Add initial prototype.

3-mid/physics/implement/box2d/contrib/testbed/tests/convex_hull.cpp

@@ -0,0 +1,112 @@
+// MIT License
+
+// Copyright (c) 2019 Erin Catto
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#include "test.h"
+
+class ConvexHull : public Test
+{
+public:
+	enum
+	{
+		e_count = b2_maxPolygonVertices
+	};
+
+	ConvexHull()
+	{
+		Generate();
+		m_auto = false;
+	}
+
+	void Generate()
+	{
+		b2Vec2 lowerBound(-8.0f, -8.0f);
+		b2Vec2 upperBound(8.0f, 8.0f);
+
+		for (int32 i = 0; i < e_count; ++i)
+		{
+			float x = 10.0f * RandomFloat();
+			float y = 10.0f * RandomFloat();
+
+			// Clamp onto a square to help create collinearities.
+			// This will stress the convex hull algorithm.
+			b2Vec2 v(x, y);
+			v = b2Clamp(v, lowerBound, upperBound);
+			m_points[i] = v;
+		}
+
+		m_count = e_count;
+	}
+
+	void Keyboard(int key) override
+	{
+		switch (key)
+		{
+		case GLFW_KEY_A:
+			m_auto = !m_auto;
+			break;
+
+		case GLFW_KEY_G:
+			Generate();
+			break;
+		}
+	}
+
+	void Step(Settings& settings) override
+	{
+		Test::Step(settings);
+
+		b2PolygonShape shape;
+		shape.Set(m_points, m_count);
+
+		g_debugDraw.DrawString(5, m_textLine, "Press g to generate a new random convex hull");
+		m_textLine += m_textIncrement;
+
+		g_debugDraw.DrawPolygon(shape.m_vertices, shape.m_count, b2Color(0.9f, 0.9f, 0.9f));
+
+		for (int32 i = 0; i < m_count; ++i)
+		{
+			g_debugDraw.DrawPoint(m_points[i], 3.0f, b2Color(0.3f, 0.9f, 0.3f));
+			g_debugDraw.DrawString(m_points[i] + b2Vec2(0.05f, 0.05f), "%d", i);
+		}
+
+		if (shape.Validate() == false)
+		{
+			m_textLine += 0;
+		}
+
+		if (m_auto)
+		{
+			Generate();
+		}
+	}
+
+	static Test* Create()
+	{
+		return new ConvexHull;
+	}
+
+	b2Vec2 m_points[b2_maxPolygonVertices];
+	int32 m_count;
+	bool m_auto;
+};
+
+static int testIndex = RegisterTest("Geometry", "Convex Hull", ConvexHull::Create);