forked from bartvdbraak/blender
c96ae81160
This adds support for ngons and attributes on subdivision meshes. Ngons are needed for proper attribute interpolation as well as correct Catmull-Clark subdivision. Several changes are made to achieve this: - new primitive `SubdFace` added to `Mesh` - 3 more textures are used to store info on patches from subd meshes - Blender export uses loop interface instead of tessface for subd meshes - `Attribute` class is updated with a simplified way to pass primitive counts around and to support ngons. - extra points for ngons are generated for O(1) attribute interpolation - curves are temporally disabled on subd meshes to avoid various bugs with implementation - old unneeded code is removed from `subd/` - various fixes and improvements Reviewed By: brecht Differential Revision: https://developer.blender.org/D2108
354 lines
8.9 KiB
C++
354 lines
8.9 KiB
C++
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "camera.h"
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#include "mesh.h"
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#include "subd_dice.h"
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#include "subd_patch.h"
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#include "util_debug.h"
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CCL_NAMESPACE_BEGIN
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/* EdgeDice Base */
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EdgeDice::EdgeDice(const SubdParams& params_)
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: params(params_)
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{
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mesh_P = NULL;
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mesh_N = NULL;
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vert_offset = 0;
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params.mesh->attributes.add(ATTR_STD_VERTEX_NORMAL);
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if(params.ptex) {
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params.mesh->attributes.add(ATTR_STD_PTEX_UV);
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params.mesh->attributes.add(ATTR_STD_PTEX_FACE_ID);
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}
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}
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void EdgeDice::reserve(int num_verts)
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{
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Mesh *mesh = params.mesh;
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vert_offset = mesh->verts.size();
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tri_offset = mesh->num_triangles();
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/* todo: optimize so we can reserve in advance, this is like push_back_slow() */
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if(vert_offset + num_verts > mesh->verts.capacity()) {
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mesh->reserve_mesh(size_t((vert_offset + num_verts) * 1.2), mesh->num_triangles());
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}
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mesh->resize_mesh(vert_offset + num_verts, tri_offset);
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Attribute *attr_vN = mesh->attributes.add(ATTR_STD_VERTEX_NORMAL);
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mesh_P = &mesh->verts[0];
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mesh_N = attr_vN->data_float3();
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}
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int EdgeDice::add_vert(Patch *patch, float2 uv)
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{
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float3 P, N;
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patch->eval(&P, NULL, NULL, &N, uv.x, uv.y);
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assert(vert_offset < params.mesh->verts.size());
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mesh_P[vert_offset] = P;
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mesh_N[vert_offset] = N;
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params.mesh->vert_patch_uv[vert_offset] = make_float2(uv.x, uv.y);
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if(params.ptex) {
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Attribute *attr_ptex_uv = params.mesh->attributes.add(ATTR_STD_PTEX_UV);
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params.mesh->attributes.resize();
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float3 *ptex_uv = attr_ptex_uv->data_float3();
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ptex_uv[vert_offset] = make_float3(uv.x, uv.y, 0.0f);
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}
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params.mesh->num_subd_verts++;
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return vert_offset++;
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}
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void EdgeDice::add_triangle(Patch *patch, int v0, int v1, int v2)
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{
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Mesh *mesh = params.mesh;
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/* todo: optimize so we can reserve in advance, this is like push_back_slow() */
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if(mesh->triangles.size() == mesh->triangles.capacity())
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mesh->reserve_mesh(mesh->verts.size(), size_t(max(mesh->num_triangles() + 1, 1) * 1.2));
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mesh->add_triangle(v0, v1, v2, patch->shader, true);
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params.mesh->triangle_patch[params.mesh->num_triangles()-1] = patch->patch_index;
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if(params.ptex) {
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Attribute *attr_ptex_face_id = params.mesh->attributes.add(ATTR_STD_PTEX_FACE_ID);
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params.mesh->attributes.resize();
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float *ptex_face_id = attr_ptex_face_id->data_float();
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ptex_face_id[tri_offset] = (float)patch->ptex_face_id();
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}
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tri_offset++;
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}
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void EdgeDice::stitch_triangles(Patch *patch, vector<int>& outer, vector<int>& inner)
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{
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if(inner.size() == 0 || outer.size() == 0)
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return; // XXX avoid crashes for Mu or Mv == 1, missing polygons
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/* stitch together two arrays of verts with triangles. at each step,
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* we compare using the next verts on both sides, to find the split
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* direction with the smallest diagonal, and use that in order to keep
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* the triangle shape reasonable. */
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for(size_t i = 0, j = 0; i+1 < inner.size() || j+1 < outer.size();) {
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int v0, v1, v2;
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v0 = inner[i];
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v1 = outer[j];
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if(j+1 == outer.size()) {
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v2 = inner[++i];
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}
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else if(i+1 == inner.size()) {
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v2 = outer[++j];
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}
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else {
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/* length of diagonals */
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float len1 = len_squared(mesh_P[inner[i]] - mesh_P[outer[j+1]]);
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float len2 = len_squared(mesh_P[outer[j]] - mesh_P[inner[i+1]]);
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/* use smallest diagonal */
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if(len1 < len2)
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v2 = outer[++j];
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else
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v2 = inner[++i];
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}
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add_triangle(patch, v0, v1, v2);
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}
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}
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/* QuadDice */
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QuadDice::QuadDice(const SubdParams& params_)
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: EdgeDice(params_)
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{
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}
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void QuadDice::reserve(EdgeFactors& ef, int Mu, int Mv)
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{
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/* XXX need to make this also work for edge factor 0 and 1 */
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int num_verts = (ef.tu0 + ef.tu1 + ef.tv0 + ef.tv1) + (Mu - 1)*(Mv - 1);
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EdgeDice::reserve(num_verts);
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}
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float2 QuadDice::map_uv(SubPatch& sub, float u, float v)
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{
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/* map UV from subpatch to patch parametric coordinates */
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float2 d0 = interp(sub.P00, sub.P01, v);
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float2 d1 = interp(sub.P10, sub.P11, v);
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return interp(d0, d1, u);
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}
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float3 QuadDice::eval_projected(SubPatch& sub, float u, float v)
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{
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float2 uv = map_uv(sub, u, v);
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float3 P;
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sub.patch->eval(&P, NULL, NULL, NULL, uv.x, uv.y);
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if(params.camera)
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P = transform_perspective(¶ms.camera->worldtoraster, P);
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return P;
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}
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int QuadDice::add_vert(SubPatch& sub, float u, float v)
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{
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return EdgeDice::add_vert(sub.patch, map_uv(sub, u, v));
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}
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void QuadDice::add_side_u(SubPatch& sub,
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vector<int>& outer, vector<int>& inner,
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int Mu, int Mv, int tu, int side, int offset)
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{
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outer.clear();
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inner.clear();
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/* set verts on the edge of the patch */
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outer.push_back(offset + ((side)? 2: 0));
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for(int i = 1; i < tu; i++) {
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float u = i/(float)tu;
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float v = (side)? 1.0f: 0.0f;
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outer.push_back(add_vert(sub, u, v));
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}
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outer.push_back(offset + ((side)? 3: 1));
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/* set verts on the edge of the inner grid */
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for(int i = 0; i < Mu-1; i++) {
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int j = (side)? Mv-1-1: 0;
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inner.push_back(offset + 4 + i + j*(Mu-1));
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}
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}
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void QuadDice::add_side_v(SubPatch& sub,
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vector<int>& outer, vector<int>& inner,
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int Mu, int Mv, int tv, int side, int offset)
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{
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outer.clear();
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inner.clear();
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/* set verts on the edge of the patch */
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outer.push_back(offset + ((side)? 1: 0));
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for(int j = 1; j < tv; j++) {
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float u = (side)? 1.0f: 0.0f;
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float v = j/(float)tv;
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outer.push_back(add_vert(sub, u, v));
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}
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outer.push_back(offset + ((side)? 3: 2));
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/* set verts on the edge of the inner grid */
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for(int j = 0; j < Mv-1; j++) {
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int i = (side)? Mu-1-1: 0;
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inner.push_back(offset + 4 + i + j*(Mu-1));
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}
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}
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float QuadDice::quad_area(const float3& a, const float3& b, const float3& c, const float3& d)
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{
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return triangle_area(a, b, d) + triangle_area(a, d, c);
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}
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float QuadDice::scale_factor(SubPatch& sub, EdgeFactors& ef, int Mu, int Mv)
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{
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/* estimate area as 4x largest of 4 quads */
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float3 P[3][3];
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for(int i = 0; i < 3; i++)
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for(int j = 0; j < 3; j++)
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P[i][j] = eval_projected(sub, i*0.5f, j*0.5f);
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float A1 = quad_area(P[0][0], P[1][0], P[0][1], P[1][1]);
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float A2 = quad_area(P[1][0], P[2][0], P[1][1], P[2][1]);
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float A3 = quad_area(P[0][1], P[1][1], P[0][2], P[1][2]);
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float A4 = quad_area(P[1][1], P[2][1], P[1][2], P[2][2]);
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float Apatch = max(A1, max(A2, max(A3, A4)))*4.0f;
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/* solve for scaling factor */
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float Atri = params.dicing_rate*params.dicing_rate*0.5f;
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float Ntris = Apatch/Atri;
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// XXX does the -sqrt solution matter
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// XXX max(D, 0.0) is highly suspicious, need to test cases
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// where D goes negative
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float N = 0.5f*(Ntris - (ef.tu0 + ef.tu1 + ef.tv0 + ef.tv1));
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float D = 4.0f*N*Mu*Mv + (Mu + Mv)*(Mu + Mv);
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float S = (Mu + Mv + sqrtf(max(D, 0.0f)))/(2*Mu*Mv);
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return S;
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}
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void QuadDice::add_corners(SubPatch& sub)
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{
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/* add verts for patch corners */
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add_vert(sub, 0.0f, 0.0f);
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add_vert(sub, 1.0f, 0.0f);
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add_vert(sub, 0.0f, 1.0f);
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add_vert(sub, 1.0f, 1.0f);
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}
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void QuadDice::add_grid(SubPatch& sub, int Mu, int Mv, int offset)
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{
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/* create inner grid */
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float du = 1.0f/(float)Mu;
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float dv = 1.0f/(float)Mv;
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for(int j = 1; j < Mv; j++) {
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for(int i = 1; i < Mu; i++) {
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float u = i*du;
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float v = j*dv;
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add_vert(sub, u, v);
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if(i < Mu-1 && j < Mv-1) {
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int i1 = offset + 4 + (i-1) + (j-1)*(Mu-1);
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int i2 = offset + 4 + i + (j-1)*(Mu-1);
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int i3 = offset + 4 + i + j*(Mu-1);
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int i4 = offset + 4 + (i-1) + j*(Mu-1);
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add_triangle(sub.patch, i1, i2, i3);
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add_triangle(sub.patch, i1, i3, i4);
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}
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}
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}
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}
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void QuadDice::dice(SubPatch& sub, EdgeFactors& ef)
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{
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/* compute inner grid size with scale factor */
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int Mu = max(ef.tu0, ef.tu1);
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int Mv = max(ef.tv0, ef.tv1);
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#if 0 /* Doesnt work very well, especially at grazing angles. */
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float S = scale_factor(sub, ef, Mu, Mv);
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#else
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float S = 1.0f;
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#endif
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Mu = max((int)ceil(S*Mu), 2); // XXX handle 0 & 1?
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Mv = max((int)ceil(S*Mv), 2); // XXX handle 0 & 1?
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/* reserve space for new verts */
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int offset = params.mesh->verts.size();
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reserve(ef, Mu, Mv);
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/* corners and inner grid */
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add_corners(sub);
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add_grid(sub, Mu, Mv, offset);
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/* bottom side */
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vector<int> outer, inner;
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add_side_u(sub, outer, inner, Mu, Mv, ef.tu0, 0, offset);
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stitch_triangles(sub.patch, outer, inner);
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/* top side */
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add_side_u(sub, outer, inner, Mu, Mv, ef.tu1, 1, offset);
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stitch_triangles(sub.patch, inner, outer);
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/* left side */
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add_side_v(sub, outer, inner, Mu, Mv, ef.tv0, 0, offset);
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stitch_triangles(sub.patch, inner, outer);
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/* right side */
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add_side_v(sub, outer, inner, Mu, Mv, ef.tv1, 1, offset);
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stitch_triangles(sub.patch, outer, inner);
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assert(vert_offset == params.mesh->verts.size());
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}
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CCL_NAMESPACE_END
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