From 68d33a6e133bd0732b58462f2de77a88978e1e1c Mon Sep 17 00:00:00 2001
From: Promit Roy <promit.roy+gh@gmail.com>
Date: Thu, 17 Mar 2022 14:55:26 -0400
Subject: [PATCH] Added support for more bone weights in GLTF2

The GLTF2 importer doesn't actually read beyond the first four bone weights (first attribute). This patch expands the parser to store as many bone weights as are available in the file.
---
 code/AssetLib/glTF2/glTF2Importer.cpp | 43 +++++++++++++++++++--------
 1 file changed, 30 insertions(+), 13 deletions(-)

diff --git a/code/AssetLib/glTF2/glTF2Importer.cpp b/code/AssetLib/glTF2/glTF2Importer.cpp
index d2fb1e9b8..47f563c16 100644
--- a/code/AssetLib/glTF2/glTF2Importer.cpp
+++ b/code/AssetLib/glTF2/glTF2Importer.cpp
@@ -935,8 +935,10 @@ static void BuildVertexWeightMapping(Mesh::Primitive &primitive, std::vector<std
     struct Weights {
         float values[4];
     };
-    Weights *weights = nullptr;
-    attr.weight[0]->ExtractData(weights);
+    Weights **weights = new Weights*[attr.weight.size()];
+    for (size_t w = 0; w < attr.weight.size(); ++w) {
+        attr.weight[w]->ExtractData(weights[w]);
+    }
 
     struct Indices8 {
         uint8_t values[4];
@@ -944,12 +946,18 @@ static void BuildVertexWeightMapping(Mesh::Primitive &primitive, std::vector<std
     struct Indices16 {
         uint16_t values[4];
     };
-    Indices8 *indices8 = nullptr;
-    Indices16 *indices16 = nullptr;
+    Indices8 **indices8 = nullptr;
+    Indices16 **indices16 = nullptr;
     if (attr.joint[0]->GetElementSize() == 4) {
-        attr.joint[0]->ExtractData(indices8);
+        indices8 = new Indices8*[attr.joint.size()];
+        for (size_t j = 0; j < attr.joint.size(); ++j) {
+            attr.joint[j]->ExtractData(indices8[j]);
+        }
     } else {
-        attr.joint[0]->ExtractData(indices16);
+        indices16 = new Indices16 *[attr.joint.size()];
+        for (size_t j = 0; j < attr.joint.size(); ++j) {
+            attr.joint[j]->ExtractData(indices16[j]);
+        }
     }
     //
     if (nullptr == indices8 && nullptr == indices16) {
@@ -958,17 +966,26 @@ static void BuildVertexWeightMapping(Mesh::Primitive &primitive, std::vector<std
         return;
     }
 
-    for (size_t i = 0; i < num_vertices; ++i) {
-        for (int j = 0; j < 4; ++j) {
-            const unsigned int bone = (indices8 != nullptr) ? indices8[i].values[j] : indices16[i].values[j];
-            const float weight = weights[i].values[j];
-            if (weight > 0 && bone < map.size()) {
-                map[bone].reserve(8);
-                map[bone].emplace_back(static_cast<unsigned int>(i), weight);
+    for (size_t w = 0; w < attr.weight.size(); ++w) {
+        for (size_t i = 0; i < num_vertices; ++i) {
+            for (int j = 0; j < 4; ++j) {
+                const unsigned int bone = (indices8 != nullptr) ? indices8[w][i].values[j] : indices16[w][i].values[j];
+                const float weight = weights[w][i].values[j];
+                if (weight > 0 && bone < map.size()) {
+                    map[bone].reserve(8);
+                    map[bone].emplace_back(static_cast<unsigned int>(i), weight);
+                }
             }
         }
     }
 
+    for (size_t w = 0; w < attr.weight.size(); ++w) {
+        delete[] weights[w];
+        if(indices8)
+            delete[] indices8[w];
+        if (indices16)
+            delete[] indices16[w];
+    }
     delete[] weights;
     delete[] indices8;
     delete[] indices16;