Preload default textures for instant texture picker opening

Fetch and parse .tex files in the background when a textured part
loads, and pass the results to TexturePickerModal as a prop. The
modal no longer fetches on mount, eliminating the loading delay.

src/lib/save-editor/TexturePickerModal.svelte

@@ -1,18 +1,17 @@
 <script>
     import { onMount } from 'svelte';
-    import { parseTex } from '../../core/formats/TexParser.js';
     import { quantizeImage, squareTexture } from '../../core/savegame/imageQuantizer.js';
     import { saveCustomTexture, listCustomTextures, deleteCustomTexture } from '../../core/savegame/textureStorage.js';
     import Carousel from '../Carousel.svelte';
 
     export let textureInfo;
     export let palette = null;
+    export let defaults = null;
     export let onSelect = () => {};
     export let onClose = () => {};
 
-    let defaults = [];
+    let defaultTextures = [];
     let customTextures = [];
-    let loadingDefaults = true;
     let fileInput;
     let activeTab = 'default';
     let selectedCustomId = null;
@@ -22,40 +21,20 @@
     let targetHeight = 128;
 
     onMount(async () => {
-        await loadDefaults();
+        initDefaults();
         await loadCustomTextures();
     });
 
-    async function loadDefaults() {
-        loadingDefaults = true;
-        const loaded = [];
-
-        for (const texFile of textureInfo.texFiles) {
-            try {
-                const response = await fetch(`/${texFile}.tex`);
-                if (!response.ok) continue;
-                const buffer = await response.arrayBuffer();
-                const parsed = parseTex(buffer);
-                if (parsed.textures.length > 0) {
-                    const tex = parsed.textures[0];
-                    loaded.push({
-                        name: texFile,
-                        ...tex,
-                        dataUrl: textureToDataUrl(tex)
-                    });
-                }
-            } catch (e) {
-                console.error(`Failed to load ${texFile}.tex:`, e);
-            }
+    function initDefaults() {
+        const source = defaults || [];
+        defaultTextures = source.map(tex => ({
+            ...tex,
+            dataUrl: textureToDataUrl(tex)
+        }));
+        if (defaultTextures.length > 0) {
+            targetWidth = defaultTextures[0].width;
+            targetHeight = defaultTextures[0].height;
         }
-
-        if (loaded.length > 0) {
-            targetWidth = loaded[0].width;
-            targetHeight = loaded[0].height;
-        }
-
-        defaults = loaded;
-        loadingDefaults = false;
     }
 
     async function loadCustomTextures() {
@@ -127,7 +106,7 @@
 
         // Use the WDB palette (passed as prop) — this is the palette the game's
         // DirectDraw surface actually uses. Fall back to first default's palette.
-        const targetPalette = palette || defaults[0]?.palette;
+        const targetPalette = palette || defaultTextures[0]?.palette;
         if (!targetPalette) return;
 
         const img = new Image();
@@ -210,11 +189,8 @@
 
         <div class="modal-body">
             {#if activeTab === 'default'}
-                {#if loadingDefaults}
-                    <div class="loading">Loading textures...</div>
-                {:else}
                     <div class="texture-grid">
-                        {#each defaults as tex}
+                        {#each defaultTextures as tex}
                             <button
                                 type="button"
                                 class="texture-thumb"
@@ -225,7 +201,6 @@
                             </button>
                         {/each}
                     </div>
-                {/if}
             {:else}
                 {#if customTextures.length > 0}
                     <div class="custom-carousel">
@@ -333,13 +308,6 @@
         padding: 14px;
     }
 
-    .loading {
-        color: var(--color-text-muted);
-        font-size: 0.85em;
-        text-align: center;
-        padding: 20px 0;
-    }
-
     .texture-grid {
         display: grid;
         grid-template-columns: repeat(2, 1fr);

src/lib/save-editor/VehicleEditor.svelte

@@ -12,6 +12,7 @@
         Act1PlaneIndices
     } from '../../core/savegame/constants.js';
     import { squareTexture } from '../../core/savegame/imageQuantizer.js';
+    import { parseTex } from '../../core/formats/TexParser.js';
     import NavButton from '../NavButton.svelte';
     import ResetButton from '../ResetButton.svelte';
     import EditorTooltip from '../EditorTooltip.svelte';
@@ -45,6 +46,7 @@
     let showTextureModal = false;
     let texturePalette = null;
     let wdbTexture = null;
+    let preloadedDefaults = null;
 
     // Current part info from flat list
     $: currentEntry = allParts[globalIndex];
@@ -207,12 +209,36 @@
             // Load part with current color, textures, and parts map for shared LOD lookup
             renderer.loadPartWithColor(partRoi, currentColorValue, textures, partsMap)
             loadedPartKey = partKey;
+
+            // Preload default .tex files in background for the texture picker
+            if (textureInfo) {
+                preloadDefaultTextures(textureInfo);
+            } else {
+                preloadedDefaults = null;
+            }
         } catch (e) {
             console.error('Failed to load part:', e);
             partError = e.message;
         }
     }
 
+    async function preloadDefaultTextures(info) {
+        const loaded = [];
+        for (const texFile of info.texFiles) {
+            const response = await fetch(`/${texFile}.tex`);
+            if (!response.ok) continue;
+            const buffer = await response.arrayBuffer();
+            const parsed = parseTex(buffer);
+            if (parsed.textures.length > 0) {
+                loaded.push({ name: texFile, ...parsed.textures[0] });
+            }
+        }
+        // Only apply if textureInfo hasn't changed since we started
+        if (textureInfo === info) {
+            preloadedDefaults = loaded;
+        }
+    }
+
     function prevPart() {
         globalIndex = globalIndex > 0 ? globalIndex - 1 : allParts.length - 1;
         loadedPartKey = null;
@@ -358,6 +384,7 @@
     <TexturePickerModal
         {textureInfo}
         palette={texturePalette}
+        defaults={preloadedDefaults}
         onSelect={handleTextureSelect}
         onClose={() => showTextureModal = false}
     />