This GitHub repository, titled "pseudo3d," showcases a remarkably concise implementation of a raycasting engine written entirely in Bash script. The provided code leverages the shell's built-in string manipulation capabilities and arithmetic functionalities to render a pseudo-3D perspective of a simple world map defined within the script itself. The world map is represented as a two-dimensional array of characters, where different characters signify different types of walls or empty space.
The core of the raycasting algorithm involves iterating through the screen's horizontal pixels, calculating the viewing angle for each pixel based on the player's position and viewing direction. For each pixel, a "ray" is cast from the player's position into the world map, effectively tracing a line until it intersects with a wall character. The distance to the wall intersection is then calculated using a simplified distance formula.
This distance value determines the height of the wall segment to be drawn on the screen for that particular pixel. Closer walls result in taller wall segments, creating the illusion of perspective. The rendering process utilizes ANSI escape codes to directly manipulate the terminal output, drawing vertical lines of varying heights representing the walls. Different wall characters in the map are visually distinguished by using different colors for the rendered wall segments, again achieved through ANSI escape codes. The rendering process updates the terminal output in real-time, providing a dynamic view as the player navigates the world.
The player's movement and rotation are handled through basic keyboard input. The script detects specific key presses, updating the player's position and viewing angle accordingly. This dynamic update combined with the real-time rendering loop creates an interactive experience where the player can explore the defined world from a first-person perspective. While rudimentary, the implementation successfully demonstrates the fundamental principles of raycasting in a surprisingly minimal and accessible manner using the Bash scripting environment. The code's brevity and reliance on built-in shell functionalities serve as a testament to the versatility and unexpected capabilities of the Bash scripting language beyond typical system administration tasks.
Summary of Comments ( 34 )
https://news.ycombinator.com/item?id=42475703
Hacker News users discuss the ingenuity and limitations of a bash raycaster. Several express admiration for the project's creativity, highlighting the unexpected capability of bash for such a task. Some commenters delve into the technical details, discussing the clever use of shell built-ins and the performance implications of using bash for computationally intensive tasks. Others point out that the "raycasting" is actually a 2.5D projection technique and not true raycasting. The novelty of the project and its demonstration of bash's flexibility are the main takeaways, though its practicality is questioned. Some users also shared links to similar projects in other unexpected languages.
The Hacker News post titled "A Raycaster in Bash" (https://news.ycombinator.com/item?id=42475703) has generated several comments discussing the project, its performance, and potential applications.
Several commenters express fascination with the project, praising the author's ingenuity and ability to implement a raycaster in a language like Bash, which isn't typically used for such computationally intensive tasks. They admire the technical achievement and the demonstration of what's possible even with limited tools.
Performance is a recurring theme. Commenters acknowledge that the Bash implementation is slow, with some sharing their own experiences and benchmarks. Suggestions are made for potential optimizations, including using a different shell like
zshfor potential performance gains, leveragingawk, and exploring alternative algorithms. The inherent limitations of Bash for this type of application are recognized, and the discussion explores the trade-offs between performance and the novelty of the implementation.The practical applications of the project are also debated. While some view it primarily as a technical demonstration or a fun experiment, others suggest potential use cases where performance isn't critical. One commenter proposes using it for generating simple visualizations in constrained environments where other tools might not be available.
The choice of Bash itself is discussed. Some commenters question the rationale behind using Bash, suggesting more suitable languages for such a project. Others defend the choice, highlighting the value of exploring unconventional approaches and pushing the boundaries of what's possible with a familiar scripting language. The discussion touches upon the educational aspects of the project and its potential to inspire creative solutions.
Beyond the technical aspects, there's appreciation for the author's clear and well-documented code. The readability and organization of the project are commended, making it easier for others to understand and learn from the implementation. The project is also seen as a testament to the flexibility and power of Bash, even beyond its typical use cases. Some commenters express interest in exploring the code further and potentially contributing to its development.