Saxum/physics.cc

#include "physics.hh"
#include "extern/bullet/Extras/Serialize/BulletWorldImporter/btBulletWorldImporter.h"


Physics::Physics() {
}

Physics::~Physics() {
}

void Physics::init(std::string geometryPath) //prepares bullet by creating all initial classes
{
    colConfig = new btDefaultCollisionConfiguration();
    dispatcher = new btCollisionDispatcher(colConfig);
    broadphase = new btDbvtBroadphase();
    solver = new btSequentialImpulseConstraintSolver();
    world = new btDiscreteDynamicsWorld(dispatcher,broadphase,solver,colConfig);
    world->setGravity(btVector3(0,-10,-0));
    if (world == NULL) {
        printf("No World after init\n");
    }
    this->geometryPath = geometryPath;
}

void Physics::takeUpdateStep(float timeDiff)
{
    counter++;
    if(counter<1)
    {
        world->stepSimulation(timeDiff); //allows the world to be simmulated correctly indipendant of the timedifferences between frames
        return;
    }
    
    for(unsigned i = 0; i < allPositionConstraints.size();i++) //this handles the spring constraints
    {
        if(allPositionConstraints[i].position != allPositionConstraints[i].body->getCenterOfMassPosition()) //if constraint != position of the body because otherwise dir = 0
        {
            btVector3 dir = allPositionConstraints[i].position - allPositionConstraints[i].body->getCenterOfMassPosition();
            dir = dir*allPositionConstraints[i].strength - allPositionConstraints[i].body->getLinearVelocity();
            allPositionConstraints[i].body->applyCentralForce(dir*allPositionConstraints[i].strength); //apply a foce upon the object pushing it towards the constraint position
        }
    }
    
    
    btVector3 position = cameraBody->getCenterOfMassPosition() - playerBall->getCenterOfMassPosition(); //gets a vector from the player to the camera
    position.normalize();
    position *= cameraDistance;
    position += playerBall->getCenterOfMassPosition(); //is the position cameraDistance away from the player in the direction of the camera
    
    //prevent the camera from being dragged along on the ground
    if (position.getY() < playerBall->getCenterOfMassPosition().getY() + 1)
        position.setY(playerBall->getCenterOfMassPosition().getY() + 1);
    
    btVector3 dir = cameraBody->getCenterOfMassPosition() - position;
    float str = 50 * dir.length() / cameraBody->getInvMass(); //getInvMass() returns the inverted mass
    cameraBody->applyCentralForce(-dir*str); //scale the force by camera mass
    counter=0;
    float speed = cameraBody->getLinearVelocity().length();
    if(speed>20.0f)
    {
        position = cameraBody->getLinearVelocity();
        position.normalize();
        cameraBody->setLinearVelocity(position*20);
    }
    world->stepSimulation(timeDiff);
}

void Physics::removePositionConstraint(int bodyIndice) //remover function for deleting all pos constraints on one body
{
    for(unsigned i = 0; i < allPositionConstraints.size(); i++)
    {
        if(allPositionConstraints[i].body == bodies[bodyIndice])
        {
            allPositionConstraints.erase(allPositionConstraints.begin()+i);
        }
    }
}

void Physics::addPositionConstraint(int bodyIndice, float strength, glm::vec3 position) //function for adding position constraints
{
    positionConstraint cons;
    cons.body = bodies[bodyIndice];
    cons.strength = strength;
    cons.position = btVector3(position.x,position.y,position.z);
    allPositionConstraints.push_back(cons);
}

//players and objects
void Physics::addPlayer(float friction, float rad, Entity entity, float mass, float dampningL, float dampningA, unsigned indice)
{
    if(bodies.size() == indice)
        throw std::invalid_argument( "Bodies out of Sync" ); //these error are to ensure that level can always communicate with physics without having to worry about synching errors
    
    btSphereShape* sphere = new btSphereShape(rad); //the first thing we need for a rigid body is the shape
    btVector3 inertia(0,0,0);
    if(mass != 0.0)
    {
        sphere->calculateLocalInertia((btScalar)mass,inertia); //from this shape we can then calculate the innertia, as long as the mass != 0 (otherwise inertia = 0)
    }
    
    glm::quat glmQuat = glm::quat_cast(entity.getRotation());
    
    btDefaultMotionState* motion = new btDefaultMotionState(btTransform(btQuaternion(glmQuat.x,glmQuat.y,glmQuat.z,glmQuat.w),btVector3(entity.getPosition().x,entity.getPosition().y,entity.getPosition().z))); //next we define the motionstate, wich describes the innital position and rotation
    
    btRigidBody::btRigidBodyConstructionInfo info(mass,motion,sphere,inertia); //next we process all data for the rigid body into info
    
    info.m_friction = friction*2; //here we modify the friction and restitution (bounciness) of the object
    info.m_restitution = 0.1f;
    
    playerBall = new btRigidBody(info); //finally we create the rigid body using the info
    
    playerBall->setDamping(dampningL, dampningA); //here we can set the dampning (how much of the motion is lost)
    
    world->addRigidBody(playerBall,COL_OBJECTS,COL_OBJECTS|COL_OBJECTS_NO_TERRAIN|COL_TERRAIN); //then we add the rigid body to the wiorld, allowing it to be simulated
    
    bodies.push_back(playerBall); //next we add the rigid body to our own list (for cleanup and for synchronitaation with level)
    //note, while we can always access playerBall through its global name, we add it to this array for synchronization purposes
    
    playerBall->setSleepingThresholds(0,0); //in a final step we make sure that the body never is removed from the active rigid bodies
    
    if(bodies.size() != indice)
        throw std::invalid_argument( "Bodies out of Sync" ); //one last check to make sure level and physics are in synch
    
    addCamera(); //now that the player exists add a camera for the player
}

void Physics::addTerrain(int width, int length, float** heightData) //The terrain adding function
{
    float* heightfield = new float[width * length]; //bullet only accepts data in a one dimensional array, so parse data into appropriate format
    int highest = -999999, j = 0, i = 0;
    for (i = 0; i < width; i++)
    {
        for (j = 0; j < length; j++) {
            heightfield[i*length+j] =  heightData[j][i]; //reverse order because they are loaded backwards
            
            if (heightData[j][i] > highest)
                highest = heightData[j][i]; //bullet needs to know the highest point of the heightmap
        }
    }
    highest++;
    
    btHeightfieldTerrainShape* terrainShape = new btHeightfieldTerrainShape(length,width,heightfield,highest,1,true,false);
    btRigidBody::btRigidBodyConstructionInfo info(0,new btDefaultMotionState(),terrainShape,btVector3(0,0,0)); //next we process all data for the rigid body into info
    info.m_friction = 1;
    info.m_restitution = 0;
    btRigidBody* tBody = new btRigidBody(info);
    
    tBody->getWorldTransform().setOrigin(btVector3(0,((float)highest)/2,0)); //we have to move the origin of our rigid body down, because bullet sets the origin (0,0,0) at (width/2, height/2, length/2) in the map the x and z are correct in our level, but y needs to be addapted
    
    terrainBody = tBody;
    if (world == NULL) {
        printf("No World while adding terrain.\n");
    }
    world->addRigidBody(terrainBody, COL_TERRAIN, COL_TERRAIN | COL_OBJECTS); //COL_XXXX are collision masks, allowing us to ignore collisions between certain object groups (required for buttons)
}

void Physics::addTriangleMeshBody(Entity entity, std::string path, float mass, float dampningL, float dampningA,unsigned indice,float scaling, bool rotate)
{
    
    if(bodies.size() == indice)
        throw std::invalid_argument( "Bodies out of Sync" );
    
    std::vector< unsigned int > vertexIndices; //temp lists for data sets
    std::vector< btVector3 > temp_vertices;
    path = "../" + geometryPath + path;
    FILE * file = fopen(path.c_str(), "r");
    if( file == NULL ){
        throw std::invalid_argument( "Impossible to open the file" ); //create correct filepath and report error if cannot open
    }
    while( 1 ){
        char lineHeader[128];
        //read the first word of the line
        int res = fscanf(file, "%s", lineHeader);
        if (res == EOF)
            break; //while not at end do loop
        if ( strcmp( lineHeader, "v" ) == 0 ){ //if a vertex
            glm::vec3 vertex;
            fscanf(file, "%f %f %f\n", &vertex.x, &vertex.y, &vertex.z );
            temp_vertices.push_back(btVector3(vertex.x,vertex.y,vertex.z)); //save vertex in array
        }
        else if ( strcmp( lineHeader, "f" ) == 0 ){ //if face (index for 3 vertexes for a triangle)
            std::string vertex1, vertex2, vertex3;
            unsigned int vertexIndex[3], uvIndex[3], normalIndex[3];
            int matches = fscanf(file, "%d/%d/%d %d/%d/%d %d/%d/%d\n", &vertexIndex[0], &uvIndex[0], &normalIndex[0], &vertexIndex[1], &uvIndex[1], &normalIndex[1], &vertexIndex[2], &uvIndex[2], &normalIndex[2]);
            vertexIndices.push_back(vertexIndex[0]);
            vertexIndices.push_back(vertexIndex[1]);
            vertexIndices.push_back(vertexIndex[2]); //save 3 indexes in array
        }
    }
    //finally start making body
    btTriangleMesh* triMesh = new btTriangleMesh();
    
    for(unsigned i = 2; i < vertexIndices.size();i+=3)
    {
        triMesh->addTriangle(temp_vertices[vertexIndices[i]],temp_vertices[vertexIndices[i-1]],temp_vertices[vertexIndices[i-2]]); //for every face (3 elements in vertexIndices) create triangle use the indices to find correct vertexes to make the triangle
    }
    
    btBvhTriangleMeshShape* shape = new btBvhTriangleMeshShape(triMesh,true);
    shape->setLocalScaling(btVector3(scaling,scaling,scaling)); //we need to add a scaling here because the objects seem to have diffrent sizes when loaded (no clue why, see composition.xml for exact scaling factors)
    
    
    glm::quat glmQuat = glm::quat_cast(entity.getRotation());
    
    btDefaultMotionState* motion = new btDefaultMotionState(btTransform(btQuaternion(glmQuat.x,glmQuat.y,glmQuat.z,glmQuat.w),btVector3(entity.getPosition().x,entity.getPosition().y,entity.getPosition().z)));
	
    btVector3 inertia(0,0,0);
    if(mass != 0.0)
    {
        shape->calculateLocalInertia((btScalar)mass,inertia);
    }
    
    btRigidBody::btRigidBodyConstructionInfo info(mass,motion,shape,inertia);
    
    btRigidBody* body = new btRigidBody(info);
    
    body->setDamping(dampningL,dampningA);
    
    bodies.push_back(body);
    
    world->addRigidBody(body,COL_OBJECTS, objectsPhysicsCollision);
    
    if(!rotate)//rotate lets certain objects get inertia (0,0,0) (not rotateable)
    {
        body->setAngularFactor(btVector3(0,0,0));
    }
    
    if(bodies.size() != indice)
        throw std::invalid_argument( "Bodies out of Sync" );
}

void Physics::addButton(float width, float height, float length, Entity entity, float mass, float dampningL, float dampningA, unsigned indice,bool rotate)
{
    
    if(bodies.size() == indice)
        throw std::invalid_argument( "Bodies out of Sync" );
    
    btBoxShape* box = new btBoxShape(btVector3(width/2,height/2,length/2));
    
    glm::quat glmQuat = glm::quat_cast(entity.getRotation());
    
    btDefaultMotionState* motion = new btDefaultMotionState(btTransform(btQuaternion(glmQuat.x,glmQuat.y,glmQuat.z,glmQuat.w),btVector3(entity.getPosition().x,entity.getPosition().y,entity.getPosition().z)));
    
    btVector3 inertia(0,0,0);
    if(mass != 0.0) //&& rotate lets certain objects get inertia (0,0,0) (not rotateable)
    {
        box->calculateLocalInertia((btScalar)mass,inertia);
    }
    btRigidBody::btRigidBodyConstructionInfo info(mass,motion,box,inertia);
    
    btRigidBody* body = new btRigidBody(info);
    
    body->setDamping(dampningL, dampningA);
    
    world->addRigidBody(body,COL_OBJECTS_NO_TERRAIN, specialPhysicsCollision); //the specialPhysicsCollision allows these objects to not collide with the terrain
    
    bodies.push_back(body);
    
     if(!rotate)
    {
        body->setAngularFactor(btVector3(0,0,0));
    }
    
    if(bodies.size() != indice)
        throw std::invalid_argument( "Bodies out of Sync" );
}

void Physics::addBox(float width, float height, float length, Entity entity, float mass, float dampningL, float dampningA, unsigned indice,bool rotate)
{
    //similar to other constructors
    if(bodies.size() == indice)
        throw std::invalid_argument( "Bodies out of Sync" );
    
    glm::quat glmQuat = glm::quat_cast(entity.getRotation());
    btBoxShape* box = new btBoxShape(btVector3(width/2,height/2,length/2));
    btDefaultMotionState* motion = new btDefaultMotionState(btTransform(btQuaternion(glmQuat.x,glmQuat.y,glmQuat.z,glmQuat.w),btVector3(entity.getPosition().x,entity.getPosition().y,entity.getPosition().z)));
    
    btVector3 inertia(0,0,0);
    if(mass != 0.0) //&& rotate lets certain objects get inertia (0,0,0) (not rotateable)
    {
        box->calculateLocalInertia((btScalar)mass,inertia);
    }
    
    
    btRigidBody::btRigidBodyConstructionInfo info(mass,motion,box,inertia);
    
    btRigidBody* body = new btRigidBody(info);
    
    body->setDamping(dampningL, dampningA);
    
    world->addRigidBody(body,COL_OBJECTS, objectsPhysicsCollision);
    
    bodies.push_back(body);
    
    if(!rotate)
    {
        body->setAngularFactor(btVector3(0,0,0));
    }
    
    if(bodies.size() != indice)
        throw std::invalid_argument( "Bodies out of Sync" );
}

void Physics::addSphere(float rad, Entity entity, float mass, float dampningL, float dampningA, unsigned indice,bool rotate)
{
    if(bodies.size() == indice) //(user's initial) height, not the actual height. More...
        throw std::invalid_argument( "Bodies out of Sync" );
    
    btSphereShape* sphere = new btSphereShape(rad);
    btVector3 inertia(0,0,0);
    if(mass != 0.0)
    {
        sphere->calculateLocalInertia((btScalar)mass,inertia);
    }
    
    glm::quat glmQuat = glm::quat_cast(entity.getRotation());
    
    btDefaultMotionState* motion = new btDefaultMotionState(btTransform(btQuaternion(glmQuat.x,glmQuat.y,glmQuat.z,glmQuat.w),btVector3(entity.getPosition().x,entity.getPosition().y,entity.getPosition().z)));
    
    btRigidBody::btRigidBodyConstructionInfo info(mass,motion,sphere,inertia);
    
    btRigidBody* body = new btRigidBody(info);
    
    body->setDamping(dampningL, dampningA);
    
    world->addRigidBody(body,COL_OBJECTS, objectsPhysicsCollision);
    
    bodies.push_back(body);
    
    if(!rotate)//rotate lets certain objects get inertia (0,0,0) (not rotateable)
    {
        body->setAngularFactor(btVector3(0,0,0));
    }
    
    body->setSleepingThresholds(0,0);
    
    if(bodies.size() != indice)
        throw std::invalid_argument( "Bodies out of Sync" );
}

void Physics::addCamera() //Camera Creator automatically called when player is created
{
    btSphereShape* sphere = new btSphereShape(0.5f); //we use this to make a more interesting camera, that does not interpenetrate with the terrain/objects
    
    btVector3 inertia(0,0,0); //rotation handled elsewhere (as it always has to look at the player)
    
    btVector3 direction(1,1,1);
    direction.normalize();
    direction*=cameraDistance; //create a offset of length 5 so we have a stable camera at the beginning
    btDefaultMotionState* motion = new btDefaultMotionState(btTransform(btQuaternion(0,0,0,1),playerBall->getCenterOfMassPosition()+direction));
    
    btRigidBody::btRigidBodyConstructionInfo info(0.001,motion,sphere,inertia);
    
    cameraBody = new btRigidBody(info);
    
    cameraBody->setDamping(0.9,0.5); //this damping factor leaves a relativly smoothe system
    
    info.m_friction = 0; 
    info.m_restitution = 0;
    
    world->addRigidBody(cameraBody,COL_OBJECTS, objectsPhysicsCollision);
    
    cameraBody->setGravity(btVector3(0,0,0));
    
    cameraBody->setSleepingThresholds(0,0); //very important, otherwise camera may go to sleep, aka not move until next collision
}


//update functions
glm::vec3 Physics::getCameraPosition()
{
    btVector3 origin = cameraBody->getCenterOfMassPosition();
    glm::vec3 save(origin.getX(),origin.getY(),origin.getZ());
    return save;
}

glm::vec3 Physics::getCameraToPlayer() //returns a glm::vec3 the goes from the camera to the player
{
    btVector3 origin = playerBall->getCenterOfMassPosition() - cameraBody->getCenterOfMassPosition();
    glm::vec3 save(origin.getX(),origin.getY(),origin.getZ());
    return save;
}

glm::vec3 Physics::getPos(int i) //this and the next function are used to synchronize the graphics data and the physics data
{
    btVector3 origin = bodies[i]->getCenterOfMassPosition();
    glm::vec3 save(origin.getX(),origin.getY(),origin.getZ());
    return save;
}

glm::mat4 Physics::getRotation(int i)
{
    btQuaternion quat = bodies[i]->getOrientation();
    
    glm::mat4 matrix = glm::rotate(
        quat.getAngle(),
        glm::vec3(quat.getAxis().getX(), quat.getAxis().getY(), quat.getAxis().getZ())
    ); //somewhat clunky, but basicly creates a rotation matrix out of the angle of the body, and its axis (from the quaterion in bullet)
    return matrix;
}

//these are used to apply a force to the camera body according to the movement of the mouse
void Physics::updateCameraPos(glm::vec2 mouseMovement, float strength, float distance)
{
    this->cameraDistance = distance;
    //note: in mouseMovement x and y are flipped in contrast to bullet
    btVector3 change =  playerBall->getCenterOfMassPosition()-cameraBody->getCenterOfMassPosition();
    change.setY(0);
    change.normalize(); //normalize so that the distance between camera and body does not matter
    change *= (mouseMovement.y); //we start with left/right movement because this needs to be calculated via a crossproduct, and the up down value would alter that
    change = btCross(btVector3(0,1,0),change);
    change.setY(mouseMovement.x/5); //scaleing because otherwise oup/down much stronger then left right
    change *= strength / cameraBody->getInvMass();
    
    cameraBody->applyCentralForce(change);
}

//use the crossproduct to correctly apply a torque to the palyer if function called
void Physics::rollForward(glm::vec3 camPos,float strength)
{
    btVector3 pos = cameraBody->getCenterOfMassPosition() - playerBall->getCenterOfMassPosition();
    pos.setY(0);
    pos.normalize();
    pos = btCross(pos,btVector3(0,1,0));
    pos *= strength;
    playerBall->applyTorque(pos);
}

void Physics::rollBack(glm::vec3 camPos,float strength)
{
    btVector3 pos = cameraBody->getCenterOfMassPosition() - playerBall->getCenterOfMassPosition();
    pos.setY(0);
    pos.normalize();
    pos = btCross(btVector3(0,1,0),pos);
    pos *= strength;
    playerBall->applyTorque(pos);
}

void Physics::rollLeft(glm::vec3 camPos,float strength)
{
    btVector3 pos = cameraBody->getCenterOfMassPosition() - playerBall->getCenterOfMassPosition();
    pos.setY(0);
    pos.normalize();
    pos *= strength;
    playerBall->applyTorque(pos);
}

void Physics::rollRight(glm::vec3 camPos,float strength)
{
    btVector3 pos = cameraBody->getCenterOfMassPosition() - playerBall->getCenterOfMassPosition();
    pos.setY(0);
    pos.normalize();
    pos *= strength;
    playerBall->applyTorque(-pos);
}


//not used right now

void Physics::addStaticGroundPlane()
{
    btCollisionShape* groundShape = new btStaticPlaneShape(btVector3(0, 1, 0), 0);
    btDefaultMotionState* groundMotionState = new btDefaultMotionState(btTransform(btQuaternion(0, 0, 0, 1), btVector3(0, 0, 0)));
    btRigidBody::btRigidBodyConstructionInfo groundRigidBodyCI(0, groundMotionState, groundShape, btVector3(0, 0, 0));
    staticGroundBody = new btRigidBody(groundRigidBodyCI);
    
    world->addRigidBody(staticGroundBody);
} //not needed anymoer, but still good for debugging


void Physics::kill() //delete dynamically allocated memory
{
    if (world == NULL) {
        return;
    }
    //btDynamimcWorld*
    for(unsigned i = 0; i < bodies.size();i++)
    {
        world->removeCollisionObject(bodies[i]); //go through the list of bodies in world for each body b, then remove exactly this body b from world
        btMotionState* motionState = bodies[i]->getMotionState();
        btCollisionShape* shape = bodies[i]->getCollisionShape();
        delete shape;
        delete motionState;
    delete bodies[i];
    }
    btMotionState* motionState = terrainBody->getMotionState(); //delete the rest that are not in the array bodies
    btCollisionShape* shape = terrainBody->getCollisionShape();
    delete shape;
    delete motionState;
    delete terrainBody;
    
    motionState = cameraBody->getMotionState();
    shape = cameraBody->getCollisionShape();
    delete shape;
    delete motionState;
    delete cameraBody; //note: palyerBall is also in the array bodies so we do not need to clean it up
    
    delete dispatcher; //clean up rest
    delete colConfig;
    delete solver;
    delete broadphase;
    delete world;
    
    //feel like a good little programmer because everything is clean
}