Declaring member variables in a class interface header file

Summary The question revolves around the declaration of member variables in a C++ class interface header file. Key concepts include understanding the difference between declaration and initialization, as well as the proper use of references and pointers as class members. The provided example includes a class OCR with members such as a reference to an … Read more

Theoretical results on performance bounds for virtual machines and bytecode interpreters

Summary This postmortem analyzes the theoretical performance bounds of virtual machines (VMs) and bytecode interpreters relative to native instruction execution. The core finding is that while interpreters introduce unavoidable overhead, modern techniques like Just-In-Time (JIT) compilation and efficient dispatch methods narrow the gap significantly. The “2x/3x slowdown” observed in WASM is not a universal theoretical … Read more

Projecting a Text onto a wave Like Loft Prior tobextrude it

Summary A user attempted to project text onto a complex, wave-like surface generated in Grasshopper (a Rhino plugin) but encountered difficulties using the Surface Morph component. The core issue was attempting to use a single Loft surface to describe a compound geometry formed by pipes and connecting bows. Surface Morph requires a valid U-V coordinate … Read more

Pango passes wrong glyph indices to custom renderer

Summary We encountered a production rendering issue where a custom Pango renderer displayed incorrect glyphs. Instead of rendering the correct characters, the PangoGlyph indices passed to our draw_glyphs function were misaligned with the actual font mapping. For example, a lowercase ‘c’ (ASCII 99) resulted in a glyph index of 102 (ASCII ‘f’). This behavior was … Read more

USB Camera Video Not Displaying on Android

Summary The issue of a USB camera not displaying video on Android devices, despite working correctly on Windows and Linux, is a complex problem that stems from the camera’s UVC implementation. The root cause lies in the VideoControl interface not including an interrupt endpoint, which is incorrectly assumed to be mandatory by many Android USB … Read more

Event handler not firing on Plotly Bar Chart

Summary The core issue is a mismatch between frontend event handling and backend event propagation. Reflex’s rx.plotly component does not automatically forward raw Plotly click events to a Python backend @rx.event handler. Plotly generates events on the client side (JavaScript), but Reflex’s on_click prop expects specific framework-controlled events. The fig.update_layout(clickmode=”event+select”) configuration correctly enables Plotly’s native … Read more

RAM + SWAP full for pyrefly

Summary The issue at hand is related to memory management in a system running Ubuntu, where the RAM and SWAP space become fully utilized when working with a specific project, particularly when using pyrefly. This results in significant performance degradation and necessitates terminating the pyrefly process to regain system stability. Root Cause The root cause … Read more

Struggling to conceptualize Look At Matrix

Summary In 3D graphics, we typically move the world to the camera, not the camera to the world. The glm::lookAt function constructs a view matrix that transforms vertices from world space to camera space. To achieve this, the matrix must perform the inverse translation and rotation of the camera’s actual orientation. The confusion arises because … Read more