0618de49ad
Use `std::min` and `std::max` instead. Though keep MIN2 and MAX2 just for C code that hasn't been moved to C++ yet. Pull Request: https://projects.blender.org/blender/blender/pulls/117384
116 lines
3.8 KiB
C++
116 lines
3.8 KiB
C++
/* SPDX-FileCopyrightText: 2023 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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#include <algorithm>
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#include "GEO_reverse_uv_sampler.hh"
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#include "BLI_math_geom.h"
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#include "BLI_math_vector.hh"
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#include "BLI_task.hh"
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#include "BLI_timeit.hh"
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namespace blender::geometry {
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static int2 uv_to_cell_key(const float2 &uv, const int resolution)
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{
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return int2{uv * resolution};
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}
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ReverseUVSampler::ReverseUVSampler(const Span<float2> uv_map, const Span<int3> corner_tris)
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: uv_map_(uv_map), corner_tris_(corner_tris)
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{
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resolution_ = std::max<int>(3, std::sqrt(corner_tris.size()) * 2);
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for (const int tri_i : corner_tris.index_range()) {
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const int3 &tri = corner_tris[tri_i];
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const float2 &uv_0 = uv_map_[tri[0]];
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const float2 &uv_1 = uv_map_[tri[1]];
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const float2 &uv_2 = uv_map_[tri[2]];
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const int2 key_0 = uv_to_cell_key(uv_0, resolution_);
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const int2 key_1 = uv_to_cell_key(uv_1, resolution_);
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const int2 key_2 = uv_to_cell_key(uv_2, resolution_);
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const int2 min_key = math::min(math::min(key_0, key_1), key_2);
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const int2 max_key = math::max(math::max(key_0, key_1), key_2);
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for (int key_x = min_key.x; key_x <= max_key.x; key_x++) {
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for (int key_y = min_key.y; key_y <= max_key.y; key_y++) {
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const int2 key{key_x, key_y};
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corner_tris_by_cell_.add(key, tri_i);
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}
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}
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}
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}
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ReverseUVSampler::Result ReverseUVSampler::sample(const float2 &query_uv) const
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{
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const int2 cell_key = uv_to_cell_key(query_uv, resolution_);
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const Span<int> tri_indices = corner_tris_by_cell_.lookup(cell_key);
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float best_dist = FLT_MAX;
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float3 best_bary_weights;
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int best_tri_index;
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/* The distance to an edge that is allowed to be inside or outside the triangle. Without this,
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* the lookup can fail for floating point accuracy reasons when the uv is almost exact on an
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* edge. */
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const float edge_epsilon = 0.00001f;
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for (const int tri_i : tri_indices) {
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const int3 &tri = corner_tris_[tri_i];
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const float2 &uv_0 = uv_map_[tri[0]];
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const float2 &uv_1 = uv_map_[tri[1]];
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const float2 &uv_2 = uv_map_[tri[2]];
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float3 bary_weights;
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if (!barycentric_coords_v2(uv_0, uv_1, uv_2, query_uv, bary_weights)) {
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continue;
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}
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/* If #query_uv is in the triangle, the distance is <= 0. Otherwise, the larger the distance,
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* the further away the uv is from the triangle. */
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const float x_dist = std::max(-bary_weights.x, bary_weights.x - 1.0f);
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const float y_dist = std::max(-bary_weights.y, bary_weights.y - 1.0f);
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const float z_dist = std::max(-bary_weights.z, bary_weights.z - 1.0f);
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const float dist = std::max({x_dist, y_dist, z_dist});
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if (dist <= 0.0f && best_dist <= 0.0f) {
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const float worse_dist = std::max(dist, best_dist);
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/* Allow ignoring multiple triangle intersections if the uv is almost exactly on an edge. */
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if (worse_dist < -edge_epsilon) {
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/* The uv sample is in multiple triangles. */
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return Result{ResultType::Multiple};
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}
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}
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if (dist < best_dist) {
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best_dist = dist;
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best_bary_weights = bary_weights;
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best_tri_index = tri_i;
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}
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}
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/* Allow using the closest (but not intersecting) triangle if the uv is almost exactly on an
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* edge. */
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if (best_dist < edge_epsilon) {
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return Result{ResultType::Ok, best_tri_index, math::clamp(best_bary_weights, 0.0f, 1.0f)};
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}
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return Result{};
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}
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void ReverseUVSampler::sample_many(const Span<float2> query_uvs,
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MutableSpan<Result> r_results) const
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{
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BLI_assert(query_uvs.size() == r_results.size());
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threading::parallel_for(query_uvs.index_range(), 256, [&](const IndexRange range) {
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for (const int i : range) {
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r_results[i] = this->sample(query_uvs[i]);
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}
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});
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}
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} // namespace blender::geometry
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