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import {
getCompositorCanvas,
initCompositor,
releaseTexture,
renderFrame,
resizeCompositor,
uploadTexture,
} from "opencut-wasm";
import type { FrameDescriptor } from "./types";
function ensureOffscreenCanvas({
source,
width,
height,
label,
}: {
source: CanvasImageSource;
width: number;
height: number;
label: string;
}): OffscreenCanvas {
if (source instanceof OffscreenCanvas) {
return source;
}
if (typeof OffscreenCanvas === "undefined") {
throw new Error(`OffscreenCanvas is required for ${label}`);
}
const canvas = new OffscreenCanvas(width, height);
const context = canvas.getContext("2d");
if (!context) {
throw new Error(`Failed to get 2d context for ${label}`);
}
context.clearRect(0, 0, width, height);
context.drawImage(source, 0, 0, width, height);
return canvas;
}
export type TextureUploadDescriptor = {
id: string;
source: CanvasImageSource;
width: number;
height: number;
};
class WasmCompositor {
private canvas: HTMLCanvasElement | null = null;
private initializedSize: { width: number; height: number } | null = null;
private retainedTextureIds = new Set<string>();
private uploadedTextures = new Map<
string,
{ source: CanvasImageSource; width: number; height: number }
>();
ensureInitialized({ width, height }: { width: number; height: number }) {
if (!this.canvas) {
initCompositor(width, height);
this.canvas = getCompositorCanvas();
this.initializedSize = { width, height };
return;
}
if (
!this.initializedSize ||
this.initializedSize.width !== width ||
this.initializedSize.height !== height
) {
resizeCompositor(width, height);
this.initializedSize = { width, height };
}
}
getCanvas(): HTMLCanvasElement {
if (!this.canvas) {
throw new Error("Compositor is not initialized");
}
return this.canvas;
}
syncTextures(textures: TextureUploadDescriptor[]) {
const nextIds = new Set(textures.map((texture) => texture.id));
for (const previousId of this.retainedTextureIds) {
if (!nextIds.has(previousId)) {
releaseTexture(previousId);
this.uploadedTextures.delete(previousId);
}
}
for (const texture of textures) {
const previousTexture = this.uploadedTextures.get(texture.id);
if (
previousTexture?.source === texture.source &&
previousTexture.width === texture.width &&
previousTexture.height === texture.height
) {
continue;
}
const sourceCanvas = ensureOffscreenCanvas({
source: texture.source,
width: texture.width,
height: texture.height,
label: `texture upload ${texture.id}`,
});
uploadTexture({
id: texture.id,
source: sourceCanvas,
width: texture.width,
height: texture.height,
});
this.uploadedTextures.set(texture.id, {
source: texture.source,
width: texture.width,
height: texture.height,
});
}
this.retainedTextureIds = nextIds;
}
render(frame: FrameDescriptor) {
renderFrame(frame);
}
}
export const wasmCompositor = new WasmCompositor();
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