Game Style and Set Top Boxes

I noticed a post over at Suns Java forums the other day. Essentially it asks about fundamental features of graphics on set top boxes and what that translates to in terms of games. Nobody ever answered.

The Past
About five years ago, common hardware for set top boxes, particularly in Europe, included the ST Microelectronics 55XX series of chips. These chips had no blitter hardware. Thus there were an awful lot of set top boxes with no blitter. Companies producing graphics libraries for these set top boxes did everything in software. Image copies, boxes, lines, circles...all were done by smart graphics libraries running on the main CPU. The trick in achieveing animation lay in one simple task: update the minimum amount of pixels as possible. The easiest way to achieve that was to move only small things on the screen. Thus were born typical set top box games that move small coloured sprites in low numbers around the screen. It was enough for Pacman , invaders, tetris, card games and other 2D, sprite based games where the screen never moves and only a minimum of pixels must be updated each refresh. The background could be placed in an iframe to speed things up. The CPUs were 100-200Mhz.




The Present
Today the vast majority of set top boxes have a blitter - a hardware device for doing DMA copies of memory with some small combinatorial functions (for blending). The blitter can copy memory from one or more sources, combine the data and write to one destination. It can also scale the output. Speeds of copying are high at scale factors of 1.0 and slower at other scale factors. It is thus easy and fast to copy whole screens now at high refresh rates. Companies with graphics libraries for set top boxes compiled their libraries with the blitter drivers enabled and allowed images and filled boxes to be drawn quickly.

Blitters have enabled 2.5D games such as Space Harrier or Burn Out.



However these games are relatively niche in their scaled 2.5D sprite based approach. Another style of game enabled is the scroller game. Now with a blitter it is possible to scroll a background image or even blit many subimages forming a background (such as required in MIDP) composite. Perhaps the classic example of a scrolling game would be Sonic the Hedgehog.



The blitter enables much bigger and bolder graphics and even HD resolution games. As yet largely unexploited.

With the addition of mass storage to set top boxes, be that in hard disk or DVD form, a further category of game became feasible. The laserdisc cartoon game is much maligned but Dragons Lair was an outright sensation when it was released. Here the player simply choses from a limited set of options as the cartoon plays. The game jumps from cartoon sequence to sequence or a death sequence if timing or choices are bad. There are a surprising number of these types of games available and some are even released in HD form. Let me know if you have seen them on set top boxes.



All this said, many games companies for set top boxes have not yet caught up and the vast majority of games available today fall into the small sprite category still.

Adding an internet connection to set top boxes enabled community and multiplayer games. So far these have been fairly limited to such things as small groups (eg 4 players) playing a game against one another and sending pre-programmed messages from a menu. Th world of true multi-player gaming has not yet reached the TV screen.

Even today Broadcom produce set top boxes with 3D hardware. Its unclear what the hardware could do with SD 3D games - could Tomb Raider I style games be achieved in SD or lower resolution? Perhaps. Texturing is still relatively slow and current 3D architectures have restrictions on the numbers of polygons in an area of the screen before dropping in performance. This makes free roaming cameras (as in Tomb Raider) diffcult to achieve. However with careful planning and design, even today on a BCM 7413, 3D games are possible at low resolutions. However, at HD, the hardware isn't yet powerful enough for 3D games for sure.


Yet even if the games can be rendered, the RCU is a crucial problem. The delay on key presses can be 0.3 seconds - fatal for most reaction games. Those complex moves in Tomb Raider would seem to be too much of a strecth for todays RCus. No, to enter into 3D worlds, to have true twitch games, hardware will have to change.


The Future
Graphics hardware is coming that will make 3D games possible, even at HD resolution. Just as interestingly lines and polygons will be added to the set top box in 2D. This means Vector graphics and FLASH based games. Sort of.

FLASH will be able to play on set top boxes well enough that some popular FLASH games like Swords and Sandals will be possible. Though, whether SnS will play unaltered is not clear yet. The point is though, similar games will play.



However equally, or even more, popular games will not. Bloons 3 Tower Defence, and in fact all Tower defence games, simply use too much CPU and most likely too many threads to be viable. Many FLASH games are simply too heavyweight on the CPU to work at all well on the set top box even once the graphics work. That is aside from the memory issues of the bigger games such as Evony.


Casual gaming would seem to be the future for set top boxes. Destined to be behind the PC in terms of raw gaming power and aiming at an audience who are more passive than those infront of a PC.

Multiplayer servers should be very possible with languages like MHP available on the set top box. Community game servers, where league tables, challenges are issued, teams form etc. will all be accessible from the set top box, not just the PC.

New hardware for controlling set top boxes will come. It is currently expensive but Hillcrest are showing the way with pointer devices as optional purchases for set tops on Amazon. Will casual gamers pay? It remains to be seen.

Last Thoughts

Set top boxes and the cable industry are facing a fight now. The internet is upon them. Embracing the internet will be the key to success. Many TVs and set top boxes are beginning to embrace widgets from the internet: small applications that can be downloaded and used directly on the TV or STB. I foresee a time when the games are widgets and app stores for the TV and STB are open and flourishing, selling games worldwide on set top boxes. In such a market it is viable for games developers to create bespoke software, games specifically aimed at set top boxes.