Add glTF draco support

jme3-plugins/build.gradle

@@ -9,9 +9,15 @@ sourceSets {
     }
 }
 
+repositories{
+    maven {
+        url "https://maven.rblb.it/jMonkeyEngine/openize-drako-java/"
+    }
+}
+
 dependencies {
     api project(':jme3-core')
-
+    implementation "org.jmonkeyengine:drako:1.4.3"
     implementation project(':jme3-plugins-json')
     implementation project(':jme3-plugins-json-gson')
     testRuntimeOnly project(':jme3-desktop')

jme3-plugins/src/gltf/java/com/jme3/scene/plugins/gltf/BufferQuantization.java

@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2009-2026 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.jme3.scene.plugins.gltf;
+
+import java.nio.ByteBuffer;
+import java.nio.FloatBuffer;
+import java.nio.ShortBuffer;
+
+import com.jme3.util.BufferUtils;
+
+/**
+ * A package-private class to perform dequantization of buffers.
+ * 
+ * This handled buffers that contain (unsigned) byte or short values and that are "normalized", i.e. supposed
+ * to be interpreted as float values.
+ * 
+ * (NOTE: Some of these methods are taken from a non-published state of JglTF, but published by the original
+ * author, as part of JMonkeyEngine)
+ */
+class BufferQuantization {
+
+    /**
+     * Dequantize the given buffer into a float buffer, treating each element of the input as a signed byte.
+     * 
+     * @param byteBuffer
+     *            The input buffer
+     * @return The result
+     */
+    static FloatBuffer dequantizeByteBuffer(ByteBuffer byteBuffer) {
+        FloatBuffer floatBuffer = BufferUtils.createFloatBuffer(byteBuffer.capacity());
+        for (int i = 0; i < byteBuffer.capacity(); i++) {
+            byte c = byteBuffer.get(i);
+            float f = dequantizeByte(c);
+            floatBuffer.put(i, f);
+        }
+        return floatBuffer;
+    }
+
+    /**
+     * Dequantize the given buffer into a float buffer, treating each element of the input as an unsigned
+     * byte.
+     * 
+     * @param byteBuffer
+     *            The input buffer
+     * @return The result
+     */
+    static FloatBuffer dequantizeUnsignedByteBuffer(ByteBuffer byteBuffer) {
+        FloatBuffer floatBuffer = BufferUtils.createFloatBuffer(byteBuffer.capacity());
+        for (int i = 0; i < byteBuffer.capacity(); i++) {
+            byte c = byteBuffer.get(i);
+            float f = dequantizeUnsignedByte(c);
+            floatBuffer.put(i, f);
+        }
+        return floatBuffer;
+    }
+
+    /**
+     * Dequantize the given buffer into a float buffer, treating each element of the input as a signed short.
+     * 
+     * @param shortBuffer
+     *            The input buffer
+     * @return The result
+     */
+    static FloatBuffer dequantizeShortBuffer(ShortBuffer shortBuffer) {
+        FloatBuffer floatBuffer = BufferUtils.createFloatBuffer(shortBuffer.capacity());
+        for (int i = 0; i < shortBuffer.capacity(); i++) {
+            short c = shortBuffer.get(i);
+            float f = dequantizeShort(c);
+            floatBuffer.put(i, f);
+        }
+        return floatBuffer;
+    }
+
+    /**
+     * Dequantize the given buffer into a float buffer, treating each element of the input as an unsigned
+     * short.
+     * 
+     * @param shortBuffer
+     *            The input buffer
+     * @return The result
+     */
+    static FloatBuffer dequantizeUnsignedShortBuffer(ShortBuffer shortBuffer) {
+        FloatBuffer floatBuffer = BufferUtils.createFloatBuffer(shortBuffer.capacity());
+        for (int i = 0; i < shortBuffer.capacity(); i++) {
+            short c = shortBuffer.get(i);
+            float f = dequantizeUnsignedShort(c);
+            floatBuffer.put(i, f);
+        }
+        return floatBuffer;
+    }
+
+    /**
+     * Dequantize the given signed byte into a floating point value
+     * 
+     * @param c
+     *            The input
+     * @return The result
+     */
+    private static float dequantizeByte(byte c) {
+        float f = Math.max(c / 127.0f, -1.0f);
+        return f;
+    }
+
+    /**
+     * Dequantize the given unsigned byte into a floating point value
+     * 
+     * @param c
+     *            The input
+     * @return The result
+     */
+    private static float dequantizeUnsignedByte(byte c) {
+        int i = Byte.toUnsignedInt(c);
+        float f = i / 255.0f;
+        return f;
+    }
+
+    /**
+     * Dequantize the given signed short into a floating point value
+     * 
+     * @param c
+     *            The input
+     * @return The result
+     */
+    private static float dequantizeShort(short c) {
+        float f = Math.max(c / 32767.0f, -1.0f);
+        return f;
+    }
+
+    /**
+     * 
+     * Dequantize the given unsigned byte into a floating point value
+     * 
+     * @param c
+     *            The input
+     * @return The result
+     */
+    private static float dequantizeUnsignedShort(short c) {
+        int i = Short.toUnsignedInt(c);
+        float f = i / 65535.0f;
+        return f;
+    }
+
+    /**
+     * Private constructor to prevent instantiation
+     */
+    private BufferQuantization() {
+        // Private constructor to prevent instantiation
+    }
+
+}

jme3-plugins/src/gltf/java/com/jme3/scene/plugins/gltf/CustomContentManager.java

@@ -63,6 +63,7 @@ public class CustomContentManager {
         defaultExtensionLoaders.put("KHR_materials_unlit", UnlitExtensionLoader.class);
         defaultExtensionLoaders.put("KHR_texture_transform", TextureTransformExtensionLoader.class);
         defaultExtensionLoaders.put("KHR_materials_emissive_strength", PBREmissiveStrengthExtensionLoader.class);
+        defaultExtensionLoaders.put("KHR_draco_mesh_compression", DracoMeshCompressionExtensionLoader.class);
 
     }