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import { createOffscreenCanvas } from "./canvas-utils";
import { effectsRegistry, resolveEffectPasses } from "@/lib/effects";
import { buildDefaultParamValues } from "@/lib/registry";
import type { ParamValues } from "@/lib/params";
import { applyMultiPassEffect } from "./webgl/webgl-utils";
import type { EffectPassData } from "./webgl/webgl-utils";
const PREVIEW_SIZE = 160;
const PREVIEW_IMAGE_PATH = "/effects/preview.jpg";
class EffectPreviewService {
private previewGl: WebGLRenderingContext | null = null;
private previewCanvas: OffscreenCanvas | HTMLCanvasElement | null = null;
private testSourceCanvas: OffscreenCanvas | HTMLCanvasElement | null = null;
private previewImageElement: HTMLImageElement | null = null;
private programCache = new Map<string, WebGLProgram>();
private onReadyCallbacks = new Set<() => void>();
readonly PREVIEW_SIZE = PREVIEW_SIZE;
constructor() {
this.loadPreviewImage();
}
onPreviewImageReady({
callback,
}: {
callback: () => void;
}): () => void {
this.onReadyCallbacks.add(callback);
return () => this.onReadyCallbacks.delete(callback);
}
renderPreview({
effectType,
params,
targetCanvas,
uniformDimensions,
}: {
effectType: string;
params: ParamValues;
targetCanvas: HTMLCanvasElement;
uniformDimensions?: { width: number; height: number };
}): void {
const size = PREVIEW_SIZE;
const source = this.getTestSource({ width: size, height: size });
if (!source) return;
const definition = effectsRegistry.get(effectType);
const resolvedParams =
Object.keys(params).length > 0
? params
: buildDefaultParamValues(definition.params);
const passes = resolveEffectPasses({
definition,
effectParams: resolvedParams,
width: uniformDimensions?.width ?? size,
height: uniformDimensions?.height ?? size,
});
const result = this.applyWebGlEffect({
source,
width: size,
height: size,
passes,
});
const targetCtx = targetCanvas.getContext(
"2d",
) as CanvasRenderingContext2D | null;
if (targetCtx) {
targetCanvas.width = size;
targetCanvas.height = size;
targetCtx.drawImage(result, 0, 0, size, size);
}
}
private loadPreviewImage(): void {
if (typeof window === "undefined") return;
const image = new Image();
image.onload = () => {
this.testSourceCanvas = null;
for (const callback of this.onReadyCallbacks) {
callback();
}
};
image.src = PREVIEW_IMAGE_PATH;
this.previewImageElement = image;
}
private createTestSource({
width,
height,
}: {
width: number;
height: number;
}): OffscreenCanvas | HTMLCanvasElement | null {
const isImageReady =
this.previewImageElement?.complete &&
(this.previewImageElement.naturalWidth ?? 0) > 0;
if (!isImageReady || !this.previewImageElement) {
return null;
}
const canvas = createOffscreenCanvas({ width, height });
const ctx = canvas.getContext("2d") as
| CanvasRenderingContext2D
| OffscreenCanvasRenderingContext2D
| null;
if (!ctx) {
throw new Error("failed to get 2d context for test source");
}
ctx.drawImage(this.previewImageElement, 0, 0, width, height);
return canvas;
}
private getOrCreatePreviewContext({
width,
height,
}: {
width: number;
height: number;
}): { canvas: OffscreenCanvas | HTMLCanvasElement; gl: WebGLRenderingContext } {
if (!this.previewCanvas || !this.previewGl) {
this.previewCanvas = createOffscreenCanvas({ width, height });
this.previewGl = this.previewCanvas.getContext("webgl", {
premultipliedAlpha: false,
}) as WebGLRenderingContext | null;
if (!this.previewGl) {
throw new Error("WebGL not supported");
}
}
if (this.previewCanvas.width !== width || this.previewCanvas.height !== height) {
this.previewCanvas.width = width;
this.previewCanvas.height = height;
}
return { canvas: this.previewCanvas, gl: this.previewGl };
}
private getTestSource({
width,
height,
}: {
width: number;
height: number;
}): CanvasImageSource | null {
if (
!this.testSourceCanvas ||
this.testSourceCanvas.width !== width ||
this.testSourceCanvas.height !== height
) {
this.testSourceCanvas = this.createTestSource({ width, height });
}
return this.testSourceCanvas;
}
private applyWebGlEffect({
source,
width,
height,
passes,
}: {
source: CanvasImageSource;
width: number;
height: number;
passes: EffectPassData[];
}): OffscreenCanvas | HTMLCanvasElement {
const { canvas: glCanvas, gl } = this.getOrCreatePreviewContext({ width, height });
applyMultiPassEffect({
context: gl,
source,
width,
height,
passes,
programCache: this.programCache,
});
const outputCanvas = createOffscreenCanvas({ width, height });
const outputCtx = outputCanvas.getContext("2d") as
| CanvasRenderingContext2D
| OffscreenCanvasRenderingContext2D
| null;
if (outputCtx) {
outputCtx.drawImage(glCanvas, 0, 0, width, height);
}
return outputCanvas;
}
}
export const effectPreviewService = new EffectPreviewService();
|
