blender
/
blender
135
420
Fork 602
Code Issues 6.3k Pull Requests 768 Projects 19 Wiki Activity

Cycles: replace spot light disk sampling with sphere sampling #109329

Merged
Weizhen Huang merged 12 commits from weizhen/blender:spot_light_to_sphere_light_with_cone into main 2023-07-07 17:15:24 +02:00
Conversation 0 Commits 12 Files Changed 8 +35 -26
3 changed files with 35 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files
Showing only changes of commit 70dec4c747 - Show all commits

57
intern/cycles/kernel/light/spot.h
View File

@ -8,17 +8,34 @@
CCL_NAMESPACE_BEGIN
ccl_device float spot_light_attenuation(const ccl_global KernelSpotLight *spot, float3 ray)
/* Transform ray to spot light local coordinate system. */
ccl_device float3 spot_light_local_ray(const ccl_global KernelSpotLight *spot, const float3 ray)
{
const float3 scaled_ray = safe_normalize(make_float3(dot(ray, spot->scaled_axis_u),
dot(ray, spot->scaled_axis_v),
dot(ray, spot->dir * spot->inv_len_z)));
return safe_normalize(make_float3(dot(ray, spot->scaled_axis_u),
dot(ray, spot->scaled_axis_v),
dot(ray, spot->dir * spot->inv_len_z)));
}
return smoothstepf((scaled_ray.z - spot->cos_half_spot_angle) * spot->spot_smooth);
/* Compute spot light attenuation of a ray given in local coordinate system. */
ccl_device float spot_light_attenuation(const ccl_global KernelSpotLight *spot, const float3 ray)
{
return smoothstepf((ray.z - spot->cos_half_spot_angle) * spot->spot_smooth);
}
ccl_device void spot_light_uv(const float3 ray,
const float half_cot_half_spot_angle,
ccl_private float *u,
ccl_private float *v)
{
/* Ensures that the spot light projects the full image regarless of the spot angle. */
const float factor = half_cot_half_spot_angle / ray.z;
/* NOTE: Return barycentric coordinates in the same notation as Embree and OptiX. */
*u = ray.y * factor + 0.5f;
*v = -(ray.x + ray.y) * factor;
}
/* TODO: is attenuation needed inside the sphere? */
/* TODO: what's the expected behaviour of texturing? */
template<bool in_volume_segment>
ccl_device_inline bool spot_light_sample(const ccl_global KernelLight *klight,
const float2 rand,
@ -81,7 +98,8 @@ ccl_device_inline bool spot_light_sample(const ccl_global KernelLight *klight,
/* Already computed when sampling the spread cone. */
}
ls->eval_fac = klight->spot.eval_fac * spot_light_attenuation(&klight->spot, -ls->D);
const float3 local_ray = spot_light_local_ray(&klight->spot, -ls->D);
ls->eval_fac = klight->spot.eval_fac * spot_light_attenuation(&klight->spot, local_ray);
if (!in_volume_segment && ls->eval_fac == 0.0f) {
return false;
}
@ -98,11 +116,7 @@ ccl_device_inline bool spot_light_sample(const ccl_global KernelLight *klight,
ls->P = ls->Ng * radius + center;
}
const Transform itfm = klight->itfm;
const float2 uv = map_to_sphere(transform_direction(&itfm, ls->Ng));
/* NOTE: Return barycentric coordinates in the same notation as Embree and OptiX. */
ls->u = uv.y;
ls->v = 1.0f - uv.x - uv.y;
spot_light_uv(local_ray, klight->spot.half_cot_half_spot_angle, &ls->u, &ls->v);
return true;
}
@ -150,13 +164,9 @@ ccl_device_forceinline void spot_light_mnee_sample_update(const ccl_global Kerne
/* PDF does not change. */
}
const Transform itfm = klight->itfm;
const float2 uv = map_to_sphere(transform_direction(&itfm, ls->Ng));
/* NOTE: Return barycentric coordinates in the same notation as Embree and OptiX. */
ls->u = uv.y;
ls->v = 1.0f - uv.x - uv.y;
ls->eval_fac = klight->spot.eval_fac * spot_light_attenuation(&klight->spot, -ls->D);
const float3 local_ray = spot_light_local_ray(&klight->spot, -ls->D);
ls->eval_fac = klight->spot.eval_fac * spot_light_attenuation(&klight->spot, local_ray);
spot_light_uv(local_ray, klight->spot.half_cot_half_spot_angle, &ls->u, &ls->v);
}
ccl_device_inline bool spot_light_intersect(const ccl_global KernelLight *klight,
@ -181,7 +191,8 @@ ccl_device_inline bool spot_light_sample_from_intersection(
const uint32_t path_flag,
ccl_private LightSample *ccl_restrict ls)
{
ls->eval_fac = klight->spot.eval_fac * spot_light_attenuation(&klight->spot, -ray_D);
const float3 local_ray = spot_light_local_ray(&klight->spot, -ray_D);
ls->eval_fac = klight->spot.eval_fac * spot_light_attenuation(&klight->spot, local_ray);
if (ls->eval_fac == 0) {
return false;
}
@ -190,11 +201,7 @@ ccl_device_inline bool spot_light_sample_from_intersection(
ls->Ng = radius > 0 ? normalize(ls->P - klight->co) : -ray_D;
const Transform itfm = klight->itfm;
const float2 uv = map_to_sphere(transform_direction(&itfm, ls->Ng));
/* NOTE: Return barycentric coordinates in the same notation as Embree and OptiX. */
ls->u = uv.y;
ls->v = 1.0f - uv.x - uv.y;
spot_light_uv(local_ray, klight->spot.half_cot_half_spot_angle, &ls->u, &ls->v);
if (ls->t == FLT_MAX) {
ls->pdf = 0.0f;

3
intern/cycles/kernel/types.h
View File

@ -1356,9 +1356,10 @@ typedef struct KernelSpotLight {
float eval_fac;
packed_float3 dir;
float cos_half_spot_angle;
float half_cot_half_spot_angle;
float inv_len_z;
float spot_smooth;
float pad[2];
float pad;
} KernelSpotLight;
/* TODO: maybe rename spot to sphere */

1
intern/cycles/scene/light.cpp
View File

@ -1321,6 +1321,7 @@ void LightManager::device_update_lights(Device *device, DeviceScene *dscene, Sce
klights[light_index].spot.scaled_axis_v = scaled_axis_v;
klights[light_index].spot.dir = dir;
klights[light_index].spot.cos_half_spot_angle = cos_half_spot_angle;
klights[light_index].spot.half_cot_half_spot_angle = 0.5f / tanf(light->spot_angle * 0.5f);
klights[light_index].spot.inv_len_z = 1.0f / len_z;
klights[light_index].spot.spot_smooth = spot_smooth;
}