Add existing to tracked

node_modules/@cesium/engine/Source/Renderer/ShaderFunction.js

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+import DeveloperError from "../Core/DeveloperError.js";
+
+/**
+ * A utility for dynamically-generating a GLSL function
+ *
+ * @alias ShaderFunction
+ * @constructor
+ *
+ * @see {@link ShaderBuilder}
+ * @param {string} signature The full signature of the function as it will appear in the shader. Do not include the curly braces.
+ * @example
+ * // generate the following function
+ * //
+ * // void assignVaryings(vec3 position)
+ * // {
+ * //    v_positionEC = (czm_modelView * vec4(a_position, 1.0)).xyz;
+ * //    v_texCoord = a_texCoord;
+ * // }
+ * const signature = "void assignVaryings(vec3 position)";
+ * const func = new ShaderFunction(signature);
+ * func.addLine("v_positionEC = (czm_modelView * vec4(a_position, 1.0)).xyz;");
+ * func.addLine("v_texCoord = a_texCoord;");
+ * const generatedLines = func.generateGlslLines();
+ *
+ * @private
+ */
+function ShaderFunction(signature) {
+  this.signature = signature;
+  this.body = [];
+}
+
+/**
+ * Adds one or more lines to the body of the function
+ * @param {string|string[]} lines One or more lines of GLSL code to add to the function body. Do not include any preceding or ending whitespace, but do include the semicolon for each line.
+ */
+ShaderFunction.prototype.addLines = function (lines) {
+  //>>includeStart('debug', pragmas.debug);
+  if (typeof lines !== "string" && !Array.isArray(lines)) {
+    throw new DeveloperError(
+      `Expected lines to be a string or an array of strings, actual value was ${lines}`,
+    );
+  }
+  //>>includeEnd('debug');
+  const body = this.body;
+
+  // Indent the body of the function by 4 spaces
+  if (Array.isArray(lines)) {
+    const length = lines.length;
+    for (let i = 0; i < length; i++) {
+      body.push(`    ${lines[i]}`);
+    }
+  } else {
+    // Single string case
+    body.push(`    ${lines}`);
+  }
+};
+
+/**
+ * Generate lines of GLSL code for use with {@link ShaderBuilder}
+ * @return {string[]}
+ */
+ShaderFunction.prototype.generateGlslLines = function () {
+  return [].concat(this.signature, "{", this.body, "}");
+};
+
+export default ShaderFunction;