Spectrum BSDF::evaluate_f(glm::vec3 outgoing_w, glm::vec3 incident_w) const {
//translate world coords to local hemisphere coords
glm::vec3 local_outgoing = world_to_local(outgoing_w);
glm::vec3 local_incident = world_to_local(incident_w);
Spectrum f;
for (int i = 0; i < _brdf_count; ++i) {
f += _brdfs[i]->evaluate_f(local_outgoing, local_incident) * _brdf_scales[i];
}
return f;
}
float BSDF::calc_pdf(const glm::vec3 &outgoing_w, const glm::vec3 &incident_w) const {
glm::vec3 local_outgoing = world_to_local(outgoing_w);
glm::vec3 local_incident = world_to_local(incident_w);
float pdf = 0;
for (int i = 0; i < _brdf_count; ++i) {
pdf += _brdfs[i]->calc_pdf(local_outgoing, local_incident) * _brdf_scales[i];
}
if (_brdf_count == 0) {
return 1;
}
return pdf / _brdf_count;
}
int point_at_world(struct robot *robot, struct vect *point)
{
struct vect local_point;
world_to_local(robot, &local_point, point);
return point_at_local(&robot->turret, &local_point);
}
Spectrum BSDF::evaluate_sample_f(glm::vec3 outgoing_w, glm::vec3* incident_w, float u1, float u2, float* pdf) const {
assert(u1 <= 1.0);
if (_brdf_count < 1) {
return Spectrum(0, 0, 0);
}
int brdf_num = glm::round(u1 * (_brdf_count-1));
BRDF* brdf = _brdfs[brdf_num];
glm::vec3 local_outgoing = world_to_local(outgoing_w);
glm::vec3 local_incident;
Spectrum f = brdf->evaluate_sample_f(local_outgoing, &local_incident, u1, u2, pdf) * _brdf_scales[brdf_num];
*incident_w = local_to_world(local_incident);
return f;
}
void get_up_vector(struct robot *robot, struct vect *result)
{
struct vect up, local_up, forward, look;
up.x = robot->position2.position.x;
up.y = robot->position2.position.y;
up.z = 1;
world_to_local(robot, &local_up, &up);
forward.x = 0;
forward.y = -1;
forward.z = 0;
struct vect normalized_look;
rotate_vector(&look, &forward, &robot->turret.turret_rotation);
// printf("%f, %f, %f\n", look.x, look.y, look.z);
float normal;
struct vect right_vector, raw;
cross(&local_up, &look, &right_vector);
// printf("%f, %f, %f\n", right_vector.x, right_vector.y, right_vector.z);
// printf("%f\n", norm(&right_vector));
cross(&right_vector, &look, &raw);
// printf("%f, %f, %f\n", raw.x, raw.y, raw.z);
normal = norm(&raw);
result->x = raw.x / normal;
result->y = raw.y / normal;
result->z = raw.z / normal;
}