#6185: Verify uploaded geometry after syncing the buffer objects

include/igeometrystore.h

@@ -55,6 +55,9 @@ class IBufferObject
     // Uploads the given data to the buffer, starting at the given offset
     virtual void setData(std::size_t offset, const unsigned char* firstElement, std::size_t numBytes) = 0;
 
+    // Downloads the specified data chunk
+    virtual std::vector<unsigned char> getData(std::size_t offset, std::size_t numBytes) = 0;
+
     // Re-allocates the memory of this buffer, does not transfer the data 
     // from the old internal buffer to the new one.
     virtual void resize(std::size_t newSize) = 0;

libs/render/ContinuousBuffer.h

@@ -5,6 +5,7 @@
 #include <limits>
 #include <vector>
 #include "igeometrystore.h"
+#include "itextstream.h"
 
 namespace render
 {
@@ -316,6 +317,7 @@ class ContinuousBuffer
             buffer->bind();
             buffer->setData(0, reinterpret_cast<unsigned char*>(_buffer.data()),
                 _buffer.size() * sizeof(ElementType));
+            verifyBufferData(buffer, "After copying everything");
             buffer->unbind();
         }
         else
@@ -360,6 +362,8 @@ class ContinuousBuffer
                         (maximumOffset - minimumOffset) * sizeof(ElementType));
                 }
 
+                verifyBufferData(buffer, "After copying elements");
+
                 buffer->unbind();
             }
         }
@@ -368,6 +372,29 @@ class ContinuousBuffer
     }
 
 private:
+    void verifyBufferData(const IBufferObject::Ptr& buffer, const char* eventString)
+    {
+        if (!std::is_same_v<ElementType, unsigned int>) return;
+
+        for (const auto& slot : _slots)
+        {
+            if (!slot.Occupied) continue;
+
+            auto bufferData = buffer->getData(slot.Offset * sizeof(ElementType), slot.Used * sizeof(ElementType));
+
+            auto bufferElements = reinterpret_cast<const ElementType*>(bufferData.data());
+
+            for (auto i = 0; i < slot.Used; ++i)
+            {
+                if (_buffer.at(slot.Offset + i) != bufferElements[i])
+                {
+                    rMessage() << "Buffer data corruption (" << eventString << ")" << std::endl;
+                    return;
+                }
+            }
+        }
+    }
+
     bool findLeftFreeSlot(const SlotInfo& slotToTouch, Handle& found)
     {
         auto numSlots = _slots.size();

libs/render/RenderVertex.h

@@ -42,6 +42,21 @@ class RenderVertex
       bitangent(bitangent_),
       colour(colour_)
     {}
+
+    bool operator==(const RenderVertex& other) const
+    {
+        return texcoord == other.texcoord &&
+            normal == other.normal &&
+            vertex == other.vertex &&
+            tangent == other.tangent &&
+            bitangent == other.bitangent &&
+            colour == other.colour;
+    }
+
+    bool operator!=(const RenderVertex& other) const
+    {
+        return !operator==(other);
+    }
 };
 
 }

radiantcore/rendersystem/backend/BufferObjectProvider.h

@@ -51,6 +51,16 @@ class BufferObjectProvider final :
             glBufferSubData(_target, static_cast<GLintptr>(offset), static_cast<GLsizeiptr>(numBytes), firstElement);
         }
 
+        std::vector<unsigned char> getData(std::size_t offset, std::size_t numBytes) override
+        {
+            std::vector<unsigned char> data;
+            data.resize(numBytes);
+
+            glGetBufferSubData(_target, static_cast<GLintptr>(offset), static_cast<GLsizeiptr>(numBytes), data.data());
+
+            return data;
+        }
+
         // Re-allocates the memory of this buffer, does not transfer the data 
         // from the old internal buffer to the new one.
         void resize(std::size_t newSize) override

test/testutil/TestBufferObjectProvider.h

@@ -29,6 +29,11 @@ class TestBufferObject final :
         }
     }
 
+    std::vector<unsigned char> getData(std::size_t offset, std::size_t numBytes) override
+    {
+        return {};
+    }
+
     void resize(std::size_t newSize) override
     {
         buffer = std::vector<unsigned char>(newSize, '\0');