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