Crappy C64 screen resolution

[saimo]

Originally Posted by AestheticDebris

It's worth noting that, whilst undoubtedly groundbreaking, the Filmation games aren't exactly nippy on the Spectrum either. The code does a lot of things in a sub-optimal way, so there's a lot of scope for speeding up the Spectrum versions (if anyone saw the need).

If the code is suboptimal, then the C64 transpiled code is subsuboptimal. Don't forget that the code of the C64 versions has NOT been handwritten, but translated from Z80 binary code by means of a tool (and then hand-optimized in some places) - and yet it performs just like the original versions.

There isn't really a C64 isometric title that does quite as well as Head over Heels does on the Spectrum (the C64 version is not bad, but some rooms are simplified for performance reasons).

Here is what emu has got to say about Head Over Heels (and Fairlight):

Yes, I’m sure Fairlight can be improved, in fact I have an unfinished C64 version based on an optimised Atari version siting on a hard drive somewhere. It only has the sprite draw routine improved but it still runs about 30% faster.

Head over Heels has a frame limiter set to 12.5 fps. So it runs at the same speed for all versions including the 16 bit versions. The more complex screens might slow down a bit but I don’t see much difference between the various versions. Adding hardware sprites into the mix does allow more colours to be used of course.

Edit: check out all emu's posts in that thread for even more interesting information.

[tomcat666]

Originally Posted by TCD

There is also an Amiga version of that game: https://amiga.abime.net/games/view/raffles

And also CPC one which is similar to C64 but MUCH more colourfull (definetly better looking ).

[TCD]

Yep, looks a lot nicer than the C64 version: [ Show youtube player ]

[AestheticDebris]

Originally Posted by tomcat666

There is one isometric game on C64 that uses multicolor mode and is very fast - it is a full isometric game with objects you can pickup and everything - Inside Outing, the main character and some of the enemies are sprites so they have individual colours. Very nice.

[ Show youtube player ]

Looks nice, the drawing/wipe effect when you change room isn't swift but it does the same thing on the Spectrum and Amstrad too so it's possibly meant to be a stylistic thing rather than just being slow to draw (like Last Ninja 2).

It's obviously not as colourful as the Amstrad version (or C64 Last Ninja 2 for that matter). I guess that's down to the complexity of arranging the colours because isometric objects don't line up nicely with the colour attributes. Still it shows that using sprites and masking them manually can be efficient.

[saimo]

@TCD

Indeed. From the video, I see that the C64 version uses for the background only 4 colors per room, so I wonder if the multicolor character mode has been used, instead of the bitmap mode, which would have allowed a lot more freedom for color placement (I can't check as I don't have access to a computer now). Anyway, even with the bitmap graphics mode, maybe the Amstrad CPC version couldn't be matched, as its bitmap mode allows complete freedom (the "maybe" is due only to the fact that, at first glance, the Amstrad CPC version keeps the very clean graphics style, without cramming too many differently-colored pixels together).

[tomcat666]

Originally Posted by saimo

Indeed. From the video, I see that the C64 version uses for the background only 4 colors per room, so I wonder if the multicolor character mode has been used.

Yes it has, but still it COULD of have 1 individual colour per each 8x8 block, which they didn't use for some reason and went for same 4 colours on the whole room. It is static screen so this should be of absolutely no performance consequence. Still CPC has an advantage here of using more colours. Nice game too.

[AestheticDebris]

Originally Posted by saimo

Here is what emu has got to say about Head Over Heels (and Fairlight):

Edit: check out all emu's posts in that thread for even more interesting information.

Interesting thread. Head over Heels does run the same speed as the Spectrum/Amstrad versions (as emu says, it's a deliberate rate limit so the speed of movement doesn't constantly jump around). However, a few of the more complex rooms pushed the C64 over that budget and so had to have their designs simplified. I've had a look to see if anyone has ever picked apart the exact differences but there doesn't seem to be anyone, oddly enough.

I do think the C64 version could have been pushed further if the sprites had been used for characters/ enemies. As I said I remember have a long chat with TMR about it back in the day and he reckoned the savings would've been enough to restore those altered rooms (and add a splash of colour). I couldn't persuade him to try and have a go though

Originally Posted by tomcat666

Yes it has, but still it COULD of have 1 individual colour per each 8x8 block, which they didn't use for some reason and went for same 4 colours on the whole room. It is static screen so this should be of absolutely no performance consequence. Still CPC has an advantage here of using more colours. Nice game too.

The problem is that these types of isometric games generally aren't built up out of fixed, square characters. You have the isometric objects stored "as is" and then you place them all to draw the screen. This is particularly important if you need to be able to push blocks around etc.

On the Amstrad, that's easy because all objects can use any of the 16 colours and it doesn't matter how they overlap. On the C64 you have to deal with the fact the pretty much every block is going to be partially overlapping with another one. So either you make them share the same colours, favour the colour of one block over another (creating attribute clash like issues) or somehow try to arrange things such that blocks always overlap with "safe" colour combos (which is difficult to guarantee).