That should mean expanding the story into a fully-playable game. But sometimes you need to take a break and have some fun, right? So for the last week, I have been working on a depth of field shader in GLSL. A few of these already existed for Blender games, but none were released with compatible licences. Also, I have been meaning to try my hand at some GLSL for a while.

It turns out that DoF shaders are remarkably easy to write: it’s just like a normal blur filter, but you vary the filter radius depending on the depth of the pixel from the camera. To stop colour from close objects from bleeding into the background, the weight of nearer samples should be modulated by how “in focus” they are, as described on page 10 in the paper Real-Time Depth of Field Simulation. The hardest part was working out how the depth buffer is scaled; the discussion determining depth of z-buffer on the WebGL mailing list was very helpful.

The results are great! With 32 samples you get a nice, smooth blur, with only a few artefacts along the edge of an in-focus object. The performance hit is acceptable for small screen sizes and my laptop graphics card, and barely noticeable with faster graphics cards. Note that the samples are evenly spaced and weighted (except as modulated by the depth) – no Gaussian-like smoothing is applied. This makes it easy to get shaped bokeh, as shown below.

Unfortunately you need a very bright object to show shaped bokeh, and maxing-out the brightness using Blender’s materials doesn’t quite cut it. The right-side of the image above has had its contrast increased to show the bokeh more clearly. The filter could apply its own brightness curve to enhance the bokeh, but the lights in the scene might need to be dimmed to account for that.

There is still some tweaking to do, but I’m really happy with these results. It makes the game look more three-dimensional, and emphasises the small scale of the scene.

Update: I have released this shader under the 2-clause (simplified) BSD licence. Download it as text, or integrated in a demo .blend file.

It wasn’t easy getting the right bolt, but I eventually found one at Bunnings that fit. Unfortunately the local hardware store didn’t have stainless steel bolts; only galvanised. Bunnings didn’t have imperial bolts, but I found that a 6mm one fit fairly well. It’s a bit loose, but when the nut is done up it holds tightly.

I bought 10m of string, but only used about half of it. I melted the cut ends with a match to stop them fraying. The free end is tied in a rolling hitch (like you would use for a guy rope on a tent), so I can adjust the length quickly.

From my quick tests it looks like it holds the camera more steady, but I couldn’t take this shot indoors without the flash. I’m looking forward to using it on a hike – after all, it fits in my camera bag!

I had four awesome team mates, and we produced a massive amount of work over the weekend. You can read about the game on our profile page, and download the game here or there. You need Blender 2.56 to play it – but don’t stress, it’s only about 20MB (that’s smaller than the game)!

The basic premise is that you are the last frog of your kind, and you need to rescue your tadpoles and return them to the water. You use your tongue as a whip to climb walls and swing up branches to reach them – but you have to return to the water regularly, or you’ll dry out!

The game plays fairly well, but there are a few things that I would like to fix. We may do another release soon – stay tuned!

Edit: another screenshot:

We wanted a puppy for a long time, but we couldn’t commit to staying home during the day to look after it. Then Jodie found Jessie on the Lost Dogs’ Home web site. We were nervous about going to look at her, because we knew that it would be hard to resist coming home with her, even if she had some flaws. Happily it seems she has none, apart from a mild ear ache and old age: she will turn 8 at the end of the year.

The cat, Kuro, hates her guts. Whenever Jessie approaches the back door, Kuro flings herself at her and slams into the glass, hissing and growling. She seems to be really on edge: last night she jumped up onto the bed, presumably to go to sleep – but I twitched, and she flipped out and bit and scratched my leg. Quite a rude awakening! As for Jessie, she couldn’t care less about the cat. But we’re keeping them separate until Kuro gets used to having a dog in her yard.

More photos:

Get it here

You’ll need Blender 2.49b to run the game. After downloading and installing Blender, you can start the game by double-clicking on Dungeon.blend or running blender Dungeon.blend. More information is available in our old and trusted companion README.txt.

Edit: The game has been tested on GNU/Linux and Windows. In theory it should work on Mac as well.

Cargo in the water churn room.

I have been working non-stop for the last few weeks getting Cargo ready for submission to the Blender game competition. It was a sprint to the finish line but now it is finally submitted! Having a deadline to work towards has really helped me to prioritise and determine the features that are most important. Friends testing the game was a huge help, too – thanks guys!

The submission can be viewed on the Bullet wiki.

And now I can sleep.

The crack is on the left, just next to the bracket. Another crack is on the far side.

I had been riding it a lot recently, but I probably didn’t ride it as much as I should have over the years – and certainly not enough off-road. Still, I guess it was just metal fatigue that caused it. On the bright side, I now have a shiny new bike:

My new bike. This one is a darker shade of yellow.

At first, when I tried it out at the shop, it felt very strange. It was like I was too close to the handlebars. But I put it next to a few other frames, and they had roughly the same dimensions. After a few more test rides it started to feel pretty good, and it was ridiculously cheap (on special), so I bought it! After adjusting the position of the handlebars and seat it’s feeling a lot more like my old bike. It’s comfortable except for the seat, which is as hard as a rock. I put my old pedals on it too, breaking an Allen key in the process.

Viva la new bike!

Edit: for those interested, it’s a Scott Sub 30. Those are the default pedals in the photo; I replaced them with SPDs.

Screenshot of the first minigame level

I’ve been working on the epic* adventure game Cargo for almost two years now. It’s starting to reach a point where I can slot the pieces together to make levels. And just in time, too! I aim to enter in the Blender Game Competition 2010, and the deadline is the end of February. So far I have made one level for it (screenshot above). It is basic but fun, and it shows off the scripts and physics fairly well. Now I need to polish up some of the graphics, add a menu screen, and hopefully some more levels. Full steam ahead!

* ;)