1 files changed, 58 insertions, 0 deletions
diff --git a/Runtime/Filters/Mesh/MeshUtility.cpp b/Runtime/Filters/Mesh/MeshUtility.cpp
new file mode 100644
index 0000000..75d8e7f
--- /dev/null
+++ b/Runtime/Filters/Mesh/MeshUtility.cpp
@@ -0,0 +1,58 @@
+#include "UnityPrefix.h"
+#include "MeshUtility.h"
+#include "Runtime/Geometry/Plane.h"
+#include "Mesh.h"
+
+using namespace std;
+
+void CalculateNormals (StrideIterator<Vector3f> verts, const UInt32* indices, int vertexCount, int triangleCount, StrideIterator<Vector3f> outNormals)
+{
+	std::fill_n (outNormals, vertexCount, Vector3f(0,0,0));
+	
+	// Add normals from faces
+	int idx = 0;
+	for( int i = 0; i < triangleCount; ++i )
+	{
+		UInt32 index0 = indices[idx+0];
+		UInt32 index1 = indices[idx+1];
+		UInt32 index2 = indices[idx+2];
+		Vector3f faceNormal = CalcRawNormalFromTriangle( verts[index0], verts[index1], verts[index2] );
+		outNormals[index0] += faceNormal;
+		outNormals[index1] += faceNormal;
+		outNormals[index2] += faceNormal;
+		idx += 3;
+	}
+
+	// Normalize
+	for (StrideIterator<Vector3f> end = outNormals + vertexCount; outNormals != end; ++outNormals )
+	{
+		*outNormals = NormalizeFast (*outNormals);
+	}
+}
+
+
+float CalculateSurfaceArea (
+	const Matrix4x4f& objectToWorld,
+	const Mesh::TemporaryIndexContainer& triangles,
+	dynamic_array<Vector3f>& vertices)
+{
+	// transform the vertices to world space,
+	// do it in place since they are a copy
+	for (int i = 0; i < vertices.size (); i++)
+		vertices[i] = objectToWorld.MultiplyPoint3 (vertices[i]);
+
+	// calculate the area
+	float cachedSurfaceArea = 0;
+	for (int i = 0; i < triangles.size () / 3; i++)
+	{	
+		DebugAssert (triangles[3 * i] < vertices.size ());
+		DebugAssert (triangles[3 * i + 1] < vertices.size ());
+		DebugAssert (triangles[3 * i + 2] < vertices.size ());
+		Vector3f a = vertices[triangles[3 * i]];
+		Vector3f b = vertices[triangles[3 * i + 1]];
+		Vector3f c = vertices[triangles[3 * i + 2]];
+		cachedSurfaceArea += Magnitude (Cross (b - a, c - a)) * 0.5f;
+	}
+
+	return cachedSurfaceArea;
+}