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UV: Simplify storage and logic for UV Packing
buildbot/vdev-code-daily-coordinator Build done. Details

This commit is contained in:
Chris Blackbourn 2023-04-27 11:50:21 +12:00
parent 249f677a1f
commit 5c6f254a66
1 changed files with 47 additions and 50 deletions
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97
source/blender/geometry/intern/uv_pack.cc
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@ -962,16 +962,18 @@ static void pack_island_xatlas(const Span<UVAABBIsland *> island_indices,
/**
* Pack islands using a mix of other strategies.
* \param islands: The islands to be packed. Will be modified with results.
* \param islands: The islands to be packed.
* \param scale: Scale islands by `scale` before packing.
* \param margin: Add `margin` units around islands before packing.
* \param params: Additional parameters. Scale and margin information is ignored.
* \param r_phis: Island layout information will be written here.
* \return Size of square covering the resulting packed UVs. The maximum `u` or `v` co-ordinate.
*/
static float pack_islands_scale_margin(const Span<PackIsland *> islands,
const float scale,
const float margin,
const UVPackIsland_Params &params)
const UVPackIsland_Params &params,
MutableSpan<uv_phi> r_phis)
{
/* #BLI_box_pack_2d produces layouts with high packing efficiency, but has `O(n^3)`
* time complexity, causing poor performance if there are lots of islands. See: #102843.
@ -988,8 +990,6 @@ static float pack_islands_scale_margin(const Span<PackIsland *> islands,
* - Call #pack_islands_alpaca_* on the remaining islands.
*/
blender::Array<uv_phi> phis(islands.size());
/* First, copy information from our input into the AABB structure. */
Array<UVAABBIsland *> aabbs(islands.size());
for (const int64_t i : islands.index_range()) {
@ -1056,7 +1056,7 @@ static float pack_islands_scale_margin(const Span<PackIsland *> islands,
scale,
margin,
params,
phis.as_mutable_span(),
r_phis,
&max_u,
&max_v);
break;
@ -1066,7 +1066,7 @@ static float pack_islands_scale_margin(const Span<PackIsland *> islands,
scale,
margin,
params.target_aspect_y,
phis.as_mutable_span(),
r_phis,
&max_u,
&max_v);
break;
@ -1076,25 +1076,11 @@ static float pack_islands_scale_margin(const Span<PackIsland *> islands,
/* Call Alpaca. */
if (params.rotate) {
pack_islands_alpaca_rotate(max_box_pack,
aabbs.as_mutable_span(),
params.target_aspect_y,
phis.as_mutable_span(),
&max_u,
&max_v);
pack_islands_alpaca_rotate(
max_box_pack, aabbs, params.target_aspect_y, r_phis, &max_u, &max_v);
}
else {
pack_islands_alpaca_turbo(max_box_pack,
aabbs.as_mutable_span(),
params.target_aspect_y,
phis.as_mutable_span(),
&max_u,
&max_v);
}
/* Write back UVs. */
for (int64_t i = 0; i < aabbs.size(); i++) {
islands[i]->place_(scale, phis[i]);
pack_islands_alpaca_turbo(max_box_pack, aabbs, params.target_aspect_y, r_phis, &max_u, &max_v);
}
return std::max(max_u / params.target_aspect_y, max_v);
@ -1103,7 +1089,7 @@ static float pack_islands_scale_margin(const Span<PackIsland *> islands,
/** Find the optimal scale to pack islands into the unit square.
* returns largest scale that will pack `islands` into the unit square.
*/
static float pack_islands_margin_fraction(const Span<PackIsland *> &island_vector,
static float pack_islands_margin_fraction(const Span<PackIsland *> &islands,
const float margin_fraction,
const UVPackIsland_Params &params)
{
@ -1118,7 +1104,10 @@ static float pack_islands_margin_fraction(const Span<PackIsland *> &island_vecto
float value_low = 0.0f;
float scale_high = 0.0f;
float value_high = 0.0f;
float scale_last = 0.0f;
blender::Array<uv_phi> phis_a(islands.size());
blender::Array<uv_phi> phis_b(islands.size());
blender::Array<uv_phi> *phis_low = nullptr;
/* Scaling smaller than `min_scale_roundoff` is unlikely to fit and
* will destroy information in existing UVs. */
@ -1166,19 +1155,23 @@ static float pack_islands_margin_fraction(const Span<PackIsland *> &island_vecto
/* Modified binary-search to improve robustness. */
scale = sqrtf(scale * sqrtf(scale_low * scale_high));
}
BLI_assert(scale_low < scale);
BLI_assert(scale < scale_high);
}
scale = std::max(scale, min_scale_roundoff);
/* Evaluate our `f`. */
scale_last = scale;
blender::Array<uv_phi> *phis_target = (phis_low == &phis_a) ? &phis_b : &phis_a;
const float max_uv = pack_islands_scale_margin(
island_vector, scale_last, margin_fraction, params);
islands, scale, margin_fraction, params, *phis_target);
const float value = sqrtf(max_uv) - 1.0f;
if (value <= 0.0f) {
scale_low = scale;
value_low = value;
phis_low = phis_target;
}
else {
scale_high = scale;
@ -1188,28 +1181,25 @@ static float pack_islands_margin_fraction(const Span<PackIsland *> &island_vecto
scale_low = scale;
break;
}
if (!phis_low) {
phis_low = phis_target; /* May as well do "something", even if it's wrong. */
}
}
}
const bool flush = true;
if (flush) {
if (phis_low) {
/* Write back best pack as a side-effect. */
if (scale_last != scale_low) {
scale_last = scale_low;
const float max_uv = pack_islands_scale_margin(
island_vector, scale_last, margin_fraction, params);
BLI_assert(max_uv == value_low);
UNUSED_VARS(max_uv);
/* TODO (?): `if (max_uv < 1.0f) { scale_last /= max_uv; }` */
for (const int64_t i : islands.index_range()) {
islands[i]->place_(scale_low, (*phis_low)[i]);
}
}
return scale_last;
return scale_low;
}
static float calc_margin_from_aabb_length_sum(const Span<PackIsland *> &island_vector,
const UVPackIsland_Params &params)
{
/* Logic matches behavior from #geometry::uv_parametrizer_pack.
/* Logic matches previous behavior from #geometry::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;
@ -1361,21 +1351,22 @@ void pack_islands(const Span<PackIsland *> &islands,
const UVPackIsland_Params &params,
float r_scale[2])
{
BLI_assert(0.0f <= params.margin);
BLI_assert(0.0f <= params.target_aspect_y);
if (islands.size() == 0) {
r_scale[0] = 1.0f;
r_scale[1] = 1.0f;
return; /* Nothing to do, just create a safe default. */
}
if (params.merge_overlap) {
return OverlapMerger::pack_islands_overlap(islands, params, r_scale);
}
finalize_geometry(islands, params);
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(islands, 1.0f, 0.0f, params);
r_scale[0] = 1.0f / max_uv;
r_scale[1] = r_scale[0];
return;
}
if (params.margin_method == ED_UVPACK_MARGIN_FRACTION) {
if (params.margin_method == ED_UVPACK_MARGIN_FRACTION && params.margin > 0.0f) {
/* Uses a line search on scale. ~10x slower than other method. */
const float scale = pack_islands_margin_fraction(islands, params.margin, params);
r_scale[0] = scale;
@ -1390,14 +1381,20 @@ void pack_islands(const Span<PackIsland *> &islands,
case ED_UVPACK_MARGIN_SCALED: /* Default for Blender 3.3 and later. */
margin = calc_margin_from_aabb_length_sum(islands, params);
break;
case ED_UVPACK_MARGIN_FRACTION: /* Added as an option in Blender 3.4. */
BLI_assert_unreachable(); /* Handled above. */
case ED_UVPACK_MARGIN_FRACTION: /* Added as an option in Blender 3.4. */
BLI_assert(params.margin == 0.0f); /* Other (slower) cases are handled above. */
break;
default:
BLI_assert_unreachable();
}
const float max_uv = pack_islands_scale_margin(islands, 1.0f, margin, params);
blender::Array<uv_phi> phis(islands.size());
const float scale = 1.0f;
const float max_uv = pack_islands_scale_margin(islands, scale, margin, params, phis);
for (const int64_t i : islands.index_range()) {
islands[i]->place_(scale, phis[i]);
}
r_scale[0] = 1.0f / max_uv;
r_scale[1] = r_scale[0];
}