order draco vertex data correctly (#5346)

playcanvas · May 23, 2023 · 5e006b9 · 5e006b9
1 parent d796969
commit 5e006b9
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Showing 3 changed files with 20 additions and 9 deletions.
diff --git a/src/framework/parsers/draco-decoder.js b/src/framework/parsers/draco-decoder.js
@@ -34,7 +34,8 @@ class JobQueue {
                 if (callback) {
                     callback(data.error, {
                         indices: data.indices,
-                        vertices: data.vertices
+                        vertices: data.vertices,
+                        attributes: data.attributes
                     });
                 }
                 this.jobCallbacks.delete(data.jobId);

diff --git a/src/framework/parsers/draco-worker.js b/src/framework/parsers/draco-worker.js
@@ -158,6 +158,9 @@ function DracoWorker(jsUrl, wasmUrl) {
             return (attributeOrder[a.attribute_type()] ?? attributeOrder.length) - (attributeOrder[b.attribute_type()] ?? attributeOrder.length);
         });
 
+        // store attribute order by unique_id
+        result.attributes = attributes.map(a => a.unique_id());
+
         // calculate total vertex size and attribute offsets
         let totalVertexSize = 0;
         const offsets = attributes.map((a) => {
@@ -226,7 +229,8 @@ function DracoWorker(jsUrl, wasmUrl) {
             jobId: data.jobId,
             error: result.error,
             indices: result.indices,
-            vertices: result.vertices
+            vertices: result.vertices,
+            attributes: result.attributes
         }, [result.indices, result.vertices].filter(t => t != null));
     };
 

diff --git a/src/framework/parsers/glb-parser.js b/src/framework/parsers/glb-parser.js
@@ -704,13 +704,6 @@ const createDracoMesh = (device, primitive, accessors, bufferViews, meshVariants
         });
     }
 
-    // sort vertex elements by engine-ideal order
-    vertexDesc.sort((lhs, rhs) => {
-        return attributeOrder[lhs.semantic] - attributeOrder[rhs.semantic];
-    });
-
-    const vertexFormat = new VertexFormat(device, vertexDesc);
-
     promises.push(new Promise((resolve, reject) => {
         // decode draco data
         const dracoExt = primitive.extensions.KHR_draco_mesh_compression;
@@ -719,6 +712,19 @@ const createDracoMesh = (device, primitive, accessors, bufferViews, meshVariants
                 console.log(err);
                 reject(err);
             } else {
+                // worker reports order of attributes as array of attribute unique_id
+                const order = { };
+                for (const [name, index] of Object.entries(dracoExt.attributes)) {
+                    order[gltfToEngineSemanticMap[name]] = decompressedData.attributes.indexOf(index);
+                }
+
+                // order vertexDesc
+                vertexDesc.sort((a, b) => {
+                    return order[a.semantic] - order[b.semantic];
+                });
+
+                const vertexFormat = new VertexFormat(device, vertexDesc);
+
                 // create vertex buffer
                 const numVertices = decompressedData.vertices.byteLength / vertexFormat.size;
                 const indexFormat = numVertices <= 65535 ? INDEXFORMAT_UINT16 : INDEXFORMAT_UINT32;