Merge pull request #1353 from srajangarg/compound

add new example for btCompoundShape

examples/ExampleBrowser/CMakeLists.txt

@@ -122,6 +122,8 @@ SET(ExtendedTutorialsSources
 	../ExtendedTutorials/SimpleBox.h
 	../ExtendedTutorials/MultipleBoxes.cpp
 	../ExtendedTutorials/MultipleBoxes.h
+	../ExtendedTutorials/CompoundBoxes.cpp
+	../ExtendedTutorials/CompoundBoxes.h
 	../ExtendedTutorials/SimpleCloth.cpp
 	../ExtendedTutorials/SimpleCloth.h
 	../ExtendedTutorials/SimpleJoint.cpp

examples/ExampleBrowser/ExampleEntries.cpp

@@ -71,6 +71,7 @@
 //Extended Tutorial Includes Added by Mobeen and Benelot
 #include "../ExtendedTutorials/SimpleBox.h"
 #include "../ExtendedTutorials/MultipleBoxes.h"
+#include "../ExtendedTutorials/CompoundBoxes.h"
 #include "../ExtendedTutorials/SimpleJoint.h"
 #include "../ExtendedTutorials/SimpleCloth.h"
 #include "../ExtendedTutorials/Chain.h"
@@ -322,6 +323,7 @@ static ExampleEntry gDefaultExamples[]=
 	ExampleEntry(0,"Extended Tutorials"),
 	ExampleEntry(1,"Simple Box", "Simplest possible demo creating a single box rigid body that falls under gravity", ET_SimpleBoxCreateFunc),
 	ExampleEntry(1,"Multiple Boxes", "Add multiple box rigid bodies that fall under gravity", ET_MultipleBoxesCreateFunc),
+	ExampleEntry(1,"Compound Boxes", "Add multiple boxes to a single CompoundShape to form a simple rigid L-beam, that falls under gravity", ET_CompoundBoxesCreateFunc),
 	ExampleEntry(1,"Simple Joint", "Create a single distance constraint between two box rigid bodies", ET_SimpleJointCreateFunc),
 	ExampleEntry(1,"Simple Cloth", "Create a simple piece of cloth", ET_SimpleClothCreateFunc),
 	ExampleEntry(1,"Simple Chain", "Create a simple chain using a pair of point2point/distance constraints. You may click and drag any box to see the chain respond.", ET_ChainCreateFunc),

examples/ExtendedTutorials/CompoundBoxes.cpp

@@ -0,0 +1,135 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2015 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.
+*/
+
+
+
+#include "CompoundBoxes.h"
+
+#include "btBulletDynamicsCommon.h"
+#include "LinearMath/btVector3.h"
+#include "LinearMath/btAlignedObjectArray.h" 
+#include "../CommonInterfaces/CommonRigidBodyBase.h"
+
+
+struct CompoundBoxesExample : public CommonRigidBodyBase
+{
+	CompoundBoxesExample(struct GUIHelperInterface* helper)
+		:CommonRigidBodyBase(helper)
+	{
+	}
+	virtual ~CompoundBoxesExample(){}
+	virtual void initPhysics();
+	virtual void renderScene();
+	void resetCamera()
+	{
+		float dist = 41;
+		float pitch = -35;
+		float yaw = 52;
+		float targetPos[3]={0,0.46,0};
+		m_guiHelper->resetCamera(dist,yaw,pitch,targetPos[0],targetPos[1],targetPos[2]);
+	}
+};
+
+void CompoundBoxesExample::initPhysics()
+{
+	m_guiHelper->setUpAxis(1);
+
+	createEmptyDynamicsWorld();
+	
+	m_guiHelper->createPhysicsDebugDrawer(m_dynamicsWorld);
+
+	if (m_dynamicsWorld->getDebugDrawer())
+		m_dynamicsWorld->getDebugDrawer()->setDebugMode(btIDebugDraw::DBG_DrawWireframe+btIDebugDraw::DBG_DrawContactPoints);
+
+	///create a few basic rigid bodies
+	btBoxShape* groundShape = createBoxShape(btVector3(btScalar(50.),btScalar(50.),btScalar(50.)));
+	m_collisionShapes.push_back(groundShape);
+
+	btTransform groundTransform;
+	groundTransform.setIdentity();
+	groundTransform.setOrigin(btVector3(0,-50,0)); 
+	{
+		btScalar mass(0.);
+		createRigidBody(mass,groundTransform,groundShape, btVector4(0,0,1,1));
+	}
+
+
+	{
+		//create a few dynamic rigidbodies
+		// Re-using the same collision is better for memory usage and performance
+        btBoxShape* cube = createBoxShape(btVector3(0.5,0.5,0.5));
+		m_collisionShapes.push_back(cube);
+
+		// create a new compound shape for making an L-beam from `cube`s
+		btCompoundShape* compoundShape = new btCompoundShape();
+
+		btTransform transform;
+		
+		// add cubes in an L-beam fashion to the compound shape
+		transform.setIdentity();
+		transform.setOrigin(btVector3(0, 0, 0));
+		compoundShape->addChildShape(transform, cube);
+
+		transform.setIdentity();
+		transform.setOrigin(btVector3(0, -1, 0));
+		compoundShape->addChildShape(transform, cube);
+
+		transform.setIdentity();
+		transform.setOrigin(btVector3(0, 0, 1));
+		compoundShape->addChildShape(transform, cube);
+
+		
+		btScalar masses[3]={1, 1, 1};
+		btTransform principal;
+		btVector3 inertia;
+		compoundShape->calculatePrincipalAxisTransform(masses, principal, inertia);
+
+		// new compund shape to store
+		btCompoundShape* compound2 = new btCompoundShape();
+		m_collisionShapes.push_back(compound2);
+#if 0
+		// less efficient way to add the entire compund shape 
+		// to a new compund shape as a child
+		compound2->addChildShape(principal.inverse(), compoundShape);
+#else	
+		// recompute the shift to make sure the compound shape is re-aligned
+		for (int i=0; i < compoundShape->getNumChildShapes(); i++)
+			compound2->addChildShape(compoundShape->getChildTransform(i) * principal.inverse(),
+									 compoundShape->getChildShape(i));
+#endif
+		delete compoundShape;
+
+		transform.setIdentity();
+		transform.setOrigin(btVector3(0, 10, 0));
+		createRigidBody(1.0, transform, compound2);	 
+	}
+
+	m_guiHelper->autogenerateGraphicsObjects(m_dynamicsWorld);
+}
+
+
+void CompoundBoxesExample::renderScene()
+{
+	CommonRigidBodyBase::renderScene();	
+}
+
+
+CommonExampleInterface*    ET_CompoundBoxesCreateFunc(CommonExampleOptions& options)
+{
+	return new CompoundBoxesExample(options.m_guiHelper);
+}
+
+
+

examples/ExtendedTutorials/CompoundBoxes.h

@@ -0,0 +1,22 @@
+/*
+Bullet Continuous Collision Detection and Physics Library
+Copyright (c) 2015 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 ET_COMPOUND_BOXES_EXAMPLE_H
+#define ET_COMPOUND_BOXES_EXAMPLE_H
+
+class CommonExampleInterface*    ET_CompoundBoxesCreateFunc(struct CommonExampleOptions& options);
+
+
+#endif //ET_COMPOUND_BOXES_EXAMPLE_H