HDR on PSP?

[Angelcurio]

QJ.net has an interview with Chris Charla of Backbone Entertainment about the upcoming Death Jr 2: Root of Evil. I was surprised to see this in there:

QJ: Is there a more relaxed feeling in development with this title compared to the first which was one of the first games to be shown for the PSP?

Chris Carla: Not at all! The new-hardware stress is gone, but that just gets replaced by the desire to see what we can do with the hardware. So, instead of stressing about when you get hardware, you stress in a new way about trying to implement lots of new technical features, like HDR lighting.

QJ: HDR lighting on the PSP? You're going to have to talk about that a little! Also, can you talk about what other kinds of technical enhancements you've made to the game's engine since the original Death Jr?

Chris Carla: Well, we used Renderware on our first game on PSP, and it wasn’t exactly perfectly tuned for PSP. After we removed it for DJ2PSP, we found our framerates hit 90fps… Meanwhile we’d been implementing these kinds of effects on PS3, and we were keeping the runtime features between them in synch as much as possible, so before we knew it, thanks to our fantastic tech staff, we had light blooms, High Dynamic Range lighting, and lots of other lighting and frame buffer effects running in the game. The net result is that we’ve probably got some of the most technically advanced features of any title on PSP at this point, which is pretty cool. We’ve done a lot more than that as well; I think people will be pleased by the tech in the game, and our loading times are still extremely short.

Original Interview: http://pspupdates.qj.net/QJ-Interviews-Death-JR-2-Root-of-Evil/pg/49/aid/61523

This was posted over a neogaf and i found it really interesting. Later on, one of the game devs made an appearance and was explaining how they achieved it, here is a screen comparison he posted over there from an old game build:

You can read the GAF thread here: http://www.neogaf.com/forum/showthread.php?t=114461

 

[mckmas8808]

Yeah it's great to see devs doing more and more on the PSP.

Here's what the developer said how they did it.

From something I said to Play magazine in an interview: HDR lighting is also known as high dynamic range lighting. It's more typically associated with next-gen systems, or high end PCs. Basically, instead of having a fixed number of intensities for color and lighting -- usually 8bit/256 intensities for each of the three color channels (red, green, blue) -- with HDR, we have much more granularity available.

In realtime, we detect the brightest element onscreen that the player can see (and that thet screen can display), and the darkest value the player can see, and we dynamically adjust the available color range onscreen to match that. So, you get much brighter brights, and much darker darks, and a world that is much more vibrantly lit.

On DJ1 and most PSP games to date, you had fixed intensity lighting. With HDR we can create much more dramatic lighting. We also have a post effect system, which lets us do things like bloom, motion blur, and egg crate effects (you see that in World of Waffles after you get gassed).

When you're playing, this will all be pretty seamless; DJ2 isn't a tech demo -- we want people to pay attention to the killenating, not the tech -- but hopefully the net effect will be that DJ2PSP will be much more dramatic looking. All the effects aside, nothing beats being able to go through the whole game co-op multiplayer! It really adds a lot to the experience.

Also, the E3 footage was really grainy, sorry. And the camera is vastly improved. It basically stays put behind you (although you can walk towards the camera and sideways without it swinging around or anything), and you can move it at any time with the shoulder buttons, in what is becoming the standard scheme for third person games on PSP. There is also a "side-step"/strafe mode, where the camera is always locked directly behind you, and which is good for shooting. Looks like we're going to ship GMC1 tomorrow am, so uh, play it when it comes out. If you buy two copies I'll buy you a Coke...

 

[see colon]

so, if i understand this correctly (and i might not be), they aren't using any high color range, but they are tone mapping the final image.

wile i think the final image looks good, wouldn't that actualy result in less color range than SDR rendering?

 

[Shifty Geezer]

I think they are using more than just 32bit RGBA though. If you were to take the source image, or rather the dark one without tone mapping, and apply photoshop filters to brighten it, you'd be missing a lot of the colour detail. You'd also run the risk of serious banding in low-key screens stretched over the full gamut. I dont know what FB formats are available on PSP or how you'd do a floating point or high-colour colourspace implementation, like nAo32 on pixel shaders.

 

[MrWibble]

From the way it's phrased, it sounds to me more like they work out (or at least guess at) the dynamic range in advance and adjust the rendering accordingly, rather than actually tone-map the output.

i.e. it's more like a dynamic contrast control rather than tone-mapping per se.

 

[nAo]

i.e. it's more like a dynamic contrast control rather than tone-mapping per se.

It reminds me of a nice game called Half Life 2: Lost Coast

 

[Shifty Geezer]

i.e. it's more like a dynamic contrast control rather than tone-mapping per se.

That would make more sense, like GT3 on PS2. And works just as well in many cases.

 

[MrWibble]

It reminds me of a nice game called Half Life 2: Lost Coast

Hehe. Could be a similar idea, albeit with shunting the correction to a pre-process on the lighting values, rather than doing it in the shader...