benilla-octo/crates/benilla-formats/tests/m2_lights.rs

//! M2 light-block parse — byte-level check against a real Elwynn campfire, the dynamic point-light
//! "hot-spot" caster (decision 0016). Pins the vanilla `0xd4` record stride and the diffuse-colour track
//! offset. Skips when the client isn't present.

use std::path::PathBuf;

use benilla_formats::{parse_m2_lights, Chain};

fn vanilla_data_dir() -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../../WoW/Data")
}

#[test]
fn elwynn_campfire_has_one_warm_point_light() {
    let data = vanilla_data_dir();
    if !data.is_dir() {
        eprintln!("skipping: vanilla client not present at {}", data.display());
        return;
    }
    let reader = Chain::open(&data).expect("open vanilla patch chain");
    let bytes = reader
        .read("World\\Azeroth\\Elwynn\\PassiveDoodads\\Campfire\\ElwynnCampfire.m2")
        .expect("read ElwynnCampfire.m2");

    let lights = parse_m2_lights(&bytes);
    assert_eq!(lights.len(), 1, "campfire has exactly one M2 light");

    let l = lights[0];
    assert!(
        l.is_point(),
        "campfire light is type 1 (point), got type {}",
        l.light_type
    );
    // The authored warm-orange diffuse pins the 0xd4 record stride AND the 0x48 diffuse-colour track
    // offset (independently cross-checked ≈ (0.71, 0.20, 0.00) — a garbled stride would not land here).
    let d = l.diffuse_color;
    assert!(
        (d[0] - 0.71).abs() < 0.03 && (d[1] - 0.20).abs() < 0.03 && d[2] < 0.05,
        "campfire diffuse ≈ (0.71, 0.20, 0.00), got {d:?}"
    );
}

/// The **held torch** — the light an NPC carries into the world (`Club_1H_Torch_A_01.m2`, the model
/// `ItemDisplayInfo` 12236 / item 1906 "Monster - Torch" resolves to). Pins the one asset the entity
/// carried-light path exists for: a `type==1` point light on bone 9, up the shaft, warm, `×3`
/// intensity, and — the gate — a visibility track whose first key is nonzero, so it CASTS.
#[test]
fn held_torch_casts_one_warm_point_light_up_the_shaft() {
    let data = vanilla_data_dir();
    if !data.is_dir() {
        eprintln!("skipping: vanilla client not present at {}", data.display());
        return;
    }
    let reader = Chain::open(&data).expect("open vanilla patch chain");
    let bytes = reader
        .read("Item\\ObjectComponents\\Weapon\\Club_1H_Torch_A_01.m2")
        .expect("read Club_1H_Torch_A_01.m2");

    let lights = parse_m2_lights(&bytes);
    assert_eq!(lights.len(), 1, "the torch has exactly one M2 light");
    let l = lights[0];
    assert!(l.casts(), "point + visibility-on: the torch really glows");
    assert_eq!(l.bone, 9, "the light hangs on the torch's own bone");
    assert!(
        (l.position[0] - 0.5765).abs() < 0.01 && l.position[1].abs() < 0.01,
        "0.58 yd up the shaft (the head), got {:?}",
        l.position
    );
    let d = l.diffuse_color.map(|c| c * l.diffuse_intensity);
    assert!(
        (d[0] - 1.40).abs() < 0.01 && (d[1] - 0.871).abs() < 0.01 && (d[2] - 0.40).abs() < 0.01,
        "diffuse × intensity ≈ (1.40, 0.87, 0.40) — flame orange, over-driven, got {d:?}"
    );
}

/// The **dark** shape (wow-re `m2-dynamic-lights.md` §9.4): a `type==1` light whose visibility track
/// ships a static `0` key never casts. 11 of the corpus's 85 point lights are this — mostly spell
/// impact VFX — so the gate is not academic; before it, every one of them lit the world.
#[test]
fn a_static_zero_visibility_key_reads_as_dark() {
    let data = vanilla_data_dir();
    if !data.is_dir() {
        eprintln!("skipping: vanilla client not present at {}", data.display());
        return;
    }
    let reader = Chain::open(&data).expect("open vanilla patch chain");
    let bytes = reader
        .read("Spells\\FlameStrike_ImpactDD_Med_Base.m2")
        .expect("read FlameStrike_ImpactDD_Med_Base.m2");

    let dark: Vec<_> = parse_m2_lights(&bytes)
        .into_iter()
        .filter(|l| l.is_point())
        .collect();
    assert!(
        !dark.is_empty(),
        "the impact model does author point lights"
    );
    assert!(
        dark.iter().all(|l| l.visibility_off && !l.casts()),
        "every one is held dark by its visibility track"
    );
}

#[test]
fn too_short_yields_no_lights() {
    // No MD20 lights array header → empty, no panic.
    assert!(parse_m2_lights(&[0u8; 16]).is_empty());
}