CH103 - Pac-Man - I

If "Pac-Man" delved into AI technology, how should this game be designed? Ethan was unsure.

However, when Evelyn pulled him into the garage, the girl's new base, and spread out design blueprints on the workbench, she already had a plan. "Ethan, levels, scores, models, rewards – we can slowly create all these things. But these four intelligent ghosts must be our primary consideration because, without them, the entire game loses its soul."

Ethan agreed with this perspective.

As he nodded in agreement, Evelyn smiled and said, "So, shall we start with creating the ghosts? First question, in your inspiration, how many common patterns do these four ghosts share?"

"Because once the common patterns are determined, the code for this segment can be directly copied."

Ethan felt like he understood but not entirely.

Understanding, in this context, meant copying.

Well, in his past life, the trope of programmers copying code was quite common. As for not understanding...

"Oh, Evelyn, I want to know what you mean by common patterns."

Ethan decisively asked.

"Common patterns? It refers to whether the ghosts share any common behaviors in your design. For example, if all four ghosts chase the player, that's a common pattern. But here, the term 'common pattern' doesn't apply because you've assigned different characteristics to each ghost."

"You've given the red ghost the characteristic of direct pursuit. So, in writing the code, its feature is to calculate in real-time the shortest distance between itself and the player and move along that path."

"For the pink ghost, you've given it the characteristic of ambushing the player. So, in writing the code, it calculates the player's position in real-time, determines some pixels forward based on the player's orientation, and turns that empty space, a potential destination for the player, into the ghost's destination. Meanwhile, with each player movement, the pink ghost's destination also changes."

"As for the blue ghost, you've given it the ability to coordinate with the red ghost for interception. In this case, you must consider the player's location as the center point, connecting one end to the red ghost and the other end to the blue ghost. In this process, the red ghost's path must be calculated first. If it moves horizontally, it's along the X-axis; if vertically, it's along the Y-axis. In this scenario, the blue ghost's path must be symmetrical to it, creating a right-angle intersection. Only when this intersection occurs can the interception effect be achieved, and the blue ghost can capture the player by surrounding."

"As for the last orange ghost, you designed its feature as patrolling. So, in writing the code, its characteristic is to stay near its spawn point, set a detection radius, and when the player enters the radius, the orange ghost calculates the shortest distance and starts pursuit. When the player leaves its detection radius, the orange ghost stops pursuit until the player reappears."

"Because their pursuit patterns are different, we can't call the ghosts' pursuits a common pattern. On the contrary, if the ghosts' behavior patterns were entirely the same, then these codes would be..."

Evelyn elongated her voice.

And Ethan nodded in understanding, adding, "Common."

"Bingo!" Evelyn snapped her fingers with a smile. "So, in your view, what are the common patterns?"

Evelyn had made her words clear, making it simpler for Ethan to describe. Although he had only played "Pac-Man" in his previous life and had not attempted to create it, determining the common patterns of these four ghosts was still straightforward. For example, fleeing and being captured.

First, fleeing meant that when the player, represented by Pac-Man, consumed the glowing dots in the corners of the map, the ghosts received a debuff. During the player's invincible state, the ghosts entered a fearful evasion mode because, at this time, the player could counter-attack them, turning color-changing flight into a common pattern for the four ghosts.

Second, being captured referred to the state where the player, in an invincible state, consumed the ghosts. Since in "Pac-Man," the ghosts could respawn after death but had to return to the central hub for recovery, this process became a common pattern for all four ghosts.

To be honest, even though Ethan had written a lot before, this segmented analysis was not on his draft paper.

Therefore, when he recalled the common patterns of these four ghosts under Evelyn's inquiry, she quickly recorded it. At the same time, Evelyn's mouth didn't stop, continuously explaining, "If we break it down, the fleeing pattern is when the ghosts detect the disappearance of any of the four glowing points on the map, and then they engage in evasive behavior in the opposite direction."

"Being captured is when the ghosts, during their escape, overlap coordinates with the player character on the map. This needs to be distinguished from the ghosts' pursuit of the player, as coordinate detection is shared, and it cannot be mistaken. So, should we add a time check? For example, after the glowing points disappear, if the ghosts overlap with the player within a certain time, they are captured?"

Looking at his sister's energetic writing, Ethan felt some emotion.

Because when he decided to make "Pac-Man," he never anticipated that creating this game would be so challenging. Separating the judgment?

That workload was too much! However, at the same time, a hint of curiosity was rising in him.

"Evelyn." He called the girl's name.

"Yeah?" She instinctively responded.

"Can I ask you a question?"

"Go ahead."

"I want to know why, in the capture judgment, you chose the time-check method?"

Ethan asked in confusion, "In my setting, when the player consumes the glowing dots, the ghosts gain a negative status, and they also change appearance. So, can't we set the detection as a change in appearance? When the player encounters a ghost with a changed appearance, the ghost dies. Is this logic not feasible?"

"Of course, it is." Evelyn understood what Ethan wanted to say.

But at the same time, she explained, "But with that setting, there would be a problem in the game detection. Assuming the player and a ghost with a negative status collide, and the ghost's negative status disappears at that moment, how should the game judge? The ghost will determine that it has no negative status, while the collision overlap code will determine that the ghost has a status."

"Because these two codes are calculated simultaneously."

"In this situation, is it the player eating the ghost, or the ghost killing the player?"

"The machine can't figure it out."

"This kind of crude judgment without distinguishing the order may lead to judgment issues in the game. So, the best anchor point for detection, I think, is the highest priority time. With this setting, the code only needs to check one variable and is less prone to errors."

"Oh, I see." Ethan understood.

"Doesn't this way reduce the amount of code written?"

"Absolutely." Evelyn nodded. "Since our memory is limited, if we can do with 4K, we definitely can't afford 8K."

"Adding more would increase the cost by more than thirty dollars."

Wow! Is cost being considered?

Ethan was surprised.

But Evelyn's confidence reassured him a lot.

Through their conversation, they had

already analyzed the AI of the four ghosts that night.

The next day, Evelyn started to stay at home, attempting to write the code.

To be honest, for any other game company facing a game that required code writing like "Pac-Man," the production progress would not be fast. After all, the popularity of personal computers in the current market was quite low.

Even if those commercial companies wanted to transition from circuit board arcade games to CPU arcade games, they would have to purchase personal computers, and then hire engineers who understood programming to create the game. In this process, various issues related to CPU compatibility may arise.

But for Ethan and Evelyn...

They had no such worries.

Because the personal computer Evelyn used was the APPLE 1 handcrafted by Steve Wozniak, given to Ethan. Moreover, the MOS 6502 was their in-house product.

When the most important CPU inventor for game development and the personal computer inventor providing the production tools could be easily found, Ethan couldn't think of anyone who could stop him from creating "Pac-Man" in this world.

Especially when he called Chuck Peddle, inquired about the assembly language of MOS 6502, and received the 151 opcodes and 56 instructions in less than an hour via fax...

Even though Evelyn had never encountered MOS 6502, she quickly got the hang of it based on the instruction set.

And when Ethan called Steve Wozniak, asking him to add a disk interface to the APPLE 1, and within less than three hours, he had all the external devices ready...

Evelyn didn't have to worry about data loss.

Of course, Ethan's call also made others curious.

Chuck Peddle asked him on the phone if he had new ideas.

Ethan smiled and said yes, promising to send him a copy once it was done.

Steve Wozniak, on the other hand, was more direct, wanting to see Ethan's inspiration.

Although it didn't comply with the rules of protecting trade secrets, Ethan agreed.

After Steve Wozniak finished reviewing it, the chubby guy got extremely excited—

"Oh! Sh*t! Is this really your inspiration?"

"Oh! My! God! Your design makes me want to play!"

"How about I join the game development?"

"I don't want money! I just want to bring it to life!"

"You can assign me any project! Whether it's writing the paths for the four ghosts or designing the basic panels, or even creating map levels—I can handle all these projects!"

"Really!"

"I'm very skilled in coding!"

This proposal made Ethan ecstatic, and Evelyn was happy to have someone share the workload.

Thus, on the first day of game development, the "Pac-Man" team went from two people to three.

Similarly, on this day, the chubby Steve Wozniak discovered a problem as soon as he got his hands on it.

"Ethan, Evelyn, did you forget something? Because in your design, all four ghosts, like the player, start from the little house in the middle of the map. However, among the four ghosts, only the red, pink, and blue ones continuously pursue the player, while the orange one monitors within a range."

"So, when the game starts, the three ghosts will chase after the player once the gate opens, while the fourth orange one will just wait in the middle. In this case, won't it be very easy for the player to avoid it?"

"My suggestion is, if possible, it should also come out of the ghost house and move continuously along the maze walls on a timer. For example, on a low difficulty, it moves for thirty seconds, advances for ten seconds, and then rests for thirty seconds. On high difficulty, change it to twenty seconds or ten seconds"

"We can make it a randomly wandering creature. When the player enters its range, it will fiercely pursue, making it more dynamic. What do you think?"

This suggestion left Ethan stunned on the spot.

Although he didn't know if the little orange ghost in the previous "Pac-Man" was designed this way, it didn't matter, right? Because Steve Wozniak's suggestion sounded fun!

"Great!"

"It adds pressure!"

"This task is yours!"

Ethan patted Steve Wozniak's shoulder, entrusting him with this important responsibility.

After all, it's all about freebies!

If a tech genius is willing to do more, how could he possibly be polite with the other party?

That's nonexistent!