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Diffstat (limited to 'intern/cycles/kernel/geom/geom_motion_triangle_intersect.h')
| -rw-r--r-- | intern/cycles/kernel/geom/geom_motion_triangle_intersect.h | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/intern/cycles/kernel/geom/geom_motion_triangle_intersect.h b/intern/cycles/kernel/geom/geom_motion_triangle_intersect.h new file mode 100644 index 00000000000..d57d74ea882 --- /dev/null +++ b/intern/cycles/kernel/geom/geom_motion_triangle_intersect.h @@ -0,0 +1,280 @@ +/* + * Copyright 2011-2016 Blender Foundation + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/* Motion Triangle Primitive + * + * These are stored as regular triangles, plus extra positions and normals at + * times other than the frame center. Computing the triangle vertex positions + * or normals at a given ray time is a matter of interpolation of the two steps + * between which the ray time lies. + * + * The extra positions and normals are stored as ATTR_STD_MOTION_VERTEX_POSITION + * and ATTR_STD_MOTION_VERTEX_NORMAL mesh attributes. + */ + +CCL_NAMESPACE_BEGIN + +/* Refine triangle intersection to more precise hit point. For rays that travel + * far the precision is often not so good, this reintersects the primitive from + * a closer distance. + */ + +ccl_device_inline float3 motion_triangle_refine(KernelGlobals *kg, + ShaderData *sd, + const Intersection *isect, + const Ray *ray, + float3 verts[3]) +{ + float3 P = ray->P; + float3 D = ray->D; + float t = isect->t; + +#ifdef __INTERSECTION_REFINE__ + if(isect->object != OBJECT_NONE) { + if(UNLIKELY(t == 0.0f)) { + return P; + } +# ifdef __OBJECT_MOTION__ + Transform tfm = ccl_fetch(sd, ob_itfm); +# else + Transform tfm = object_fetch_transform(kg, + isect->object, + OBJECT_INVERSE_TRANSFORM); +# endif + + P = transform_point(&tfm, P); + D = transform_direction(&tfm, D*t); + D = normalize_len(D, &t); + } + + P = P + D*t; + + /* Compute refined intersection distance. */ + const float3 e1 = verts[0] - verts[2]; + const float3 e2 = verts[1] - verts[2]; + const float3 s1 = cross(D, e2); + + const float invdivisor = 1.0f/dot(s1, e1); + const float3 d = P - verts[2]; + const float3 s2 = cross(d, e1); + float rt = dot(e2, s2)*invdivisor; + + /* Compute refined position. */ + P = P + D*rt; + + if(isect->object != OBJECT_NONE) { +# ifdef __OBJECT_MOTION__ + Transform tfm = ccl_fetch(sd, ob_tfm); +# else + Transform tfm = object_fetch_transform(kg, + isect->object, + OBJECT_TRANSFORM); +# endif + + P = transform_point(&tfm, P); + } + + return P; +#else + return P + D*t; +#endif +} + +/* Same as above, except that isect->t is assumed to be in object space + * for instancing. + */ + +#ifdef __SUBSURFACE__ +# if defined(__KERNEL_CUDA__) && (defined(i386) || defined(_M_IX86)) +ccl_device_noinline +# else +ccl_device_inline +# endif +float3 motion_triangle_refine_subsurface(KernelGlobals *kg, + ShaderData *sd, + const Intersection *isect, + const Ray *ray, + float3 verts[3]) +{ + float3 P = ray->P; + float3 D = ray->D; + float t = isect->t; + +# ifdef __INTERSECTION_REFINE__ + if(isect->object != OBJECT_NONE) { +# ifdef __OBJECT_MOTION__ + Transform tfm = ccl_fetch(sd, ob_itfm); +# else + Transform tfm = object_fetch_transform(kg, + isect->object, + OBJECT_INVERSE_TRANSFORM); +# endif + + P = transform_point(&tfm, P); + D = transform_direction(&tfm, D); + D = normalize(D); + } + + P = P + D*t; + + /* compute refined intersection distance */ + const float3 e1 = verts[0] - verts[2]; + const float3 e2 = verts[1] - verts[2]; + const float3 s1 = cross(D, e2); + + const float invdivisor = 1.0f/dot(s1, e1); + const float3 d = P - verts[2]; + const float3 s2 = cross(d, e1); + float rt = dot(e2, s2)*invdivisor; + + P = P + D*rt; + + if(isect->object != OBJECT_NONE) { +# ifdef __OBJECT_MOTION__ + Transform tfm = ccl_fetch(sd, ob_tfm); +# else + Transform tfm = object_fetch_transform(kg, + isect->object, + OBJECT_TRANSFORM); +# endif + + P = transform_point(&tfm, P); + } + + return P; +# else /* __INTERSECTION_REFINE__ */ + return P + D*t; +# endif /* __INTERSECTION_REFINE__ */ +} +#endif /* __SUBSURFACE__ */ + + +/* Ray intersection. We simply compute the vertex positions at the given ray + * time and do a ray intersection with the resulting triangle. + */ + +ccl_device_inline bool motion_triangle_intersect(KernelGlobals *kg, + Intersection *isect, + float3 P, + float3 dir, + float time, + uint visibility, + int object, + int prim_addr) +{ + /* Primitive index for vertex location lookup. */ + int prim = kernel_tex_fetch(__prim_index, prim_addr); + int fobject = (object == OBJECT_NONE) + ? kernel_tex_fetch(__prim_object, prim_addr) + : object; + /* Get vertex locations for intersection. */ + float3 verts[3]; + motion_triangle_vertices(kg, fobject, prim, time, verts); + /* Ray-triangle intersection, unoptimized. */ + float t, u, v; + if(ray_triangle_intersect_uv(P, + dir, + isect->t, + verts[2], verts[0], verts[1], + &u, &v, &t)) + { +#ifdef __VISIBILITY_FLAG__ + /* Visibility flag test. we do it here under the assumption + * that most triangles are culled by node flags. + */ + if(kernel_tex_fetch(__prim_visibility, prim_addr) & visibility) +#endif + { + isect->t = t; + isect->u = u; + isect->v = v; + isect->prim = prim_addr; + isect->object = object; + isect->type = PRIMITIVE_MOTION_TRIANGLE; + return true; + } + } + return false; +} + +/* Special ray intersection routines for subsurface scattering. In that case we + * only want to intersect with primitives in the same object, and if case of + * multiple hits we pick a single random primitive as the intersection point. + */ +#ifdef __SUBSURFACE__ +ccl_device_inline void motion_triangle_intersect_subsurface( + KernelGlobals *kg, + SubsurfaceIntersection *ss_isect, + float3 P, + float3 dir, + float time, + int object, + int prim_addr, + float tmax, + uint *lcg_state, + int max_hits) +{ + /* Primitive index for vertex location lookup. */ + int prim = kernel_tex_fetch(__prim_index, prim_addr); + int fobject = (object == OBJECT_NONE) + ? kernel_tex_fetch(__prim_object, prim_addr) + : object; + /* Get vertex locations for intersection. */ + float3 verts[3]; + motion_triangle_vertices(kg, fobject, prim, time, verts); + /* Ray-triangle intersection, unoptimized. */ + float t, u, v; + if(ray_triangle_intersect_uv(P, + dir, + tmax, + verts[2], verts[0], verts[1], + &u, &v, &t)) + { + for(int i = min(max_hits, ss_isect->num_hits) - 1; i >= 0; --i) { + if(ss_isect->hits[i].t == t) { + return; + } + } + ss_isect->num_hits++; + int hit; + if(ss_isect->num_hits <= max_hits) { + hit = ss_isect->num_hits - 1; + } + else { + /* Reservoir sampling: if we are at the maximum number of + * hits, randomly replace element or skip it. + */ + hit = lcg_step_uint(lcg_state) % ss_isect->num_hits; + + if(hit >= max_hits) + return; + } + /* Record intersection. */ + Intersection *isect = &ss_isect->hits[hit]; + isect->t = t; + isect->u = u; + isect->v = v; + isect->prim = prim_addr; + isect->object = object; + isect->type = PRIMITIVE_MOTION_TRIANGLE; + /* Record geometric normal. */ + ss_isect->Ng[hit] = normalize(cross(verts[1] - verts[0], + verts[2] - verts[0])); + } +} +#endif /* __SUBSURFACE__ */ + +CCL_NAMESPACE_END |