Entry 121

Streams 3, 4 and 6's effect tasks and the letterbox

2026-09-25rendertest

Filescrates/piney-stream/src/effect.rscrates/piney-stream/src/scene.rscrates/piney-stream/src/draw.rscrates/piney-desktop/src/view.rscrates/piney-desktop/src/camera.rscrates/piney-desktop/src/noiz.rscrates/piney-desktop/src/fade.rscrates/piney-stream/tests/effects.rstools/test_stream_rs.pycrates/piney-game/src/session/tests/survey.rsdocs/engine/stream.md

Of the stream effect tasks, only str0001, str0120 and str0300 were ported. The scenes of streams 3, 4 and 6 played with no effects.

The tasks

• Func_str0090 (stream 3). This task uses the same effect objects as the others. It turns on a feedback of 1.001 at alpha 0x6c. Cue 6 or 16 puts the feedback in its fading state with no fade time, so it keeps drawing at alpha 0.
• Func_str0110 (stream 4). Plain feedbacks, timed feedbacks, the noise, the inversion and the fog off, by cue (docs/engine/stream.md).
• Func_str0130 (stream 6). Before making its objects it letterboxes the scene's view: ccView::SetFrame(0, 48, 512, 288, 256, 192, 0.75, 0.75). Its only cue, 899, fades the letterbox to black over the frames left.

The letterbox

The scene's layers and the task's own layer share one view, so SetFrame changes everything drawn in them:

• The 3D. The centre moves to (2048, 2104) and the picture is drawn at 3/4 size. piney_desktop::view::Frame holds the arguments, and camera::frame_projection turns them into a projection. The scene draw also uses the frame's scissor (rows 56-391).
• The effects. The bands, the feedback and the inversion read the view's scissor, clip box and layer_screen scales. In the port they now read them from noiz::EffView. So the bands' Init makes 21-row bands and draws 168 numbers, not 216.
• The fade. EntryFade is given the view's rectangle. ccScFade::SendPacket draws on the font layer through that layer's default view: the corner by ApplyLayerScreenMatrix, the size truncated. That is fade::draw_rect. The whole-frame fade gives the old constant corners.

The game's own SetFrame, run in eemu, sets the default scy to 0x44ffffff, one ulp under 2048. This is the EE's truncating multiply. The port's default_projection now goes through the same EE float arithmetic, so it gives the same value.

Checked

• tools/test_stream_rs.py effects str0090 | str0110 | str0130. Each runs the game's task in eemu and writes a fixture. crates/piney-stream/tests/effects.rs plays streams 3, 4 and 6 for real. Every pass's primitives match bit for bit (by hash), and so does rand after each pass: 1,203 passes and 637 primitives for stream 3, 1,496 and 1,474 for stream 4, 1,043 and 67 for stream 6.
• view::tests::letterbox_frame checks the frame's centre, clip box and scissor against the values the game's SetFrame leaves in eemu.
• stream_shot --stream 6 --frame 400 shows the black bars above and below the scene.
• Also. session::tests::survey::story_survey (ignored, a diagnostic) runs each M1 story start under the autopilot. It prints what each start reached, the host calls left at their defaults, and any panic.