gfx-rs/wgpu

Bunnymark example does not recompute its projection matrix and other parameters when the canvas size changes

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#5,890 opened on Jun 28, 2024

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 (12 comments) (0 reactions) (1 assignee)Rust (9,290 stars) (703 forks)batch import
good first issuetype: bug

Description

Description examples/src/bunnymark/mod.rs computes an Orthographic RH matrix on page load, but if the canvas is resized, the matrix is not recomputed.

See all uses of config.width and config.height inside examples/src/bunnymark/mod.rs

Repro steps (1) Open https://wgpu.rs/examples/?backend=webgpu&example=bunnymark in Chrome 126.0.6478.127 (2) Resize the window

Expected vs observed behavior Observed: Bunnies bounce outside of the canvas or don't bounce to the top

Expected: bunnies bounce within the resized canvas

Extra materials

https://github.com/gfx-rs/wgpu/assets/105083895/a41bfd50-c2df-4200-937a-0ee0bcf3bc5a

Platform macOS using Chrome Version 128.0.6562.0 (Official Build) canary (arm64)

Contributor guide

Tech stack
rust
Domain
developer experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Rust basicswgpu fundamentalsunderstanding of orthographic projection
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Examine `examples/src/bunnymark/mod.rs` for all uses of `config.width` and `config.height`. The projection matrix is computed once on load using these values. To fix, add a resize handler that recomputes the matrix when the canvas size changes. Consult the linked video to confirm the issue. The code likely initializes the matrix in a setup function; you'll need to store the matrix or update it in a resize callback.