Shader graph: Pow node, base held at 0, exponent broadcast for colours (#80)

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/core/shaders.test.ts

@@ -451,6 +451,25 @@ describe('compileShader', () => {
     expect(fragment).toMatch(/vec3 n\d+_result = floor\(n\d+_color\);/);
     expect(fragment).toMatch(/float alpha = clamp\(n\d+_result, 0\.0, 1\.0\);/);
   });
+
+  it('writes Pow as the GLSL call with the base held at 0, the exponent broadcast for a colour', () => {
+    const f = makeProject();
+    const s = shaderEditor(f, 'Gamma');
+    const uv = s.add(SHADER_UV);
+    const eased = s.add('ShaderPow', { exponent: 2 });
+    const tint = s.add('ShaderColor', { value: 0xff8000 });
+    const gamma = s.add('ShaderPow', { exponent: 2.2 });
+    const output = s.add(SHADER_OUTPUT);
+    s.link(uv, 'u', eased, 'value');
+    s.link(eased, 'result', output, 'alpha');
+    s.link(tint, 'color', gamma, 'value');
+    s.link(gamma, 'result', output, 'color');
+    const build = compileShader(s.asset().graph);
+    expect(build.problems).toEqual({});
+    const { fragment } = build.compiled!;
+    expect(fragment).toMatch(/float n\d+_result = pow\(max\(n\d+_u, 0\.0\), 2\.0\);/);
+    expect(fragment).toMatch(/vec3 n\d+_result = pow\(max\(n\d+_color, 0\.0\), vec3\(2\.2\)\);/);
+  });
 });
 
 describe('a sprite wearing a shader', () => {