘Swooper’!

I’d been thinking of doing a Galaxians-style enemy for some time but it was watching the ridiculous (but genius) scene in Starship Troopers where Rico takes out the tanker bug that really cemented the idea in my head. A similar bug would fit perfectly into the Jetboard Joust world and also really suit the ‘Galaxians’ style of attack.

So I started by working on the basic movement style which was really very simple, I use LERPing to rotate the enemy towards the player whilst applying a constant velocity in the direction the enemy is currently facing. This worked fine once I’d tweaked the parameters, resulting on a nice circling motion of the enemy round the player which I felt was quite insect-like.

What was more complex was to get the enemies flying in formation. My standard approach to this kind of problem, and one I also used in this case, is to create a ‘hive mind’ class that manages the positioning of all the enemies. The individual enemies can report back to the ‘hive mind’ with various info regarding their environment but it’s the hive that tells them where to position themselves.

I tested a number of different algorithms for this – the one I ended up with allocates a leader for the hive who operates effectively as a solo entity with the movement pattern I described above. The hive mind calculates the ideal positioning of the other enemies in the swarm and I use LERPing again to move them towards this ideal position as well as to rotate them to align with the leader’s current rotation.

If certain parameters are met some of the swarms member’s will go solo, leaving the pack to chase the player in a more aggressive manner. The hive mind class manages this to make sure the entire swarm doesn’t break up at once.

I was particularly pleased with the way the swarm reorganises itself once one of its members is destroyed or goes solo to chase the player!

The art for this enemy came together very quickly (for a change) – I used the tanker bug from Starship Troopers as my only reference and it just kind of worked! The thing that took longest was getting the rotation of the wings to line up properly when the bugs are in flight. My only slight worry with the art is that I’ve used very dark colours – this makes it look pretty badass most of the time but it might be too hard to see clearly in some palettes.

I was so pleased with the way this enemy came together that I added a smaller version, the Mini-Swooper! This operate in exactly the same way as the larger version only more of them can leave the pack at once and they don’t fire at the player, they just attack them physically. They are also faster.

As a footnote – until looking it up just recently I was always convinced that ‘Galaxian’ was called ‘Galaxians’. It actually freaked me out a bit it was called ‘Galaxian’! Must be one of those collective false memory things like being convinced the Monopoly man wore a monocle!

Dev Time: 2 days
Total Dev Time: approx 255.5 days

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Badass Bugs – Taking Out A Couple of Swoopers

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Mini Swooper Mayhem

Jetboard Joust Devlog #97 – Creepy Crawlies!

No prizes for guessing the classic arcade game that’s the inspiration for this latest enemy – yup, it’s another of Atari’s masterpieces – Centipede! Working title for this enemy is the ‘Scuttler’ (I already have a ‘Crawler‘ and a ‘Squirmer‘)!

The mechanics of this enemy are pretty simple, I thought the hardest thing to get right would be the algorithm that makes the segments ‘follow’ the head (I’ve had to right similar code in the past and got myself into a right mess) but the code I came up with, unbelievably, worked pretty much right of the bat!

There’s probably a better way of doing it but my basic approach here is to ‘remember’ the direction each segment is travelling and to continue moving in that direction by default each frame. If the total horizontal and vertical distance between one segment and the next is less than the desired segment spacing no movement occurs. If the segment aligns horizontally or vertically with the segment in front we switch orientation (i.e. from horizontal to vertical or vice versa). This seems to work well enough for my purposes but if anyone has any better ways of doing this I’d be interested to hear them as it’s a gamedev problem I seem to run into quite a bit.

Unlike the Atari Centipede I don’t have any mushrooms to run into to initiate a change of direction so I had to improvise a bit here. Changing direction when it hits buildings was an obvious one, but I also have it switch direction when it hits the edge of the screen (i.e. camera area) and, with a certain amount of leeway, when it aligns with the player on the opposing axis. This approach seems to maintain an authentic ‘Centipede’ feel whilst working within the confines of the Jetboard Joust gameplay.

I also added a slight ‘sway’ to the segments as they move as a fixed horizontal or vertical movement just seemed too ‘static’ in context even though it would have been truer to the original game. I want to tip my hat to these classics rather than slavishly replicate them.

Of course I also had to have the centipede splitting into two when it’s health is reduced which means things can get pretty manic (in a good way, though I’ve toned it down a bit since this video as things were getting too out of hand too quickly).

I’ve also been working on a Centipede style retro arcade palette but have been running into a few issues trying to get this to look good across all sprites. The red outline you can see is used on some of the sprites in the original arcade game. I like the way it looks here as I designed the sprite around it but it looks terrible on many of the sprites I’ve already designed so I think I’m going to have to use a more generic approach. If I ever make another game I’m going to make sure I treat my outline colour as a completely separate part of the palette – lesson learned!

Dev Time: 2 days
Total Dev Time: approx 253.5 days

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Close Up Of The Scuttler – Centipede Tribute Palette!

Jetboard Joust Devlog #96 – Splitting Up!

Bit fed up with parameter tweaking, so before I finish the final first round of config by going through the treasure chamber guardians and bosses I thought I’d try and get the final non-jetboarding enemies wrapped up.

There’s going to be three of them in all I think, and I’m pretty keen to have each of them be a mini-homage to a classic arcade game, much like of already included one to Space Invaders. First up is Asteroids and an enemy I’m tentatively calling the ‘splitter’.

Originally I had imagined this enemy being a kind of giant jellyfish that split into smaller versions of itself when attacked, but then I happened across the first Starship Troopers movie whilst late-night channel surfing one evening.

It’s a pretty good movie and I haven’t seen it for ages so I ended up sticking with it to the end, and whilst watching it occurred to me that the theme of humans battling off waves of attacks from an insectoid alien race (often with fairly ‘conventional’ weaponry) wasn’t too far removed from Jetboard Joust!

I also thought that the gelatinous ‘brain bug’ at the end of the movie would work very well as an enemy that could split into smaller versions of itself so I used this as the inspiration behind my designs for the ‘splitter’. I drew inspiration partly from the movie and partly from an illustration I found from a 1970s board game version of the book which was simpler and more comic-like.

Rather than try and draw the entire enemy as one piece of art I wanted to build it from smaller components so I could easily make versions at different sizes. First off I created a pulsing body. I tried a number of different versions of this and ended up using a variation of the segments from the ‘squirmer‘ boss. The segments all pulse at the same rate with but start from a randomised offset.

I then added a series of eyes based on the eyes from the ‘spinner‘ boss and a mouth based on the mouth from the mini worms that the ‘squirmer’ gives birth to. It took a while to get the placement of the eyes right, the end result heavily references the movie ‘brain bug’.

Once I was happy with the general placement of the eyes and mouth I needed to make them feel part of the pulsing body as, when simply placed statically they looked far too ‘stuck on’.

I ended up linking each facial feature with a body segment and changing the location of that feature based on the current scale of that segment. This seemed to work pretty well in giving the impression that the features and body were joined rather than overlaid layers.

Enemy movement, as in Asteroids, is very straightforward as – a simple linear motion with a reflective bounce when an obstruction is hit. What was slightly tricky was deciding what to do when the enemy left the camera area. Originally I had it wrapping immediately to the other side of the camera (true to Asteroids). This was kind of cool, and I really liked the fact it was true to its roots, but unfortunately it made the gameplay way too intense – particularly when other enemies were encountered at the same time. I didn’t like the way it made the scanner look broken either.

So I tried simply having them wrap when they reach the edge of the game ‘world’ but this wasn’t intense enough and kind of dull. Eventually I settled on a halfway house between the two, if the enemies are offscreen or nearing the edge of the screen a decision is made as to whether the quickest route to the player is to travel in the same direction or to reverse direction (I take world wrapping and the current player velocity into account). The enemy switches direction (or not) based on this. This keeps the gameplay intense as things tend to cluster round the player but it still makes sense within the overall gameplay paradigm – and it doesn’t make the scanner look like it’s broken.

Something else I’ve been doing which has taken up at least a day of this dev time is working on a ZX Spectrum themed palette and improving some of my palette code. I can now have three different palettes for enemies as opposed to just one. Whilst doing this I discovered some bugs in my palette shaders which were particularly apparent when dealing with 100% RGB values as are used in some of these retro palettes, these are now fixed.

Dev Time: 4 days
Total Dev Time: approx 251.5 days

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The Brain Bug from the 1970s Starship Troopers Board Game

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The Final ‘Splitter’ Design

Asteroids-Style Wrap Logic – Too Much Mayhem / Broken Scanner!


The Final ‘Splitter’ Alongside Other Enemies – ZX Spectrum Palette

Jetboard Joust Devlog #95 – Configuring Things Out pt. 1

This is one of those devlog entries that seems kind of dull because there’s been a lot of ‘under the hood’ type goings on and not a lot of eye-candy to show for it.

But, it’s taken time and it’s really important to the game’s development so I’m going to blog it anyway, boring or not!

What I’ve been focussing on is the overall structure of the game world and how difficulty progresses throughout the game. At this stage it has been very much a first pass at this, as much about providing the tools to allow me to tweak gameplay efficiently as it has been about balancing the gameplay itself.

I’ve broken down what I’ve been doing into three key tasks:

1. Code Refactoring
As with any game of significant scope, there are multiple interconnected parameters that affect gameplay difficulty in Jetboard Joust and it’s a hell of a lot easier to tweak things if the code that manages these parameters is in one place rather than split across a myriad of individual class files. Consequently I’ve set up a static ‘Config’ class that contains all the algorithms and configuration parameters for pretty much anything to do with rewards and difficulty throughout the game. This has involved a lot of tedious cut and paste but I know it’ll be worth the effort in the long run (it already has really). I’ve set up generic parameters here for the amount things like enemy health and weapon damage/difficulty scale throughout the game so at least I have a baseline to work with and can tweak individual scaling from there if necessary.

2. Mapping
I’ve created a template in InDesign for mapping out levels in each of the game worlds and have been through this with a first pass attempt at placing weapon unlocks and new enemy ‘reveals’ in each. There seems to be enough content to fill four level ‘pyramids’ of around twenty rows each with a reveal rate of a new enemy or weapon every couple of rows. I need a couple of different ‘non-jetboarding’ enemy types but was expecting that anyway, I added an additional jetboarding enemy to span the difficulty gap between the ‘minion’ and ‘master minion’ which was fairly simple to do. I may make the fifth and final world smaller, probably ten rows, with the final boss right at the end.

3. Auto-Levelling
In order to be able to arbitrarily test game difficulty I need to be able to jump to a particular level and have an idea how the player might have ‘levelled up’ at that point. What weapons will they have unlocked and how powerful will they be? What will their base health be? It’s not straightforward to figure this stuff out so I ended up writing an algorithm that takes a destination point within the game pyramid, figures out the location of each treasure chamber before that point, then does a mock play though of the game to unlock each treasure item. On the way I collect the cash that would be awarded for defeating enemies, rescuing babies, and completing ‘sectors’ (rows of the pyramid). Once cash is earned it is spent on the most expensive upgrade available.

It took quite a while to test this code and get it working but it’s going to be invaluable for testing as I can now start the game at any point and have the player ‘levelled up’ as appropriate. Using this code I can also monitor things like how long it will take to level up a particular weapon, how much a player might earn for completing a level at the point weapons are unlocked (hence what a sensible starting price for updates might be) and all sorts of other stuff I haven’t even thought of yet!

4. Basic Gameplay Testing
Using the code above I began going through the game to check and tweak parameter scaling at key points (i.e. the ‘reveal’ level for each weapon and enemy) to make sure things seemed sensibly balanced. Unsurprisingly they were way off to start with but after much fiddling I’ve reached the point where relationships at least seem workable, haven’t done the treasure chamber guardians and bosses at all yet though.

One thing that became apparent was that weapons that are unlocked earlier in the game need to have a greater number of upgrade levels than ones that come later on, otherwise they either ‘max out’ too quickly and end up becoming useless on high level enemies or they cost far to much to upgrade in the early stages. This was particularly apparent with the default weapon (the pistol) so I ended up adding a new default weapon (the .45 magnum, essentially a pistol on steroids) which is unlocked about halfway through the game and has enough grunt to take the player through to the end of the game.

I also ran into a shedload of bugs, it’s been ages since I looked at many of these enemies/weapons so there’s a ton of small issues created by various changes I’ve made. Fixed a bunch of them as I went along (partly why this phase took so long) but I’ve still got a very long TODO list in Trello!

Dev Time: 6 days
Total Dev Time: approx 247.5 days

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Mapping Out The Levels

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Debug Output From The Auto-Levelling Code

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A New Type Of Minion Enemy

Jetboard Joust Devlog #94 – The Armed and the Dangerous

So far this year I’ve been focussing on weapons and the weapon unlock/upgrade mechanic in preparation for doing the wider gameplay and difficulty balancing. I’ve broken this down into three key areas…

1. Ammo Drops
It became clear whilst testing the bosses that the way I was calculating ammo drops was flawed and I needed a better method. The method I eventually came up with is simpler than its predecessor, works far more effectively and should ‘scale’ automatically as weapons are upgraded and the player faces enemies that soak up more ammo. For each weapon I now work out the maximum amount of damage that can be done to any enemy from a clip’s worth of ammo (the amount contained in a single ammo drop). I then scale this amount based on the accuracy of the weapon in question (weapons that have a lower accuracy scale down more as one must assume that not every shot will hit its target). Once the player has dealt out damage to any combination of enemies that exceeds the resultant ammo refresh rate a new ammo drop is awarded. It’s important to record the damage dealt as the amount of damage that would be dealt if the enemy had infinite health, otherwise enemies that are destroyed by the attack score too little and this can really skew the system.

To test this I set up a ‘sponge’ enemy that does nothing but takes loads of damage and tried out all the different weapons on it in turn, tweaking the accuracy scaling and checking the method I was using to calculate the max damage per clip was correct on each one. This was easy for weapons that simply fire bullet-style projectiles but more complex for weapons like the flamethrower. For ‘area of effect’ style weapons like the grenade launcher, RPG and sonic boom I can only really approximate an idea of maximum damage.

Whilst in the process of the above I got pretty distracted re-working the shotgun blast effect as it still didn’t seem to give an accurate indication of the blast’s area of effect. This is the third time I have re-worked this(!)

2. Weapon Switching
To date the player has only been allowed to carry one weapon at a time. If the currently armed weapon runs out of ammo they were automatically switched to the default weapon (pistol) which has infinite ammo. If they wanted to arm a more powerful weapon again (pretty much guaranteed) they would have to pick one up from a weapon crate AND find an ammo drop to recharge it should it have run out.

I decided this mechanic was no fun and therefore, according to the Scott Rogers principle, had to go. Now I am allowing the player to carry two weapons at once – the default weapon with infinite ammo and a (generally) more powerful secondary weapon. If the secondary weapon runs out of ammo the player is switched automatically to the pistol as before but this time all they need to do to recharge it is collect an ammo drop. The new mechanic seems to feel much more natural and fun to me, though I’m a little worried it might give the player the opportunity to over-exploit powerful weapons but we shall see…

As an adjunct to the above I also implemented a key to switch weapons so that the player can switch to the pistol if they want to save ammo on powerful but understocked weapons such as the RPG.

3. Weapon Unlocks
Previously, in order to unlock a weapon, the player had to catch the jetboard of an enemy that was armed with it. This worked OK, but it was a bit easy and I didn’t really think it made a big enough deal of the weapon unlock process.

I’ve decided instead to have weapon unlocks as a type of treasure. Rather than being guarded by a boss, the treasure chambers that contains these weapon unlocks will be guarded by a fleet of enemies armed with the weapon in question. This enables me to make more of the treasure chamber mechanic, adds another layer to the gameplay, and also allows me to use the big ‘weapon upgrade’ icons (which I was rather pleased with) in-game as pickups.

It didn’t take me long to design these ‘guardian’ enemies but I spent a fair bit of time on implementing some special AI for them. Firstly I enabled them to swoop down and steal the player’s health pickups to heal themselves (I may allow other enemies to do this once the reach a certain level), and secondly I implemented a special ‘wrap attack’ whereby if a bunch of them have been chasing the player in the same direction for some time a few will take advantage of the world wrapping by peeling off and heading in the opposite direction to meet the player head on!

The video demonstrates unlocking the shotgun by defeating a small fleet of enemy guardians. They’re pretty tough opponents – as you can see I had to rely pretty heavily on the jetboard attack here and was pretty lucky managing to take out three of them in one go!

Dev Time: 241.5 days
Total Dev Time: approx 4.5 days

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Using a ‘Bullet Sponge’ to Test Ammo Drops

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Enemy AI Now Enables Them To Steal the Player’s health Pickups

Unlocking The Shotgun – Note The Guardian’s ‘Wrap Attack’ Technique

Jetboard Joust Devlog #93 – Sucker Punch pt. 2

Well, I got there in time for Christmas (just)! The last boss is finally done, bar some polishing and tweaking of difficulty, and I’m extremely glad to have put this one to bed.

I ended up pulling out quite a few of the stops for this one (it’s the final boss after all) so there’s five/six separate stages to the fight and multiple different attacks and animations within each phase. The audio alone took around two solid days.

So here’s a description of each stage of the battle – I ended up switching the first stage (as described in my previous post) to stage two.

Stage One – Claws
In the first stage the Octopoid has grabby, snappy claws at the end of its tentacles which it lashes out at the player to cause large amounts of damage. It also has a secondary attack where it stops to fire mini black holes from its claws. I’m not entirely happy with the look of these mini black holes yet, that something I’m going to come back to.

The Octopoid moves pretty fast at this stage, and if you let yourself become entangled in its tentacles it can be pretty hard to break free!

To complete the stage the player has to destroy each claw – when a claw has taken a certain amount of damage it breaks off and falls to the ground. The rest of the boss is invulnerable to damage.

Stage Two – Dive Bomb / Black Holes
I wrote about this stage in the previous post so won’t go over it again here. It made sense to have the stage second as a) I thought it would look weird if the boss suddenly sprouted claws, and b) As the player is shooting at the boss’s mouth tentacles to cause damage it makes sense to have these destroyed at the end of the stage and I wanted the Cthulhu tentacles in play as long as possible!

Stage Three – Lasers
With its mouth tentacles destroyed, the Octopoid’s gnashing teeth are revealed and it begins to fire lasers at the player from the end of its tentacles. It moves pretty erratically in this stage as if it’s somewhat out of control.

To complete the stage the player must destroy each tentacle (once the end of a tentacle has taken a certain amount of damage the entire tentacle self-destructs). When each tentacle is destroyed the boss goes into a crazy spin which can be devastating to the player if they’re too close.

Stage Four – Dropping Squockets
By this stage the Octopoid is looking rather the worse for wear as it has lost all it’s tentacles. It still has plenty of fight left in it though! Its two attacks in this stage are a ram attack where it simply launches itself at the player, and the ability to spit out bubbles contain mini squocket enemies. These mini squockets are armed with rocket harpoons which they will launch at the player given the opportunity.

To complete this stage the player must keep ducking behind the boss and deal damage to its bulbous cranium. The front of the boss is invulnerable to weapons.

Stage Five – Phase Inversion
This stage is really an extension to stage four. The octopoid has lost half its skull by now, leaving its brain dangerously exposed. It still launches itself at the player in a ram attack but also spits out antimatter ‘ink’ based on the ‘Black Hole Blaster‘ weapon (which is probably going to be renamed the Phase Inverter but I’m not 100% decided on that yet).

Of course it’s the exposed brain that takes damage here and enables the player to move onto the final stage of the battle…

Stage Six – Skull Spin
There’s not much left of the Octopoid by now so it launches itself at the player in a fast and ferocious spinning attack whilst spitting out black holes as per stage two. If the player doesn’t keep moving here they will come a cropper pretty quickly as they’ll get sucked into a black hole and battered to kingdom come by what little the boss has left!

All the boss is vulnerable to damage now and, for added drama, I had it lose each eye and then its teeth as the player gradually pounds it into oblivion. Hopefully this makes for a fitting end to an epic battle!

I’ll be tweaking the difficulty of each stage considerably when I get to balancing the weapons and difficulty across the game (the next thing I’ll be working on) – I’ve nerfed the boss’s abilities quite considerably in the video so I could compress the whole battle into a reasonable space of time! Also this video (like most of them) has been blown up 150% as my computer is incapable of capturing 1280*720 at 60fps – it struggles even at this resolution. The rotations particularly look much better at the proper resolution. I need to find a solution to this for when I create my ‘proper’ promo reel.

Dev Time: 10 days (so that’s 19 days in total for this boss – groan)!
Total Dev Time: approx 237 days

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