"Raytracing on a Grid" updated

Commenter SyntaxError has spotted and corrected several bugs in the code I presented in my article Raytracing on a Grid; I mention this in case anybody used the first or second pieces of example code as a basis for their own work. The code in the article has been updated and retested.

The core of the problem was that I was failing to account for the fact that zero multiplied by infinity yields an undefined result. This happened when both endpoints had identical horizontal or vertical coordinates, which you'd think I would have caught earlier.

Mini-reviews

I actually managed to play some games over the holidays, something I haven't done much of in a long time. My opinions:

Torchlight: Pretty but extremely repetitive Diablo clone. Still good for a few hours of fun.

Might and Magic: Clash of Heroes: Fantastic gameplay burdened with a generic fantasy license (saying this as a one-time Might and Magic fan). Inventing a puzzle-based battle system has been a goal of mine for a long time and I'm very impressed with the one Capybara has concocted here. I saw Critter Crunch on PSN last month and there are definite similarities. I loved the fiction surrounding Critter Crunch. Here it's the usual overwrought elves-n-paladins stuff, but you should try your best to overlook that because the gameplay's great.

Zelda: Spirit Tracks: Partway into this one. Moderately interesting. The train seems like it has potential to be a real drag.

Halo: ODST: Meh. Fight a bunch of dudes through a series of tunnels that are supposed to be a city. Some day there will be a game set in a city where you can actually go into any building and the layouts are not intentionally mazelike to compensate for hardware handicaps. This is not that day. This is essentially the Halo 3 Remix, at least in the single-player.

Assassin's Creed: (the first one) Surprisingly less polished than I would have expected given the size of the development teams in Montreal. I'm only partway into this one; I like the environments. The animation is atrocious though, with pops and hitches continually violating characters' appearance of weight.

Mass Effect: Also only partway into this one. I love their character rendering system during cutscenes. Very cinematic lighting. Of course the lip-sync brings everything crashing down. Animation is the Achilles' heel of all current CG, even $350 million epics like Avatar.

Saira: Tried the demo, decided it was a bit too frustrating for me. I loved Nifflas' previous games though. If you haven't, check them out.

Another small lander prototype update

Updates will likely continue to be slight in the time leading up to Christmas.

There is a new version of the lander prototype.

Changes:

• Increased rocket thrust: main nozzle by 75%, steering jets by 150%.
• Added inset rocket view in upper-right corner of screen; useful when zoomed out. This will likely be replaced or augmented by indicators displayed over the rocket's location in the main display, so you don't have to look elsewhere.
• Altered camera framing algorithm to emphasize the interesting band of radii on the planet. It can be made smoother than it is; just haven't finished yet.
• Limited full-scene antialiasing to 4X, rather than 8X. I got really bad performance on one of the machines I tested on so this is an attempt to improve that.

Slight update to lunar lander prototype

I've uploaded a new version to the website with a couple of small changes:

• Tuned the steering jet controller so it doesn't overshoot
• Changed X/Z zoom controls to operate continuously
• Fixed camera smoothing so it doesn't lag behind the rocket

Lunar Lander: prototype version 1 released

Here is the first released version of my Lunar Lander program. It runs under Windows and requires Direct3D 9 to be installed. I had hoped to have more of a game by my deadline but didn't have time to implement much, so I've tried to tie things off so it is relatively bug-free and playable. Once some of the holiday madness subsides I will make another release.

You can fly the orange, spherical rocket around the planet and attempt to make soft landings. There are a couple of control schemes of varying difficulty. Controls in a nutshell:

• Steer with the mouse
• Accelerate with the left mouse button
• Zoom view in/out with X/Z or 1-5
• Restart if you get stuck with R
• Esc pauses and displays additional help.

Known issues:

• Occasionally the aiming rockets will rotate the vehicle the long way around.
• It is possible to get positive feedback by pressing Tab to accelerate time while simultaneously increasing the orbit size; this will blow up the simulation and require a restart.

Once again, thanks to Scott Lembke for his Chipmunk physics engine, a heavily-modified version of which lurks within. Thanks also to my testers: Tom Elmer, Seth McNeill and David McNeill. Enjoy!

I've released a couple of other little games in the past:

• ThiefRL, an attempt to amalgamate Thief with Rogue
• SpaceRL, a very small Roguelike exploring zero-gravity movement

Merging and sizing rocket prototypes

I continue to work on my Lunar-Lander-on-a-globe. The prototype with the Chipmunk-based rigid body dynamics has been merged into the prototype with the round planet. However, the dimensions of the two were completely different: the planet has sea-level radius of one; the rocket from the other prototype had a radius of 15. I'm still attempting to get all of the physical and control parameters adjusted to make things playable.

It finally became imperative to produce a workable camera. I've left zoom control manual for now but am otherwise quite happy with what I've got. It's yet another use of a critically-damped spring, to drive the camera parameters toward their goal positions. The goal positions are chosen to interpolate based on zoom level between a small circle surrounding the rocket and a bounding circle around the planet and rocket.

Next steps are to finish tuning the physics and control parameters; implement death and reset, and add some goal landing spots. Then I think I will do a release of what I have and shift focus to holiday-related chores. Some time around Christmas/New Year I should be able to devote energy to making it into a more interesting game.

Child of Fire, Red Cliff reviews

The weekend, while long, was busy. We hosted two events: Thanksgiving and my daughter's fourth birthday party. I wasted what little free time was left reading Child of Fire: A Twenty Palaces Novel and watching John Woo's historical epic Red Cliff.

Child of Fire came to my attention via John Scalzi's Big Idea series, where authors get to plug their new books. First-time author Harry Connolly wrote an entry about his book that intrigued me despite the book's atrocious name. I finally got around to picking up a copy of the book and reading it. It's very well written and I'm looking forward to his future work. Recommended if you like Dashiell Hammett or Chandler.

Red Cliff is based on a 3rd-century battle retold in the 14th century Chinese novel Romance of the Three Kingdoms. When I worked at Midway we watched a bunch of Woo's films in preparation for working on a videogame with him. A lot of his trademark Wooisms can be found in this massive historical epic (cut down to 2.5 hours for US release). For instance, in Hard Boiled Chow Yun Fat's character blasts his way out of a hospital with a shotgun in one hand and a baby in the other. The opening of Red Cliff features a very similar incident, which I'm guessing was not in the original novel. Other Woo-bits include doves (of course) and Mexican standoffs, albeit with swords rather than guns. And random slo-mo of the duplicated-frame sort.

The characters felt really stale to me. I am interested in reading the original novel now to see if they are this one-dimensional there. The two characters that I felt stood out were Kong Rong (played by Wang Qingxiang), who was the tactical genius on the rebel side; and Xiao Qiao (played by Lin Chi-ling) who holds a Helen-of-Troy position in the story but with a strong Judith moment near the end.

I'd played one or two of the Dynasty Warriors games previously so a lot of the supporting hero characters (like Guan Yu) felt familiar. It is a little odd to have my scant historical knowledge derived from there, but that's how it is!