diff options
author | Brecht Van Lommel <brechtvanlommel@gmail.com> | 2017-09-08 02:42:14 +0300 |
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committer | Brecht Van Lommel <brechtvanlommel@gmail.com> | 2017-09-12 13:45:29 +0300 |
commit | cd6c9e9e5f4726ab0b0b2c58249f98dab5c5d267 (patch) | |
tree | c40d2b865394ed4cfe3b4da23e650c783d4578de /intern/cycles/kernel/kernel_path_volume.h | |
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/kernel_path_volume.h')
-rw-r--r-- | intern/cycles/kernel/kernel_path_volume.h | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/intern/cycles/kernel/kernel_path_volume.h b/intern/cycles/kernel/kernel_path_volume.h index c9c7f447c42..fb6b8d56a38 100644 --- a/intern/cycles/kernel/kernel_path_volume.h +++ b/intern/cycles/kernel/kernel_path_volume.h @@ -31,7 +31,6 @@ ccl_device_inline void kernel_path_volume_connect_light( return; /* 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); @@ -45,7 +44,7 @@ ccl_device_inline void kernel_path_volume_connect_light( light_ray.time = sd->time; # endif - if(light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) + if(light_sample(kg, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) { float terminate = path_state_rng_light_termination(kg, state); if(direct_emission(kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate)) { @@ -195,16 +194,15 @@ ccl_device void kernel_branched_path_volume_connect_light( for(int j = 0; j < num_samples; j++) { /* sample random position on random triangle */ - float light_t = path_branched_rng_1D_for_decision(kg, state->rng_hash, state, j, num_samples, PRNG_LIGHT); float light_u, light_v; path_branched_rng_2D(kg, state->rng_hash, state, j, num_samples, PRNG_LIGHT_U, &light_u, &light_v); /* only sample triangle lights */ if(kernel_data.integrator.num_all_lights) - light_t = 0.5f*light_t; + light_u = 0.5f*light_u; LightSample ls; - light_sample(kg, light_t, light_u, light_v, sd->time, ray->P, state->bounce, &ls); + light_sample(kg, light_u, light_v, sd->time, ray->P, state->bounce, &ls); float3 tp = throughput; @@ -219,7 +217,7 @@ ccl_device void kernel_branched_path_volume_connect_light( kernel_assert(result == VOLUME_PATH_SCATTERED); /* todo: split up light_sample so we don't have to call it again with new position */ - if(light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) { + if(light_sample(kg, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) { if(kernel_data.integrator.num_all_lights) ls.pdf *= 2.0f; @@ -239,12 +237,11 @@ ccl_device void kernel_branched_path_volume_connect_light( } else { /* sample random position on random light */ - 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); LightSample ls; - light_sample(kg, light_t, light_u, light_v, sd->time, ray->P, state->bounce, &ls); + light_sample(kg, light_u, light_v, sd->time, ray->P, state->bounce, &ls); float3 tp = throughput; @@ -259,7 +256,7 @@ ccl_device void kernel_branched_path_volume_connect_light( kernel_assert(result == VOLUME_PATH_SCATTERED); /* todo: split up light_sample so we don't have to call it again with new position */ - if(light_sample(kg, light_t, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) { + if(light_sample(kg, light_u, light_v, sd->time, sd->P, state->bounce, &ls)) { /* sample random light */ float terminate = path_state_rng_light_termination(kg, state); if(direct_emission(kg, sd, emission_sd, &ls, state, &light_ray, &L_light, &is_lamp, terminate)) { |