Entry 156

"The streams' effect nodes: str0001's clouds"

2026-09-26render

Filescrates/piney-stream/src/scene.rscrates/piney-stream/src/lib.rscrates/piney-stream/tests/stream.rscrates/piney-stream/tests/stream_fixture.txttools/test_stream_rs.pydocs/engine/stream.mddocs/engine/animation.md

A GAPS item: the streams' effect objects. The port's scene kept an effect node only for its place in the draw list's layer order, and drew nothing for it.

What there is

A survey of every stream file found Eff nodes in four streams and Particle nodes in none:

• str0001 (stream 2, "Epitaph of the Twilight"): 181 nodes EFF_srzsmo00 to EFF_srzsmo180, all EFF_srzsmo1 of str0001e, each with an F_Obj record every one of its 2,041 frames. They are the clouds the relic stands among. Without them the relic stood on a bare dark floor.
• str0580: 15 smoke nodes. Their records keep them at the origin, so they never start (stream.md already noted they draw nothing).
• str0570 and str9104: one Eff node each, with no records.

The game's code

• ccEffObj::Init, StartAnm, EndAnm, Animate and DrawNoAnm, and DecodeF_Obj's effect branch (stream.md, "Effect nodes").
• A node's "part" bit comes from its Obj2 flags. Decode_Eff copies them into the Eff chunk's +0x10.
• With the part bit, a stopped node restarts wherever a record puts it off the origin. The clouds loop that way.
• A record also sets the Eff's scale, turn and transparency, and a translation-only matrix.

The port

• piney_stream::scene::EffNode holds each node's state: its parent, its Eff chunk and patNum, the part bit, and what the records set. Scene::new builds them in the ended state.
• f_obj_eff is the record's branch.
• Scene::reset ends them, as ResetScene does.
• Scene::eff_world gives DrawNoAnm's lwMatrix.
• Stream::draw_effect_nodes draws each running node through piney-effect's Eff. The template for each chunk is read into the effects' assets once. This happens when the player gives the stream its effects, which piney-game always does.

Checks

• The fixture. tools/test_stream_rs.py fixture now lets DrawNoAnm run in eemu and records each ccEff::Draw(pattern): the pattern, the place DrawNoAnm set, the scale, the turn and the transparency, as a hash of the sorted records a step. Stream 2's run grew from 60 to 200 steps so that nodes stop and restart. That is up to 181 draws a step, and the port's nodes match on every step.
• Nothing else moved. No other scene of the fixture draws an effect, and its other lines are unchanged.
• Pictures. stream_shot --stream 2 --frame 900 with --fx shows the white cloud sea under the relic. Without it, the bare floor.