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Refactor: Cycles light sampling code reorganization

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* Split light types into own files, move light type specific code from
  light tree and MNEE.
* Move flat light distribution code into own kernel file and host side
  building function, in preparation of light tree addition. Add light/sample.h
  as main entry point to kernel light sampling.
* Better separate calculation of pdf for selecting a light, and pdf for
  sampling a point on the light. The selection pdf is now also stored in
  LightSampling for MNEE to correctly recalculate the full pdf when the
  shading position changes but the point on the light remains fixed.
* Improvement to kernel light storage, using packed_float3, better variable
  names, etc.

Includes contributions by Brecht Van Lommel and Weizhen Huang.

Ref T77889
This commit is contained in:
Brecht Van Lommel
2022-11-30 20:17:45 +01:00
parent db1728096a
commit ac51d331df
22 changed files with 1535 additions and 1287 deletions
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347
intern/cycles/scene/light.cpp
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@@ -263,30 +263,20 @@ bool LightManager::object_usable_as_light(Object *object)
return false;
}
void LightManager::device_update_distribution(Device *,
void LightManager::device_update_distribution(Device *device,
DeviceScene *dscene,
Scene *scene,
Progress &progress)
{
KernelIntegrator *kintegrator = &dscene->data.integrator;
KernelFilm *kfilm = &dscene->data.film;
/* Update CDF over lights. */
progress.set_status("Updating Lights", "Computing distribution");
/* count */
size_t num_lights = 0;
size_t num_portals = 0;
size_t num_background_lights = 0;
/* Counts emissive triangles in the scene. */
size_t num_triangles = 0;
bool background_mis = false;
foreach (Light *light, scene->lights) {
if (light->is_enabled) {
num_lights++;
}
if (light->is_portal) {
num_portals++;
}
}
foreach (Object *object, scene->objects) {
if (progress.get_cancel())
return;
@@ -295,9 +285,10 @@ void LightManager::device_update_distribution(Device *,
continue;
}
/* Count triangles. */
/* Count emissive triangles. */
Mesh *mesh = static_cast<Mesh *>(object->get_geometry());
size_t mesh_num_triangles = mesh->num_triangles();
for (size_t i = 0; i < mesh_num_triangles; i++) {
int shader_index = mesh->get_shader()[i];
Shader *shader = (shader_index < mesh->get_used_shaders().size()) ?
@@ -310,14 +301,20 @@ void LightManager::device_update_distribution(Device *,
}
}
size_t num_distribution = num_triangles + num_lights;
const size_t num_lights = kintegrator->num_lights;
const size_t num_background_lights = kintegrator->num_background_lights;
const size_t num_distribution = num_triangles + num_lights;
/* Distribution size. */
kintegrator->num_distribution = num_distribution;
VLOG_INFO << "Total " << num_distribution << " of light distribution primitives.";
/* emission area */
/* Emission area. */
KernelLightDistribution *distribution = dscene->light_distribution.alloc(num_distribution + 1);
float totarea = 0.0f;
/* triangles */
/* Triangles. */
size_t offset = 0;
int j = 0;
@@ -390,9 +387,9 @@ void LightManager::device_update_distribution(Device *,
j++;
}
float trianglearea = totarea;
/* point lights */
bool use_lamp_mis = false;
const float trianglearea = totarea;
/* Lights. */
int light_index = 0;
if (num_lights > 0) {
@@ -407,20 +404,6 @@ void LightManager::device_update_distribution(Device *,
distribution[offset].lamp.size = light->size;
totarea += lightarea;
if (light->light_type == LIGHT_DISTANT) {
use_lamp_mis |= (light->angle > 0.0f && light->use_mis);
}
else if (light->light_type == LIGHT_POINT || light->light_type == LIGHT_SPOT) {
use_lamp_mis |= (light->size > 0.0f && light->use_mis);
}
else if (light->light_type == LIGHT_AREA) {
use_lamp_mis |= light->use_mis;
}
else if (light->light_type == LIGHT_BACKGROUND) {
num_background_lights++;
background_mis |= light->use_mis;
}
light_index++;
offset++;
}
@@ -441,82 +424,42 @@ void LightManager::device_update_distribution(Device *,
if (progress.get_cancel())
return;
/* update device */
KernelIntegrator *kintegrator = &dscene->data.integrator;
KernelBackground *kbackground = &dscene->data.background;
KernelFilm *kfilm = &dscene->data.film;
/* Update integrator state. */
kintegrator->use_direct_light = (totarea > 0.0f);
if (kintegrator->use_direct_light) {
/* number of emissives */
kintegrator->num_distribution = num_distribution;
/* precompute pdfs */
kintegrator->pdf_triangles = 0.0f;
kintegrator->pdf_lights = 0.0f;
/* sample one, with 0.5 probability of light or triangle */
kintegrator->num_all_lights = num_lights;
if (trianglearea > 0.0f) {
kintegrator->pdf_triangles = 1.0f / trianglearea;
if (num_lights)
kintegrator->pdf_triangles *= 0.5f;
}
/* Precompute pdfs for distribution sampling.
* Sample one, with 0.5 probability of light or triangle. */
kintegrator->distribution_pdf_triangles = 0.0f;
kintegrator->distribution_pdf_lights = 0.0f;
if (trianglearea > 0.0f) {
kintegrator->distribution_pdf_triangles = 1.0f / trianglearea;
if (num_lights) {
kintegrator->pdf_lights = 1.0f / num_lights;
if (trianglearea > 0.0f)
kintegrator->pdf_lights *= 0.5f;
kintegrator->distribution_pdf_triangles *= 0.5f;
}
kintegrator->use_lamp_mis = use_lamp_mis;
/* bit of an ugly hack to compensate for emitting triangles influencing
* amount of samples we get for this pass */
kfilm->pass_shadow_scale = 1.0f;
if (kintegrator->pdf_triangles != 0.0f)
kfilm->pass_shadow_scale /= 0.5f;
if (num_background_lights < num_lights)
kfilm->pass_shadow_scale /= (float)(num_lights - num_background_lights) / (float)num_lights;
/* CDF */
dscene->light_distribution.copy_to_device();
/* Portals */
if (num_portals > 0) {
kbackground->portal_offset = light_index;
kbackground->num_portals = num_portals;
kbackground->portal_weight = 1.0f;
}
else {
kbackground->num_portals = 0;
kbackground->portal_offset = 0;
kbackground->portal_weight = 0.0f;
}
/* Map */
kbackground->map_weight = background_mis ? 1.0f : 0.0f;
}
else {
dscene->light_distribution.free();
kintegrator->num_distribution = 0;
kintegrator->num_all_lights = 0;
kintegrator->pdf_triangles = 0.0f;
kintegrator->pdf_lights = 0.0f;
kintegrator->use_lamp_mis = false;
kbackground->num_portals = 0;
kbackground->portal_offset = 0;
kbackground->portal_weight = 0.0f;
kbackground->sun_weight = 0.0f;
kbackground->map_weight = 0.0f;
kfilm->pass_shadow_scale = 1.0f;
if (num_lights) {
kintegrator->distribution_pdf_lights = 1.0f / num_lights;
if (trianglearea > 0.0f) {
kintegrator->distribution_pdf_lights *= 0.5f;
}
}
/* bit of an ugly hack to compensate for emitting triangles influencing
* amount of samples we get for this pass */
kfilm->pass_shadow_scale = 1.0f;
if (kintegrator->distribution_pdf_triangles != 0.0f) {
kfilm->pass_shadow_scale /= 0.5f;
}
if (num_background_lights < num_lights) {
kfilm->pass_shadow_scale /= (float)(num_lights - num_background_lights) / (float)num_lights;
}
/* Copy distribution to device. */
dscene->light_distribution.copy_to_device();
}
static void background_cdf(
@@ -564,31 +507,34 @@ void LightManager::device_update_background(Device *device,
Scene *scene,
Progress &progress)
{
KernelIntegrator *kintegrator = &dscene->data.integrator;
KernelBackground *kbackground = &dscene->data.background;
Light *background_light = NULL;
bool background_mis = false;
/* find background light */
foreach (Light *light, scene->lights) {
if (light->light_type == LIGHT_BACKGROUND) {
if (light->light_type == LIGHT_BACKGROUND && light->is_enabled) {
background_light = light;
break;
background_mis |= light->use_mis;
}
}
kbackground->portal_weight = kintegrator->num_portals > 0 ? 1.0f : 0.0f;
kbackground->map_weight = background_mis ? 1.0f : 0.0f;
kbackground->sun_weight = 0.0f;
/* no background light found, signal renderer to skip sampling */
if (!background_light || !background_light->is_enabled) {
kbackground->map_res_x = 0;
kbackground->map_res_y = 0;
kbackground->map_weight = 0.0f;
kbackground->sun_weight = 0.0f;
kbackground->use_mis = (kbackground->portal_weight > 0.0f);
return;
}
progress.set_status("Updating Lights", "Importance map");
assert(dscene->data.integrator.use_direct_light);
int2 environment_res = make_int2(0, 0);
Shader *shader = scene->background->get_shader(scene);
int num_suns = 0;
@@ -632,6 +578,7 @@ void LightManager::device_update_background(Device *device,
kbackground->sun = make_float4(
sun_direction.x, sun_direction.y, sun_direction.z, half_angle);
/* empirical value */
kbackground->sun_weight = 4.0f;
environment_res.x = max(environment_res.x, 512);
environment_res.y = max(environment_res.y, 256);
@@ -714,27 +661,83 @@ void LightManager::device_update_background(Device *device,
dscene->light_background_conditional_cdf.copy_to_device();
}
void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *scene)
void LightManager::device_update_lights(Device *, DeviceScene *dscene, Scene *scene)
{
int num_scene_lights = scene->lights.size();
/* Counts lights in the scene. */
size_t num_lights = 0;
size_t num_portals = 0;
size_t num_background_lights = 0;
size_t num_distant_lights = 0;
bool use_light_mis = false;
int num_lights = 0;
foreach (Light *light, scene->lights) {
if (light->is_enabled || light->is_portal) {
if (light->is_enabled) {
num_lights++;
if (light->light_type == LIGHT_DISTANT) {
num_distant_lights++;
}
else if (light->light_type == LIGHT_POINT || light->light_type == LIGHT_SPOT) {
use_light_mis |= (light->size > 0.0f && light->use_mis);
}
else if (light->light_type == LIGHT_AREA) {
use_light_mis |= light->use_mis;
}
else if (light->light_type == LIGHT_BACKGROUND) {
num_distant_lights++;
num_background_lights++;
}
}
if (light->is_portal) {
num_portals++;
}
}
KernelLight *klights = dscene->lights.alloc(num_lights);
/* Update integrator settings. */
KernelIntegrator *kintegrator = &dscene->data.integrator;
kintegrator->num_lights = num_lights;
kintegrator->num_distant_lights = num_distant_lights;
kintegrator->num_background_lights = num_background_lights;
kintegrator->use_light_mis = use_light_mis;
if (num_lights == 0) {
VLOG_WORK << "No effective light, ignoring points update.";
return;
}
kintegrator->num_portals = num_portals;
kintegrator->portal_offset = num_lights;
/* Create KernelLight for every portal and enabled light in the scene. */
KernelLight *klights = dscene->lights.alloc(num_lights + num_portals);
int light_index = 0;
int portal_index = num_lights;
foreach (Light *light, scene->lights) {
/* Consider moving portals update to their own function
* keeping this one more manageable. */
if (light->is_portal) {
assert(light->light_type == LIGHT_AREA);
float3 extentu = light->axisu * (light->sizeu * light->size);
float3 extentv = light->axisv * (light->sizev * light->size);
float area = len(extentu) * len(extentv);
if (light->round) {
area *= -M_PI_4_F;
}
float invarea = (area != 0.0f) ? 1.0f / area : 1.0f;
float3 dir = light->dir;
dir = safe_normalize(dir);
klights[portal_index].co = light->co;
klights[portal_index].area.extentu = extentu;
klights[portal_index].area.extentv = extentv;
klights[portal_index].area.invarea = invarea;
klights[portal_index].area.dir = dir;
klights[portal_index].tfm = light->tfm;
klights[portal_index].itfm = transform_inverse(light->tfm);
portal_index++;
continue;
}
if (!light->is_enabled) {
continue;
}
@@ -781,10 +784,7 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
if (light->use_mis && radius > 0.0f)
shader_id |= SHADER_USE_MIS;
klights[light_index].co[0] = co.x;
klights[light_index].co[1] = co.y;
klights[light_index].co[2] = co.z;
klights[light_index].co = co;
klights[light_index].spot.radius = radius;
klights[light_index].spot.invarea = invarea;
}
@@ -803,10 +803,7 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
if (light->use_mis && area > 0.0f)
shader_id |= SHADER_USE_MIS;
klights[light_index].co[0] = dir.x;
klights[light_index].co[1] = dir.y;
klights[light_index].co[2] = dir.z;
klights[light_index].co = dir;
klights[light_index].distant.invarea = invarea;
klights[light_index].distant.radius = radius;
klights[light_index].distant.cosangle = cosangle;
@@ -814,6 +811,8 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
else if (light->light_type == LIGHT_BACKGROUND) {
uint visibility = scene->background->get_visibility();
dscene->data.background.light_index = light_index;
shader_id &= ~SHADER_AREA_LIGHT;
shader_id |= SHADER_USE_MIS;
@@ -831,9 +830,9 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
}
}
else if (light->light_type == LIGHT_AREA) {
float3 axisu = light->axisu * (light->sizeu * light->size);
float3 axisv = light->axisv * (light->sizev * light->size);
float area = len(axisu) * len(axisv);
float3 extentu = light->axisu * (light->sizeu * light->size);
float3 extentv = light->axisv * (light->sizev * light->size);
float area = len(extentu) * len(extentv);
if (light->round) {
area *= -M_PI_4_F;
}
@@ -854,20 +853,11 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
if (light->use_mis && area != 0.0f)
shader_id |= SHADER_USE_MIS;
klights[light_index].co[0] = co.x;
klights[light_index].co[1] = co.y;
klights[light_index].co[2] = co.z;
klights[light_index].area.axisu[0] = axisu.x;
klights[light_index].area.axisu[1] = axisu.y;
klights[light_index].area.axisu[2] = axisu.z;
klights[light_index].area.axisv[0] = axisv.x;
klights[light_index].area.axisv[1] = axisv.y;
klights[light_index].area.axisv[2] = axisv.z;
klights[light_index].co = co;
klights[light_index].area.extentu = extentu;
klights[light_index].area.extentv = extentv;
klights[light_index].area.invarea = invarea;
klights[light_index].area.dir[0] = dir.x;
klights[light_index].area.dir[1] = dir.y;
klights[light_index].area.dir[2] = dir.z;
klights[light_index].area.dir = dir;
klights[light_index].area.tan_spread = tan_spread;
klights[light_index].area.normalize_spread = normalize_spread;
}
@@ -876,8 +866,8 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
float radius = light->size;
float invarea = (radius > 0.0f) ? 1.0f / (M_PI_F * radius * radius) : 1.0f;
float spot_angle = cosf(light->spot_angle * 0.5f);
float spot_smooth = (1.0f - spot_angle) * light->spot_smooth;
float cos_half_spot_angle = cosf(light->spot_angle * 0.5f);
float spot_smooth = (1.0f - cos_half_spot_angle) * light->spot_smooth;
float3 dir = light->dir;
dir = safe_normalize(dir);
@@ -885,17 +875,12 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
if (light->use_mis && radius > 0.0f)
shader_id |= SHADER_USE_MIS;
klights[light_index].co[0] = co.x;
klights[light_index].co[1] = co.y;
klights[light_index].co[2] = co.z;
klights[light_index].co = co;
klights[light_index].spot.radius = radius;
klights[light_index].spot.invarea = invarea;
klights[light_index].spot.spot_angle = spot_angle;
klights[light_index].spot.cos_half_spot_angle = cos_half_spot_angle;
klights[light_index].spot.spot_smooth = spot_smooth;
klights[light_index].spot.dir[0] = dir.x;
klights[light_index].spot.dir[1] = dir.y;
klights[light_index].spot.dir[2] = dir.z;
klights[light_index].spot.dir = dir;
}
klights[light_index].shader_id = shader_id;
@@ -918,49 +903,7 @@ void LightManager::device_update_points(Device *, DeviceScene *dscene, Scene *sc
light_index++;
}
/* TODO(sergey): Consider moving portals update to their own function
* keeping this one more manageable.
*/
foreach (Light *light, scene->lights) {
if (!light->is_portal)
continue;
assert(light->light_type == LIGHT_AREA);
float3 co = light->co;
float3 axisu = light->axisu * (light->sizeu * light->size);
float3 axisv = light->axisv * (light->sizev * light->size);
float area = len(axisu) * len(axisv);
if (light->round) {
area *= -M_PI_4_F;
}
float invarea = (area != 0.0f) ? 1.0f / area : 1.0f;
float3 dir = light->dir;
dir = safe_normalize(dir);
klights[light_index].co[0] = co.x;
klights[light_index].co[1] = co.y;
klights[light_index].co[2] = co.z;
klights[light_index].area.axisu[0] = axisu.x;
klights[light_index].area.axisu[1] = axisu.y;
klights[light_index].area.axisu[2] = axisu.z;
klights[light_index].area.axisv[0] = axisv.x;
klights[light_index].area.axisv[1] = axisv.y;
klights[light_index].area.axisv[2] = axisv.z;
klights[light_index].area.invarea = invarea;
klights[light_index].area.dir[0] = dir.x;
klights[light_index].area.dir[1] = dir.y;
klights[light_index].area.dir[2] = dir.z;
klights[light_index].tfm = light->tfm;
klights[light_index].itfm = transform_inverse(light->tfm);
light_index++;
}
VLOG_INFO << "Number of lights sent to the device: " << light_index;
VLOG_INFO << "Number of lights without contribution: " << num_scene_lights - light_index;
VLOG_INFO << "Number of lights sent to the device: " << num_lights;
dscene->lights.copy_to_device();
}
@@ -986,11 +929,7 @@ void LightManager::device_update(Device *device,
device_free(device, dscene, need_update_background);
device_update_points(device, dscene, scene);
if (progress.get_cancel())
return;
device_update_distribution(device, dscene, scene, progress);
device_update_lights(device, dscene, scene);
if (progress.get_cancel())
return;
@@ -1000,6 +939,10 @@ void LightManager::device_update(Device *device,
return;
}
device_update_distribution(device, dscene, scene, progress);
if (progress.get_cancel())
return;
device_update_ies(dscene);
if (progress.get_cancel())
return;