初始提交: UE5.3项目基础框架

Plugins/CesiumForUnreal/Source/ThirdParty/include/CesiumGltf/getOffsetFromOffsetsBuffer.h

@@ -0,0 +1,46 @@
+#pragma once
+
+#include "CesiumGltf/PropertyType.h"
+
+#include <CesiumUtility/Assert.h>
+#include <CesiumUtility/SpanHelper.h>
+
+#include <cstddef>
+#include <span>
+
+namespace CesiumGltf {
+static size_t getOffsetFromOffsetsBuffer(
+    size_t index,
+    const std::span<const std::byte>& offsetBuffer,
+    PropertyComponentType offsetType) noexcept {
+  switch (offsetType) {
+  case PropertyComponentType::Uint8: {
+    CESIUM_ASSERT(index < offsetBuffer.size() / sizeof(uint8_t));
+    const uint8_t offset = *reinterpret_cast<const uint8_t*>(
+        offsetBuffer.data() + index * sizeof(uint8_t));
+    return static_cast<size_t>(offset);
+  }
+  case PropertyComponentType::Uint16: {
+    CESIUM_ASSERT(index < offsetBuffer.size() / sizeof(uint16_t));
+    const uint16_t offset = *reinterpret_cast<const uint16_t*>(
+        offsetBuffer.data() + index * sizeof(uint16_t));
+    return static_cast<size_t>(offset);
+  }
+  case PropertyComponentType::Uint32: {
+    CESIUM_ASSERT(index < offsetBuffer.size() / sizeof(uint32_t));
+    const uint32_t offset = *reinterpret_cast<const uint32_t*>(
+        offsetBuffer.data() + index * sizeof(uint32_t));
+    return static_cast<size_t>(offset);
+  }
+  case PropertyComponentType::Uint64: {
+    CESIUM_ASSERT(index < offsetBuffer.size() / sizeof(uint64_t));
+    const uint64_t offset = *reinterpret_cast<const uint64_t*>(
+        offsetBuffer.data() + index * sizeof(uint64_t));
+    return static_cast<size_t>(offset);
+  }
+  default:
+    CESIUM_ASSERT(false && "Offset type is invalid");
+    return 0;
+  }
+}
+} // namespace CesiumGltf