diff options
Diffstat (limited to 'intern/cycles/kernel/geom/geom_triangle_intersect.h')
| -rw-r--r-- | intern/cycles/kernel/geom/geom_triangle_intersect.h | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/intern/cycles/kernel/geom/geom_triangle_intersect.h b/intern/cycles/kernel/geom/geom_triangle_intersect.h new file mode 100644 index 00000000000..b965bddf330 --- /dev/null +++ b/intern/cycles/kernel/geom/geom_triangle_intersect.h @@ -0,0 +1,230 @@ +/* + * Adapted from code Copyright 2009-2010 NVIDIA Corporation + * Modifications Copyright 2011, 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. + */ + +/* Triangle/Ray intersections + * + * Basic triangle with 3 vertices is used to represent mesh surfaces. For BVH + * ray intersection we use a precomputed triangle storage to accelerate + * intersection at the cost of more memory usage */ + +CCL_NAMESPACE_BEGIN + +/* Ray-Triangle intersection for BVH traversal + * + * Based on Sven Woop's algorithm with precomputed triangle storage */ + +ccl_device_inline bool triangle_intersect(KernelGlobals *kg, Intersection *isect, + float3 P, float3 dir, uint visibility, int object, int triAddr) +{ + /* compute and check intersection t-value */ + float4 v00 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+0); + float4 v11 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+1); + + float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z; + float invDz = 1.0f/(dir.x*v00.x + dir.y*v00.y + dir.z*v00.z); + float t = Oz * invDz; + + if(t > 0.0f && t < isect->t) { + /* compute and check barycentric u */ + float Ox = v11.w + P.x*v11.x + P.y*v11.y + P.z*v11.z; + float Dx = dir.x*v11.x + dir.y*v11.y + dir.z*v11.z; + float u = Ox + t*Dx; + + if(u >= 0.0f) { + /* compute and check barycentric v */ + float4 v22 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+2); + float Oy = v22.w + P.x*v22.x + P.y*v22.y + P.z*v22.z; + float Dy = dir.x*v22.x + dir.y*v22.y + dir.z*v22.z; + float v = Oy + t*Dy; + + if(v >= 0.0f && u + v <= 1.0f) { +#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, triAddr) & visibility) +#endif + { + /* record intersection */ + isect->t = t; + isect->u = u; + isect->v = v; + isect->prim = triAddr; + isect->object = object; + isect->type = PRIMITIVE_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 triangle_intersect_subsurface(KernelGlobals *kg, Intersection *isect_array, + float3 P, float3 dir, int object, int triAddr, float tmax, uint *num_hits, uint *lcg_state, int max_hits) +{ + /* compute and check intersection t-value */ + float4 v00 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+0); + float4 v11 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+1); + + float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z; + float invDz = 1.0f/(dir.x*v00.x + dir.y*v00.y + dir.z*v00.z); + float t = Oz * invDz; + + if(t > 0.0f && t < tmax) { + /* compute and check barycentric u */ + float Ox = v11.w + P.x*v11.x + P.y*v11.y + P.z*v11.z; + float Dx = dir.x*v11.x + dir.y*v11.y + dir.z*v11.z; + float u = Ox + t*Dx; + + if(u >= 0.0f) { + /* compute and check barycentric v */ + float4 v22 = kernel_tex_fetch(__tri_woop, triAddr*TRI_NODE_SIZE+2); + float Oy = v22.w + P.x*v22.x + P.y*v22.y + P.z*v22.z; + float Dy = dir.x*v22.x + dir.y*v22.y + dir.z*v22.z; + float v = Oy + t*Dy; + + if(v >= 0.0f && u + v <= 1.0f) { + (*num_hits)++; + + int hit; + + if(*num_hits <= max_hits) { + hit = *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) % *num_hits; + + if(hit >= max_hits) + return; + } + + /* record intersection */ + Intersection *isect = &isect_array[hit]; + isect->t = t; + isect->u = u; + isect->v = v; + isect->prim = triAddr; + isect->object = object; + isect->type = PRIMITIVE_TRIANGLE; + } + } + } +} +#endif + +/* 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 triangle_refine(KernelGlobals *kg, ShaderData *sd, const Intersection *isect, const Ray *ray) +{ + 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 = 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; + + float4 v00 = kernel_tex_fetch(__tri_woop, isect->prim*TRI_NODE_SIZE+0); + float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z; + float invDz = 1.0f/(D.x*v00.x + D.y*v00.y + D.z*v00.z); + float rt = Oz * invDz; + + P = P + D*rt; + + if(isect->object != OBJECT_NONE) { +#ifdef __OBJECT_MOTION__ + Transform tfm = 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 */ +ccl_device_inline float3 triangle_refine_subsurface(KernelGlobals *kg, ShaderData *sd, const Intersection *isect, const Ray *ray) +{ + 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 = 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; + + float4 v00 = kernel_tex_fetch(__tri_woop, isect->prim*TRI_NODE_SIZE+0); + float Oz = v00.w - P.x*v00.x - P.y*v00.y - P.z*v00.z; + float invDz = 1.0f/(D.x*v00.x + D.y*v00.y + D.z*v00.z); + float rt = Oz * invDz; + + P = P + D*rt; + + if(isect->object != OBJECT_NONE) { +#ifdef __OBJECT_MOTION__ + Transform tfm = 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 +} + +CCL_NAMESPACE_END |