CH106 - Pac-Man - IV

On the second day of their return home, December 26th, Evelyn successfully finished writing the chasing code for the Red Ghost.

When connected to the display of APPLE 1, the yellow Pac-Man ran frantically in the maze, closely pursued by the red ghost. The constant pursuit brought joy to Ethan and Evelyn.

Especially when they discovered that no matter how the yellow Pac-Man tried to escape, the red ghost would always chase in the shortest distance. After a relentless pursuit, the two celebrated the birth of an AI.

"Oh, Evelyn—did we just succeed?" exclaimed Ethan.

"I think so!"

Evelyn burst into laughter, "Not to mention anything else, at least my algorithm works flawlessly on level 1!"

The success of Little Red on level 1 thrilled Ethan.

Having completed all 255 maps, he transformed into the quality inspector of Pac-Man level 1, driving the yellow Pac-Man through the maps to test Little Red's performance.

Though he found numerous bugs during this process;

For instance, when encountering a long maze corridor, if the yellow Pac-Man was too far ahead, already emerging from the other end while the red ghost had just entered or was a quarter of the way in, it might retreat from the corridor due to the algorithm's proximity principle, giving players a god-like perspective.

However, these fixable bugs didn't dampen his excitement.

After all, he was developing one of the most amazing pixel games of his previous life! Just mimicking its appearance was already a success! The subsequent fine-tuning was a breeze. When Woz returned after the holiday, the progress astonished him.

"Oh! Damn! You guys finished Little Red?"

"Oh! No! Is the testing done too?"

"Darn! Don't you guys ever rest?"

"Time is money, my friend!" Ethan, in high spirits, cosplayed as a goblin from World of Warcraft.

"If we don't speed up, how can we make money?"

Woz was bewildered by such words.

Evelyn punched Ethan, then smiled at Woz, "Oh, Stephen, it's mainly because developing 'Pac-Man' is so interesting. Unlike those dull jobs, it brings us joy, so... we got hooked."

Woz found that explanation acceptable.

Upon seeing Ethan and Evelyn's rapid development progress, he also got motivated. Rolling up his sleeves, he swore to himself that he would finish the AI code for Little Orange, the roaming ghost, within a week.

When the tech guru showed determination, the development of "Pac-Man" entered a high-speed phase.

On January 15, 1976, Woz's first version of Little Orange's chase code was officially completed.

On January 19, 1976, Ethan, controlling the yellow Pac-Man, spent four days running Little Orange's code on all 255 maps.

On January 24, 1976, Evelyn completed the first version of the ambush code for Little Pink.

The next day, they took a collective break because it was Evelyn's birthday, and Ethan accompanied her to Anaheim, California.

The day after, back to work.

On January 29, 1976, Ethan, controlling the yellow Pac-Man, was blocked by Little Red and Little Pink on 255 maps for four days.

On February 11, 1976, Woz's blocking code was officially completed, and the most challenging Little Blue Ghost finally appeared.

On February 24, 1976, Ethan, controlling the yellow Pac-Man, was beaten by Little Red, Little Pink, Little Blue, and Little Orange on all 255 maps.

During this final concentrated test, they also discovered countless bugs.

For instance, because Little Pink and Little Blue had similar behavior patterns— the former ambushed on the player's route, while the latter coordinated with Little Red to block— on simple terrains, their path feedback was the same.

If it was a single path, there was no problem, but at a three-way intersection, this unusual path feedback could turn artificial intelligence into artificial stupidity, giving away a perfectly fine route to the player.

So, a change was necessary. Evelyn decided to add a judgment for Little Pink: prioritize the path where the companion is not present.

Another example was Little Orange's algorithm, which involved unconscious roaming and guarding. Only when the player appeared in his area would he pursue.

At this point, if the player manipulated the edge detection, they could easily toy with Little Orange.

When Ethan played "Hey, I'm in," "Hey, I'm out," "Hey, I'm in again," "Hey, I'm out again," Little Orange's feedback in the game became a silly dance of "move forward and pursue," "stop and stand still," "move forward and pursue," "stop and stand still."

After Ethan played around with Little Orange like a playful dog, Evelyn admired Ethan's imagination, while Woz...

The chubby guy couldn't sit still! He couldn't tolerate his own AI turning into an idiot! He decided to add another algorithm for Little Orange: if the player's presence appeared multiple times in his range within a short period, let's say five seconds, he would go into a rampage state, crazily chasing like Little Red.

Only if the player escaped the detection range and stayed away for ten seconds would Little Orange return to normal.

After these shortcomings were pointed out one by one, the related modifications were put on the agenda.

Then came rounds and rounds of endless testing.

By March 20, 1976, following the normal game difficulty, Ethan completed all 255 levels. The sudden appearance of "WIN" told them a fact...

After five months...

The "Pac-Man" project was finally successfully developed!

And after spending five days building the circuit motherboard with the embedded game CPU and placing it inside the arcade shell adorned with the yellow Pac-Man and four ghosts...

The world's first "Pac-Man" arcade machine was born!

"We did it!"

Ethan stood with hands on hips, looking at the game interface shimmering with five-coloured lights.

"Next..."

"Now it's time to announce your existence to the world..."

Ethan patted Pac-Man.

A face full of joy.