Add existing to tracked

node_modules/obj2gltf/lib/loadTexture.js

@@ -0,0 +1,133 @@
+"use strict";
+const Cesium = require("cesium");
+const fsExtra = require("fs-extra");
+const jpeg = require("jpeg-js");
+const path = require("path");
+const PNG = require("pngjs").PNG;
+const Promise = require("bluebird");
+const Texture = require("./Texture");
+
+const defaultValue = (a, b) => a ?? b;
+const defined = Cesium.defined;
+
+module.exports = loadTexture;
+
+/**
+ * Load a texture file.
+ *
+ * @param {String} texturePath Path to the texture file.
+ * @param {Object} [options] An object with the following properties:
+ * @param {Boolean} [options.checkTransparency=false] Do a more exhaustive check for texture transparency by looking at the alpha channel of each pixel.
+ * @param {Boolean} [options.decode=false] Whether to decode the texture.
+ * @param {Boolean} [options.keepSource=false] Whether to keep the source image contents in memory.
+ * @returns {Promise} A promise resolving to a Texture object.
+ *
+ * @private
+ */
+function loadTexture(texturePath, options) {
+  options = defaultValue(options, {});
+  options.checkTransparency = defaultValue(options.checkTransparency, false);
+  options.decode = defaultValue(options.decode, false);
+  options.keepSource = defaultValue(options.keepSource, false);
+
+  return fsExtra.readFile(texturePath).then(function (source) {
+    const name = path.basename(texturePath, path.extname(texturePath));
+    const extension = path.extname(texturePath).toLowerCase();
+    const texture = new Texture();
+    texture.source = source;
+    texture.name = name;
+    texture.extension = extension;
+    texture.path = texturePath;
+
+    let decodePromise;
+    if (extension === ".png") {
+      decodePromise = decodePng(texture, options);
+    } else if (extension === ".jpg" || extension === ".jpeg") {
+      decodePromise = decodeJpeg(texture, options);
+    }
+
+    if (defined(decodePromise)) {
+      return decodePromise.then(function () {
+        return texture;
+      });
+    }
+
+    return texture;
+  });
+}
+
+function hasTransparency(pixels) {
+  const pixelsLength = pixels.length / 4;
+  for (let i = 0; i < pixelsLength; ++i) {
+    if (pixels[i * 4 + 3] < 255) {
+      return true;
+    }
+  }
+  return false;
+}
+
+function getChannels(colorType) {
+  switch (colorType) {
+    case 0: // greyscale
+      return 1;
+    case 2: // RGB
+      return 3;
+    case 4: // greyscale + alpha
+      return 2;
+    case 6: // RGB + alpha
+      return 4;
+    default:
+      return 3;
+  }
+}
+
+function parsePng(data) {
+  return new Promise(function (resolve, reject) {
+    new PNG().parse(data, function (error, decodedResults) {
+      if (defined(error)) {
+        reject(error);
+        return;
+      }
+      resolve(decodedResults);
+    });
+  });
+}
+
+function decodePng(texture, options) {
+  // Color type is encoded in the 25th bit of the png
+  const source = texture.source;
+  const colorType = source[25];
+  const channels = getChannels(colorType);
+
+  const checkTransparency = channels === 4 && options.checkTransparency;
+  const decode = options.decode || checkTransparency;
+
+  if (decode) {
+    return parsePng(source).then(function (decodedResults) {
+      if (options.checkTransparency) {
+        texture.transparent = hasTransparency(decodedResults.data);
+      }
+      if (options.decode) {
+        texture.pixels = decodedResults.data;
+        texture.width = decodedResults.width;
+        texture.height = decodedResults.height;
+        if (!options.keepSource) {
+          texture.source = undefined; // Unload resources
+        }
+      }
+    });
+  }
+}
+
+function decodeJpeg(texture, options) {
+  if (options.decode) {
+    const source = texture.source;
+    const decodedResults = jpeg.decode(source);
+    texture.pixels = decodedResults.data;
+    texture.width = decodedResults.width;
+    texture.height = decodedResults.height;
+    if (!options.keepSource) {
+      texture.source = undefined; // Unload resources
+    }
+  }
+}