Where does rustarok need write? about rustarok

[vsoch]

Here is the full backtrace

Singularity rustarok_latest.sif:/code> RUST_BACKTRACE=full cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.60s
     Running `target/debug/rustarok`
[00:00:04.421] (7fc375044f40) INFO   GRF loading: 4421ms
[00:00:04.944] (7fc375044f40) INFO   rsw loaded: 123ms
[src/asset/gat.rs:137] non_walkable_cells.iter().filter(|&&it| it).count() = 60788
[src/asset/gat.rs:184] rectangles.len() = 1317
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 30, kind: Other, message: "Read-only file system" }', src/libcore/result.rs:1084:5
stack backtrace:
   0:     0x55e7d2ae990b - backtrace::backtrace::libunwind::trace::h89fcc71e59e3bc5b
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/libunwind.rs:88
   1:     0x55e7d2ae990b - backtrace::backtrace::trace_unsynchronized::h0bad9be1379e729a
                               at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.34/src/backtrace/mod.rs:66
   2:     0x55e7d2ae990b - std::sys_common::backtrace::_print::hd3382a1f33c473da
                               at src/libstd/sys_common/backtrace.rs:47
   3:     0x55e7d2ae990b - std::sys_common::backtrace::print::h0ec6f03cfb8e76a6
                               at src/libstd/sys_common/backtrace.rs:36
   4:     0x55e7d2ae990b - std::panicking::default_hook::{{closure}}::h96cbf7b454e3f557
                               at src/libstd/panicking.rs:200
   5:     0x55e7d2ae95e6 - std::panicking::default_hook::h95a8f00337383d83
                               at src/libstd/panicking.rs:214
   6:     0x55e7d2aea07d - std::panicking::rust_panic_with_hook::h92f98b46e22f14ed
                               at src/libstd/panicking.rs:477
   7:     0x55e7d2ae9c02 - std::panicking::continue_panic_fmt::h25abfbb4e5b7043a
                               at src/libstd/panicking.rs:384
   8:     0x55e7d2ae9ae6 - rust_begin_unwind
                               at src/libstd/panicking.rs:311
   9:     0x55e7d2b06b9d - core::panicking::panic_fmt::h7e9f94035af782b3
                               at src/libcore/panicking.rs:85
  10:     0x55e7d2b06c97 - core::result::unwrap_failed::hf7591c1dd9412006
                               at src/libcore/result.rs:1084
  11:     0x55e7d18dfb80 - core::result::Result<T,E>::unwrap::he99716b5bd479fb8
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libcore/result.rs:852
  12:     0x55e7d1cfd5f2 - rustarok::asset::gat::Gat::load::h5f7cfb0dbf5f6a46
                               at src/asset/gat.rs:98
  13:     0x55e7d1b8d2ad - rustarok::asset::AssetLoader::load_gat::h6df7cf26be4c8b32
                               at src/asset/mod.rs:225
  14:     0x55e7d1a7f08b - rustarok::runtime_assets::map::load_map::{{closure}}::h8167556557d793ca
                               at src/runtime_assets/map.rs:103
  15:     0x55e7d1c2de82 - rustarok::common::measure_time::h4c287301525f77ad
                               at src/common.rs:7
  16:     0x55e7d19eb436 - rustarok::runtime_assets::map::load_map::h65ca5dfd2f8caa64
                               at src/runtime_assets/map.rs:103
  17:     0x55e7d1d3cf95 - rustarok::main::hb7c72c5818772e1c
                               at src/main.rs:158
  18:     0x55e7d1b6eb30 - std::rt::lang_start::{{closure}}::h81a88e942b930602
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/rt.rs:64
  19:     0x55e7d2ae9a83 - std::rt::lang_start_internal::{{closure}}::h4e93c1949c7a1955
                               at src/libstd/rt.rs:49
  20:     0x55e7d2ae9a83 - std::panicking::try::do_call::h9440ccd4dc467eaa
                               at src/libstd/panicking.rs:296
  21:     0x55e7d2aee8da - __rust_maybe_catch_panic
                               at src/libpanic_unwind/lib.rs:80
  22:     0x55e7d2aea58d - std::panicking::try::hc046e7ee42ee744f
                               at src/libstd/panicking.rs:275
  23:     0x55e7d2aea58d - std::panic::catch_unwind::h27dfc457c200aee0
                               at src/libstd/panic.rs:394
  24:     0x55e7d2aea58d - std::rt::lang_start_internal::hea1b49a567afe309
                               at src/libstd/rt.rs:48
  25:     0x55e7d1b6eb09 - std::rt::lang_start::h3d0a7211be25b391
                               at /rustc/625451e376bb2e5283fc4741caa0a3e8a2ca4d54/src/libstd/rt.rs:64
  26:     0x55e7d1d4314a - main
  27:     0x7fc3791bc09b - __libc_start_main
  28:     0x55e7d171532a - _start
  29:                0x0 - <unknown>

[bbodi]

Hi, nice catch!

TL;DR: Comment out the code in gat.rs from line 98 to 115, or make it optional based on having write rights.

Long story:
The game read map walkability data from the map file, but its resolution is single-cell based. So generating nphysics rectangles for all the cells separately is expensive and the game would be really slow. Therefore, there is an algorithm which merges single cells into the largest possible rectangles, it reduces the number of rectangles the game has to create from ~90k to 100-300 in some maps.
However this merging takes time, so I cached its result and wrote into a file. By commenting out those lines, you skip this caching part and the game will always do the merging process on startup.

[vsoch]

Awesome! Let me give this a try.

[bbodi]

I fixed the issue and tested it with a read-only working directory, it worked.

Thanks for noticing the bug!