Pizza Tycoon, a 1994 DOS game, has been reimagined with an open-source engine called Pizza Legacy, which brings the game into the modern age. The original game's traffic simulation on a 25 MHz 386 CPU is a fascinating topic, and the author delves into the assembly code to understand how it was achieved. The algorithm is simple yet effective: each road tile has a direction associated with it, creating a grid of one-way roads. This design ensures that cars can only travel in specific directions, preventing them from going around in circles. When a car reaches a crossing, a random direction is chosen, with the additional rule of not making consecutive turns in the same direction. This approach adds a layer of realism to the game's traffic flow.
Collision detection is another crucial aspect of the game's mechanics. It involves checking the list of cars for potential collisions and preventing movement if a collision is detected. This check is optimized to consider road directions and one-way rules, with a 10-tick wait if a block is encountered. Interestingly, this mechanism enables the formation of brief traffic jams, enhancing the game's realism. Despite some small bugs and unchecked conditions, the overall effect is impressive, showcasing natural car movement that is likely to have influenced games like Sim City.
The author's exploration of the original game's code provides valuable insights into the challenges of simulating traffic on limited hardware. It highlights the ingenuity of developers who had to work within the constraints of their time, creating a realistic and engaging experience. This analysis also underscores the importance of understanding the past to appreciate the advancements in modern gaming, where brute-force rendering and dedicated cores for pathfinding are commonplace.
