Add initial prototype.

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

@@ -0,0 +1,108 @@
+// 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 MobileBalanced : public Test
+{
+public:
+
+	enum
+	{
+		e_depth = 4
+	};
+
+	MobileBalanced()
+	{
+		b2Body* ground;
+
+		// Create ground body.
+		{
+			b2BodyDef bodyDef;
+			bodyDef.position.Set(0.0f, 20.0f);
+			ground = m_world->CreateBody(&bodyDef);
+		}
+
+		float a = 0.5f;
+		b2Vec2 h(0.0f, a);
+
+		b2Body* root = AddNode(ground, b2Vec2_zero, 0, 3.0f, a);
+
+		b2RevoluteJointDef jointDef;
+		jointDef.bodyA = ground;
+		jointDef.bodyB = root;
+		jointDef.localAnchorA.SetZero();
+		jointDef.localAnchorB = h;
+		m_world->CreateJoint(&jointDef);
+	}
+
+	b2Body* AddNode(b2Body* parent, const b2Vec2& localAnchor, int32 depth, float offset, float a)
+	{
+		float density = 20.0f;
+		b2Vec2 h(0.0f, a);
+
+		b2Vec2 p = parent->GetPosition() + localAnchor - h;
+
+		b2BodyDef bodyDef;
+		bodyDef.type = b2_dynamicBody;
+		bodyDef.position = p;
+		b2Body* body = m_world->CreateBody(&bodyDef);
+
+		b2PolygonShape shape;
+		shape.SetAsBox(0.25f * a, a);
+		body->CreateFixture(&shape, density);
+
+		if (depth == e_depth)
+		{
+			return body;
+		}
+
+		shape.SetAsBox(offset, 0.25f * a, b2Vec2(0, -a), 0.0f);
+		body->CreateFixture(&shape, density);
+
+		b2Vec2 a1 = b2Vec2(offset, -a);
+		b2Vec2 a2 = b2Vec2(-offset, -a);
+		b2Body* body1 = AddNode(body, a1, depth + 1, 0.5f * offset, a);
+		b2Body* body2 = AddNode(body, a2, depth + 1, 0.5f * offset, a);
+
+		b2RevoluteJointDef jointDef;
+		jointDef.bodyA = body;
+		jointDef.localAnchorB = h;
+
+		jointDef.localAnchorA = a1;
+		jointDef.bodyB = body1;
+		m_world->CreateJoint(&jointDef);
+
+		jointDef.localAnchorA = a2;
+		jointDef.bodyB = body2;
+		m_world->CreateJoint(&jointDef);
+
+		return body;
+	}
+
+	static Test* Create()
+	{
+		return new MobileBalanced;
+	}
+};
+
+static int testIndex = RegisterTest("Solver", "Mobile Balanced", MobileBalanced::Create);