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

/**
 * A shader's `Pass` node (#301): a cut in the graph, whose inputs are drawn into a picture of their
 * own first, read by the nodes that read a picture.
 */
import { describe, expect, it } from 'vitest';
import { AddNodeCommand, ConnectCommand } from '../../src/core/commands/graphCommands';
import { CreateAssetCommand } from '../../src/core/commands/assetCommands';
import { portsCompatible } from '../../src/core/graph/Graph';
import { findAssetOf } from '../../src/core/model/Project';
import { compileShader, perCornerProblem, TOO_MANY_PASSES } from '../../src/core/shader/compile';
import {
  MAX_PASSES,
  ShaderAdd,
  SHADER_BLUR,
  SHADER_OUTPUT,
  SHADER_PASS,
  SHADER_SAMPLE,
  SHADER_TEXTURE_ALPHA,
  SHADER_TEXTURE_COLOR,
  SHADER_TEXTURE_SIZE,
  SHADER_VERTEX_OUTPUT,
} from '../../src/core/shader/nodes';
import { MAX_PASS_PIXELS, passPixels } from '../../src/viewport/quadPadding';
import { makeSpriteScene } from '../helpers';

function shader(outParams = {}) {
  const f = makeSpriteScene();
  const create = new CreateAssetCommand('shader', 'Bloom');
  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 }));
  /** An edge no command would lay, for what a hand-edited file may hold. */
  const wire = (from: string, fromPort: string, to: string, toPort: string) =>
    asset().graph.edges.push({
      id: `e${asset().graph.edges.length}`,
      from: { node: from, port: fromPort },
      to: { node: to, port: toPort },
    });
  const out = add(SHADER_OUTPUT, outParams);
  return { add, link, wire, out, build: () => compileShader(asset().graph) };
}

/** A Pass whose picture a Texture color hands to the Output. */
function passedOn(passParams = {}, outParams = {}) {
  const s = shader(outParams);
  const pass = s.add(SHADER_PASS, passParams);
  const read = s.add(SHADER_TEXTURE_COLOR);
  s.link(pass, 'picture', read, 'picture');
  s.link(read, 'color', s.out, 'color');
  return { ...s, pass, read };
}

describe('Pass (#301)', () => {
  it('draws the Pass first, untinted, and the Output reads its picture through the padding', () => {
    const compiled = passedOn().build().compiled!;
    expect(compiled.passes).toHaveLength(1);
    const [pass] = compiled.passes;
    expect(pass!.fragment).toContain('const vec4 vColor = vec4(1.0);');
    expect(pass!.fragment).not.toContain('in vec4 vColor;');
    expect(pass!.fragment).not.toContain('uPass');
    expect(compiled.fragment).toContain('in vec4 vColor;');
    expect(compiled.fragment).toContain('uniform sampler2D uPass0;');
    expect(compiled.fragment).toContain('uniform vec2 uPassPad;');
    expect(compiled.fragment).toMatch(
      /vec3 n\d+_color = straight\(texelAt\(uPass0, passUv\(vTextureCoord\)\) \* vColor\);/,
    );
  });

  it('leaves a shader without a Pass as it was: no picture to draw, no sampler to bind', () => {
    const s = shader();
    s.link(s.add(SHADER_TEXTURE_COLOR), 'color', s.out, 'color');
    const compiled = s.build().compiled!;
    expect(compiled.passes).toEqual([]);
    expect(compiled.fragment).not.toContain('uPass');
    expect(compiled.fragment).not.toContain('passUv');
  });

  it('draws a pass before the pass that reads it, and each program declares only what it reads', () => {
    const s = shader();
    const first = s.add(SHADER_PASS);
    const across = s.add(SHADER_BLUR, { direction: 'horizontal' });
    const second = s.add(SHADER_PASS);
    const down = s.add(SHADER_SAMPLE);
    s.link(first, 'picture', across, 'picture');
    s.link(across, 'color', second, 'color');
    s.link(across, 'alpha', second, 'alpha');
    s.link(second, 'picture', down, 'picture');
    s.link(down, 'color', s.out, 'color');
    const compiled = s.build().compiled!;
    expect(compiled.passes).toHaveLength(2);
    expect(compiled.passes[0]!.fragment).not.toContain('uPass');
    expect(compiled.passes[1]!.fragment).toContain('uniform sampler2D uPass0;');
    expect(compiled.passes[1]!.fragment).toContain(
      '= blur(uPass0, passUv(vec2(vTextureCoord.x, vTextureCoord.y)),',
    );
    expect(compiled.fragment).toContain('uniform sampler2D uPass1;');
    expect(compiled.fragment).not.toContain('uPass0');
  });

  it('draws a Pass two nodes read once, and one nothing reads not at all', () => {
    const s = passedOn();
    const alpha = s.add(SHADER_TEXTURE_ALPHA);
    s.link(s.pass, 'picture', alpha, 'picture');
    s.link(alpha, 'value', s.out, 'alpha');
    s.add(SHADER_PASS);
    expect(s.build().compiled!.passes).toHaveLength(1);
  });

  it('takes the size from Resolution and the edge from the Output', () => {
    expect(passedOn().build().compiled!.passes[0]!.scale).toBe(1);
    expect(passedOn({ resolution: 'half' }).build().compiled!.passes[0]!.scale).toBe(0.5);
    expect(passedOn({ resolution: 'quarter' }).build().compiled!.passes[0]!.scale).toBe(0.25);
    expect(passedOn({}, { edge: 'repeat' }).build().compiled!.passEdge).toBe('repeat');
  });

  it('measures the picture it is fed', () => {
    const s = passedOn();
    const size = s.add(SHADER_TEXTURE_SIZE);
    const add = s.add(ShaderAdd.type);
    s.link(s.pass, 'picture', size, 'picture');
    s.link(size, 'width', add, 'a');
    s.link(add, 'result', s.out, 'alpha');
    expect(s.build().compiled!.fragment).toContain('(vec2(textureSize(uPass0, 0)) * uPixelScale).x');
  });

  it('names a ring through a picture on the Pass, and compiles nothing', () => {
    const s = shader();
    const pass = s.add(SHADER_PASS);
    const read = s.add(SHADER_TEXTURE_COLOR);
    const out = s.add(SHADER_TEXTURE_COLOR);
    s.wire(pass, 'picture', read, 'picture');
    s.wire(read, 'color', pass, 'color');
    s.link(pass, 'picture', out, 'picture');
    s.link(out, 'color', s.out, 'color');
    const build = s.build();
    expect(build.compiled).toBeNull();
    expect(build.problems[pass]).toBe('Feeds itself');
  });

  it(`stops at ${MAX_PASSES} passes`, () => {
    const s = shader();
    let picture = '';
    for (let n = 0; n <= MAX_PASSES; n++) {
      const pass = s.add(SHADER_PASS);
      if (picture) {
        const read = s.add(SHADER_TEXTURE_COLOR);
        s.link(picture, 'picture', read, 'picture');
        s.link(read, 'color', pass, 'color');
      }
      picture = pass;
    }
    const last = s.add(SHADER_TEXTURE_COLOR);
    s.link(picture, 'picture', last, 'picture');
    s.link(last, 'color', s.out, 'color');
    const build = s.build();
    expect(build.compiled).toBeNull();
    expect(Object.values(build.problems)).toContain(TOO_MANY_PASSES);
  });

  it('lets a picture go only where a picture is read', () => {
    expect(portsCompatible('picture', 'picture')).toBe(true);
    expect(portsCompatible('picture', 'any')).toBe(false);
    expect(portsCompatible('any', 'picture')).toBe(false);
    expect(portsCompatible('picture', 'vec3')).toBe(false);
    const s = shader();
    const pass = s.add(SHADER_PASS);
    const add = s.add(ShaderAdd.type);
    s.wire(pass, 'picture', add, 'a');
    s.link(add, 'result', s.out, 'color');
    expect(s.build().problems[add]).toBe('"a" cannot take a picture');
  });

  it('has no picture per corner', () => {
    const s = shader();
    const pass = s.add(SHADER_PASS);
    const alpha = s.add(SHADER_TEXTURE_ALPHA);
    const corner = s.add(SHADER_VERTEX_OUTPUT);
    s.link(pass, 'picture', alpha, 'picture');
    s.link(alpha, 'value', corner, 'x');
    expect(s.build().problems[corner]).toBe(perCornerProblem('Pass'));
  });

  it('sizes its picture as the wearer’s with the margin, at its resolution, within limits', () => {
    expect(passPixels(16, 16, null, 1)).toEqual({ w: 16, h: 16 });
    expect(passPixels(16, 8, { u: 2 / 16, v: 2 / 8 }, 1)).toEqual({ w: 20, h: 12 });
    expect(passPixels(16, 8, { u: 2 / 16, v: 2 / 8 }, 0.5)).toEqual({ w: 10, h: 6 });
    expect(passPixels(2, 2, null, 0.25)).toEqual({ w: 1, h: 1 });
    expect(passPixels(4096, 100, null, 1)).toEqual({ w: MAX_PASS_PIXELS, h: 100 });
  });
});