Let's talk... PSP graphics + Design

[Panajev2001a]

Front-buffer is 1/4th, Back-buffer is one fourth, Z-buffer is one fourth.

So we can scale by dividing by 4 the non texture related portion of VRAM ( Maybe I exagerated multiplying by 4 the VRAM, but let's keep work this out ).

On the GS you would "normally" leave ~1.5 MB for textures ( part used for streaming buffer and part as static texture bufffer ).

2.5 MB would be taken by Frame-buffers and Z-buffer: 2.5 / 4 = 0.625 MB.

2 - 0.625 = 1.375 MB

That is like 68.75% of VRAM.

PSP's GPU also seems to have better than GS's texture compression ( enough to deserve its own space in the specs announcement ) and that should help leverage the Texture space.

The pipe that connects the GS and the GIF ( GIF-to-GS bus ) reaches 1.2 GB/s peak: the PSP's GPU is on a ( shared ) 2.6 GB/s one.

There is a good chance we will get to stream more textures per frame than we did before: the pipe is larger, there is less vertex data floating around ( more use of HOS, no re-sending, hopefully, geometry for multi-pass rendering, texture compression, etc... ) and System RAM's latency is lower than what even RAMBUS Direct DRAM with on-die memory controller offered ( it's e-DRAM after-all ).

Also with 1/4th of the resolution we likely need less texture resolution to convey a similar level of detail without pixellization or shimmering ( which higher resolution texture helps and mip-mapping and texture filtering have to come to the resque ):

512x256 texture maps now are MORE than enough to have textures mapped on polygons which take the whole screen ( imagine a HUGE rectangle facing the screen and its normal being anti-parallel to the view vector ). This polygon will take at the most 480x272 pixels and in this case we would have MINOR pixellization ( we have bi-linear filtering for shimmering and pixellization anyways ): the Pixels:Texels ratio is only ( and we have to take into account that we have a vertical stretching of the texture to cover this polygon as raw math would tell us we have more texels than pixels ) 1:1.0625.

With a 256x256 map the Pixels:Texels ratio would be approximately 1:2 and that will result in minor blurring.

The Pixels:Texel ratio for a 640x480 screen resolution and a 256x256 map ( displayed in similar conditions ) would be 1:4.6875 or almost 1:5.

Condensed version by Fafalada:

Not that I really disagree with Pana's explanation but I think it can be put a bit more simple then that.
First and foremost, the screen is actually physically smaller then 1/4 the size of an average TV - eg. pixels will be quite small and perceived detail will be that much higher - try playing PSOne on that LCD if you haven't yet to observe the effect (this also relates to the talk of uber AA and filtering and what not).
Second, the issue of pixel resolution - typical objective of on screen texturing is to get average 1:1 pixel/texel ratio. Smaller pixel resolution - less texels needed to get the ratio, it's fairly simple math.

In short you have much smaller texture requirement then DC to get equivalent detail. Personally I'm more wondering about executable sizes myself, if you directly ported a PS2 game over it'd take nearly half of main memory with that alone.

Sigh, sob... he did a great job and was concise

I fell into the trap of making it too long and articulated while I could have simplified it ( I forgot to mention that the physical screen size was also smallr and how that would affect things )

 

[notAFanB]

The PSP GPU includes TC also in case you missed it (though we don't know what kind yet).

it'll launch in coming year so they've got to be able to implement some form of VQ in this age trivially.

Personally I'm more wondering about executable sizes myself, if you directly ported a PS2 game over it'd take nearly half of main memory with that alone.

even taking into account games from the round up surely animation+vertex data will likely eat up alot of Main RAM? and that's before we look at EXE sizes and what not.

 

[chaphack]

Additionally, battery life was said to be comparable to other high-end devices (roughly 3-6 hours),

http://ps2.ign.com/articles/450/450203p1.html?fromint=1

roughly 3-6 hrs....hmmm hmmmm.... :?

 

[notAFanB]

Additionally, battery life was said to be comparable to other high-end devices (roughly 3-6 hours),

uh oh, think I'll wait for the first test reviews.

 

[chaphack]

Ehy remember one old topic/poll on PSP battery life. IF it IS indeed 3-6hrs then many of us got it about right! 8)

 

[zurich]

Ehy remember one old topic/poll on PSP battery life. IF it IS indeed 3-6hrs then many of us got it about right! 8)

The topic wasn't what you THINK the PSP batterly life would be, rather what you'd demand it to be (minimum) before considering to purchase it. IIRC, the '6-8' hours group was #1.

 

[ChryZ]

http://ps2.ign.com/articles/450/450203p1.html?fromint=1[/URL]]Other minor but significant details were made public, most notably that developers should have PSP emulators very shortly, and actual hardware development kits later this winter. Given the PSP's scheduled winter 2004 release, this give developers almost exactly a year to get a game completed.

Nice!

 

[chaphack]

http://www.beyond3d.com/forum/viewtopic.php?t=7163&start=0&postdays=0&postorder=asc&highlight=

actually #1 was 4-6.

 

[zurich]

http://www.beyond3d.com/forum/viewtopic.php?t=7163&start=0&postdays=0&postorder=asc&highlight=

actually #1 was 4-6.

My bad. 3-6 is a little disappointing for me, considering on handhelds I prefer strategy/RPG games which can get a bit involving at a time.

 

[notAFanB]

I cannot beleive 4 ppls voted for 2-4hrs........ that's around 2/3 'zoned out' gaming sessions on a puzzle game. :?

 

[V3]

From that sentence, 3-6 hours doesn't sound official to me, though that's what you get for other high end portable devices. I expect PSP to be in that region as well.

My expectation still roughly the same 2 hours of gaming and 8 hours of music.

Interestingly, PSP going to include digital and anolog. I hope its comfortable.

 

[chaphack]

Now we shall have to wait and see whether the battery will last and outlast PSP multimedia capabilities.

For example, you played an extrexxme WiFi enabled 3D games for 90mins to find out that you only have either 150mins left for websurfing OR 80mins left for movie OR 120mins left for mp3 OR 60mins left another WiFi game OR 90mins left for another 1P game.

 

[notAFanB]

Now we shall have to wait and see whether the battery will last and outlast PSP multimedia capabilities.

For example, you played an extrexxme WiFi enabled 3D games for 90mins to find out that you only have either 150mins left for websurfing OR 80mins left for movie OR 120mins left for mp3 OR 60mins left another WiFi game OR 90mins left for another 1P game.

in other words it's like a below average laptop.

 

[cybamerc]

Battery life is a joke. Also the thing is going to be friggin' huge with both a d-pad and an analog stick. I'm starting to think they might go for a horisontal design similar to the original GBA. If it's gonna be bulky it might as well be comfortable to hold (GBA SP is designed for kiddy hands after all, not grown up hands like those of Sony fans).

 

[rabidrabbit]

The analog stick will propably be a much smaller stick than those in DualShocks. Maybe a small 'pin' like that 'mouse substitute' in some laptops (IBM).
Or a larger 'mushroom' head, but with a very short stem.

 

[cybamerc]

The stick could very well be small but there still has to be room for a thumb - a big, manly thumb (because PSP is for big, manly men).

 

[Fafalada]

even taking into account games from the round up surely animation+vertex data will likely eat up alot of Main RAM? and that's before we look at EXE sizes and what not.

Well you can always instance geometry more if you have too much drawing resources to spare (I figure that's what early stuff will be doing more anyhow, until people get proper handle on utilizing the hardware support for HOS and stuff).
And I do hope to still get the nice mesh compression schemes available on PS2, along with likely more efficient access to indexed vertex arrays and that should help too.

 

[Squeak]

The stick could very well be small but there still has to be room for a thumb - a big, manly thumb (because PSP is for big, manly men).

They will probably not do any kind of "stick", as it takes up way to much space, both vertically and horizontally. My guess would be a concave disc with concentric ridges for better grip, and very little travel length, but high sensitivity.

 

[cybamerc]

Squeak:

> They will probably not do any kind of "stick", as it takes up way to
> much space, both vertically and horizontally.

Well, it could be more of a nub than an actual stick. This is what rabitrabbit was alluding to. This disc approach would be another possibility but would take up far more space.

IMO, it really depends on the overall design. If it's a flip-top design and they go with an actual stick or "nub" the unit will be very thick. A slideable disc would likely make it fairly high. OTOH, going with a horisontal design would make it somewhat less portable and arguably not as cool.

 

[rabidrabbit]

Oh, but there could be a hole for the stick on the upper half of the 'flip top', on the part where the screen is. There would only've to be somewhat empty space around the screen (at least on the other side). Then it wouldn't have to bee so 'low'.
Perhaps the 'stick' could even then be used to control something (by pressing, like R3, L3 ?), even when the device is 'closed'.