void GLUTMotion(int x, int y)
{
// Invert y coordinate
y = GLUTwindow_height - y;
// Compute mouse movement
int dx = x - GLUTmouse[0];
int dy = y - GLUTmouse[1];
// Process mouse motion event
if ((dx != 0) || (dy != 0)) {
R3Point mesh_center = mesh->Center();
if ((GLUTbutton[0] && (GLUTmodifiers & GLUT_ACTIVE_SHIFT)) || GLUTbutton[1]) {
// Scale world
double factor = (double) dx / (double) GLUTwindow_width;
factor += (double) dy / (double) GLUTwindow_height;
factor = exp(2.0 * factor);
factor = (factor - 1.0) / factor;
R3Vector translation = (mesh_center - camera_eye) * factor;
camera_eye += translation;
glutPostRedisplay();
}
else if (GLUTbutton[0] && (GLUTmodifiers & GLUT_ACTIVE_CTRL)) {
// Translate world
double length = R3Distance(mesh_center, camera_eye) * tan(camera_yfov);
double vx = length * (double) dx / (double) GLUTwindow_width;
double vy = length * (double) dy / (double) GLUTwindow_height;
R3Vector camera_right = camera_up % camera_towards;
R3Vector translation = -((camera_right * vx) + (camera_up * vy));
camera_eye += translation;
glutPostRedisplay();
}
else if (GLUTbutton[0]) {
// Rotate world
double vx = (double) dx / (double) GLUTwindow_width;
double vy = (double) dy / (double) GLUTwindow_height;
double theta = 4.0 * (fabs(vx) + fabs(vy));
R3Vector camera_right = camera_up % camera_towards;
R3Vector vector = (camera_right * vx) + (camera_up * vy);
R3Vector rotation_axis = vector % camera_towards;
rotation_axis.Normalize();
camera_eye.Rotate(R3Line(mesh_center, rotation_axis), theta);
camera_towards.Rotate(rotation_axis, theta);
camera_up.Rotate(rotation_axis, theta);
camera_right = camera_up % camera_towards;
camera_up = camera_towards % camera_right;
camera_towards.Normalize();
camera_up.Normalize();
glutPostRedisplay();
}
}
// Remember mouse position
GLUTmouse[0] = x;
GLUTmouse[1] = y;
}
void R3Point::
Rotate(const R3Vector& axis, RNAngle theta)
{
// Rotate point counterclockwise around axis through origin by radians ???
R3Vector v = Vector();
v.Rotate(axis, theta);
*this = v.Point();
}
void R3Point::
Rotate(const R3Line& axis, RNAngle theta)
{
// Translate axis to origin
R3Vector v = *this - axis.Point();
// Rotate point counterclockwise around axis through origin by radians ???
v.Rotate(axis.Vector(), theta);
// Translate axis back from origin
*this = axis.Point() + v;
}
void GenerateParticles(R3Scene *scene, double current_time, double delta_time)
{
for (int i = 0; i < scene->NParticleSources(); i++) {
R3ParticleSource *source = scene->ParticleSource(i);
// spheres
if (source->shape->type == R3_SPHERE_SHAPE) {
// remainder term for fraction of particle
double numberweshouldmake = delta_time * source->rate + source->remainder;
int nparts = (int) floor(numberweshouldmake);
source->remainder = numberweshouldmake - nparts;
for (int p = 0; p < nparts; p++) {
R3Particle *newpart = new R3Particle();
// calculate position and velocity
double u = RandomNumber();
double theta = 2*PI*u;
double v = RandomNumber();
double phi = acos(2*v-1);
double r = source->shape->sphere->Radius();
R3Point center = source->shape->sphere->Center();
double x = r*cos(theta)*sin(phi);
double y = r*sin(theta)*sin(phi);
double z = r*cos(phi);
R3Vector n = R3Vector(x,y,z);
n.Normalize();
// find tangent vector, use lecture notes to get velocity
R3Plane plane = R3Plane(R3Point(0,0,0),n);
R3Vector a;
do {
a = R3Vector(RandomNumber(),RandomNumber(),RandomNumber());
a.Project(plane);
} while (a.Length() == 0.0);
a.Normalize();
double t1 = 2*PI*RandomNumber();
double t2 = sin(source->angle_cutoff)*RandomNumber();
a.Rotate(n,t1);
R3Vector vec = R3Vector(a);
R3Vector cross = R3Vector(vec);
cross.Cross(n);
vec.Rotate(cross,acos(t2));
newpart->position = center + n*r;
newpart->velocity = vec*source->velocity;
//update
newpart->mass = source->mass;
newpart->fixed = source->fixed;
newpart->drag = source->drag;
newpart->elasticity = source->elasticity;
newpart->lifetime = source->lifetime;
newpart->lifetimeactive = source->lifetimeactive;
newpart->material = source->material;
scene->particles.push_back(newpart);
}
}
// CIRCLE
if (source->shape->type == R3_CIRCLE_SHAPE) {
double numberweshouldmake = delta_time * source->rate + source->remainder;
int nparts = (int) floor(numberweshouldmake);
source->remainder = numberweshouldmake - nparts;
for (int p = 0; p < nparts; p++) {
R3Particle *newpart = new R3Particle();
// calculate position and velocity
double r = source->shape->circle->Radius();
R3Point center = source->shape->circle->Center();
R3Plane plane = source->shape->circle->Plane();
R3Vector n = plane.Normal();
n.Normalize();
// get a random point on a circle
double xcirc, ycirc;
do {
xcirc = 2*r*(RandomNumber() - 0.5);
ycirc = 2*r*(RandomNumber() - 0.5);
} while (xcirc*xcirc + ycirc*ycirc > r*r);
// get basis vectors of circle
R3Vector tang;
do {
tang = R3Vector(RandomNumber(),RandomNumber(),RandomNumber());
tang.Project(plane);
} while (tang.Length() == 0.0);
R3Vector othertang = R3Vector(tang);
othertang.Cross(n);
othertang.Normalize();
tang.Normalize();
R3Point pos = center + tang*xcirc + othertang*ycirc;
R3Vector a = R3Vector(tang);
double t1 = 2*PI*RandomNumber();
double t2 = sin(source->angle_cutoff)*RandomNumber();
a.Rotate(n,t1);
R3Vector vec = R3Vector(a);
R3Vector cross = R3Vector(vec);
cross.Cross(n);
vec.Rotate(cross,acos(t2));
newpart->position = pos;
newpart->velocity = vec*source->velocity;
newpart->mass = source->mass;
newpart->fixed = source->fixed;
newpart->drag = source->drag;
newpart->elasticity = source->elasticity;
newpart->lifetime = source->lifetime;
newpart->lifetimeactive = source->lifetimeactive;
newpart->material = source->material;
scene->particles.push_back(newpart);
}
}
}
for (int i = 0; i < (int)scene->enemies.size(); i++) {
R3Enemy *enemy = scene->enemies[i];
// spheres
if (enemy->shape->type == R3_SPHERE_SHAPE) {
// remainder term for fraction of particle
double numberweshouldmake = delta_time * enemy->rate + enemy->remainder;
int nparts = (int) floor(numberweshouldmake);
enemy->remainder = numberweshouldmake - nparts;
for (int p = 0; p < nparts; p++) {
R3Particle *newpart = new R3Particle();
// calculate position and velocity
double u = RandomNumber();
double theta = 2*PI*u;
double v = RandomNumber();
double phi = acos(2*v-1);
double r = enemy->shape->sphere->Radius();
R3Point center = enemy->shape->sphere->Center();
double x = r*cos(theta)*sin(phi);
double y = r*sin(theta)*sin(phi);
double z = r*cos(phi);
R3Vector n = R3Vector(x,y,z);
n.Normalize();
// find tangent vector, use lecture notes to get velocity
R3Plane plane = R3Plane(R3Point(0,0,0),n);
R3Vector a;
do {
a = R3Vector(RandomNumber(),RandomNumber(),RandomNumber());
a.Project(plane);
} while (a.Length() == 0.0);
a.Normalize();
double t1 = 2*PI*RandomNumber();
double t2 = sin(enemy->angle_cutoff)*RandomNumber();
a.Rotate(n,t1);
R3Vector vec = R3Vector(a);
R3Vector cross = R3Vector(vec);
cross.Cross(n);
vec.Rotate(cross,acos(t2));
newpart->position = center + n*r;
newpart->velocity = vec*enemy->velocity;
//update
newpart->mass = enemy->mass;
newpart->fixed = enemy->fixed;
newpart->drag = enemy->drag;
newpart->elasticity = enemy->elasticity;
newpart->lifetime = enemy->lifetime;
newpart->lifetimeactive = enemy->lifetimeactive;
newpart->material = enemy->material;
scene->particles.push_back(newpart);
}
}
// CIRCLE
if (enemy->shape->type == R3_CIRCLE_SHAPE) {
double numberweshouldmake = delta_time * enemy->rate + enemy->remainder;
int nparts = (int) floor(numberweshouldmake);
enemy->remainder = numberweshouldmake - nparts;
for (int p = 0; p < nparts; p++) {
R3Particle *newpart = new R3Particle();
// calculate position and velocity
double r = enemy->shape->circle->Radius();
R3Point center = enemy->shape->circle->Center();
R3Plane plane = enemy->shape->circle->Plane();
R3Vector n = plane.Normal();
n.Normalize();
// get a random point on a circle
double xcirc, ycirc;
do {
xcirc = 2*r*(RandomNumber() - 0.5);
ycirc = 2*r*(RandomNumber() - 0.5);
} while (xcirc*xcirc + ycirc*ycirc > r*r);
// get basis vectors of circle
R3Vector tang;
do {
tang = R3Vector(RandomNumber(),RandomNumber(),RandomNumber());
tang.Project(plane);
} while (tang.Length() == 0.0);
R3Vector othertang = R3Vector(tang);
othertang.Cross(n);
othertang.Normalize();
tang.Normalize();
R3Point pos = center + tang*xcirc + othertang*ycirc;
R3Vector a = R3Vector(tang);
double t1 = 2*PI*RandomNumber();
double t2 = sin(enemy->angle_cutoff)*RandomNumber();
a.Rotate(n,t1);
R3Vector vec = R3Vector(a);
R3Vector cross = R3Vector(vec);
cross.Cross(n);
vec.Rotate(cross,acos(t2));
newpart->position = pos;
newpart->velocity = vec * 1.0;
newpart->mass = enemy->mass;
newpart->fixed = enemy->fixed;
newpart->drag = enemy->drag;
newpart->elasticity = enemy->elasticity;
newpart->lifetime = enemy->lifetime;
newpart->lifetimeactive = enemy->lifetimeactive;
newpart->material = enemy->material;
scene->particles.push_back(newpart);
}
}
}
}