// Trace the path of a photon emitted from the given light source.
private void shootPhoton() {
// The three properties of this light.
Vector3 origin = current_light.getLocation();
Vector3 direction = current_light.getDirection();
photonColor photon = current_light.diffuse(0);
trace(origin, direction, photon, recursion_limit, Geometry.INDICE_VACUUM);
}
// Helps to reconfigure the coordinates.
// Returns the total attenuation.
private double light_line_helper(
double x1,
double x2,
double y1,
double y2,
boolean rotated,
boolean invert1,
photonColor photon_start) {
// Left End point calculations.
int x1_int = (int) x1;
int y1_int = (int) y1;
double per_x1_c = x1 - x1_int;
double per_y1_c = y1 - y1_int;
double per_x1 = 1 - per_x1_c;
double per_y1 = 1 - per_y1_c;
double scalar_1 = per_x1 * per_y1;
irradiance.addIrradiance(x1_int, y1_int, photon_start, scalar_1, rotated);
scalar_1 = per_x1 * per_y1_c;
irradiance.addIrradiance(x1_int, y1_int + 1, photon_start, scalar_1, rotated);
// Right End point calculations.
int x2_int = (int) x2;
int y2_int = (int) y2;
double per_x2_c = x2 - x2_int;
double per_y2_c = y2 - y2_int;
double per_y2 = 1 - per_y2_c;
double scalar_2 = per_x2_c * per_y2_c;
irradiance.addIrradiance(x2_int + 1, y2_int + 1, photon_start, scalar_2, rotated);
scalar_2 = per_x2_c * per_y2;
irradiance.addIrradiance(x2_int + 1, y2_int, photon_start, scalar_2, rotated);
// Draw the main body.
// ASSERT this is positive.
double dx = x2 - x1;
double dy = y2 - y1;
double distance = BryceMath.distance(x1, y1, x2, y2);
for (int x = x1_int + 1; x <= x2_int; x++) {
double percentage = (x - x1) / dx;
double y = y1 + dy * percentage;
int y_int = (int) y;
double per_y_c = y - y_int;
double per_y = 1 - per_y_c;
// An within pixel accuracy approximation for the attenuation.
// For more prescision, use the actual distance.
double partial_distance = invert1 ? (1 - percentage) * distance : percentage * distance;
double attenuation = current_light.attenuation(partial_distance);
irradiance.addIrradiance(x, y_int, photon_start, per_y * attenuation, rotated);
irradiance.addIrradiance(x, y_int + 1, photon_start, per_y_c * attenuation, rotated);
}
return current_light.attenuation(distance);
}
