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Lights: Option to use old point light falloff #117832

Merged
Brecht Van Lommel merged 14 commits from brecht/blender:point-sphere-light into blender-v4.1-release 2024-02-07 19:07:23 +01:00
Conversation 16 Commits 14 Files Changed 27 +190 -103
5 changed files with 190 additions and 103 deletions
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116
intern/cycles/kernel/light/point.h
View File

@ -24,41 +24,49 @@ ccl_device_inline bool point_light_sample(const ccl_global KernelLight *klight,
ls->eval_fac = klight->spot.eval_fac;
/* Spherical light geometry. */
float cos_theta;
if (d_sq > r_sq) {
/* Outside sphere. */
const float one_minus_cos = sin_sqr_to_one_minus_cos(r_sq / d_sq);
ls->D = sample_uniform_cone(-lightN, one_minus_cos, rand, &cos_theta, &ls->pdf);
}
else {
/* Inside sphere. */
const bool has_transmission = (shader_flags & SD_BSDF_HAS_TRANSMISSION);
if (has_transmission) {
ls->D = sample_uniform_sphere(rand);
ls->pdf = M_1_2PI_F * 0.5f;
if (klight->spot.is_sphere) {
/* Spherical light geometry. */
float cos_theta;
if (d_sq > r_sq) {
/* Outside sphere. */
const float one_minus_cos = sin_sqr_to_one_minus_cos(r_sq / d_sq);
ls->D = sample_uniform_cone(-lightN, one_minus_cos, rand, &cos_theta, &ls->pdf);
}
else {
sample_cos_hemisphere(N, rand, &ls->D, &ls->pdf);
/* Inside sphere. */
const bool has_transmission = (shader_flags & SD_BSDF_HAS_TRANSMISSION);
if (has_transmission) {
ls->D = sample_uniform_sphere(rand);
ls->pdf = M_1_2PI_F * 0.5f;
}
else {
sample_cos_hemisphere(N, rand, &ls->D, &ls->pdf);
}
cos_theta = -dot(ls->D, lightN);
}
cos_theta = -dot(ls->D, lightN);
}
/* Law of cosines. */
ls->t = d * cos_theta - copysignf(safe_sqrtf(r_sq - d_sq + d_sq * sqr(cos_theta)), d_sq - r_sq);
/* Law of cosines. */
ls->t = d * cos_theta -
copysignf(safe_sqrtf(r_sq - d_sq + d_sq * sqr(cos_theta)), d_sq - r_sq);
ls->P = P + ls->D * ls->t;
if (r_sq == 0) {
/* Use intensity instead of radiance for point light. */
ls->eval_fac /= sqr(ls->t);
/* `ls->Ng` is not well-defined for point light, so use the incoming direction instead. */
ls->Ng = -ls->D;
/* Remap sampled point onto the sphere to prevent precision issues with small radius. */
ls->P = P + ls->D * ls->t;
ls->Ng = normalize(ls->P - klight->co);
ls->P = ls->Ng * klight->spot.radius + klight->co;
}
else {
ls->Ng = normalize(ls->P - klight->co);
/* Remap sampled point onto the sphere to prevent precision issues with small radius. */
ls->P = ls->Ng * klight->spot.radius + klight->co;
/* Point light with ad-hoc radius based on orienteded disk. */
ls->P = klight->co;
if (r_sq > 0.0f) {
ls->P += disk_light_sample(lightN, rand) * klight->spot.radius;
}
ls->D = normalize_len(ls->P - P, &ls->t);
ls->Ng = -ls->D;
/* PDF. */
const float invarea = (r_sq > 0.0f) ? 1.0f / (r_sq * M_PI_F) : 1.0f;
ls->pdf = invarea * light_pdf_area_to_solid_angle(lightN, -ls->D, ls->t);
}
/* Texture coordinates. */
@ -92,7 +100,7 @@ ccl_device_forceinline void point_light_mnee_sample_update(const ccl_global Kern
const float radius = klight->spot.radius;
if (radius > 0) {
if (klight->spot.is_sphere) {
const float d_sq = len_squared(P - klight->co);
const float r_sq = sqr(radius);
const float t_sq = sqr(ls->t);
@ -126,8 +134,16 @@ ccl_device_inline bool point_light_intersect(const ccl_global KernelLight *kligh
return false;
}
float3 P;
return ray_sphere_intersect(ray->P, ray->D, ray->tmin, ray->tmax, klight->co, radius, &P, t);
if (klight->spot.is_sphere) {
float3 P;
return ray_sphere_intersect(ray->P, ray->D, ray->tmin, ray->tmax, klight->co, radius, &P, t);
}
else {
float3 P;
const float3 diskN = normalize(ray->P - klight->co);
return ray_disk_intersect(
ray->P, ray->D, ray->tmin, ray->tmax, klight->co, diskN, radius, &P, t);
}
}
ccl_device_inline bool point_light_sample_from_intersection(
@ -139,14 +155,24 @@ ccl_device_inline bool point_light_sample_from_intersection(
const uint32_t path_flag,
ccl_private LightSample *ccl_restrict ls)
{
const float radius = klight->spot.radius;
const float r_sq = sqr(klight->spot.radius);
ls->eval_fac = klight->spot.eval_fac;
if (radius > 0) {
if (klight->spot.is_sphere) {
const float d_sq = len_squared(ray_P - klight->co);
ls->pdf = point_light_pdf(d_sq, r_sq, N, ray_D, path_flag);
ls->Ng = normalize(ls->P - klight->co);
}
else {
if (ls->t != FLT_MAX) {
const float3 lightN = normalize(ray_P - klight->co);
const float invarea = (r_sq > 0.0f) ? 1.0f / (r_sq * M_PI_F) : 1.0f;
ls->pdf = invarea * light_pdf_area_to_solid_angle(lightN, -ray_D, ls->t);
}
else {
ls->pdf = 0.0f;
}
ls->Ng = -ray_D;
}
@ -178,16 +204,24 @@ ccl_device_forceinline bool point_light_tree_parameters(const ccl_global KernelL
const float radius = klight->spot.radius;
if (dist_point_to_centroid > radius) {
/* Equivalent to a disk light with the same angular span. */
cos_theta_u = cos_from_sin(radius / dist_point_to_centroid);
distance = dist_point_to_centroid * make_float2(1.0f / cos_theta_u, 1.0f);
if (klight->spot.is_sphere) {
if (dist_point_to_centroid > radius) {
/* Equivalent to a disk light with the same angular span. */
cos_theta_u = cos_from_sin(radius / dist_point_to_centroid);
distance = dist_point_to_centroid * make_float2(1.0f / cos_theta_u, 1.0f);
}
else {
/* Similar to background light. */
cos_theta_u = -1.0f;
/* HACK: pack radiance scaling in the distance. */
distance = one_float2() * radius / M_SQRT2_F;
}
}
else {
/* Similar to background light. */
cos_theta_u = -1.0f;
/* HACK: pack radiance scaling in the distance. */
distance = one_float2() * radius / M_SQRT2_F;
const float hypotenus = sqrtf(sqr(radius) + sqr(dist_point_to_centroid));
cos_theta_u = dist_point_to_centroid / hypotenus;
distance = make_float2(hypotenus, dist_point_to_centroid);
}
return true;

170
intern/cycles/kernel/light/spot.h
View File

@ -52,70 +52,96 @@ ccl_device_inline bool spot_light_sample(const ccl_global KernelLight *klight,
ls->eval_fac = klight->spot.eval_fac;
/* Spherical light geometry. */
float cos_theta;
ls->t = FLT_MAX;
if (d_sq > r_sq) {
/* Outside sphere. */
const float one_minus_cos_half_spot_spread = 1.0f - klight->spot.cos_half_spot_angle;
const float one_minus_cos_half_angle = sin_sqr_to_one_minus_cos(r_sq / d_sq);
if (klight->spot.is_sphere) {
/* Spherical light geometry. */
float cos_theta;
ls->t = FLT_MAX;
if (d_sq > r_sq) {
/* Outside sphere. */
const float one_minus_cos_half_spot_spread = 1.0f - klight->spot.cos_half_spot_angle;
const float one_minus_cos_half_angle = sin_sqr_to_one_minus_cos(r_sq / d_sq);
if (in_volume_segment || one_minus_cos_half_angle < one_minus_cos_half_spot_spread) {
/* Sample visible part of the sphere. */
ls->D = sample_uniform_cone(-lightN, one_minus_cos_half_angle, rand, &cos_theta, &ls->pdf);
}
else {
/* Sample spread cone. */
ls->D = sample_uniform_cone(
-klight->spot.dir, one_minus_cos_half_spot_spread, rand, &cos_theta, &ls->pdf);
if (in_volume_segment || one_minus_cos_half_angle < one_minus_cos_half_spot_spread) {
/* Sample visible part of the sphere. */
ls->D = sample_uniform_cone(-lightN, one_minus_cos_half_angle, rand, &cos_theta, &ls->pdf);
}
else {
/* Sample spread cone. */
ls->D = sample_uniform_cone(
-klight->spot.dir, one_minus_cos_half_spot_spread, rand, &cos_theta, &ls->pdf);
if (!ray_sphere_intersect(
P, ls->D, 0.0f, FLT_MAX, klight->co, klight->spot.radius, &ls->P, &ls->t))
{
/* Sampled direction does not intersect with the light. */
return false;
if (!ray_sphere_intersect(
P, ls->D, 0.0f, FLT_MAX, klight->co, klight->spot.radius, &ls->P, &ls->t))
{
/* Sampled direction does not intersect with the light. */
return false;
}
}
}
}
else {
/* Inside sphere. */
const bool has_transmission = (shader_flags & SD_BSDF_HAS_TRANSMISSION);
if (has_transmission) {
ls->D = sample_uniform_sphere(rand);
ls->pdf = M_1_2PI_F * 0.5f;
else {
/* Inside sphere. */
const bool has_transmission = (shader_flags & SD_BSDF_HAS_TRANSMISSION);
if (has_transmission) {
ls->D = sample_uniform_sphere(rand);
ls->pdf = M_1_2PI_F * 0.5f;
}
else {
sample_cos_hemisphere(N, rand, &ls->D, &ls->pdf);
}
cos_theta = -dot(ls->D, lightN);
}
/* Attenuation. */
const float3 local_ray = spot_light_to_local(&klight->spot, -ls->D);
if (d_sq > r_sq) {
ls->eval_fac *= spot_light_attenuation(&klight->spot, local_ray);
}
if (!in_volume_segment && ls->eval_fac == 0.0f) {
return false;
}
if (ls->t == FLT_MAX) {
/* Law of cosines. */
ls->t = d * cos_theta -
copysignf(safe_sqrtf(r_sq - d_sq + d_sq * sqr(cos_theta)), d_sq - r_sq);
ls->P = P + ls->D * ls->t;
}
else {
sample_cos_hemisphere(N, rand, &ls->D, &ls->pdf);
/* Already computed when sampling the spread cone. */
}
cos_theta = -dot(ls->D, lightN);
}
/* Attenuation. */
const float3 local_ray = spot_light_to_local(&klight->spot, -ls->D);
if (d_sq > r_sq) {
ls->eval_fac *= spot_light_attenuation(&klight->spot, local_ray);
}
if (!in_volume_segment && ls->eval_fac == 0.0f) {
return false;
}
/* Remap sampled point onto the sphere to prevent precision issues with small radius. */
ls->Ng = normalize(ls->P - klight->co);
ls->P = ls->Ng * klight->spot.radius + klight->co;
if (ls->t == FLT_MAX) {
/* Law of cosines. */
ls->t = d * cos_theta -
copysignf(safe_sqrtf(r_sq - d_sq + d_sq * sqr(cos_theta)), d_sq - r_sq);
ls->P = P + ls->D * ls->t;
/* Texture coordinates. */
spot_light_uv(local_ray, klight->spot.half_cot_half_spot_angle, &ls->u, &ls->v);
}
else {
/* Already computed when sampling the spread cone. */
/* Point light with ad-hoc radius based on orienteded disk. */
ls->P = klight->co;
if (r_sq > 0.0f) {
ls->P += disk_light_sample(lightN, rand) * klight->spot.radius;
}
ls->D = normalize_len(ls->P - P, &ls->t);
ls->Ng = -ls->D;
/* Attenuation. */
const float3 local_ray = spot_light_to_local(&klight->spot, -ls->D);
ls->eval_fac *= spot_light_attenuation(&klight->spot, local_ray);
if (!in_volume_segment && ls->eval_fac == 0.0f) {
return false;
}
/* PDF. */
const float invarea = (r_sq > 0.0f) ? 1.0f / (r_sq * M_PI_F) : 1.0f;
ls->pdf = invarea * light_pdf_area_to_solid_angle(lightN, -ls->D, ls->t);
/* Texture coordinates. */
spot_light_uv(local_ray, klight->spot.half_cot_half_spot_angle, &ls->u, &ls->v);
}
/* Remap sampled point onto the sphere to prevent precision issues with small radius. */
ls->Ng = normalize(ls->P - klight->co);
ls->P = ls->Ng * klight->spot.radius + klight->co;
/* Texture coordinates. */
spot_light_uv(local_ray, klight->spot.half_cot_half_spot_angle, &ls->u, &ls->v);
return true;
}
@ -147,7 +173,7 @@ ccl_device_forceinline void spot_light_mnee_sample_update(const ccl_global Kerne
const float radius = klight->spot.radius;
bool use_attenuation = true;
if (radius > 0) {
if (klight->spot.is_sphere) {
const float d_sq = len_squared(P - klight->co);
const float r_sq = sqr(radius);
const float t_sq = sqr(ls->t);
@ -203,16 +229,25 @@ ccl_device_inline bool spot_light_sample_from_intersection(
ls->eval_fac = klight->spot.eval_fac;
if (r_sq > 0) {
if (klight->spot.is_sphere) {
ls->pdf = spot_light_pdf(klight->spot.cos_half_spot_angle, d_sq, r_sq, N, ray_D, path_flag);
ls->Ng = normalize(ls->P - klight->co);
}
else {
if (ls->t != FLT_MAX) {
const float3 lightN = normalize(ray_P - klight->co);
const float invarea = (r_sq > 0.0f) ? 1.0f / (r_sq * M_PI_F) : 1.0f;
ls->pdf = invarea * light_pdf_area_to_solid_angle(lightN, -ray_D, ls->t);
}
else {
ls->pdf = 0.0f;
}
ls->Ng = -ray_D;
}
/* Attenuation. */
const float3 local_ray = spot_light_to_local(&klight->spot, -ray_D);
if (d_sq > r_sq) {
if (!klight->spot.is_sphere || d_sq > r_sq) {
ls->eval_fac *= spot_light_attenuation(&klight->spot, local_ray);
}
if (ls->eval_fac == 0) {
@ -238,16 +273,29 @@ ccl_device_forceinline bool spot_light_tree_parameters(const ccl_global KernelLi
const float radius = klight->spot.radius;
cos_theta_u = (dist_point_to_centroid > radius) ? cos_from_sin(radius / dist_point_to_centroid) :
-1.0f;
if (klight->spot.is_sphere) {
cos_theta_u = (dist_point_to_centroid > radius) ?
cos_from_sin(radius / dist_point_to_centroid) :
-1.0f;
if (in_volume_segment) {
return true;
if (in_volume_segment) {
return true;
}
distance = (dist_point_to_centroid > radius) ?
dist_point_to_centroid * make_float2(1.0f / cos_theta_u, 1.0f) :
one_float2() * radius / M_SQRT2_F;
}
else {
const float hypotenus = sqrtf(sqr(radius) + sqr(dist_point_to_centroid));
cos_theta_u = dist_point_to_centroid / hypotenus;
distance = (dist_point_to_centroid > radius) ?
dist_point_to_centroid * make_float2(1.0f / cos_theta_u, 1.0f) :
one_float2() * radius / M_SQRT2_F;
if (in_volume_segment) {
return true;
}
distance = make_float2(hypotenus, dist_point_to_centroid);
}
point_to_centroid = point_to_centroid_;
return true;

2
intern/cycles/kernel/types.h
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@ -1369,7 +1369,7 @@ typedef struct KernelSpotLight {
float half_cot_half_spot_angle;
float inv_len_z;
float spot_smooth;
float pad;
int is_sphere;
} KernelSpotLight;
/* PointLight is SpotLight with only radius and invarea being used. */

3
intern/cycles/scene/light.cpp
View File

@ -110,6 +110,8 @@ NODE_DEFINE(Light)
SOCKET_INT(map_resolution, "Map Resolution", 0);
SOCKET_FLOAT(average_radiance, "Average Radiance", 0.0f);
SOCKET_BOOLEAN(is_sphere, "Is Sphere", true);
SOCKET_FLOAT(spot_angle, "Spot Angle", M_PI_4_F);
SOCKET_FLOAT(spot_smooth, "Spot Smooth", 0.0f);
@ -1253,6 +1255,7 @@ void LightManager::device_update_lights(Device *device, DeviceScene *dscene, Sce
klights[light_index].co = light->get_co();
klights[light_index].spot.radius = radius;
klights[light_index].spot.eval_fac = eval_fac;
klights[light_index].spot.is_sphere = light->get_is_sphere() && radius != 0.0f;
}
else if (light->light_type == LIGHT_DISTANT) {
shader_id &= ~SHADER_AREA_LIGHT;

2
intern/cycles/scene/light.h
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@ -48,6 +48,8 @@ class Light : public Node {
NODE_SOCKET_API(int, map_resolution)
NODE_SOCKET_API(float, average_radiance)
NODE_SOCKET_API(bool, is_sphere)
NODE_SOCKET_API(float, spot_angle)
NODE_SOCKET_API(float, spot_smooth)