Ampandheaust
9ca12c237e
Amp-Thread-ID: https://ampcode.com/threads/T-01a01ff8-b91f-724f-8952-f07c6b5042fd Co-authored-by: Heaust Azure <heaust.azure@gmail.com>
53 lines
2.2 KiB
Markdown
53 lines
2.2 KiB
Markdown
# Scene and shared data
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Think of every handle as an array index, not an object mirrored into core. `Node.position`, `Node.rotor`, and `Node.scale` are component views into separate flat SOA arrays.
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## Direct transform movement
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```ts
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import { Node } from "@yawn/handles";
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const pivot = new Node(scene, { position: [0, 1, 0] });
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await pivot.ready;
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canvas.addEventListener("pointermove", (event) => {
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pivot.position.x += event.movementX * 0.002;
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pivot.position.y -= event.movementY * 0.002;
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});
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```
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The pointer handler sends no messages. Each component property reads or writes its lane in the arena shared with the render worker. Replace complete transforms with `setPosition([x, y, z])`, `setRotor([x, y, z, w])`, and `setScale([x, y, z])`. `translate(...)`, `rotate(...)`, and `rotateX/Y/Z(...)` are convenience methods over those same SAB lanes. The camera helpers use this same pattern; see [Cameras and controls](/guide/cameras).
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<Playground example="sab" />
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## Add an application-specific row
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```ts
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const particles = await scene.ensureRows("particleVelocity", 10_000, 16, "f32");
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particles.row(42).set([1, 0, 0, 0]);
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```
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Rows are 16-byte-stride-aligned and arena allocations are 64-byte aligned. Formats are `f32`, `u32`, or `i32`.
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## Timing and render signals
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Core always creates `signals` as:
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```text
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[deltaTime, frameCount, elapsedTime, targetFps, skipRender, sabDirty, bundleDirty, 0]
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```
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```ts
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const signals = scene.array("signals").row(0);
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signals[4] = 1; // keep timing, skip GPU work
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signals[4] = 0; // resume and request a frame
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```
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The handles layer sets `sabDirty` for writes made through `scene.array(...)` and its node, camera, mesh, material, and light APIs. It sets `bundleDirty` before rebuilding a graph whose recorded pipeline, bindings, geometry, or draw commands changed. Core clears `sabDirty` when it starts a frame; switching to the replacement loadout clears `bundleDirty` and requests a fresh frame.
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Use messages for rare control changes (`setFps`, graph updates, allocation); use SAB writes for existing hot state. Code using `@yawn/core` directly must set `signals[5] = 1` after completing its own row writes.
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<script setup>
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import Playground from "../.vitepress/Playground.vue";
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</script>
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