where: B(x)i dAi is the total energy leaving a small area dAi around a point x. E(x)i dAi is the emitted energy. ρ(x) is the reflectivity of the point, giving reflected energy per unit area by multiplying by the incident energy per unit area (the total energy which arrives from other patches). S denotes that the integration variable x' runs over all the surfaces in the scene r is the distance between x and x' θx and θx' are the angles between the line joining x and x' and vectors normal to the surface at x and x' respectively. Vis(x,x' ) is a visibility function, defined to be 1 if the two points x and x' are visible from each other, and 0 if they are not.
where: B(x)i dAi is the total energy leaving a small area dAi around a point x. E(x)i dAi is the emitted energy. ρ(x) is the reflectivity of the point, giving reflected energy per unit area by multiplying by the incident energy per unit area (the total energy which arrives from other patches). S denotes that the integration variable x' runs over all the surfaces in the scene r is the distance between x and x' θx and θx' are the angles between the line joining x and x' and vectors normal to the surface at x and x' respectively. Vis(x,x' ) is a visibility function, defined to be 1 if the two points x and x' are visible from each other, and 0 if they are not.