void Render(ExampleClock& clock) {
if(long(clock.Now().Seconds()) % 4 == 0) {
status += clock.Interval().Seconds();
} else if(status != double(long(status))) {
if(status - double(long(status)) < 0.5)
status = double(long(status));
else
status = 1.0 + double(long(status));
}
gl.Clear().ColorBuffer().DepthBuffer();
point_prog.status = GLfloat(0.5 - 0.5 * CosineWave(status * 0.5));
CamMatrixf camera = CamMatrixf::Orbiting(
Vec3f(),
5.5f,
FullCircles(clock.Now().Seconds() / 19.0),
Degrees(45 + SineWave(clock.Now().Seconds() / 15.0) * 40));
point_prog.camera_matrix.Set(camera);
point_prog.model_matrix.Set(
ModelMatrixf::RotationX(RightAngles(status)));
shape.Draw();
}
// Updates the emitter
// Changes its position, emits new particles
void Update(ExampleClock& clock)
{
assert(positions.size() == directions.size());
assert(positions.size() == ages.size());
assert(positions.size() == ids.size());
double time_diff = clock.Interval().Seconds();
double drag = 0.1 * time_diff;
if(drag > 1.0) drag = 1.0;
// go through the existing particles
for(std::size_t i=0, n=positions.size(); i!=n; ++i)
{
// update the age
ages[i] += time_diff / lifetime;
// if the particle is "too old"
if(ages[i] > 1.0)
{
// try to spawn a new one in its place
SpawnParticle(
clock.Now().Seconds(),
positions[i],
directions[i],
ages[i],
ids[i]
);
}
else
{
// otherwise just update its motion
directions[i] *= (1.0 - drag);
positions[i] += directions[i] * time_diff;
}
}
Vec3f position;
Vec3f direction;
float age;
int id;
// spawn new particles if necessary
while(SpawnParticle(clock.Now().Seconds(), position, direction, age, id))
{
positions.push_back(position);
directions.push_back(direction);
ages.push_back(age);
ids.push_back(id);
}
}
