Reverted some of ker's changes to bring back the concepts of width, height, and depth.

library/PolyVoxCore/source/GradientEstimators.cpp

@@ -41,15 +41,22 @@ namespace PolyVox
 
 			VolumeSampler<uint8_t> volIter(volumeData);
 
-			Vector3DFloat v3dGradient = computeNormal(volumeData, v3dPos, normalGenerationMethod);
+			//Check all corners are within the volume, allowing a boundary for gradient estimation
+			bool lowerCornerInside = volumeData->getEnclosingRegion().containsPoint(v3dFloor,2);
+			bool upperCornerInside = volumeData->getEnclosingRegion().containsPoint(v3dFloor+Vector3DInt32(1,1,1),2);
 
-			if(v3dGradient.lengthSquared() > 0.0001)
+			if(lowerCornerInside && upperCornerInside) //If this test fails the vertex will be left as it was
 			{
-				//If we got a normal of significant length then update it.
-				//Otherwise leave it as it was (should be the 'simple' version)
-				v3dGradient.normalise();
-				iterSurfaceVertex->setNormal(v3dGradient);
-			}
+				Vector3DFloat v3dGradient = computeNormal(volumeData, v3dPos, normalGenerationMethod);
+				
+				if(v3dGradient.lengthSquared() > 0.0001)
+				{
+					//If we got a normal of significant length then update it.
+					//Otherwise leave it as it was (should be the 'simple' version)
+					v3dGradient.normalise();
+					iterSurfaceVertex->setNormal(v3dGradient);
+				}
+			} //(lowerCornerInside && upperCornerInside)
 			++iterSurfaceVertex;
 		}
 	}

library/PolyVoxCore/source/Region.cpp

@@ -57,6 +57,14 @@ namespace PolyVox
 		m_v3dUpperCorner = v3dUpperCorner;
 	}
 
+	void Region::setToMaxSize(void)
+	{
+		int32_t iMin = (std::numeric_limits<int32_t>::min)();
+		int32_t iMax = (std::numeric_limits<int32_t>::max)();
+		m_v3dLowerCorner = Vector3DInt32(iMin, iMin,iMin);
+		m_v3dUpperCorner = Vector3DInt32(iMax, iMax,iMax);
+	}
+
 	bool Region::containsPoint(const Vector3DFloat& pos, float boundary) const
 	{
 		return (pos.getX() <= m_v3dUpperCorner.getX() - boundary)

library/PolyVoxCore/source/VoxelFilters.cpp

@@ -29,6 +29,13 @@ namespace PolyVox
 {
 	float computeSmoothedVoxel(VolumeSampler<uint8_t>& volIter)
 	{
+		assert(volIter.getPosX() >= 1);
+		assert(volIter.getPosY() >= 1);
+		assert(volIter.getPosZ() >= 1);
+		assert(volIter.getPosX() <= volIter.getVolume()->getWidth() - 2);
+		assert(volIter.getPosY() <= volIter.getVolume()->getHeight() - 2);
+		assert(volIter.getPosZ() <= volIter.getVolume()->getDepth() - 2);
+
 		float sum = 0.0;
 
 		if(volIter.peekVoxel1nx1ny1nz() != 0) sum += 1.0f;