nEngine/packages/render/test/filters.test.ts

import { describe, expect, it } from "vitest";
import type { ShaderDef } from "@nengine/core";
import {
  filterParams,
  BLUR_DEFAULT_STRENGTH,
  GRAYSCALE_DEFAULT_FACTOR,
  BRIGHTNESS_DEFAULT_FACTOR,
  HUE_DEFAULT_DEGREES,
} from "../src/filters.js";

const def = (overrides: Partial<ShaderDef> = {}): ShaderDef => ({ id: "fx", filter: "blur", ...overrides });

describe("filterParams (pure shader-def → numeric/color parameters)", () => {
  it("maps blur with a strength param", () => {
    expect(filterParams(def({ filter: "blur", params: { strength: 4 } }))).toEqual({ kind: "blur", strength: 4 });
  });

  it("defaults blur strength when absent", () => {
    expect(filterParams(def({ filter: "blur" }))).toEqual({ kind: "blur", strength: BLUR_DEFAULT_STRENGTH });
  });

  it("maps tint from a #rrggbb color string", () => {
    expect(filterParams(def({ filter: "tint", params: { color: "#2f3b4c" } }))).toEqual({ kind: "tint", color: "#2f3b4c" });
  });

  it("maps tint from r/g/b components (clamped to 0-255)", () => {
    expect(filterParams(def({ filter: "tint", params: { r: 47, g: 59, b: 76 } }))).toEqual({ kind: "tint", color: "#2f3b4c" });
    expect(filterParams(def({ filter: "tint", params: { r: 300, g: -5, b: 0 } }))).toEqual({ kind: "tint", color: "#ff0000" });
  });

  it("defaults tint to white when no color params are given", () => {
    expect(filterParams(def({ filter: "tint" }))).toEqual({ kind: "tint", color: "#ffffff" });
  });

  it("maps grayscale with a factor", () => {
    expect(filterParams(def({ filter: "grayscale", params: { factor: 0.7 } }))).toEqual({ kind: "grayscale", factor: 0.7 });
    expect(filterParams(def({ filter: "grayscale" }))).toEqual({ kind: "grayscale", factor: GRAYSCALE_DEFAULT_FACTOR });
  });

  it("maps sepia without params", () => {
    expect(filterParams(def({ filter: "sepia" }))).toEqual({ kind: "sepia" });
  });

  it("maps hue with degrees", () => {
    expect(filterParams(def({ filter: "hue", params: { degrees: 120 } }))).toEqual({ kind: "hue", degrees: 120 });
    expect(filterParams(def({ filter: "hue" }))).toEqual({ kind: "hue", degrees: HUE_DEFAULT_DEGREES });
  });

  it("maps brightness with a factor", () => {
    expect(filterParams(def({ filter: "brightness", params: { factor: 1.2 } }))).toEqual({ kind: "brightness", factor: 1.2 });
    expect(filterParams(def({ filter: "brightness" }))).toEqual({ kind: "brightness", factor: BRIGHTNESS_DEFAULT_FACTOR });
  });

  it("ignores non-numeric params (falls back to defaults)", () => {
    expect(filterParams(def({ filter: "blur", params: { strength: "high" } }))).toEqual({ kind: "blur", strength: BLUR_DEFAULT_STRENGTH });
  });
});