add rule to detect unused textures in model files

package-scripts/linting-rules/no-unused-textures-in-models.js

@@ -0,0 +1,89 @@
+const { readFileSync } = require('fs');
+const { differenceBy, uniq } = require('lodash');
+
+const name = 'no-unused-textures-in-models';
+const applicableExtensions = ['.ajmodel'];
+
+/**
+ * Iterates through each face of each cube (the model's default variant)
+ * and returns a (deduplicated) list of found textures
+ */
+const getDefaultVariantTextures = (ajmodel) => {
+  const defaultVariantTextureIdxs = [];
+  const cubes = ajmodel.elements.filter(({ type }) => type === 'cube');
+  for (const element of cubes) {
+    // side = 'north', 'south', etc.
+    for (const side of Object.keys(element.faces)) {
+      const textureIdx = element.faces[side].texture;
+      if (typeof textureIdx !== 'undefined') {
+        defaultVariantTextureIdxs.push(textureIdx);
+      }
+    }
+  }
+  // Deduplicate and convert from texture-index to texture object
+  const defaultTextures = uniq(defaultVariantTextureIdxs).map(
+    (idx) => ajmodel.textures[idx],
+  );
+
+  return defaultTextures;
+};
+
+/**
+ * Takes in an allowlist of texture UUIDs (ones that are used in the default variant),
+ * iterates through a model's variants, and returns a list of (target) textures from
+ * each variant's texture map whose source texture was found in the allowlist
+ */
+const getAllowedVariantTextures = (ajmodel, allowlist) => {
+  const allowedVariantTextures = [];
+  for (const variant of ajmodel.animated_java.variants) {
+    // Skip the default variant since that's what our allowlist consists of
+    if (variant.default) {
+      continue;
+    }
+    for (const [source, target] of Object.entries(variant.textureMap)) {
+      if (allowlist.includes(source)) {
+        allowedVariantTextures.push(
+          ajmodel.textures.find(({ uuid }) => uuid === target),
+        );
+      }
+    }
+  }
+  return uniq(allowedVariantTextures);
+};
+
+/** Errors for textures defined in a model file that aren't actually used by any cube's face (in any variant) */
+const noUnusedTexturesInModels = (file) => {
+  // Return early if file does not match any applicable extension
+  if (applicableExtensions.every((extension) => !file.endsWith(extension))) {
+    return [];
+  }
+
+  const errors = [];
+
+  const ajmodel = JSON.parse(readFileSync(file, 'utf8'));
+
+  const defaultTextures = getDefaultVariantTextures(ajmodel);
+  const defaultTextureUuids = defaultTextures.map(({ uuid }) => uuid);
+  const variantTextures = getAllowedVariantTextures(
+    ajmodel,
+    defaultTextureUuids,
+  );
+
+  const allSeenTextures = uniq(defaultTextures.concat(variantTextures));
+  const unusedTextures = differenceBy(
+    ajmodel.textures,
+    allSeenTextures,
+    'uuid',
+  );
+  if (unusedTextures.length > 0) {
+    const unusedTextureNames = unusedTextures.map(({ name }) => name);
+    errors.push(`delete unused textures: [ ${unusedTextureNames.join(', ')} ]`);
+  }
+
+  return errors;
+};
+
+module.exports = {
+  function: noUnusedTexturesInModels,
+  name,
+};