diff options
| author | Brecht Van Lommel <brechtvanlommel@gmail.com> | 2017-09-08 02:42:14 +0300 |
|---|---|---|
| committer | Brecht Van Lommel <brechtvanlommel@gmail.com> | 2017-09-12 13:45:29 +0300 |
| commit | cd6c9e9e5f4726ab0b0b2c58249f98dab5c5d267 (patch) | |
| tree | c40d2b865394ed4cfe3b4da23e650c783d4578de /intern/cycles/kernel/split | |
| parent | d454a44e96649103772ae2c8707ee1ef5e46080c (diff) | |
Cycles: improve sample stratification on area lights for path tracing.
Previously we used a 1D sequence to select a light, and another 2D sequence
to sample a point on the light. For multiple lights this meant each light
would get a random subset of a 2D stratified sequence, which is not
guaranteed to be stratified anymore.
Now we use only a 2D sequence, split into segments along the X axis, one for
each light. The samples that fall within a segment then each are a stratified
sequence, at least in the limit. So for example for two lights, we split up
the unit square into two segments [0,0.5[ x [0,1[ and [0.5,1[ x [0,1[.
This doesn't make much difference in most scenes, mainly helps if you have a
few large area lights or some types of HDR backgrounds.
Diffstat (limited to 'intern/cycles/kernel/split')
| -rw-r--r-- | intern/cycles/kernel/split/kernel_direct_lighting.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/intern/cycles/kernel/split/kernel_direct_lighting.h b/intern/cycles/kernel/split/kernel_direct_lighting.h index 8e3f7555550..5009828df92 100644 --- a/intern/cycles/kernel/split/kernel_direct_lighting.h +++ b/intern/cycles/kernel/split/kernel_direct_lighting.h @@ -81,14 +81,13 @@ ccl_device void kernel_direct_lighting(KernelGlobals *kg, if(flag) { /* Sample illumination from lights to find path contribution. */ - float light_t = path_state_rng_1D(kg, state, PRNG_LIGHT); float light_u, light_v; path_state_rng_2D(kg, state, PRNG_LIGHT_U, &light_u, &light_v); float terminate = path_state_rng_light_termination(kg, state); LightSample ls; if(light_sample(kg, - light_t, light_u, light_v, + light_u, light_v, sd->time, sd->P, state->bounce, |