Shaders and modular assembly

• Define modules as plain objects with a name, fs code and inject fragments.
• Inject at an existing hook such as fs:#main-end, otherwise nothing happens.
• Use ShaderAssembler.assembleGLSLShaderPair when building pipelines manually.

const vs = device.createShader({
  stage: 'vertex',
  source: [
    '#version 300 es',
    'in vec3 positions;',
    'in vec2 uvs;',
    'out vec2 vUV;',
    'void main() {',
    '  vUV = uvs;',
    '  gl_Position = vec4(positions, 1.0);',
    '}'
  ].join('\n')
});

const fs = device.createShader({
  stage: 'fragment',
  source: [
    '#version 300 es',
    'precision highp float;',
    'in vec2 vUV;',
    'uniform sampler2D uTexture;',
    'out vec4 fragColor;',
    'void main() { fragColor = texture(uTexture, vUV); }'
  ].join('\n')
});

console.log(vs.compilationStatus);   // 'success' 或 'error'
console.log(vs.getCompilationInfoSync());

const waveModule = {
  name: 'wave',
  fs: [
    'float wave(float x, float freq) {',
    '  return sin(x * freq) * 0.5 + 0.5;',
    '}'
  ].join('\n'),
  inject: {
    'fs:#main-end': 'fragColor.rgb *= wave(vUV.x, 6.0);'
  }
};

const model = new luma.Model(device, {
  vs: vsSource,
  fs: fsSource,
  modules: [waveModule],
  attributes: { positions: positions, uvs: uvs },
  bufferLayout: [
    { name: 'positions', stepMode: 'vertex', format: 'float32x3' },
    { name: 'uvs', stepMode: 'vertex', format: 'float32x2' }
  ],
  vertexCount: 6,
  topology: 'triangle-list'
});

• luma.ShaderModule is undefined at runtime in v9, so new ShaderModule throws.
• Duplicate helper names across modules cause redefinition compile errors.