diff options
Diffstat (limited to 'intern/cycles')
-rw-r--r-- | intern/cycles/kernel/kernel_light.h | 32 | ||||
-rw-r--r-- | intern/cycles/kernel/kernel_light_common.h | 57 |
2 files changed, 81 insertions, 8 deletions
diff --git a/intern/cycles/kernel/kernel_light.h b/intern/cycles/kernel/kernel_light.h index 93b05f0ffce..f288ca3051a 100644 --- a/intern/cycles/kernel/kernel_light.h +++ b/intern/cycles/kernel/kernel_light.h @@ -119,11 +119,11 @@ ccl_device_inline bool lamp_light_sample( klight->area.axisu[0], klight->area.axisu[1], klight->area.axisu[2]); float3 axisv = make_float3( klight->area.axisv[0], klight->area.axisv[1], klight->area.axisv[2]); - float3 D = make_float3(klight->area.dir[0], klight->area.dir[1], klight->area.dir[2]); + float3 Ng = make_float3(klight->area.dir[0], klight->area.dir[1], klight->area.dir[2]); float invarea = fabsf(klight->area.invarea); bool is_round = (klight->area.invarea < 0.0f); - if (dot(ls->P - P, D) > 0.0f) { + if (dot(ls->P - P, Ng) > 0.0f) { return false; } @@ -135,15 +135,25 @@ ccl_device_inline bool lamp_light_sample( ls->pdf = invarea; } else { + float3 sample_axisu = axisu; + float3 sample_axisv = axisv; + + if (klight->area.tan_spread > 0.0f) { + if (!light_spread_clamp_area_light( + P, Ng, &ls->P, &sample_axisu, &sample_axisv, klight->area.tan_spread)) { + return false; + } + } + inplane = ls->P; - ls->pdf = rect_light_sample(P, &ls->P, axisu, axisv, randu, randv, true); + ls->pdf = rect_light_sample(P, &ls->P, sample_axisu, sample_axisv, randu, randv, true); inplane = ls->P - inplane; } ls->u = dot(inplane, axisu) * (1.0f / dot(axisu, axisu)) + 0.5f; ls->v = dot(inplane, axisv) * (1.0f / dot(axisv, axisv)) + 0.5f; - ls->Ng = D; + ls->Ng = Ng; ls->D = normalize_len(ls->P - P, &ls->t); ls->eval_fac = 0.25f * invarea; @@ -155,7 +165,7 @@ ccl_device_inline bool lamp_light_sample( } if (is_round) { - ls->pdf *= lamp_light_pdf(kg, D, -ls->D, ls->t); + ls->pdf *= lamp_light_pdf(kg, Ng, -ls->D, ls->t); } } } @@ -290,7 +300,17 @@ ccl_device bool lamp_light_eval( ls->pdf = invarea * lamp_light_pdf(kg, Ng, -D, ls->t); } else { - ls->pdf = rect_light_sample(P, &light_P, axisu, axisv, 0, 0, false); + float3 sample_axisu = axisu; + float3 sample_axisv = axisv; + + if (klight->area.tan_spread > 0.0f) { + if (!light_spread_clamp_area_light( + P, Ng, &light_P, &sample_axisu, &sample_axisv, klight->area.tan_spread)) { + return false; + } + } + + ls->pdf = rect_light_sample(P, &light_P, sample_axisu, sample_axisv, 0, 0, false); } ls->eval_fac = 0.25f * invarea; diff --git a/intern/cycles/kernel/kernel_light_common.h b/intern/cycles/kernel/kernel_light_common.h index 7efd1e74202..1f4aecc0b68 100644 --- a/intern/cycles/kernel/kernel_light_common.h +++ b/intern/cycles/kernel/kernel_light_common.h @@ -147,16 +147,69 @@ ccl_device float spot_light_attenuation(float3 dir, float spot_angle, float spot } ccl_device float light_spread_attenuation(const float3 D, - const float3 Ng, + const float3 lightNg, const float tan_spread, const float normalize_spread) { - const float cos_a = -dot(D, Ng); + /* Model a softbox grid, computing the ratio of light not hidden by the + * slats of the grid at a given angle. (seee D10594). */ + const float cos_a = -dot(D, lightNg); const float sin_a = safe_sqrtf(1.0f - sqr(cos_a)); const float tan_a = sin_a / cos_a; return max((1.0f - (tan_spread * tan_a)) * normalize_spread, 0.0f); } +/* Compute subset of area light that actually has an influence on the shading point, to + * reduce noise with low spread. */ +ccl_device bool light_spread_clamp_area_light(const float3 P, + const float3 lightNg, + float3 *lightP, + float3 *axisu, + float3 *axisv, + const float tan_spread) +{ + /* Closest point in area light plane and distance to that plane. */ + const float3 closest_P = P - dot(lightNg, P - *lightP) * lightNg; + const float t = len(closest_P - P); + + /* Radius of circle on area light that actually affects the shading point. */ + const float radius = t / tan_spread; + + /* TODO: would be faster to store as normalized vector + length, also in rect_light_sample. */ + float len_u, len_v; + const float3 u = normalize_len(*axisu, &len_u); + const float3 v = normalize_len(*axisv, &len_v); + + /* Local uv coordinates of closest point. */ + const float closest_u = dot(u, closest_P - *lightP); + const float closest_v = dot(v, closest_P - *lightP); + + /* Compute rectangle encompassing the circle that affects the shading point, + * clamped to the bounds of the area light. */ + const float min_u = max(closest_u - radius, -len_u * 0.5f); + const float max_u = min(closest_u + radius, len_u * 0.5f); + const float min_v = max(closest_v - radius, -len_v * 0.5f); + const float max_v = min(closest_v + radius, len_v * 0.5f); + + /* Skip if rectangle is empty. */ + if (min_u >= max_u || min_v >= max_v) { + return false; + } + + /* Compute new area light center position and axes from rectangle in local + * uv coordinates. */ + const float new_center_u = 0.5f * (min_u + max_u); + const float new_center_v = 0.5f * (min_v + max_v); + const float new_len_u = 0.5f * (max_u - min_u); + const float new_len_v = 0.5f * (max_v - min_v); + + *lightP = *lightP + new_center_u * u + new_center_v * v; + *axisu = u * new_len_u * 2.0f; + *axisv = v * new_len_v * 2.0f; + + return true; +} + ccl_device float lamp_light_pdf(KernelGlobals *kg, const float3 Ng, const float3 I, float t) { float cos_pi = dot(Ng, I); |