From b222c21715384efc2eaa53d3ba295fb34da5b599 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 9 Apr 2023 12:24:55 +0100
Subject: Start to factor out geometric place from face controller split

---
 assetFactory/faceController.cpp | 16 ++++++++--------
 assetFactory/faceController.h   |  4 ++--
 lib/geometricPlane.cpp          |  9 +++++++++
 lib/geometricPlane.h            | 12 ++++++++++++
 4 files changed, 31 insertions(+), 10 deletions(-)
 create mode 100644 lib/geometricPlane.cpp
 create mode 100644 lib/geometricPlane.h

diff --git a/assetFactory/faceController.cpp b/assetFactory/faceController.cpp
index 7992fba..37aaa4c 100644
--- a/assetFactory/faceController.cpp
+++ b/assetFactory/faceController.cpp
@@ -76,7 +76,6 @@ FaceController::extrude(ModelFactoryMesh & mesh, const std::string & faceName, O
 	return newFaces;
 }
 
-enum class PlaneRelation { Above, Below, On };
 Shape::CreatedFaces
 FaceController::split(
 		ModelFactoryMesh & mesh, const std::string & name, OpenMesh::FaceHandle & fh, const Split & split) const
@@ -84,15 +83,16 @@ FaceController::split(
 	// Map face vertex handles to their relationship to the split plane
 	const auto vertices = materializeRange(mesh.fv_range(fh));
 	auto vertexRelations = vertices * [&split, &mesh](OpenMesh::VertexHandle vh) {
-		const auto d = glm::dot(split.normal, mesh.point(vh) - split.origin);
-		return std::make_pair(vh, d < 0.f ? PlaneRelation::Below : d > 0.f ? PlaneRelation::Above : PlaneRelation::On);
+		return std::make_pair(vh, split.getRelation(mesh.point(vh)));
 	};
 	// Insert new vertices where half edges intersect the split plane
 	for (size_t curIdx = 0; curIdx < vertexRelations.size(); ++curIdx) {
 		const size_t nextIdx = (curIdx + 1) % vertexRelations.size();
 		const auto &current = vertexRelations[curIdx], next = vertexRelations[nextIdx];
-		if ((current.second == PlaneRelation::Above && next.second == PlaneRelation::Below)
-				|| (current.second == PlaneRelation::Below && next.second == PlaneRelation::Above)) {
+		if ((current.second == GeometricPlane::PlaneRelation::Above
+					&& next.second == GeometricPlane::PlaneRelation::Below)
+				|| (current.second == GeometricPlane::PlaneRelation::Below
+						&& next.second == GeometricPlane::PlaneRelation::Above)) {
 			const auto origin = mesh.point(current.first), dir = glm::normalize(mesh.point(next.first) - origin);
 
 			float dist {};
@@ -101,7 +101,7 @@ FaceController::split(
 			auto where = vertexRelations.begin();
 			++curIdx;
 			std::advance(where, curIdx);
-			vertexRelations.emplace(where, newv, PlaneRelation::On);
+			vertexRelations.emplace(where, newv, GeometricPlane::PlaneRelation::On);
 		}
 	}
 	// Create vertex vectors
@@ -113,8 +113,8 @@ FaceController::split(
 			}
 		}
 	};
-	filterVertices(out.front(), PlaneRelation::Above);
-	filterVertices(out.back(), PlaneRelation::Below);
+	filterVertices(out.front(), GeometricPlane::PlaneRelation::Above);
+	filterVertices(out.back(), GeometricPlane::PlaneRelation::Below);
 
 	if (out.back().size() > 2) {
 		Shape::CreatedFaces newFaces;
diff --git a/assetFactory/faceController.h b/assetFactory/faceController.h
index 8d30dc6..0376241 100644
--- a/assetFactory/faceController.h
+++ b/assetFactory/faceController.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "geometricPlane.h"
 #include "modelFactoryMesh_fwd.h"
 #include "mutation.h"
 #include "persistence.h"
@@ -10,10 +11,9 @@
 
 class FaceController : public Mutation, public Style, public Persistence::Persistable {
 public:
-	class Split : public Persistable {
+	class Split : public Persistable, public GeometricPlane {
 	public:
 		std::string id;
-		glm::vec3 origin, normal;
 
 	private:
 		friend Persistence::SelectionPtrBase<std::unique_ptr<Split>>;
diff --git a/lib/geometricPlane.cpp b/lib/geometricPlane.cpp
new file mode 100644
index 0000000..cb52997
--- /dev/null
+++ b/lib/geometricPlane.cpp
@@ -0,0 +1,9 @@
+#include "geometricPlane.h"
+#include <glm/geometric.hpp>
+
+GeometricPlane::PlaneRelation
+GeometricPlane::getRelation(glm::vec3 p) const
+{
+	const auto d = glm::dot(normal, p - origin);
+	return d < 0.f ? PlaneRelation::Below : d > 0.f ? PlaneRelation::Above : PlaneRelation::On;
+}
diff --git a/lib/geometricPlane.h b/lib/geometricPlane.h
new file mode 100644
index 0000000..96816f2
--- /dev/null
+++ b/lib/geometricPlane.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#include <glm/vec3.hpp>
+
+class GeometricPlane {
+public:
+	enum class PlaneRelation { Above, Below, On };
+
+	glm::vec3 origin, normal;
+
+	PlaneRelation getRelation(glm::vec3 point) const;
+};
-- 
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