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

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intern/cycles/kernel/light/spot.h

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

				#pragma once

				#include "kernel/light/common.h"

				CCL_NAMESPACE_BEGIN

				ccl_device float spot_light_attenuation(float3 dir,
				float cos_half_spot_angle,
				float spot_smooth,
				float3 N)
				{
				float attenuation = dot(dir, N);

				if (attenuation <= cos_half_spot_angle) {
				attenuation = 0.0f;
				}
				else {
				float t = attenuation - cos_half_spot_angle;

				if (t < spot_smooth && spot_smooth != 0.0f)
				attenuation *= smoothstepf(t / spot_smooth);
				}

				return attenuation;
				}

				template<bool in_volume_segment>
				ccl_device_inline bool spot_light_sample(const ccl_global KernelLight *klight,
				const float randu,
				const float randv,
				const float3 P,
				ccl_private LightSample *ls)
				{
				ls->P = klight->co;

				const float3 center = klight->co;
				const float radius = klight->spot.radius;
				/* disk oriented normal */
				const float3 lightN = normalize(P - center);
				ls->P = center;

				if (radius > 0.0f) {
				/* disk light */
				ls->P += disk_light_sample(lightN, randu, randv) * radius;
				}

				const float invarea = klight->spot.invarea;
				ls->pdf = invarea;

				ls->D = normalize_len(ls->P - P, &ls->t);
				/* we set the light normal to the outgoing direction to support texturing */
				ls->Ng = -ls->D;

				ls->eval_fac = (0.25f * M_1_PI_F) * invarea;

				/* spot light attenuation */
				ls->eval_fac *= spot_light_attenuation(
				klight->spot.dir, klight->spot.cos_half_spot_angle, klight->spot.spot_smooth, -ls->D);
				if (!in_volume_segment && ls->eval_fac == 0.0f) {
				return false;
				}

				float2 uv = map_to_sphere(ls->Ng);
				ls->u = uv.x;
				ls->v = uv.y;

				ls->pdf *= lamp_light_pdf(lightN, -ls->D, ls->t);
				return true;
				}

				ccl_device_forceinline void spot_light_update_position(const ccl_global KernelLight *klight,
				ccl_private LightSample *ls,
				const float3 P)
				{
				ls->D = normalize_len(ls->P - P, &ls->t);
				ls->Ng = -ls->D;

				float2 uv = map_to_sphere(ls->Ng);
				ls->u = uv.x;
				ls->v = uv.y;

				float invarea = klight->spot.invarea;
				ls->eval_fac = (0.25f * M_1_PI_F) * invarea;
				ls->pdf = invarea;

				/* spot light attenuation */
				ls->eval_fac *= spot_light_attenuation(
				klight->spot.dir, klight->spot.cos_half_spot_angle, klight->spot.spot_smooth, ls->Ng);
				}

				ccl_device_inline bool spot_light_intersect(const ccl_global KernelLight *klight,
				const ccl_private Ray *ccl_restrict ray,
				ccl_private float *t)
				{
				/* Spot/Disk light. */
				const float3 lightP = klight->co;
				const float radius = klight->spot.radius;
				if (radius == 0.0f) {
				return false;
				}
				/* disk oriented normal */
				const float3 lightN = normalize(ray->P - lightP);
				/* One sided. */
				if (dot(ray->D, lightN) >= 0.0f) {
				return false;
				}

				float3 P;
				return ray_disk_intersect(ray->P, ray->D, ray->tmin, ray->tmax, lightP, lightN, radius, &P, t);
				}

				ccl_device_inline bool spot_light_sample_from_intersection(
				const ccl_global KernelLight *klight,
				ccl_private const Intersection *ccl_restrict isect,
				const float3 ray_P,
				const float3 ray_D,
				ccl_private LightSample *ccl_restrict ls)
				{
				/* the normal of the oriented disk */
				const float3 lightN = normalize(ray_P - klight->co);
				/* We set the light normal to the outgoing direction to support texturing. */
				ls->Ng = -ls->D;

				float invarea = klight->spot.invarea;
				ls->eval_fac = (0.25f * M_1_PI_F) * invarea;
				ls->pdf = invarea;

				/* spot light attenuation */
				ls->eval_fac *= spot_light_attenuation(
				klight->spot.dir, klight->spot.cos_half_spot_angle, klight->spot.spot_smooth, -ls->D);

				if (ls->eval_fac == 0.0f) {
				return false;
				}

				float2 uv = map_to_sphere(ls->Ng);
				ls->u = uv.x;
				ls->v = uv.y;

				/* compute pdf */
				if (ls->t != FLT_MAX) {
				ls->pdf *= lamp_light_pdf(lightN, -ls->D, ls->t);
				}
				else {
				ls->pdf = 0.f;
				}

				return true;
				}
				CCL_NAMESPACE_END