Differential D16655 Diff 58189 intern/cycles/kernel/light/sample.h

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intern/cycles/kernel/light/sample.h

/* SPDX-License-Identifier: Apache-2.0		/* SPDX-License-Identifier: Apache-2.0
* Copyright 2011-2022 Blender Foundation */		* Copyright 2011-2022 Blender Foundation */

#pragma once		#pragma once

#include "kernel/integrator/path_state.h"		#include "kernel/integrator/path_state.h"
#include "kernel/integrator/surface_shader.h"		#include "kernel/integrator/surface_shader.h"

		#include "kernel/light/distribution.h"
#include "kernel/light/light.h"		#include "kernel/light/light.h"

#include "kernel/sample/mapping.h"		#include "kernel/sample/mapping.h"
#include "kernel/sample/mis.h"		#include "kernel/sample/mis.h"

CCL_NAMESPACE_BEGIN		CCL_NAMESPACE_BEGIN

/* Evaluate shader on light. */		/* Evaluate shader on light. */
▲ Show 20 Lines • Show All 255 Lines • ▼ Show 20 Lines	ccl_device_inline void light_sample_to_volume_shadow_ray(
ccl_private const ShaderData *ccl_restrict sd,		ccl_private const ShaderData *ccl_restrict sd,
ccl_private const LightSample *ccl_restrict ls,		ccl_private const LightSample *ccl_restrict ls,
const float3 P,		const float3 P,
ccl_private Ray *ray)		ccl_private Ray *ray)
{		{
shadow_ray_setup(sd, ls, P, ray, false);		shadow_ray_setup(sd, ls, P, ray, false);
}		}

		/* Multiple importance sampling weights. */

ccl_device_inline float light_sample_mis_weight_forward(KernelGlobals kg,		ccl_device_inline float light_sample_mis_weight_forward(KernelGlobals kg,
const float forward_pdf,		const float forward_pdf,
const float nee_pdf)		const float nee_pdf)
{		{
#ifdef WITH_CYCLES_DEBUG		#ifdef WITH_CYCLES_DEBUG
if (kernel_data.integrator.direct_light_sampling_type == DIRECT_LIGHT_SAMPLING_FORWARD) {		if (kernel_data.integrator.direct_light_sampling_type == DIRECT_LIGHT_SAMPLING_FORWARD) {
return 1.0f;		return 1.0f;
}		}
Show All 16 Lines	#ifdef WITH_CYCLES_DEBUG
else if (kernel_data.integrator.direct_light_sampling_type == DIRECT_LIGHT_SAMPLING_NEE) {		else if (kernel_data.integrator.direct_light_sampling_type == DIRECT_LIGHT_SAMPLING_NEE) {
return 1.0f;		return 1.0f;
}		}
else		else
#endif		#endif
return power_heuristic(nee_pdf, forward_pdf);		return power_heuristic(nee_pdf, forward_pdf);
}		}

		/* Next event estimation sampling.
		*
		* Sample a position on a light in the scene, from a position on a surface or
		* from a volume segment. */

		ccl_device_inline bool light_sample_from_volume_segment(KernelGlobals kg,
		float randu,
		const float randv,
		const float time,
		const float3 P,
		const float3 D,
		const float t,
		const int bounce,
		const uint32_t path_flag,
		ccl_private LightSample *ls)
		{
		return light_distribution_sample<true>(kg, randu, randv, time, P, bounce, path_flag, ls);
		}

		ccl_device bool light_sample_from_position(KernelGlobals kg,
		ccl_private const RNGState *rng_state,
		const float randu,
		const float randv,
		const float time,
		const float3 P,
		const float3 N,
		const int shader_flags,
		const int bounce,
		const uint32_t path_flag,
		ccl_private LightSample *ls)
		{
		return light_distribution_sample<false>(kg, randu, randv, time, P, bounce, path_flag, ls);
		}

		ccl_device_inline bool light_sample_new_position(KernelGlobals kg,
		const float randu,
		const float randv,
		const float time,
		const float3 P,
		ccl_private LightSample *ls)
		{
		/* Sample a new position on the same light, for volume sampling. */
		if (ls->type == LIGHT_TRIANGLE) {
		if (!triangle_light_sample<false>(kg, ls->prim, ls->object, randu, randv, time, ls, P)) {
		return false;
		}
		return true;
		}
		else {
		if (!light_sample<false>(kg, ls->lamp, randu, randv, P, 0, ls)) {
		return false;
		}
		ls->pdf *= ls->pdf_selection;
		return true;
		}
		}

		ccl_device_forceinline void light_sample_update_position(KernelGlobals kg,
		ccl_private LightSample *ls,
		const float3 P)
		{
		/* Update light sample for new shading point position, while keeping
		* position on the light fixed. */

		/* NOTE : preserve pdf in area measure. */
		light_update_position(kg, ls, P);

		/* Re-apply already computed selection pdf. */
		ls->pdf *= ls->pdf_selection;
		}

		/* Forward sampling.
		*
		* Multiple importance sampling weights for hitting surface, light or background
		* through indirect light ray.
		*
		* The BSDF or phase pdf from the previous bounce was stored in mis_ray_pdf and
		* is used for balancing with the light sampling pdf. */

		ccl_device_inline float light_sample_mis_weight_forward_surface(KernelGlobals kg,
		IntegratorState state,
		const uint32_t path_flag,
		const ccl_private ShaderData *sd)
		{
		const float bsdf_pdf = INTEGRATOR_STATE(state, path, mis_ray_pdf);
		const float t = sd->ray_length;
		float pdf = triangle_light_pdf(kg, sd, t);

		/* Light selection pdf. */
		/* Handled in triangle_light_pdf for effeciency. */

		return light_sample_mis_weight_forward(kg, bsdf_pdf, pdf);
		}

		ccl_device_inline float light_sample_mis_weight_forward_lamp(KernelGlobals kg,
		IntegratorState state,
		const uint32_t path_flag,
		const ccl_private LightSample *ls,
		const float3 P)
		{
		const float mis_ray_pdf = INTEGRATOR_STATE(state, path, mis_ray_pdf);
		float pdf = ls->pdf;

		/* Light selection pdf. */
		pdf *= light_distribution_pdf_lamp(kg);

		return light_sample_mis_weight_forward(kg, mis_ray_pdf, pdf);
		}

		ccl_device_inline float light_sample_mis_weight_forward_distant(KernelGlobals kg,
		IntegratorState state,
		const uint32_t path_flag,
		const ccl_private LightSample *ls)
		{
		const float3 ray_P = INTEGRATOR_STATE(state, ray, P);
		return light_sample_mis_weight_forward_lamp(kg, state, path_flag, ls, ray_P);
		}

		ccl_device_inline float light_sample_mis_weight_forward_background(KernelGlobals kg,
		IntegratorState state,
		const uint32_t path_flag)
		{
		const float3 ray_P = INTEGRATOR_STATE(state, ray, P);
		const float3 ray_D = INTEGRATOR_STATE(state, ray, D);
		const float mis_ray_pdf = INTEGRATOR_STATE(state, path, mis_ray_pdf);

		float pdf = background_light_pdf(kg, ray_P, ray_D);

		/* Light selection pdf. */
		pdf *= light_distribution_pdf_lamp(kg);

		return light_sample_mis_weight_forward(kg, mis_ray_pdf, pdf);
		}

CCL_NAMESPACE_END		CCL_NAMESPACE_END