Differential D12888 Diff 43495 intern/cycles/kernel/integrator/integrator_subsurface_random_walk.h

Changeset View

Standalone View

intern/cycles/kernel/integrator/integrator_subsurface_random_walk.h

Show First 20 Lines • Show All 174 Lines • ▼ Show 20 Lines	ccl_device_forceinline float3 subsurface_random_walk_pdf(float3 sigma_t,
}		}
return hit ? T : sigma_t * T;		return hit ? T : sigma_t * T;
}		}

/* Define the below variable to get the similarity code active,		/* Define the below variable to get the similarity code active,
* and the value represents the cutoff level */		* and the value represents the cutoff level */
#define SUBSURFACE_RANDOM_WALK_SIMILARITY_LEVEL 9		#define SUBSURFACE_RANDOM_WALK_SIMILARITY_LEVEL 9

ccl_device_inline bool subsurface_random_walk(INTEGRATOR_STATE_ARGS,		ccl_device_inline bool subsurface_random_walk(KernelGlobals kg,
		IntegratorState state,
RNGState rng_state,		RNGState rng_state,
ccl_private Ray &ray,		ccl_private Ray &ray,
ccl_private LocalIntersection &ss_isect)		ccl_private LocalIntersection &ss_isect)
{		{
float bssrdf_u, bssrdf_v;		float bssrdf_u, bssrdf_v;
path_state_rng_2D(kg, &rng_state, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);		path_state_rng_2D(kg, &rng_state, PRNG_BSDF_U, &bssrdf_u, &bssrdf_v);

const float3 P = INTEGRATOR_STATE(ray, P);		const float3 P = INTEGRATOR_STATE(state, ray, P);
const float3 N = INTEGRATOR_STATE(ray, D);		const float3 N = INTEGRATOR_STATE(state, ray, D);
const float ray_dP = INTEGRATOR_STATE(ray, dP);		const float ray_dP = INTEGRATOR_STATE(state, ray, dP);
const float time = INTEGRATOR_STATE(ray, time);		const float time = INTEGRATOR_STATE(state, ray, time);
const float3 Ng = INTEGRATOR_STATE(isect, Ng);		const float3 Ng = INTEGRATOR_STATE(state, isect, Ng);
const int object = INTEGRATOR_STATE(isect, object);		const int object = INTEGRATOR_STATE(state, isect, object);

/* Sample diffuse surface scatter into the object. */		/* Sample diffuse surface scatter into the object. */
float3 D;		float3 D;
float pdf;		float pdf;
sample_cos_hemisphere(-N, bssrdf_u, bssrdf_v, &D, &pdf);		sample_cos_hemisphere(-N, bssrdf_u, bssrdf_v, &D, &pdf);
if (dot(-Ng, D) <= 0.0f) {		if (dot(-Ng, D) <= 0.0f) {
return false;		return false;
}		}
Show All 9 Lines
#ifndef __KERNEL_OPTIX__		#ifndef __KERNEL_OPTIX__
/* Compute or fetch object transforms. */		/* Compute or fetch object transforms. */
Transform ob_itfm ccl_optional_struct_init;		Transform ob_itfm ccl_optional_struct_init;
Transform ob_tfm = object_fetch_transform_motion_test(kg, object, time, &ob_itfm);		Transform ob_tfm = object_fetch_transform_motion_test(kg, object, time, &ob_itfm);
#endif		#endif

/* Convert subsurface to volume coefficients.		/* Convert subsurface to volume coefficients.
* The single-scattering albedo is named alpha to avoid confusion with the surface albedo. */		* The single-scattering albedo is named alpha to avoid confusion with the surface albedo. */
const float3 albedo = INTEGRATOR_STATE(subsurface, albedo);		const float3 albedo = INTEGRATOR_STATE(state, subsurface, albedo);
const float3 radius = INTEGRATOR_STATE(subsurface, radius);		const float3 radius = INTEGRATOR_STATE(state, subsurface, radius);
const float anisotropy = INTEGRATOR_STATE(subsurface, anisotropy);		const float anisotropy = INTEGRATOR_STATE(state, subsurface, anisotropy);

float3 sigma_t, alpha;		float3 sigma_t, alpha;
float3 throughput = INTEGRATOR_STATE_WRITE(path, throughput);		float3 throughput = INTEGRATOR_STATE_WRITE(state, path, throughput);
subsurface_random_walk_coefficients(albedo, radius, anisotropy, &sigma_t, &alpha, &throughput);		subsurface_random_walk_coefficients(albedo, radius, anisotropy, &sigma_t, &alpha, &throughput);
float3 sigma_s = sigma_t * alpha;		float3 sigma_s = sigma_t * alpha;

/* Theoretically it should be better to use the exact alpha for the channel we're sampling at		/* Theoretically it should be better to use the exact alpha for the channel we're sampling at
* each bounce, but in practice there doesn't seem to be a noticeable difference in exchange		* each bounce, but in practice there doesn't seem to be a noticeable difference in exchange
* for making the code significantly more complex and slower (if direction sampling depends on		* for making the code significantly more complex and slower (if direction sampling depends on
* the sampled channel, we need to compute its PDF per-channel and consider it for MIS later on).		* the sampled channel, we need to compute its PDF per-channel and consider it for MIS later on).
*		*
▲ Show 20 Lines • Show All 218 Lines • ▼ Show 20 Lines	else if (throughput.x < VOLUME_THROUGHPUT_EPSILON &&
throughput.z < VOLUME_THROUGHPUT_EPSILON) {		throughput.z < VOLUME_THROUGHPUT_EPSILON) {
/* Avoid unnecessary work and precision issue when throughput gets really small. */		/* Avoid unnecessary work and precision issue when throughput gets really small. */
break;		break;
}		}
}		}

if (hit) {		if (hit) {
kernel_assert(isfinite3_safe(throughput));		kernel_assert(isfinite3_safe(throughput));
INTEGRATOR_STATE_WRITE(path, throughput) = throughput;		INTEGRATOR_STATE_WRITE(state, path, throughput) = throughput;
}		}

return hit;		return hit;
}		}

CCL_NAMESPACE_END		CCL_NAMESPACE_END