Hardcore Rust: A Ray Tracer Without Dynamic Memory Allocation

This post details a case study of writing a Rust application using only a minimal, artificially constrained API (no dynamic memory allocation). The author critiques RAII (Resource Acquisition Is Initialization) for leading to messy resource management and proposes a "hard mode": splitting the program into a `std` binary and a `#![no_std] no_alloc` library, allowing only the binary to directly request resources from the OS. Using a toy ray tracer as an example, the author meticulously explains handling pixel buffers, parallelization, the memory allocator, and scene parsing in this "hard mode," ultimately achieving a ray tracer without dynamic memory allocation.