1 files changed, 114 insertions, 0 deletions
diff --git a/core/extrude.cpp b/core/extrude.cpp
new file mode 100644
index 0000000..637bed5
--- /dev/null
+++ b/core/extrude.cpp
@@ -0,0 +1,114 @@
+// This code contains NVIDIA Confidential Information and is disclosed to you
+// under a form of NVIDIA software license agreement provided separately to you.
+//
+// Notice
+// NVIDIA Corporation and its licensors retain all intellectual property and
+// proprietary rights in and to this software and related documentation and
+// any modifications thereto. Any use, reproduction, disclosure, or
+// distribution of this software and related documentation without an express
+// license agreement from NVIDIA Corporation is strictly prohibited.
+//
+// ALL NVIDIA DESIGN SPECIFICATIONS, CODE ARE PROVIDED "AS IS.". NVIDIA MAKES
+// NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO
+// THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT,
+// MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// Information and code furnished is believed to be accurate and reliable.
+// However, NVIDIA Corporation assumes no responsibility for the consequences of use of such
+// information or for any infringement of patents or other rights of third parties that may
+// result from its use. No license is granted by implication or otherwise under any patent
+// or patent rights of NVIDIA Corporation. Details are subject to change without notice.
+// This code supersedes and replaces all information previously supplied.
+// NVIDIA Corporation products are not authorized for use as critical
+// components in life support devices or systems without express written approval of
+// NVIDIA Corporation.
+//
+// Copyright (c) 2013-2016 NVIDIA Corporation. All rights reserved.
+
+#include "maths.h"
+
+#include <vector>
+
+void Extrude(const Vec3* points, int numPoints, std::vector<Vec3>& vertices, std::vector<Vec3>& normals, std::vector<int>& triangles, float radius, int resolution, int smoothing)
+{
+	if (numPoints < 2)
+		return;
+
+	Vec3 u, v;
+	Vec3 w = SafeNormalize(Vec3(points[1]) - Vec3(points[0]), Vec3(0.0f, 1.0f, 0.0f));
+
+	BasisFromVector(w, &u, &v);
+
+	Matrix44 frame;
+	frame.SetCol(0, Vec4(u.x, u.y, u.z, 0.0f));
+	frame.SetCol(1, Vec4(v.x, v.y, v.z, 0.0f));
+	frame.SetCol(2, Vec4(w.x, w.y, w.z, 0.0f));
+	frame.SetCol(3, Vec4(0.0f, 0.0f, 0.0f, 1.0f));
+
+	for (int i = 0; i < numPoints - 1; ++i)
+	{
+		Vec3 next;
+
+		if (i < numPoints - 1)
+			next = Normalize(Vec3(points[i + 1]) - Vec3(points[i - 1]));
+		else
+			next = Normalize(Vec3(points[i]) - Vec3(points[i - 1]));
+
+		int a = Max(i - 1, 0);
+		int b = i;
+		int c = Min(i + 1, numPoints - 1);
+		int d = Min(i + 2, numPoints - 1);
+
+		Vec3 p1 = Vec3(points[b]);
+		Vec3 p2 = Vec3(points[c]);
+		Vec3 m1 = 0.5f*(Vec3(points[c]) - Vec3(points[a]));
+		Vec3 m2 = 0.5f*(Vec3(points[d]) - Vec3(points[b]));
+
+		// ensure last segment handled correctly
+		int segments = (i < numPoints - 2) ? smoothing : smoothing + 1;
+
+		for (int s = 0; s < segments; ++s)
+		{
+			Vec3 pos = HermiteInterpolate(p1, p2, m1, m2, s / float(smoothing));
+			Vec3 dir = Normalize(HermiteTangent(p1, p2, m1, m2, s / float(smoothing)));
+
+			Vec3 cur = frame.GetAxis(2);
+			const float angle = acosf(Dot(cur, dir));
+
+			// if parallel then don't need to do anything
+			if (fabsf(angle) > 0.001f)
+				frame = RotationMatrix(angle, SafeNormalize(Cross(cur, dir)))*frame;
+
+			size_t startIndex = vertices.size();
+
+			for (int c = 0; c < resolution; ++c)
+			{
+				float angle = k2Pi / resolution;
+
+				// transform position and normal to world space
+				Vec4 v = frame*Vec4(cosf(angle*c), sinf(angle*c), 0.0f, 0.0f);
+
+				vertices.push_back(Vec3(v)*radius + pos);
+				normals.push_back(Vec3(v));
+			}
+
+			// output triangles
+			if (startIndex != 0)
+			{
+				for (int i = 0; i < resolution; ++i)
+				{
+					int curIndex = static_cast<int>(startIndex + i);
+					int nextIndex = static_cast<int>(startIndex + (i + 1) % resolution);
+
+					triangles.push_back(curIndex);
+					triangles.push_back(curIndex - resolution);
+					triangles.push_back(nextIndex - resolution);
+
+					triangles.push_back(nextIndex - resolution);
+					triangles.push_back(nextIndex);
+					triangles.push_back(curIndex);
+				}
+			}
+		}
+	}
+}