#5622: Implement fingerprinting of patch nodes (layer or grouping inf…

…ormation are disregarded)
codereader · May 22, 2021 · c33d883 · c33d883
1 parent f27c073
commit c33d883
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Showing 4 changed files with 45 additions and 2 deletions.
diff --git a/include/icomparablenode.h b/include/icomparablenode.h
@@ -21,4 +21,7 @@ class IComparableNode :
     virtual std::size_t getFingerprint() = 0;
 };
 
+// The number of digits that are considered when hashing floating point values in fingerprinting
+constexpr std::size_t SignificantFingerprintDoubleDigits = 6;
+
 }
diff --git a/radiantcore/brush/BrushNode.cpp b/radiantcore/brush/BrushNode.cpp
@@ -63,7 +63,7 @@ const AABB& BrushNode::localAABB() const {
 
 std::size_t BrushNode::getFingerprint()
 {
-    constexpr std::size_t SignificantDigits = 6;
+    constexpr std::size_t SignificantDigits = scene::SignificantFingerprintDoubleDigits;
 
     if (m_brush.getNumFaces() == 0)
     {

diff --git a/radiantcore/patch/PatchNode.cpp b/radiantcore/patch/PatchNode.cpp
@@ -5,6 +5,7 @@
 #include "iradiant.h"
 #include "icounter.h"
 #include "math/Frustum.h"
+#include "math/Hash.h"
 
 // Construct a PatchNode with no arguments
 PatchNode::PatchNode(patch::PatchDefType type) :
@@ -45,6 +46,40 @@ scene::INode::Type PatchNode::getNodeType() const
 	return Type::Patch;
 }
 
+std::size_t PatchNode::getFingerprint()
+{
+    constexpr std::size_t SignificantDigits = scene::SignificantFingerprintDoubleDigits;
+
+    if (m_patch.getHeight() * m_patch.getWidth() == 0)
+    {
+        return 0; // empty patches produce a zero fingerprint
+    }
+
+    // Width & Height
+    auto hash = m_patch.getHeight();
+    math::combineHash(hash, m_patch.getWidth());
+
+    // Subdivision Settings
+    if (m_patch.subdivisionsFixed())
+    {
+        math::combineHash(hash, static_cast<std::size_t>(m_patch.getSubdivisions().x()));
+        math::combineHash(hash, static_cast<std::size_t>(m_patch.getSubdivisions().y()));
+    }
+
+    // Material Name
+    math::combineHash(hash, std::hash<std::string>()(m_patch.getShader()));
+
+    // Combine all control point data
+    for (const auto& ctrl : m_patch.getControlPoints())
+    {
+        math::combineHash(hash, math::hashVector3(ctrl.vertex, SignificantDigits));
+        math::combineHash(hash, math::hashDouble(ctrl.texcoord.x(), SignificantDigits));
+        math::combineHash(hash, math::hashDouble(ctrl.texcoord.y(), SignificantDigits));
+    }
+
+    return hash;
+}
+
 void PatchNode::allocate(std::size_t size) {
 	// Clear the control instance vector and reserve <size> memory
 	m_ctrl_instances.clear();

diff --git a/radiantcore/patch/PatchNode.h b/radiantcore/patch/PatchNode.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "irenderable.h"
+#include "icomparablenode.h"
 #include "iscenegraph.h"
 #include "itraceable.h"
 #include "imap.h"
@@ -22,7 +23,8 @@ class PatchNode :
 	public PlaneSelectable,
 	public LitObject,
 	public Transformable,
-	public ITraceable
+	public ITraceable,
+    public scene::IComparableNode
 {
 	selection::DragPlanes m_dragPlanes;
 
@@ -60,6 +62,9 @@ class PatchNode :
 	std::string name() const override;
 	Type getNodeType() const override;
 
+    // IComparableNode implementation
+    std::size_t getFingerprint() override;
+
 	// Bounded implementation
 	const AABB& localAABB() const override;