Add an example of a stack of boxes of large mass ratio. The default

solver cannot solve it effectively.

examples/BulletRobotics/BoxStack.cpp

@@ -0,0 +1,119 @@
+
+#include "BoxStack.h"
+
+#include "../CommonInterfaces/CommonGraphicsAppInterface.h"
+#include "Bullet3Common/b3AlignedObjectArray.h"
+#include "../CommonInterfaces/CommonRenderInterface.h"
+#include "../CommonInterfaces/CommonExampleInterface.h"
+#include "../CommonInterfaces/CommonGUIHelperInterface.h"
+#include "../SharedMemory/PhysicsServerSharedMemory.h"
+#include "../SharedMemory/PhysicsClientC_API.h"
+#include "../CommonInterfaces/CommonParameterInterface.h"
+#include "../SharedMemory/SharedMemoryPublic.h"
+#include <string>
+
+#include "../RobotSimulator/b3RobotSimulatorClientAPI.h"
+#include "../Utils/b3Clock.h"
+
+class BoxStackExample : public CommonExampleInterface
+{
+	CommonGraphicsApp* m_app;
+	GUIHelperInterface* m_guiHelper;
+	b3RobotSimulatorClientAPI m_robotSim;
+	int m_options;
+
+public:
+	BoxStackExample(GUIHelperInterface* helper, int options)
+		: m_app(helper->getAppInterface()),
+		  m_guiHelper(helper),
+		  m_options(options)
+	{
+		m_app->setUpAxis(2);
+	}
+
+	virtual ~BoxStackExample()
+	{
+	}
+
+	virtual void physicsDebugDraw(int debugDrawMode)
+	{
+		m_robotSim.debugDraw(debugDrawMode);
+	}
+	virtual void initPhysics()
+	{
+		int mode = eCONNECT_EXISTING_EXAMPLE_BROWSER;
+		m_robotSim.setGuiHelper(m_guiHelper);
+		bool connected = m_robotSim.connect(mode);
+
+		b3Printf("robotSim connected = %d", connected);
+
+		m_robotSim.configureDebugVisualizer(COV_ENABLE_RGB_BUFFER_PREVIEW, 0);
+		m_robotSim.configureDebugVisualizer(COV_ENABLE_DEPTH_BUFFER_PREVIEW, 0);
+		m_robotSim.configureDebugVisualizer(COV_ENABLE_SEGMENTATION_MARK_PREVIEW, 0);
+
+		b3RobotSimulatorLoadUrdfFileArgs args;
+		b3RobotSimulatorChangeDynamicsArgs dynamicsArgs;
+		int massRatio = 4;
+		int mass = 1;
+		for (int i = 0; i < 8; i++)
+		{
+			args.m_startPosition.setValue(0, 0, i * .06);
+			int boxIdx = m_robotSim.loadURDF("cube_small.urdf", args);
+			dynamicsArgs.m_mass = mass;
+			m_robotSim.changeDynamics(boxIdx, -1, dynamicsArgs);
+			mass *= massRatio;
+		}
+
+		m_robotSim.loadURDF("plane.urdf");
+		m_robotSim.setGravity(btVector3(0, 0, -10));
+	}
+
+	virtual void exitPhysics()
+	{
+		m_robotSim.disconnect();
+	}
+	virtual void stepSimulation(float deltaTime)
+	{
+		m_robotSim.stepSimulation();
+	}
+	virtual void renderScene()
+	{
+		m_robotSim.renderScene();
+	}
+
+	virtual bool mouseMoveCallback(float x, float y)
+	{
+		return m_robotSim.mouseMoveCallback(x, y);
+	}
+	virtual bool mouseButtonCallback(int button, int state, float x, float y)
+	{
+		return m_robotSim.mouseButtonCallback(button, state, x, y);
+	}
+	virtual bool keyboardCallback(int key, int state)
+	{
+		return false;
+	}
+
+	virtual void resetCamera()
+	{
+		float dist = 1.5;
+		float pitch = -10;
+		float yaw = 18;
+		float targetPos[3] = {-0.2, 0.8, 0.3};
+
+		m_guiHelper->resetCamera(dist, yaw, pitch, targetPos[0], targetPos[1], targetPos[2]);
+
+		if (m_app->m_renderer && m_app->m_renderer->getActiveCamera())
+		{
+			m_app->m_renderer->getActiveCamera()->setCameraDistance(dist);
+			m_app->m_renderer->getActiveCamera()->setCameraPitch(pitch);
+			m_app->m_renderer->getActiveCamera()->setCameraYaw(yaw);
+			m_app->m_renderer->getActiveCamera()->setCameraTargetPosition(targetPos[0], targetPos[1], targetPos[2]);
+		}
+	}
+};
+
+class CommonExampleInterface* BoxStackExampleCreateFunc(struct CommonExampleOptions& options)
+{
+	return new BoxStackExample(options.m_guiHelper, options.m_option);
+}

examples/BulletRobotics/BoxStack.h

@@ -0,0 +1,21 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2016 Google Inc. http://bulletphysics.org
+
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose, 
+including commercial applications, and to alter it and redistribute it freely, 
+subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*/
+
+#ifndef BOX_STACK_EXAMPLE_H
+#define BOX_STACK_EXAMPLE_H
+
+class CommonExampleInterface* BoxStackExampleCreateFunc(struct CommonExampleOptions& options);
+
+#endif  //BOX_STACK_EXAMPLE_H

examples/ExampleBrowser/CMakeLists.txt

@@ -146,6 +146,8 @@ SET(ExtendedTutorialsSources
 SET(BulletExampleBrowser_SRCS
         ../BulletRobotics/FixJointBoxes.cpp
 
+        ../BulletRobotics/BoxStack.cpp
+
 	../TinyRenderer/geometry.cpp
 	../TinyRenderer/model.cpp
 	../TinyRenderer/tgaimage.cpp

examples/ExampleBrowser/ExampleEntries.cpp

@@ -130,8 +130,8 @@ static ExampleEntry gDefaultExamples[] =
 
 		ExampleEntry(1, "Soft Contact", "Using the error correction parameter (ERP) and constraint force mixing (CFM) values for contacts to simulate compliant contact.", RigidBodySoftContactCreateFunc),
 
-
 		ExampleEntry(0, "Bullet Robotics"),
+		ExampleEntry(1, "Box Stack", "Create a stack of boxes using C API", BoxStackExampleCreateFunc),
 		ExampleEntry(1, "FixJoint Boxes", "FixJoint Boxes", FixJointBoxesCreateFunc),
 
 		ExampleEntry(0, "MultiBody"),