From c2256bf7f714bbd41388af3e184b3d84b496fbf3 Mon Sep 17 00:00:00 2001 From: Chris Blackbourn Date: Wed, 12 Oct 2022 10:57:17 +1300 Subject: Fix T90782: add uv pack option to specify margin as a fraction A refactor of the margin calculation of UV packing, in anticipation of multiple packing methods soon becoming available. Three margin scaling methods are now available: * "Add", Simple method, just add the margin. [0] (The default margin scale from Blender 2.8 and earlier.) * "Scaled", Use scale of existing UVs to multiply margin. (The default from Blender 3.3+) * "Fraction", a new (slow) method to precisely specify a fraction of the UV unit square for margin. [1] The "fraction" code path implements a novel combined search / secant root finding method which exploits domain knowledge to accelerate convergence while remaining robust against bad input. [0]: Resolves T85978 [1]: Resolves T90782 Differential Revision: https://developer.blender.org/D16121 --- source/blender/editors/uvedit/uvedit_islands.cc | 247 +++++++++++++++++++----- 1 file changed, 203 insertions(+), 44 deletions(-) (limited to 'source/blender/editors/uvedit/uvedit_islands.cc') diff --git a/source/blender/editors/uvedit/uvedit_islands.cc b/source/blender/editors/uvedit/uvedit_islands.cc index 2648ec5e2f6..4009447ba7e 100644 --- a/source/blender/editors/uvedit/uvedit_islands.cc +++ b/source/blender/editors/uvedit/uvedit_islands.cc @@ -403,6 +403,203 @@ int bm_mesh_calc_uv_islands(const Scene *scene, /** \} */ +static float pack_islands_scale_margin(const blender::Vector &island_vector, + BoxPack *box_array, + const float scale, + const float margin) +{ + for (const int index : island_vector.index_range()) { + FaceIsland *island = island_vector[index]; + BoxPack *box = &box_array[index]; + box->index = index; + box->w = BLI_rctf_size_x(&island->bounds_rect) * scale + 2 * margin; + box->h = BLI_rctf_size_y(&island->bounds_rect) * scale + 2 * margin; + } + float max_u, max_v; + BLI_box_pack_2d(box_array, island_vector.size(), &max_u, &max_v); + return max_ff(max_u, max_v); +} + +static float pack_islands_margin_fraction(const blender::Vector &island_vector, + BoxPack *box_array, + const float margin_fraction) +{ + /* + * Root finding using a combined search / modified-secant method. + * First, use a robust search procedure to bracket the root within a factor of 10. + * Then, use a modified-secant method to converge. + * + * This is a specialized solver using domain knowledge to accelerate convergence. + */ + + float scale_low = 0.0f; + float value_low = 0.0f; + float scale_high = 0.0f; + float value_high = 0.0f; + float scale_last = 0.0f; + + /* Scaling smaller than `min_scale_roundoff` is unlikely to fit and + * will destroy information in existing UVs. */ + float min_scale_roundoff = 1e-5f; + + /* Certain inputs might have poor convergence properties. + * Use `max_iteration` to prevent an infinite loop. */ + int max_iteration = 25; + for (int iteration = 0; iteration < max_iteration; iteration++) { + float scale = 1.0f; + + if (iteration == 0) { + BLI_assert(iteration == 0); + BLI_assert(scale == 1.0f); + BLI_assert(scale_low == 0.0f); + BLI_assert(scale_high == 0.0f); + } + else if (scale_low == 0.0f) { + BLI_assert(scale_high > 0.0f); + /* Search mode, shrink layout until we can find a scale that fits. */ + scale = scale_high * 0.1f; + } + else if (scale_high == 0.0f) { + BLI_assert(scale_low > 0.0f); + /* Search mode, grow layout until we can find a scale that doesn't fit. */ + scale = scale_low * 10.0f; + } + else { + /* Bracket mode, use modified secant method to find root. */ + BLI_assert(scale_low > 0.0f); + BLI_assert(scale_high > 0.0f); + BLI_assert(value_low <= 0.0f); + BLI_assert(value_high >= 0.0f); + if (scale_high < scale_low * 1.0001f) { + /* Convergence. */ + break; + } + + /* Secant method for area. */ + scale = (sqrtf(scale_low) * value_high - sqrtf(scale_high) * value_low) / + (value_high - value_low); + scale = scale * scale; + + if (iteration & 1) { + /* Modified binary-search to improve robustness. */ + scale = sqrtf(scale * sqrtf(scale_low * scale_high)); + } + } + + scale = max_ff(scale, min_scale_roundoff); + + /* Evaluate our `f`. */ + scale_last = scale; + float max_uv = pack_islands_scale_margin( + island_vector, box_array, scale_last, margin_fraction); + float value = sqrtf(max_uv) - 1.0f; + + if (value <= 0.0f) { + scale_low = scale; + value_low = value; + } + else { + scale_high = scale; + value_high = value; + if (scale == min_scale_roundoff) { + /* Unable to pack without damaging UVs. */ + scale_low = scale; + break; + } + } + } + + const bool flush = true; + if (flush) { + /* Write back best pack as a side-effect. First get best pack. */ + if (scale_last != scale_low) { + scale_last = scale_low; + float max_uv = pack_islands_scale_margin( + island_vector, box_array, scale_last, margin_fraction); + UNUSED_VARS(max_uv); + /* TODO (?): `if (max_uv < 1.0f) { scale_last /= max_uv; }` */ + } + + /* Then expand FaceIslands by the correct amount. */ + for (const int index : island_vector.index_range()) { + BoxPack *box = &box_array[index]; + box->x /= scale_last; + box->y /= scale_last; + FaceIsland *island = island_vector[index]; + BLI_rctf_pad( + &island->bounds_rect, margin_fraction / scale_last, margin_fraction / scale_last); + } + } + return scale_last; +} + +static float calc_margin_from_aabb_length_sum(const blender::Vector &island_vector, + const struct UVPackIsland_Params ¶ms) +{ + /* Logic matches behavior from #GEO_uv_parametrizer_pack. + * Attempt to give predictable results + * not dependent on current UV scale by using + * `aabb_length_sum` (was "`area`") to multiply + * the margin by the length (was "area"). + */ + double aabb_length_sum = 0.0f; + for (FaceIsland *island : island_vector) { + float w = BLI_rctf_size_x(&island->bounds_rect); + float h = BLI_rctf_size_y(&island->bounds_rect); + aabb_length_sum += sqrtf(w * h); + } + return params.margin * aabb_length_sum * 0.1f; +} + +static BoxPack *pack_islands_params(const blender::Vector &island_vector, + const struct UVPackIsland_Params ¶ms, + float r_scale[2]) +{ + BoxPack *box_array = static_cast( + MEM_mallocN(sizeof(*box_array) * island_vector.size(), __func__)); + + if (params.margin == 0.0f) { + /* Special case for zero margin. Margin_method is ignored as all formulas give same result. */ + const float max_uv = pack_islands_scale_margin(island_vector, box_array, 1.0f, 0.0f); + r_scale[0] = 1.0f / max_uv; + r_scale[1] = r_scale[0]; + return box_array; + } + + if (params.margin_method == ED_UVPACK_MARGIN_FRACTION) { + /* Uses a line search on scale. ~10x slower than other method. */ + const float scale = pack_islands_margin_fraction(island_vector, box_array, params.margin); + r_scale[0] = scale; + r_scale[1] = scale; + /* pack_islands_margin_fraction will pad FaceIslands, return early. */ + return box_array; + } + + float margin = params.margin; + switch (params.margin_method) { + case ED_UVPACK_MARGIN_ADD: /* Default for Blender 2.8 and earlier. */ + break; /* Nothing to do. */ + case ED_UVPACK_MARGIN_SCALED: /* Default for Blender 3.3 and later. */ + margin = calc_margin_from_aabb_length_sum(island_vector, params); + break; + case ED_UVPACK_MARGIN_FRACTION: /* Added as an option in Blender 3.4. */ + BLI_assert_unreachable(); /* Handled above. */ + break; + default: + BLI_assert_unreachable(); + } + + const float max_uv = pack_islands_scale_margin(island_vector, box_array, 1.0f, margin); + r_scale[0] = 1.0f / max_uv; + r_scale[1] = r_scale[0]; + + for (int index = 0; index < island_vector.size(); index++) { + FaceIsland *island = island_vector[index]; + BLI_rctf_pad(&island->bounds_rect, margin, margin); + } + return box_array; +} + /* -------------------------------------------------------------------- */ /** \name Public UV Island Packing * @@ -455,19 +652,12 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, return; } - float margin = scene->toolsettings->uvcalc_margin; - double area = 0.0f; - - BoxPack *boxarray = static_cast( - MEM_mallocN(sizeof(*boxarray) * island_vector.size(), __func__)); - /* Coordinates of bounding box containing all selected UVs. */ float selection_min_co[2], selection_max_co[2]; INIT_MINMAX2(selection_min_co, selection_max_co); for (int index = 0; index < island_vector.size(); index++) { FaceIsland *island = island_vector[index]; - /* Skip calculation if using specified UDIM option. */ if (udim_params && (udim_params->use_target_udim == false)) { float bounds_min[2], bounds_max[2]; @@ -489,17 +679,6 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, bm_face_array_calc_bounds( island->faces, island->faces_len, island->cd_loop_uv_offset, &island->bounds_rect); - - BoxPack *box = &boxarray[index]; - box->index = index; - box->x = 0.0f; - box->y = 0.0f; - box->w = BLI_rctf_size_x(&island->bounds_rect); - box->h = BLI_rctf_size_y(&island->bounds_rect); - - if (margin > 0.0f) { - area += double(sqrtf(box->w * box->h)); - } } /* Center of bounding box containing all selected UVs. */ @@ -509,28 +688,8 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, selection_center[1] = (selection_min_co[1] + selection_max_co[1]) / 2.0f; } - if (margin > 0.0f) { - /* Logic matches behavior from #GEO_uv_parametrizer_pack, - * use area so multiply the margin by the area to give - * predictable results not dependent on UV scale. */ - margin = (margin * float(area)) * 0.1f; - for (int i = 0; i < island_vector.size(); i++) { - FaceIsland *island = island_vector[i]; - BoxPack *box = &boxarray[i]; - - BLI_rctf_pad(&island->bounds_rect, margin, margin); - box->w = BLI_rctf_size_x(&island->bounds_rect); - box->h = BLI_rctf_size_y(&island->bounds_rect); - } - } - - float boxarray_size[2]; - BLI_box_pack_2d(boxarray, island_vector.size(), &boxarray_size[0], &boxarray_size[1]); - - /* Don't change the aspect when scaling. */ - boxarray_size[0] = boxarray_size[1] = max_ff(boxarray_size[0], boxarray_size[1]); - - const float scale[2] = {1.0f / boxarray_size[0], 1.0f / boxarray_size[1]}; + float scale[2] = {1.0f, 1.0f}; + BoxPack *box_array = pack_islands_params(island_vector, *params, scale); /* Tile offset. */ float base_offset[2] = {0.0f, 0.0f}; @@ -580,14 +739,14 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, } for (int i = 0; i < island_vector.size(); i++) { - FaceIsland *island = island_vector[boxarray[i].index]; + FaceIsland *island = island_vector[box_array[i].index]; const float pivot[2] = { island->bounds_rect.xmin, island->bounds_rect.ymin, }; const float offset[2] = { - ((boxarray[i].x * scale[0]) - island->bounds_rect.xmin) + base_offset[0], - ((boxarray[i].y * scale[1]) - island->bounds_rect.ymin) + base_offset[1], + ((box_array[i].x * scale[0]) - island->bounds_rect.xmin) + base_offset[0], + ((box_array[i].y * scale[1]) - island->bounds_rect.ymin) + base_offset[1], }; for (int j = 0; j < island->faces_len; j++) { BMFace *efa = island->faces[j]; @@ -607,7 +766,7 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, MEM_freeN(island); } - MEM_freeN(boxarray); + MEM_freeN(box_array); } /** \} */ -- cgit v1.2.3 From 4767a8eb4aae460ecbee8e6c3eacf4aa81a24c07 Mon Sep 17 00:00:00 2001 From: Chris Blackbourn Date: Thu, 13 Oct 2022 23:06:52 +1300 Subject: Cleanup: simplify uv packing api Affects paint.add_simple_uvs No user visible changes. Differential Revision: https://developer.blender.org/D16231 --- source/blender/editors/uvedit/uvedit_islands.cc | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'source/blender/editors/uvedit/uvedit_islands.cc') diff --git a/source/blender/editors/uvedit/uvedit_islands.cc b/source/blender/editors/uvedit/uvedit_islands.cc index 4009447ba7e..bdd05b06d94 100644 --- a/source/blender/editors/uvedit/uvedit_islands.cc +++ b/source/blender/editors/uvedit/uvedit_islands.cc @@ -609,6 +609,7 @@ static BoxPack *pack_islands_params(const blender::Vector &island_ void ED_uvedit_pack_islands_multi(const Scene *scene, Object **objects, const uint objects_len, + BMesh **bmesh_override, const struct UVMapUDIM_Params *udim_params, const struct UVPackIsland_Params *params) { @@ -616,9 +617,17 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, for (uint ob_index = 0; ob_index < objects_len; ob_index++) { Object *obedit = objects[ob_index]; - BMEditMesh *em = BKE_editmesh_from_object(obedit); - - const int cd_loop_uv_offset = CustomData_get_offset(&em->bm->ldata, CD_MLOOPUV); + BMesh *bm = nullptr; + if (bmesh_override) { + /* Note: obedit is still required for aspect ratio and ID_RECALC_GEOMETRY. */ + bm = bmesh_override[ob_index]; + } + else { + BMEditMesh *em = BKE_editmesh_from_object(obedit); + bm = em->bm; + } + BLI_assert(bm); + const int cd_loop_uv_offset = CustomData_get_offset(&bm->ldata, CD_MLOOPUV); if (cd_loop_uv_offset == -1) { continue; } @@ -634,7 +643,7 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, ListBase island_list = {nullptr}; bm_mesh_calc_uv_islands(scene, - em->bm, + bm, &island_list, params->only_selected_faces, params->only_selected_uvs, -- cgit v1.2.3 From e3075f3cf7ce2fae086f3cd09867e4f0455e4115 Mon Sep 17 00:00:00 2001 From: Chris Blackbourn Date: Thu, 20 Oct 2022 12:35:17 +1300 Subject: Cleanup: simplify uv packing api Part of a wider set of changes to migrate UV packing from uv_parametrizer.cc to uvedit_islands.cc. This allows UV packing improvements including margin calculation, correctness fixes such as support for non-manifold geometry, and new packing algorithms including speed and quality improvements. See for example c2256bf7f714, T82637 This change migrates UV.unwrap and Live UV Unwrap. Differential Revision: https://developer.blender.org/D16296 --- source/blender/editors/uvedit/uvedit_islands.cc | 26 +++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) (limited to 'source/blender/editors/uvedit/uvedit_islands.cc') diff --git a/source/blender/editors/uvedit/uvedit_islands.cc b/source/blender/editors/uvedit/uvedit_islands.cc index bdd05b06d94..92745667505 100644 --- a/source/blender/editors/uvedit/uvedit_islands.cc +++ b/source/blender/editors/uvedit/uvedit_islands.cc @@ -600,6 +600,22 @@ static BoxPack *pack_islands_params(const blender::Vector &island_ return box_array; } +static bool island_has_pins(FaceIsland *island) +{ + BMLoop *l; + BMIter iter; + const int cd_loop_uv_offset = island->cd_loop_uv_offset; + for (int i = 0; i < island->faces_len; i++) { + BM_ITER_ELEM (l, &iter, island->faces[i], BM_LOOPS_OF_FACE) { + MLoopUV *luv = static_cast(BM_ELEM_CD_GET_VOID_P(l, cd_loop_uv_offset)); + if (luv->flag & MLOOPUV_PINNED) { + return true; + } + } + } + return false; +} + /* -------------------------------------------------------------------- */ /** \name Public UV Island Packing * @@ -651,8 +667,14 @@ void ED_uvedit_pack_islands_multi(const Scene *scene, aspect_y, cd_loop_uv_offset); - int index; - LISTBASE_FOREACH_INDEX (struct FaceIsland *, island, &island_list, index) { + /* Remove from linked list and append to blender::Vector. */ + LISTBASE_FOREACH_MUTABLE (struct FaceIsland *, island, &island_list) { + BLI_remlink(&island_list, island); + if (params->ignore_pinned && island_has_pins(island)) { + MEM_freeN(island->faces); + MEM_freeN(island); + continue; + } island_vector.append(island); } } -- cgit v1.2.3