diff options
| -rw-r--r-- | intern/cycles/blender/addon/properties.py | 12 | ||||
| -rw-r--r-- | intern/cycles/blender/addon/ui.py | 4 | ||||
| -rw-r--r-- | intern/cycles/blender/blender_sync.cpp | 1 | ||||
| -rw-r--r-- | intern/cycles/kernel/kernel_types.h | 3 | ||||
| -rw-r--r-- | intern/cycles/kernel/kernel_volume.h | 77 | ||||
| -rw-r--r-- | intern/cycles/render/integrator.cpp | 3 | ||||
| -rw-r--r-- | intern/cycles/render/integrator.h | 1 |
7 files changed, 87 insertions, 14 deletions
diff --git a/intern/cycles/blender/addon/properties.py b/intern/cycles/blender/addon/properties.py index c80e8a3250c..3920510e38f 100644 --- a/intern/cycles/blender/addon/properties.py +++ b/intern/cycles/blender/addon/properties.py @@ -107,6 +107,11 @@ enum_integrator = ( ('BRANCHED_PATH', "Branched Path Tracing", "Path tracing integrator that branches on the first bounce, giving more control over the number of light and material samples"), ('PATH', "Path Tracing", "Pure path tracing integrator"), ) + +enum_volume_homogeneous_sampling = ( + ('DISTANCE', "Distance", "Use Distance Sampling"), + ('EQUI_ANGULAR', "Equi-angular", "Use Equi-angular Sampling"), + ) class CyclesRenderSettings(bpy.types.PropertyGroup): @@ -140,6 +145,13 @@ class CyclesRenderSettings(bpy.types.PropertyGroup): items=enum_integrator, default='PATH', ) + + cls.volume_homogeneous_sampling = EnumProperty( + name="Homogeneous Sampling", + description="Sampling method to use for homogeneous volumes", + items=enum_volume_homogeneous_sampling, + default='DISTANCE', + ) cls.use_square_samples = BoolProperty( name="Square Samples", diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py index c0ce80426c0..cb50db23767 100644 --- a/intern/cycles/blender/addon/ui.py +++ b/intern/cycles/blender/addon/ui.py @@ -167,6 +167,10 @@ class CyclesRender_PT_volume_sampling(CyclesButtonsPanel, Panel): scene = context.scene cscene = scene.cycles + layout.prop(cscene, "volume_homogeneous_sampling", text="Homogeneous") + + layout.label("Heterogeneous:") + split = layout.split() split.prop(cscene, "volume_step_size") split.prop(cscene, "volume_max_steps") diff --git a/intern/cycles/blender/blender_sync.cpp b/intern/cycles/blender/blender_sync.cpp index 8e2197a2aa6..1d507ed9b1d 100644 --- a/intern/cycles/blender/blender_sync.cpp +++ b/intern/cycles/blender/blender_sync.cpp @@ -172,6 +172,7 @@ void BlenderSync::sync_integrator() integrator->transparent_min_bounce = get_int(cscene, "transparent_min_bounces"); integrator->transparent_shadows = get_boolean(cscene, "use_transparent_shadows"); + integrator->volume_homogeneous_sampling = RNA_enum_get(&cscene, "volume_homogeneous_sampling"); integrator->volume_max_steps = get_int(cscene, "volume_max_steps"); integrator->volume_step_size = get_float(cscene, "volume_step_size"); diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h index 5ee25a6cb98..8d7adb2b6d7 100644 --- a/intern/cycles/kernel/kernel_types.h +++ b/intern/cycles/kernel/kernel_types.h @@ -824,7 +824,6 @@ typedef struct KernelIntegrator { /* clamp */ float sample_clamp_direct; float sample_clamp_indirect; - float pad1, pad2, pad3; /* branched path */ int branched; @@ -843,10 +842,12 @@ typedef struct KernelIntegrator { int sampling_pattern; /* volume render */ + int volume_homogeneous_sampling; int use_volumes; int volume_max_steps; float volume_step_size; int volume_samples; + int pad1, pad2; } KernelIntegrator; typedef struct KernelBVH { diff --git a/intern/cycles/kernel/kernel_volume.h b/intern/cycles/kernel/kernel_volume.h index dc2ddf1098e..4d058763f22 100644 --- a/intern/cycles/kernel/kernel_volume.h +++ b/intern/cycles/kernel/kernel_volume.h @@ -228,21 +228,72 @@ ccl_device VolumeIntegrateResult kernel_volume_integrate_homogeneous(KernelGloba else sample_sigma_t = sigma_t.z; - /* xi is [0, 1[ so log(0) should never happen, division by zero is - * avoided because sample_sigma_t > 0 when SD_SCATTER is set */ - float xi = path_state_rng_1D(kg, rng, state, PRNG_SCATTER_DISTANCE); - float sample_t = min(t, -logf(1.0f - xi)/sample_sigma_t); - - transmittance = volume_color_attenuation(sigma_t, sample_t); - - if(sample_t < t) { - float pdf = dot(sigma_t, transmittance); - new_tp = *throughput * coeff.sigma_s * transmittance * (3.0f / pdf); - t = sample_t; + /* distance sampling */ + if(kernel_data.integrator.volume_homogeneous_sampling == 0 || !kernel_data.integrator.num_all_lights) { + /* xi is [0, 1[ so log(0) should never happen, division by zero is + * avoided because sample_sigma_t > 0 when SD_SCATTER is set */ + float xi = path_state_rng_1D(kg, rng, state, PRNG_SCATTER_DISTANCE); + float sample_t = min(t, -logf(1.0f - xi)/sample_sigma_t); + + transmittance = volume_color_attenuation(sigma_t, sample_t); + + if(sample_t < t) { + float pdf = dot(sigma_t, transmittance); + new_tp = *throughput * coeff.sigma_s * transmittance * (3.0f / pdf); + t = sample_t; + } + else { + float pdf = (transmittance.x + transmittance.y + transmittance.z); + new_tp = *throughput * transmittance * (3.0f / pdf); + } } + /* equi-angular sampling */ else { - float pdf = (transmittance.x + transmittance.y + transmittance.z); - new_tp = *throughput * transmittance * (3.0f / pdf); + /* decide if we are going to scatter or not, based on sigma_t. this + * is not ideal, instead we should perhaps split the path here and + * do both, and at least add multiple importance sampling */ + float xi = path_state_rng_1D(kg, rng, state, PRNG_SCATTER_DISTANCE); + float sample_transmittance = expf(-sample_sigma_t * t); + + if(xi < sample_transmittance) { + /* no scattering */ + float3 transmittance = volume_color_attenuation(sigma_t, t); + float pdf = (transmittance.x + transmittance.y + transmittance.z); + new_tp = *throughput * transmittance * (3.0f / pdf); + } + else { + /* rescale random number so we can reuse it */ + xi = (xi - sample_transmittance)/(1.0f - sample_transmittance); + + /* equi-angular scattering somewhere on segment 0..t */ + /* see "Importance Sampling Techniques for Path Tracing in Participating Media" */ + + /* light RNGs */ + float light_t = path_state_rng_1D(kg, rng, state, PRNG_LIGHT); + float light_u, light_v; + path_state_rng_2D(kg, rng, state, PRNG_LIGHT_U, &light_u, &light_v); + + /* light sample */ + LightSample ls; + light_sample(kg, light_t, light_u, light_v, ray->time, ray->P, &ls); + if(ls.pdf == 0.0f) + return VOLUME_PATH_MISSED; + + /* sampling */ + float delta = dot((ls.P - ray->P) , ray->D); + float D = sqrtf(len_squared(ls.P - ray->P) - delta * delta); + float theta_a = -atan2f(delta, D); + float theta_b = atan2f(t - delta, D); + float t_ = D * tan((xi * theta_b) + (1 - xi) * theta_a); + + float pdf = D / ((theta_b - theta_a) * (D * D + t_ * t_)); + float sample_t = min(t, delta + t_); + + transmittance = volume_color_attenuation(sigma_t, sample_t); + + new_tp = *throughput * coeff.sigma_s * transmittance / ((1.0f - sample_transmittance) * pdf); + t = sample_t; + } } } else if(closure_flag & SD_ABSORPTION) { diff --git a/intern/cycles/render/integrator.cpp b/intern/cycles/render/integrator.cpp index f48e04f31e1..5b26440594a 100644 --- a/intern/cycles/render/integrator.cpp +++ b/intern/cycles/render/integrator.cpp @@ -41,6 +41,7 @@ Integrator::Integrator() transparent_probalistic = true; transparent_shadows = false; + volume_homogeneous_sampling = 0; volume_max_steps = 1024; volume_step_size = 0.1; @@ -104,6 +105,7 @@ void Integrator::device_update(Device *device, DeviceScene *dscene, Scene *scene kintegrator->transparent_shadows = transparent_shadows; + kintegrator->volume_homogeneous_sampling = volume_homogeneous_sampling; kintegrator->volume_max_steps = volume_max_steps; kintegrator->volume_step_size = volume_step_size; @@ -176,6 +178,7 @@ bool Integrator::modified(const Integrator& integrator) transparent_max_bounce == integrator.transparent_max_bounce && transparent_probalistic == integrator.transparent_probalistic && transparent_shadows == integrator.transparent_shadows && + volume_homogeneous_sampling == integrator.volume_homogeneous_sampling && volume_max_steps == integrator.volume_max_steps && volume_step_size == integrator.volume_step_size && no_caustics == integrator.no_caustics && diff --git a/intern/cycles/render/integrator.h b/intern/cycles/render/integrator.h index 573b258af60..4a8240c3941 100644 --- a/intern/cycles/render/integrator.h +++ b/intern/cycles/render/integrator.h @@ -41,6 +41,7 @@ public: bool transparent_probalistic; bool transparent_shadows; + int volume_homogeneous_sampling; int volume_max_steps; float volume_step_size; |