Add scale to matrix instead of translation

CesiumGS · Aug 15, 2024 · aacdaba · aacdaba
1 parent 5130b8b
commit aacdaba
Showing 1 changed file with 10 additions and 4 deletions.
diff --git a/Source/CesiumRuntime/Private/CesiumGltfComponent.cpp b/Source/CesiumRuntime/Private/CesiumGltfComponent.cpp
@@ -1937,9 +1937,8 @@ static void loadInstancingData(
     if (translationAccessor.status() == AccessorViewStatus::Valid) {
       for (int64_t i = 0; i < count; ++i) {
         glm::dvec3 translation(translationAccessor[i]);
-        instanceTransforms[i] = glm::translate(
-            instanceTransforms[i],
-            translation * CesiumPrimitiveData::positionScaleFactor);
+        instanceTransforms[i] =
+            glm::translate(instanceTransforms[i], translation);
       }
     }
   } else {
@@ -1983,9 +1982,16 @@ static void loadInstancingData(
     UE_LOG(LogCesium, Warning, TEXT("Invalid accessor for instance scales"));
   }
   result.InstanceTransforms.resize(count);
+
+  double scale = CesiumPrimitiveData::positionScaleFactor;
+  glm::dmat4 scaleMatrix = glm::dmat4(
+      glm::dvec4(scale, 0.0, 0.0, 0.0),
+      glm::dvec4(0.0, scale, 0.0, 0.0),
+      glm::dvec4(0.0, 0.0, scale, 0.0),
+      glm::dvec4(0.0, 0.0, 0.0, 1.0));
   for (int64_t i = 0; i < count; ++i) {
     glm::dmat4 unrealMat =
-        yInvertMatrix * instanceTransforms[i] * yInvertMatrix;
+        scaleMatrix * yInvertMatrix * instanceTransforms[i] * yInvertMatrix;
     auto unrealFMatrix = VecMath::createMatrix(unrealMat);
     result.InstanceTransforms[i].SetFromMatrix(unrealFMatrix);
   }