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--- public:t-gede-14-1:lab9 [2014/03/24 21:50] – [Lab] marino
+++ public:t-gede-14-1:lab9 [2024/04/29 13:33] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== LAB9: Particle Systems (Optional) ======
+====== LAB9: Physics ======
-In this lab we will scratch the surface of using the Bullet physics blibrary with Ogre. This lab is intirely optional but can replace another previously unfinished lab, and counts toward participation.
-Unfortunately I was unable to give me the proper amount of time to make this lab interesting enough, but the classic brick wall
+In this lab we will scratch the surface of using the Bullet physics blibrary with Ogre.
+{{ :public:t-gede-14-1:ogrebullet1.png?nolink |}}{{ :public:t-gede-14-1:ogrebullet2.png?nolink |}}
 ===== Discussion =====
 Discussion thread for this lab is on Piazza
@@ Line 11: / Line 9: @@
 You can use your own project or start fresh with the base application {{:public:t-gede-14-1:lab6_handout.7z|code}}
-===== Lab =====
+===== Bullet =====
-  - Setup Project.
+  - Setup Bullet Project.
-  - Downlaod [[https://code.google.com/p/bullet/downloads/detail?name=bullet-2.82-r2704.zip&can=2&q=|Bullet]]
+  - Downlaod [[https://github.com/bulletphysics/bullet3/releases|Bullet]] I recommend downloading the 2.83 version. If you want to test something else, that is fine, I just haven't tested that with the following code.
   - Build Bullet
     - Run <bullet root>\build\vs2010.bat to generate the VS 2010 project files.
@@ Line 20: / Line 18: @@
     - Change the C/C++->Code Generation->Runtime Library to Multi Threaded DLL (/MDd (Debug) and /MD (Release))
     - Build the solution for debug and release.
+===== Lab =====
+And now for the Ogre project.
   - **Add** ''<Bullet Root>\lib;'' to ''Linker->General->Additional Library Directories'' (Debug and Release)
   - **Add** ''<Bullet Root>\src;'' to ''C++->General->Additional Include Directories'' (Debug and Release)
@@ Line 31: / Line 32: @@
 #include "btBulletCollisionCommon.h"
 #include "btBulletDynamicsCommon.h"
+#include "OgreMotionState.h"
 #include <vector>
 #include <map>
@@ Line 44: / Line 46: @@
 public:
 	Physics();
+        void initObjects();
 	virtual ~Physics();
 	btDiscreteDynamicsWorld* getDynamicsWorld();
@@ Line 54: / Line 57: @@
 #include "Physics.h"
+Physics::Physics() {
+}
 Physics::~Physics() {
@@ Line 76: / Line 83: @@
 </code>
-  - **Create a pointer** to physics in your Application, and initialize it in the startup function.
+  - **Create a pointer** to physics in your Application, and initialize it in the startup function.<code|cpp>	_physicsEngine = new Physics();
+	_physicsEngine->initObjects();</code>
   - **Before we start** there are some basic changes that have to made to the environment, in order to make the physics look more realist, we must make sure that our environmet is in a logical scale. If you have the handout code, Sinbad will be around 9.5 units high, Bullet library uses 1 unit as equal to 1 meter.
     - **You can check out Sinbad's actualt height** by doing ''_SinbadNode->getBoundingBox().getSize()'', this function will return the bounding box the the sceneNode, which is an axis aligned box that encompasses the entities of the SceneNode and is defined by the vertex extremas + an additional 2% scale.
@@ Line 85: / Line 93: @@
     - Add this function to your Physics class. <code cpp>btRigidBody* AddDynamicCubeRigidBoidy(Ogre::SceneNode* node, Ogre::Entity* ent, btScalar mass)
-	btRigidBody* Physics::AddDynamicCubeRigidBoidy(Ogre::SceneNode* node, Ogre::Entity* ent, btScalar mass) {
+btRigidBody* Physics::AddDynamicCubeRigidBoidy(Ogre::SceneNode* node, Ogre::Entity* ent, btScalar mass) {
-	Ogre::Vector3 aabbSize = ent->getBoundingBox().getSize() / 1.02;
+	Ogre::Vector3 aabbSize = ent->getBoundingBox().getSize() / 1.02f;
-	btScalar x = 0.5 * node->getScale().x * aabbSize.x;
+	btScalar x = 0.5f * node->getScale().x * aabbSize.x;
-	btScalar y = 0.5 * node->getScale().y * aabbSize.y;
+	btScalar y = 0.5f * node->getScale().y * aabbSize.y;
-	btScalar z = 0.5 * node->getScale().z * aabbSize.z;
+	btScalar z = 0.5f * node->getScale().z * aabbSize.z;
 	btCollisionShape* colShape = new btBoxShape(btVector3(x, y, z));
@@ Line 156: / Line 164: @@
 #endif //OGREMOTIONSTATE_H</code>
+  - **Now we are ready to create some rigid Bodies.**
+    - **Lets start by setting the ground as a collision plane**. Make the following changes and add the bullet code to the definition of your ground plane. <code cpp>// Create the plane.
+	Ogre::Plane plane(Ogre::Vector3::UNIT_Y, 0);
+	Ogre::MeshManager::getSingleton().createPlane("plane", Ogre::ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME, plane,
+, 1500, 200, 200, true, 1, 5, 5, Ogre::Vector3::UNIT_Z);
+	// Set the plane as the ground and add a texture to it.
+	Ogre::Entity* ground = _sceneManager->createEntity("LightPlaneEntity", "plane");
+	Ogre::SceneNode* groundNode = _sceneManager->getRootSceneNode()->createChildSceneNode();
+	groundNode->attachObject(ground);
+	ground->setMaterialName("Examples/BeachStones");
+	groundNode->setPosition(0, -1, 0);
+	// Create the collision shape, and give it the ground plane normals.
+	btCollisionShape* groundShape = new btStaticPlaneShape(btVector3(plane.normal.x, plane.normal.y, plane.normal.z), 0);
+	// Create the collision transform.
+	btTransform groundTransform;
+	// Set up the collision location and orientation.
+	groundTransform.setIdentity();
+	groundTransform.setOrigin(btVector3(groundNode->getPosition().x, groundNode->getPosition().y, groundNode->getPosition().z));
+	btQuaternion initRotation(groundNode->getOrientation().x, groundNode->getOrientation().y, groundNode->getOrientation().z, groundNode->getOrientation().w);
+	groundTransform.setRotation(initRotation);
+	// Give the plane a mass of 0, because our plane will be static, thus will not moce.
+	btScalar mass(0.0f);
+	// Set the ground as a static object.
+	bool isDynamic = false;
+	// This plane isnt going to be moving so i dont care about setting the motion state
+	btDefaultMotionState* myMotionState = new btDefaultMotionState(groundTransform);
+	btRigidBody::btRigidBodyConstructionInfo rbInfo(mass, myMotionState, groundShape);
+	btRigidBody* body = new btRigidBody(rbInfo);
+	//add the body to the dynamics world
+	_physicsEngine->getDynamicsWorld()->addRigidBody(body);</code>
+    - **Now lets add some cubes :)**, add this function to your create scene function. <code cpp>	int ringCount = 16;
+	int ringheight = 10;
+	for (int i = 0; i < ringheight; ++i) {
+		for (int j = 0; j < ringCount; ++j) {
+			Ogre::Entity* cubeEnt = _sceneManager->createEntity("Cube.mesh");
+			Ogre::SceneNode* cubeNode = _sceneManager->getRootSceneNode()->createChildSceneNode();
+			cubeNode->setScale(0.006f, 0.004f, 0.006f);
+			Ogre::Radian angle((Ogre::Math::TWO_PI / ringCount)*j + (Ogre::Math::TWO_PI / ringCount)*0.5f*(i%2) );
+			cubeNode->setOrientation(Ogre::Quaternion(-angle, Ogre::Vector3::UNIT_Y));
+			//cubeNode->setPosition(j*0.62+((i%2)*0.31f), i*0.405-(1-0.2), 0);
+			cubeNode->setPosition(Ogre::Math::Cos(angle) * 1.9f, i*0.405f - (1 - 0.2f), Ogre::Math::Sin(angle) * 1.9f);
+			cubeNode->attachObject(cubeEnt);
+			btRigidBody* temp = _physicsEngine->AddDynamicCubeRigidBoidy(cubeNode, cubeEnt, 1);
+			temp->setFriction(1);
+		}
+	}
+</code>
+  - **And finally we must update the dynamicWorld** and of course make the camera shoot some boxes! For this you will need to pass to the FrameListener a pointer to the sceneManager and the Physics engine.
+      - **You can either do that via the constructor**, or use the lazy way, and make them public, and set them like so ''_listener->_physicsEngine = _physicsEngine;''
+      - **Make the following modifications to your frameListener** \\  **Make** the FrameListener also inherit from OIS::MouseListener <code cpp>class MyFrameListener : public Ogre::FrameListener, OIS::MouseListener</code> And add the three virtual functions of OIS::MouseListener <code cpp>virtual bool mousePressed(const OIS::MouseEvent &arg, OIS::MouseButtonID id) {
+	mouseMask |= 1 << (int)id;
+	return true;
+}
+virtual bool mouseMoved(const OIS::MouseEvent &arg) {
+	return true;
+}
+virtual bool mouseReleased(const OIS::MouseEvent &arg, OIS::MouseButtonID id) {
+	return true;
+}</code> **And** in the constructor: replace<code cpp>_Mouse = static_cast<OIS::Mouse*>(_InputManager->createInputObject(OIS::OISMouse, false));
+</code> with this <code cpp>// 7.3 Initialize the Mouse input listener.
+try {
+	_Mouse = static_cast<OIS::Mouse*>(_InputManager->createInputObject(OIS::OISMouse, true));
+	_Mouse->setEventCallback(this);
+	std::cout << "Successfuly created Mouse";
+}
+catch (...) {
+	std::cout << "Failed to initialize Mouse";
+	_Mouse = 0;
+}</code> Also make sure to add the int member variable mouseMask, and set it to 0 in the FrameListener constructor. Now you can query whether a mouse button was pressed like so '' (mouseMask & (1 << (int)OIS::MouseButtonID::MB_Left)) '' **make sure** to add ''mouseMask = 0'' before your call to ''_Mouse->capture()'' in you FrameStarted function so we don't retain old mouse states :).
+    - **Now we spawn a cube from the origin of the camera** and give it some linear velocity in the direction of the camera. You will have to pass a pointer to the SceneManager into the frameListener. <code>if (  (mouseMask & (1 << (int)OIS::MouseButtonID::MB_Left))  ) {
+	// Create a cube entity.
+	Ogre::Entity* cubeEnt = _sceneManager->createEntity("Cube.mesh");
+	Ogre::SceneNode* cubeNode = _sceneManager->getRootSceneNode()->createChildSceneNode();
+	cubeNode->setScale(0.005f, 0.005f, 0.005f);
+	// Set the position of the cube to the front of the origin of the camera
+	cubeNode->setPosition(_Cam->getPosition() + _Cam->getDirection());
+	cubeNode->attachObject(cubeEnt);
+	// Now make the cube a rigid body, give it some linearVelocity and add it to the physics world
+	btRigidBody* boxBody = _physicsEngine->AddDynamicCubeRigidBoidy(cubeNode, cubeEnt, 2);
+	boxBody->setLinearVelocity(btVector3(_Cam->getDirection().x, _Cam->getDirection().y, _Cam->getDirection().z) * 30);
+}</code>
+  - **Finally** we update the physics world <code cpp>// Now update the physics world with the delta time. "Note: normally we would want to have the physics world update a little more independant of the framerate, but this will do for now :)"
+	_physicsEngine->getDynamicsWorld()->stepSimulation(evt.timeSinceLastFrame);</code>
+<box red 100% | **Attention!**>
+** Compile and run using a Release built target!!! Very important, unless you plan to fry some eggs and bacon on your laptop :)** Just make sure to use the Release version of the plugins file when you run the application.It can be found under ''<YourOgreSDK>\bin\Release\plugins.cfg'' **Check out these pre-processor variables to help you out**<code|cpp>#if _DEBUG
+	cf.load("../LabFiles/OgreConfig/resources_d.cfg");
+#elif NDEBUG
+	cf.load("../LabFiles/OgreConfig/resources.cfg");
+#endif
+#if _DEBUG
+	_root = new Ogre::Root("../LabFiles/OgreConfig/plugins_d.cfg","../LabFiles/OgreConfig/ogre.cfg", "../LabFiles/ogre.log");
+#elif NDEBUG
+	_root = new Ogre::Root("../LabFiles/OgreConfig/plugins.cfg","../LabFiles/OgreConfig/ogre.cfg", "../LabFiles/ogre.log");
+#endif</code></box>
 ===== When You Are Finished =====
 Upload your **commented source files** into Lab9 in MySchool (zip them up if more than one).