feuerwerk/tests/core/shader-blur.test.ts

/**
 * A shader's `Blur` node (#300): the picture softened around a spot in one pass, the loop written
 * by the compiler into the prelude.
 */
import { describe, expect, it } from 'vitest';
import { AddNodeCommand, ConnectCommand } from '../../src/core/commands/graphCommands';
import { CreateAssetCommand } from '../../src/core/commands/assetCommands';
import { findAssetOf } from '../../src/core/model/Project';
import { SHADER_PROPERTY } from '../../src/core/properties/shaders';
import { compileShader, perCornerProblem } from '../../src/core/shader/compile';
import {
  BLUR_FN,
  SHADER_BLUR,
  SHADER_OUTPUT,
  SHADER_VERTEX_OUTPUT,
  SHEET_EDGE,
} from '../../src/core/shader/nodes';
import { makeSpriteScene } from '../helpers';

function shader(outParams = {}) {
  const f = makeSpriteScene();
  const create = new CreateAssetCommand('shader', 'Soften');
  f.stack.execute(create);
  const id = create.asset.id;
  const asset = () => findAssetOf(f.project, id, 'shader')!;
  const add = (type: string, params = {}) => {
    const command = new AddNodeCommand(id, type, 0, 0, params);
    f.stack.execute(command);
    return command.node.id;
  };
  const link = (from: string, fromPort: string, to: string, toPort: string) =>
    f.stack.execute(new ConnectCommand(id, { node: from, port: fromPort }, { node: to, port: toPort }));
  const out = add(SHADER_OUTPUT, outParams);
  return { add, link, out, build: () => compileShader(asset().graph) };
}

/** A Blur feeding both outputs of the Output node. */
function blurred(params = {}, outParams = {}) {
  const s = shader(outParams);
  const blur = s.add(SHADER_BLUR, params);
  s.link(blur, 'color', s.out, 'color');
  s.link(blur, 'alpha', s.out, 'alpha');
  return { ...s, blur };
}

const calls = (fragment: string) => fragment.split('void main()')[1]!.match(/blur\(/g)?.length ?? 0;

describe('Blur (#300)', () => {
  it('samples once per pixel, premultiplied, and both outputs read that one sum', () => {
    const fragment = blurred().build().compiled!.fragment;
    expect(fragment).toContain(BLUR_FN);
    expect(fragment).toContain(
      'vec4 n0_prepared = blur(vec2(vTextureCoord.x, vTextureCoord.y), 2.0, vec2(1.0, 1.0), 0.0) * vColor;',
    );
    expect(fragment).toContain('vec3 n1_color = straight(n0_prepared);');
    expect(fragment).toContain('float n2_alpha = n0_prepared.a;');
    expect(calls(fragment)).toBe(1);
  });

  it('turns Kind and Direction into the arguments of the one helper', () => {
    const call = (params: object) =>
      blurred(params)
        .build()
        .compiled!.fragment.match(/= blur\(.*;/)![0];
    expect(call({ kind: 'gaussian' })).toContain('vec2(1.0, 1.0), 1.0)');
    expect(call({ direction: 'horizontal' })).toContain('vec2(1.0, 0.0), 0.0)');
    expect(call({ direction: 'vertical' })).toContain('vec2(0.0, 1.0), 0.0)');
    expect(call({ kind: 'nonsense', direction: 'nonsense' })).toContain('vec2(1.0, 1.0), 0.0)');
  });

  it('holds the radius at 0 to 8 in the program, and takes it from a Property as a uniform', () => {
    expect(BLUR_FN).toContain('float r = clamp(radius, 0.0, 8.0);');
    const s = blurred({ radius: 3.5 });
    expect(s.build().compiled!.fragment).toContain('blur(vec2(vTextureCoord.x, vTextureCoord.y), 3.5,');
    const soft = s.add(SHADER_PROPERTY, { name: 'soft', default: 2, min: 0, max: 8 });
    s.link(soft, 'value', s.blur, 'radius');
    const compiled = s.build().compiled!;
    expect(compiled.uniforms).toEqual([{ name: 'soft', kind: 'number', default: 2 }]);
    expect(compiled.fragment).toMatch(/= blur\(vec2\(vTextureCoord\.x, vTextureCoord\.y\), n\d+_value,/);
  });

  it('reads at the UV it is fed', () => {
    const s = blurred();
    const uv = s.add('ShaderUV');
    const flip = s.add('ShaderSubtract', { a: 1 });
    s.link(uv, 'u', flip, 'b');
    s.link(flip, 'result', s.blur, 'u');
    expect(s.build().compiled!.fragment).toMatch(/= blur\(vec2\(n\d+_result, vTextureCoord\.y\), 2\.0,/);
  });

  it('leaves the helper out of a shader that does not reach it', () => {
    const s = shader();
    s.add(SHADER_BLUR);
    const fragment = s.build().compiled!.fragment;
    expect(fragment).not.toContain('blurWeight');
    expect(calls(fragment)).toBe(0);
  });

  it('reads past the border, so the picture comes with the Output’s Edge', () => {
    expect(blurred().build().compiled!.edge).toBe('clamp');
    expect(blurred({}, { edge: 'repeat' }).build().compiled!.edge).toBe('repeat');
    expect(blurred({}, { edge: 'transparent' }).build().compiled!.edge).toBe(SHEET_EDGE);
  });

  it('reads the picture, so it cannot feed the Vertex output', () => {
    const s = shader();
    const corner = s.add(SHADER_VERTEX_OUTPUT);
    const blur = s.add(SHADER_BLUR);
    s.link(blur, 'alpha', corner, 'x');
    const build = s.build();
    expect(build.compiled).toBeNull();
    expect(build.problems[corner]).toBe(perCornerProblem('Blur'));
  });
});