diff options
author | Mikhail Matrosov <ktdfly> | 2021-06-28 14:54:18 +0300 |
---|---|---|
committer | Brecht Van Lommel <brecht@blender.org> | 2021-06-28 15:05:22 +0300 |
commit | 9c6a382f9540c8e334a16b7740b5ba6bb294fca9 (patch) | |
tree | f8b4d0f1c557e7ef70c0f417fd22d9abf1912f74 /intern | |
parent | ce25b5812b4ad2f9c6d29bf254374235bc7100f7 (diff) |
Cycles: reduce shadow terminator artifacts
Offset rays from the flat surface to match where they would be for a smooth
surface as specified by the normals. In the shading panel there is now a
Shading Offset (existing option) and Geometry Offset (new).
The Geometry Offset works as follows:
* 0: disabled
* 0.001: only terminated triangles (normal points to the light, geometry
doesn't) are affected
* 0.1 (default): triangles at grazing angles are affected, and the effect
fades out
* 1: all triangles are affected
Limitations:
* The artifact is still visible in some cases, it could be that some quads
require to be treated specifically as quads.
* Inconsistent normals cause artifacts.
* If small objects cast shadows to a big low poly surface, the shadows can
appear to be in a wrong place - because the surface moved slightly above
the geometry. This can be noticed only at grazing angles to light.
* Approximated surfaces of two non-intersecting low-poly objects can overlap
that causes off-the-wall shadows.
Generally, using one or a few levels of subdivision can get rid of artifacts
faster than before.
Differential Revision: https://developer.blender.org/D11065
Diffstat (limited to 'intern')
-rw-r--r-- | intern/cycles/blender/addon/properties.py | 9 | ||||
-rw-r--r-- | intern/cycles/blender/addon/ui.py | 26 | ||||
-rw-r--r-- | intern/cycles/blender/blender_object.cpp | 8 | ||||
-rw-r--r-- | intern/cycles/kernel/bvh/bvh_util.h | 79 | ||||
-rw-r--r-- | intern/cycles/kernel/closure/bsdf.h | 9 | ||||
-rw-r--r-- | intern/cycles/kernel/geom/geom_triangle.h | 13 | ||||
-rw-r--r-- | intern/cycles/kernel/kernel_emission.h | 3 | ||||
-rw-r--r-- | intern/cycles/kernel/kernel_types.h | 3 | ||||
-rw-r--r-- | intern/cycles/render/object.cpp | 7 | ||||
-rw-r--r-- | intern/cycles/render/object.h | 3 |
10 files changed, 138 insertions, 22 deletions
diff --git a/intern/cycles/blender/addon/properties.py b/intern/cycles/blender/addon/properties.py index cda1355eb2d..71e2f9fc3a5 100644 --- a/intern/cycles/blender/addon/properties.py +++ b/intern/cycles/blender/addon/properties.py @@ -1254,12 +1254,19 @@ class CyclesObjectSettings(bpy.types.PropertyGroup): ) shadow_terminator_offset: FloatProperty( - name="Shadow Terminator Offset", + name="Shadow Terminator Shading Offset", description="Push the shadow terminator towards the light to hide artifacts on low poly geometry", min=0.0, max=1.0, default=0.0, ) + shadow_terminator_geometry_offset: FloatProperty( + name="Shadow Terminator Geometry Offset", + description="Offset rays from the surface to reduce shadow terminator artifact on low poly geometry. Only affects triangles at grazing angles to light", + min=0.0, max=1.0, + default=0.1, + ) + is_shadow_catcher: BoolProperty( name="Shadow Catcher", description="Only render shadows on this object, for compositing renders into real footage", diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py index 62a2fa7f036..3d990467f04 100644 --- a/intern/cycles/blender/addon/ui.py +++ b/intern/cycles/blender/addon/ui.py @@ -1223,20 +1223,31 @@ class CYCLES_OBJECT_PT_shading(CyclesButtonsPanel, Panel): @classmethod def poll(cls, context): - return CyclesButtonsPanel.poll(context) and (context.object) + if not CyclesButtonsPanel.poll(context): + return False + + ob = context.object + return ob and has_geometry_visibility(ob) + + def draw(self, context): + pass + + +class CYCLES_OBJECT_PT_shading_shadow_terminator(CyclesButtonsPanel, Panel): + bl_label = "Shadow Terminator" + bl_parent_id = "CYCLES_OBJECT_PT_shading" + bl_context = "object" def draw(self, context): layout = self.layout layout.use_property_split = True - flow = layout.grid_flow(row_major=False, columns=0, even_columns=True, even_rows=False, align=False) - layout = self.layout + flow = layout.grid_flow(row_major=False, columns=0, even_columns=True, even_rows=False, align=True) + ob = context.object cob = ob.cycles - - if has_geometry_visibility(ob): - col = flow.column() - col.prop(cob, "shadow_terminator_offset") + flow.prop(cob, "shadow_terminator_geometry_offset", text="Geometry Offset") + flow.prop(cob, "shadow_terminator_offset", text="Shading Offset") class CYCLES_OBJECT_PT_visibility(CyclesButtonsPanel, Panel): @@ -2316,6 +2327,7 @@ classes = ( CYCLES_PT_context_material, CYCLES_OBJECT_PT_motion_blur, CYCLES_OBJECT_PT_shading, + CYCLES_OBJECT_PT_shading_shadow_terminator, CYCLES_OBJECT_PT_visibility, CYCLES_OBJECT_PT_visibility_ray_visibility, CYCLES_OBJECT_PT_visibility_culling, diff --git a/intern/cycles/blender/blender_object.cpp b/intern/cycles/blender/blender_object.cpp index cb84013c551..635392fb3d4 100644 --- a/intern/cycles/blender/blender_object.cpp +++ b/intern/cycles/blender/blender_object.cpp @@ -290,8 +290,12 @@ Object *BlenderSync::sync_object(BL::Depsgraph &b_depsgraph, bool is_shadow_catcher = get_boolean(cobject, "is_shadow_catcher"); object->set_is_shadow_catcher(is_shadow_catcher); - float shadow_terminator_offset = get_float(cobject, "shadow_terminator_offset"); - object->set_shadow_terminator_offset(shadow_terminator_offset); + float shadow_terminator_shading_offset = get_float(cobject, "shadow_terminator_offset"); + object->set_shadow_terminator_shading_offset(shadow_terminator_shading_offset); + + float shadow_terminator_geometry_offset = get_float(cobject, + "shadow_terminator_geometry_offset"); + object->set_shadow_terminator_geometry_offset(shadow_terminator_geometry_offset); /* sync the asset name for Cryptomatte */ BL::Object parent = b_ob.parent(); diff --git a/intern/cycles/kernel/bvh/bvh_util.h b/intern/cycles/kernel/bvh/bvh_util.h index a694e4dc259..168c2939136 100644 --- a/intern/cycles/kernel/bvh/bvh_util.h +++ b/intern/cycles/kernel/bvh/bvh_util.h @@ -71,6 +71,85 @@ ccl_device_inline float3 ray_offset(float3 P, float3 Ng) #endif } +/* This function should be used to compute a modified ray start position for + * rays leaving from a surface. The algorithm slightly distorts flat surface + * of a triangle. Surface is lifted by amount h along normal n in the incident + * point. */ + +ccl_device_inline float3 smooth_surface_offset(KernelGlobals *kg, ShaderData *sd, float3 Ng) +{ + float3 V[3], N[3]; + triangle_vertices_and_normals(kg, sd->prim, V, N); + + const float u = sd->u, v = sd->v; + const float w = 1 - u - v; + float3 P = V[0] * u + V[1] * v + V[2] * w; /* Local space */ + float3 n = N[0] * u + N[1] * v + N[2] * w; /* We get away without normalization */ + n = transform_direction(&(sd->ob_tfm), n); /* Normal x scale, world space */ + + /* Parabolic approximation */ + float a = dot(N[2] - N[0], V[0] - V[2]); + float b = dot(N[2] - N[1], V[1] - V[2]); + float c = dot(N[1] - N[0], V[1] - V[0]); + float h = a * u * (u - 1) + (a + b + c) * u * v + b * v * (v - 1); + + /* Check flipped normals */ + if (dot(n, Ng) > 0) { + /* Local linear envelope */ + float h0 = max(max(dot(V[1] - V[0], N[0]), dot(V[2] - V[0], N[0])), 0.0f); + float h1 = max(max(dot(V[0] - V[1], N[1]), dot(V[2] - V[1], N[1])), 0.0f); + float h2 = max(max(dot(V[0] - V[2], N[2]), dot(V[1] - V[2], N[2])), 0.0f); + h0 = max(dot(V[0] - P, N[0]) + h0, 0.0f); + h1 = max(dot(V[1] - P, N[1]) + h1, 0.0f); + h2 = max(dot(V[2] - P, N[2]) + h2, 0.0f); + h = max(min(min(h0, h1), h2), h * 0.5f); + } + else { + float h0 = max(max(dot(V[0] - V[1], N[0]), dot(V[0] - V[2], N[0])), 0.0f); + float h1 = max(max(dot(V[1] - V[0], N[1]), dot(V[1] - V[2], N[1])), 0.0f); + float h2 = max(max(dot(V[2] - V[0], N[2]), dot(V[2] - V[1], N[2])), 0.0f); + h0 = max(dot(P - V[0], N[0]) + h0, 0.0f); + h1 = max(dot(P - V[1], N[1]) + h1, 0.0f); + h2 = max(dot(P - V[2], N[2]) + h2, 0.0f); + h = min(-min(min(h0, h1), h2), h * 0.5f); + } + + return n * h; +} + +/* Ray offset to avoid shadow terminator artifact. */ + +ccl_device_inline float3 ray_offset_shadow(KernelGlobals *kg, ShaderData *sd, float3 L) +{ + float NL = dot(sd->N, L); + bool transmit = (NL < 0.0f); + float3 Ng = (transmit ? -sd->Ng : sd->Ng); + float3 P = ray_offset(sd->P, Ng); + + if ((sd->type & PRIMITIVE_ALL_TRIANGLE) && (sd->shader & SHADER_SMOOTH_NORMAL)) { + const float offset_cutoff = + kernel_tex_fetch(__objects, sd->object).shadow_terminator_geometry_offset; + /* Do ray offset (heavy stuff) only for close to be terminated triangles: + * offset_cutoff = 0.1f means that 10-20% of rays will be affected. Also + * make a smooth transition near the threshold. */ + if (offset_cutoff > 0.0f) { + float NgL = dot(Ng, L); + float offset_amount = 0.0f; + if (NL < offset_cutoff) { + offset_amount = clamp(2.0f - (NgL + NL) / offset_cutoff, 0.0f, 1.0f); + } + else { + offset_amount = clamp(1.0f - NgL / offset_cutoff, 0.0f, 1.0f); + } + if (offset_amount > 0.0f) { + P += smooth_surface_offset(kg, sd, Ng) * offset_amount; + } + } + } + + return P; +} + #if defined(__VOLUME_RECORD_ALL__) || (defined(__SHADOW_RECORD_ALL__) && defined(__KERNEL_CPU__)) /* ToDo: Move to another file? */ ccl_device int intersections_compare(const void *a, const void *b) diff --git a/intern/cycles/kernel/closure/bsdf.h b/intern/cycles/kernel/closure/bsdf.h index 6070fd983f5..6f2f2ebb202 100644 --- a/intern/cycles/kernel/closure/bsdf.h +++ b/intern/cycles/kernel/closure/bsdf.h @@ -462,7 +462,7 @@ ccl_device_inline int bsdf_sample(KernelGlobals *kg, else { /* Shadow terminator offset. */ const float frequency_multiplier = - kernel_tex_fetch(__objects, sd->object).shadow_terminator_offset; + kernel_tex_fetch(__objects, sd->object).shadow_terminator_shading_offset; if (frequency_multiplier > 1.0f) { *eval *= shift_cos_in(dot(*omega_in, sc->N), frequency_multiplier); } @@ -488,12 +488,9 @@ ccl_device_inline const float3 omega_in, float *pdf) { - /* For curves use the smooth normal, particularly for ribbons the geometric - * normal gives too much darkening otherwise. */ - const float3 Ng = (sd->type & PRIMITIVE_ALL_CURVE) ? sd->N : sd->Ng; float3 eval; - if (dot(Ng, omega_in) >= 0.0f) { + if (dot(sd->N, omega_in) >= 0.0f) { switch (sc->type) { case CLOSURE_BSDF_DIFFUSE_ID: case CLOSURE_BSDF_BSSRDF_ID: @@ -589,7 +586,7 @@ ccl_device_inline } /* Shadow terminator offset. */ const float frequency_multiplier = - kernel_tex_fetch(__objects, sd->object).shadow_terminator_offset; + kernel_tex_fetch(__objects, sd->object).shadow_terminator_shading_offset; if (frequency_multiplier > 1.0f) { eval *= shift_cos_in(dot(omega_in, sc->N), frequency_multiplier); } diff --git a/intern/cycles/kernel/geom/geom_triangle.h b/intern/cycles/kernel/geom/geom_triangle.h index ebc5abc017a..0a9460aa166 100644 --- a/intern/cycles/kernel/geom/geom_triangle.h +++ b/intern/cycles/kernel/geom/geom_triangle.h @@ -75,6 +75,19 @@ ccl_device_inline void triangle_vertices(KernelGlobals *kg, int prim, float3 P[3 P[2] = float4_to_float3(kernel_tex_fetch(__prim_tri_verts, tri_vindex.w + 2)); } +/* Triangle vertex locations and vertex normals */ + +ccl_device_inline void triangle_vertices_and_normals(KernelGlobals *kg, int prim, float3 P[3], float3 N[3]) +{ + const uint4 tri_vindex = kernel_tex_fetch(__tri_vindex, prim); + P[0] = float4_to_float3(kernel_tex_fetch(__prim_tri_verts, tri_vindex.w + 0)); + P[1] = float4_to_float3(kernel_tex_fetch(__prim_tri_verts, tri_vindex.w + 1)); + P[2] = float4_to_float3(kernel_tex_fetch(__prim_tri_verts, tri_vindex.w + 2)); + N[0] = float4_to_float3(kernel_tex_fetch(__tri_vnormal, tri_vindex.x)); + N[1] = float4_to_float3(kernel_tex_fetch(__tri_vnormal, tri_vindex.y)); + N[2] = float4_to_float3(kernel_tex_fetch(__tri_vnormal, tri_vindex.z)); +} + /* Interpolate smooth vertex normal from vertices */ ccl_device_inline float3 diff --git a/intern/cycles/kernel/kernel_emission.h b/intern/cycles/kernel/kernel_emission.h index 96ecc624067..aebf2ec8e28 100644 --- a/intern/cycles/kernel/kernel_emission.h +++ b/intern/cycles/kernel/kernel_emission.h @@ -176,8 +176,7 @@ ccl_device_noinline_cpu bool direct_emission(KernelGlobals *kg, if (ls->shader & SHADER_CAST_SHADOW) { /* setup ray */ - bool transmit = (dot(sd->Ng, ls->D) < 0.0f); - ray->P = ray_offset(sd->P, (transmit) ? -sd->Ng : sd->Ng); + ray->P = ray_offset_shadow(kg, sd, ls->D); if (ls->t == FLT_MAX) { /* distant light */ diff --git a/intern/cycles/kernel/kernel_types.h b/intern/cycles/kernel/kernel_types.h index 86b3b3b3365..85d75b36e5f 100644 --- a/intern/cycles/kernel/kernel_types.h +++ b/intern/cycles/kernel/kernel_types.h @@ -1479,7 +1479,8 @@ typedef struct KernelObject { float cryptomatte_object; float cryptomatte_asset; - float shadow_terminator_offset; + float shadow_terminator_shading_offset; + float shadow_terminator_geometry_offset; float pad1, pad2, pad3; } KernelObject; static_assert_align(KernelObject, 16); diff --git a/intern/cycles/render/object.cpp b/intern/cycles/render/object.cpp index f65f8bc6e90..5fe4e9ed57f 100644 --- a/intern/cycles/render/object.cpp +++ b/intern/cycles/render/object.cpp @@ -93,7 +93,8 @@ NODE_DEFINE(Object) SOCKET_POINT(dupli_generated, "Dupli Generated", zero_float3()); SOCKET_POINT2(dupli_uv, "Dupli UV", zero_float2()); SOCKET_TRANSFORM_ARRAY(motion, "Motion", array<Transform>()); - SOCKET_FLOAT(shadow_terminator_offset, "Terminator Offset", 0.0f); + SOCKET_FLOAT(shadow_terminator_shading_offset, "Shadow Terminator Shading Offset", 0.0f); + SOCKET_FLOAT(shadow_terminator_geometry_offset, "Shadow Terminator Geometry Offset", 0.1f); SOCKET_STRING(asset_name, "Asset Name", ustring()); SOCKET_BOOLEAN(is_shadow_catcher, "Shadow Catcher", false); @@ -507,7 +508,9 @@ void ObjectManager::device_update_object_transform(UpdateObjectTransformState *s kobject.cryptomatte_asset = util_hash_to_float(hash_asset); } - kobject.shadow_terminator_offset = 1.0f / (1.0f - 0.5f * ob->shadow_terminator_offset); + kobject.shadow_terminator_shading_offset = 1.0f / + (1.0f - 0.5f * ob->shadow_terminator_shading_offset); + kobject.shadow_terminator_geometry_offset = ob->shadow_terminator_geometry_offset; /* Object flag. */ if (ob->use_holdout) { diff --git a/intern/cycles/render/object.h b/intern/cycles/render/object.h index e4bc7ac3d8e..ebb7733c2aa 100644 --- a/intern/cycles/render/object.h +++ b/intern/cycles/render/object.h @@ -64,7 +64,8 @@ class Object : public Node { NODE_SOCKET_API(bool, hide_on_missing_motion) NODE_SOCKET_API(bool, use_holdout) NODE_SOCKET_API(bool, is_shadow_catcher) - NODE_SOCKET_API(float, shadow_terminator_offset) + NODE_SOCKET_API(float, shadow_terminator_shading_offset) + NODE_SOCKET_API(float, shadow_terminator_geometry_offset) NODE_SOCKET_API(float3, dupli_generated) NODE_SOCKET_API(float2, dupli_uv) |