130 lines
3.9 KiB
C++
130 lines
3.9 KiB
C++
/* SPDX-License-Identifier: Apache-2.0
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* Copyright 2011-2022 Blender Foundation */
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#pragma once
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#include "kernel/light/common.h"
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CCL_NAMESPACE_BEGIN
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template<bool in_volume_segment>
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ccl_device_inline bool point_light_sample(const ccl_global KernelLight *klight,
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const float2 rand,
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const float3 P,
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ccl_private LightSample *ls)
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{
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float3 center = klight->co;
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float radius = klight->spot.radius;
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/* disk oriented normal */
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const float3 lightN = normalize(P - center);
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ls->P = center;
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if (radius > 0.0f) {
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ls->P += disk_light_sample(lightN, rand) * radius;
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}
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ls->pdf = klight->spot.invarea;
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ls->D = normalize_len(ls->P - P, &ls->t);
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/* we set the light normal to the outgoing direction to support texturing */
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ls->Ng = -ls->D;
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ls->eval_fac = M_1_PI_F * 0.25f * klight->spot.invarea;
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float2 uv = map_to_sphere(ls->Ng);
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ls->u = uv.x;
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ls->v = uv.y;
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ls->pdf *= lamp_light_pdf(lightN, -ls->D, ls->t);
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return true;
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}
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ccl_device_forceinline void point_light_mnee_sample_update(const ccl_global KernelLight *klight,
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ccl_private LightSample *ls,
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const float3 P)
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{
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ls->D = normalize_len(ls->P - P, &ls->t);
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ls->Ng = -ls->D;
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float2 uv = map_to_sphere(ls->Ng);
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ls->u = uv.x;
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ls->v = uv.y;
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float invarea = klight->spot.invarea;
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ls->eval_fac = (0.25f * M_1_PI_F) * invarea;
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/* NOTE : preserve pdf in area measure. */
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ls->pdf = invarea;
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}
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ccl_device_inline bool point_light_intersect(const ccl_global KernelLight *klight,
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const ccl_private Ray *ccl_restrict ray,
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ccl_private float *t)
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{
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/* Sphere light (aka, aligned disk light). */
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const float3 lightP = klight->co;
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const float radius = klight->spot.radius;
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if (radius == 0.0f) {
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return false;
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}
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/* disk oriented normal */
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const float3 lightN = normalize(ray->P - lightP);
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float3 P;
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return ray_disk_intersect(ray->P, ray->D, ray->tmin, ray->tmax, lightP, lightN, radius, &P, t);
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}
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ccl_device_inline bool point_light_sample_from_intersection(
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const ccl_global KernelLight *klight,
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ccl_private const Intersection *ccl_restrict isect,
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const float3 ray_P,
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const float3 ray_D,
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ccl_private LightSample *ccl_restrict ls)
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{
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const float3 lighN = normalize(ray_P - klight->co);
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/* We set the light normal to the outgoing direction to support texturing. */
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ls->Ng = -ls->D;
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float invarea = klight->spot.invarea;
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ls->eval_fac = (0.25f * M_1_PI_F) * invarea;
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ls->pdf = invarea;
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float2 uv = map_to_sphere(ls->Ng);
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ls->u = uv.x;
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ls->v = uv.y;
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/* compute pdf */
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if (ls->t != FLT_MAX) {
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ls->pdf *= lamp_light_pdf(lighN, -ls->D, ls->t);
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}
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else {
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ls->pdf = 0.f;
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}
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return true;
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}
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template<bool in_volume_segment>
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ccl_device_forceinline bool point_light_tree_parameters(const ccl_global KernelLight *klight,
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const float3 centroid,
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const float3 P,
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ccl_private float &cos_theta_u,
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ccl_private float2 &distance,
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ccl_private float3 &point_to_centroid)
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{
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if (in_volume_segment) {
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cos_theta_u = 1.0f; /* Any value in [-1, 1], irrelevant since theta = 0 */
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return true;
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}
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float min_distance;
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point_to_centroid = safe_normalize_len(centroid - P, &min_distance);
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const float radius = klight->spot.radius;
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const float hypotenus = sqrtf(sqr(radius) + sqr(min_distance));
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cos_theta_u = min_distance / hypotenus;
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distance = make_float2(hypotenus, min_distance);
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return true;
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}
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CCL_NAMESPACE_END
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