diff options
Diffstat (limited to 'intern/cycles/subd/dice.cpp')
| -rw-r--r-- | intern/cycles/subd/dice.cpp | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/intern/cycles/subd/dice.cpp b/intern/cycles/subd/dice.cpp new file mode 100644 index 00000000000..461fa0bcd9c --- /dev/null +++ b/intern/cycles/subd/dice.cpp @@ -0,0 +1,283 @@ +/* + * Copyright 2011-2013 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. + */ + +#include "scene/camera.h" +#include "scene/mesh.h" + +#include "subd/dice.h" +#include "subd/patch.h" + +CCL_NAMESPACE_BEGIN + +/* EdgeDice Base */ + +EdgeDice::EdgeDice(const SubdParams ¶ms_) : params(params_) +{ + mesh_P = NULL; + mesh_N = NULL; + vert_offset = 0; + + params.mesh->attributes.add(ATTR_STD_VERTEX_NORMAL); + + if (params.ptex) { + params.mesh->attributes.add(ATTR_STD_PTEX_UV); + params.mesh->attributes.add(ATTR_STD_PTEX_FACE_ID); + } +} + +void EdgeDice::reserve(int num_verts, int num_triangles) +{ + Mesh *mesh = params.mesh; + + vert_offset = mesh->get_verts().size(); + tri_offset = mesh->num_triangles(); + + mesh->resize_mesh(mesh->get_verts().size() + num_verts, mesh->num_triangles()); + mesh->reserve_mesh(mesh->get_verts().size() + num_verts, mesh->num_triangles() + num_triangles); + + Attribute *attr_vN = mesh->attributes.add(ATTR_STD_VERTEX_NORMAL); + + mesh_P = mesh->verts.data() + vert_offset; + mesh_N = attr_vN->data_float3() + vert_offset; + + params.mesh->num_subd_verts += num_verts; +} + +void EdgeDice::set_vert(Patch *patch, int index, float2 uv) +{ + float3 P, N; + + patch->eval(&P, NULL, NULL, &N, uv.x, uv.y); + + assert(index < params.mesh->verts.size()); + + mesh_P[index] = P; + mesh_N[index] = N; + params.mesh->vert_patch_uv[index + vert_offset] = make_float2(uv.x, uv.y); +} + +void EdgeDice::add_triangle(Patch *patch, int v0, int v1, int v2) +{ + Mesh *mesh = params.mesh; + + mesh->add_triangle(v0 + vert_offset, v1 + vert_offset, v2 + vert_offset, patch->shader, true); + params.mesh->triangle_patch[params.mesh->num_triangles() - 1] = patch->patch_index; + + tri_offset++; +} + +void EdgeDice::stitch_triangles(Subpatch &sub, int edge) +{ + int Mu = max(sub.edge_u0.T, sub.edge_u1.T); + int Mv = max(sub.edge_v0.T, sub.edge_v1.T); + Mu = max(Mu, 2); + Mv = max(Mv, 2); + + int outer_T = sub.edges[edge].T; + int inner_T = ((edge % 2) == 0) ? Mv - 2 : Mu - 2; + + if (inner_T < 0 || outer_T < 0) + return; // XXX avoid crashes for Mu or Mv == 1, missing polygons + + /* stitch together two arrays of verts with triangles. at each step, + * we compare using the next verts on both sides, to find the split + * direction with the smallest diagonal, and use that in order to keep + * the triangle shape reasonable. */ + for (size_t i = 0, j = 0; i < inner_T || j < outer_T;) { + int v0, v1, v2; + + v0 = sub.get_vert_along_grid_edge(edge, i); + v1 = sub.get_vert_along_edge(edge, j); + + if (j == outer_T) { + v2 = sub.get_vert_along_grid_edge(edge, ++i); + } + else if (i == inner_T) { + v2 = sub.get_vert_along_edge(edge, ++j); + } + else { + /* length of diagonals */ + float len1 = len_squared(mesh_P[sub.get_vert_along_grid_edge(edge, i)] - + mesh_P[sub.get_vert_along_edge(edge, j + 1)]); + float len2 = len_squared(mesh_P[sub.get_vert_along_edge(edge, j)] - + mesh_P[sub.get_vert_along_grid_edge(edge, i + 1)]); + + /* use smallest diagonal */ + if (len1 < len2) + v2 = sub.get_vert_along_edge(edge, ++j); + else + v2 = sub.get_vert_along_grid_edge(edge, ++i); + } + + add_triangle(sub.patch, v1, v0, v2); + } +} + +/* QuadDice */ + +QuadDice::QuadDice(const SubdParams ¶ms_) : EdgeDice(params_) +{ +} + +float2 QuadDice::map_uv(Subpatch &sub, float u, float v) +{ + /* map UV from subpatch to patch parametric coordinates */ + float2 d0 = interp(sub.c00, sub.c01, v); + float2 d1 = interp(sub.c10, sub.c11, v); + return interp(d0, d1, u); +} + +float3 QuadDice::eval_projected(Subpatch &sub, float u, float v) +{ + float2 uv = map_uv(sub, u, v); + float3 P; + + sub.patch->eval(&P, NULL, NULL, NULL, uv.x, uv.y); + if (params.camera) + P = transform_perspective(¶ms.camera->worldtoraster, P); + + return P; +} + +void QuadDice::set_vert(Subpatch &sub, int index, float u, float v) +{ + EdgeDice::set_vert(sub.patch, index, map_uv(sub, u, v)); +} + +void QuadDice::set_side(Subpatch &sub, int edge) +{ + int t = sub.edges[edge].T; + + /* set verts on the edge of the patch */ + for (int i = 0; i < t; i++) { + float f = i / (float)t; + + float u, v; + switch (edge) { + case 0: + u = 0; + v = f; + break; + case 1: + u = f; + v = 1; + break; + case 2: + u = 1; + v = 1.0f - f; + break; + case 3: + default: + u = 1.0f - f; + v = 0; + break; + } + + set_vert(sub, sub.get_vert_along_edge(edge, i), u, v); + } +} + +float QuadDice::quad_area(const float3 &a, const float3 &b, const float3 &c, const float3 &d) +{ + return triangle_area(a, b, d) + triangle_area(a, d, c); +} + +float QuadDice::scale_factor(Subpatch &sub, int Mu, int Mv) +{ + /* estimate area as 4x largest of 4 quads */ + float3 P[3][3]; + + for (int i = 0; i < 3; i++) + for (int j = 0; j < 3; j++) + P[i][j] = eval_projected(sub, i * 0.5f, j * 0.5f); + + float A1 = quad_area(P[0][0], P[1][0], P[0][1], P[1][1]); + float A2 = quad_area(P[1][0], P[2][0], P[1][1], P[2][1]); + float A3 = quad_area(P[0][1], P[1][1], P[0][2], P[1][2]); + float A4 = quad_area(P[1][1], P[2][1], P[1][2], P[2][2]); + float Apatch = max(A1, max(A2, max(A3, A4))) * 4.0f; + + /* solve for scaling factor */ + float Atri = params.dicing_rate * params.dicing_rate * 0.5f; + float Ntris = Apatch / Atri; + + // XXX does the -sqrt solution matter + // XXX max(D, 0.0) is highly suspicious, need to test cases + // where D goes negative + float N = 0.5f * (Ntris - (sub.edge_u0.T + sub.edge_u1.T + sub.edge_v0.T + sub.edge_v1.T)); + float D = 4.0f * N * Mu * Mv + (Mu + Mv) * (Mu + Mv); + float S = (Mu + Mv + sqrtf(max(D, 0.0f))) / (2 * Mu * Mv); + + return S; +} + +void QuadDice::add_grid(Subpatch &sub, int Mu, int Mv, int offset) +{ + /* create inner grid */ + float du = 1.0f / (float)Mu; + float dv = 1.0f / (float)Mv; + + for (int j = 1; j < Mv; j++) { + for (int i = 1; i < Mu; i++) { + float u = i * du; + float v = j * dv; + + set_vert(sub, offset + (i - 1) + (j - 1) * (Mu - 1), u, v); + + if (i < Mu - 1 && j < Mv - 1) { + int i1 = offset + (i - 1) + (j - 1) * (Mu - 1); + int i2 = offset + i + (j - 1) * (Mu - 1); + int i3 = offset + i + j * (Mu - 1); + int i4 = offset + (i - 1) + j * (Mu - 1); + + add_triangle(sub.patch, i1, i2, i3); + add_triangle(sub.patch, i1, i3, i4); + } + } + } +} + +void QuadDice::dice(Subpatch &sub) +{ + /* compute inner grid size with scale factor */ + int Mu = max(sub.edge_u0.T, sub.edge_u1.T); + int Mv = max(sub.edge_v0.T, sub.edge_v1.T); + +#if 0 /* Doesn't work very well, especially at grazing angles. */ + float S = scale_factor(sub, ef, Mu, Mv); +#else + float S = 1.0f; +#endif + + Mu = max((int)ceilf(S * Mu), 2); // XXX handle 0 & 1? + Mv = max((int)ceilf(S * Mv), 2); // XXX handle 0 & 1? + + /* inner grid */ + add_grid(sub, Mu, Mv, sub.inner_grid_vert_offset); + + /* sides */ + set_side(sub, 0); + set_side(sub, 1); + set_side(sub, 2); + set_side(sub, 3); + + stitch_triangles(sub, 0); + stitch_triangles(sub, 1); + stitch_triangles(sub, 2); + stitch_triangles(sub, 3); +} + +CCL_NAMESPACE_END |