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Optimize the bresenham algorithm to avoid an unneeded vector allocation #112731

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Optimize the bresenham algorithm to avoid an unneeded vector allocation #112731

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79 changes: 58 additions & 21 deletions core/math/geometry_2d.h
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include "core/math/vector2i.h"
#include "core/math/vector3.h"
#include "core/math/vector3i.h"
#include "core/templates/iterable.h"
#include "core/templates/vector.h"

class Geometry2D {
Expand Down Expand Up @@ -461,41 +462,77 @@ class Geometry2D {
return H;
}

static Vector<Point2i> bresenham_line(const Point2i &p_from, const Point2i &p_to) {
Vector<Point2i> points;

Vector2i delta = (p_to - p_from).abs() * 2;
Vector2i step = (p_to - p_from).sign();
Vector2i current = p_from;

if (delta.x > delta.y) {
int err = delta.x / 2;
class BresenhamIterator {
bool is_end;
Vector2i to;

for (; current.x != p_to.x; current.x += step.x) {
points.push_back(current);
Vector2i pos;
int err;
Vector2i delta;
Vector2i step;

public:
_FORCE_INLINE_ void operator++() {
if (pos == to) {
is_end = true;
return;
}
if (delta.x > delta.y) {
err -= delta.y;
if (err < 0) {
current.y += step.y;
pos.y += step.y;
err += delta.x;
}
}
} else {
int err = delta.y / 2;

for (; current.y != p_to.y; current.y += step.y) {
points.push_back(current);

pos.x += step.x;
} else {
err -= delta.x;
if (err < 0) {
current.x += step.x;
pos.x += step.x;
err += delta.y;
}
pos.y += step.y;
}
}

points.push_back(current);
_FORCE_INLINE_ Vector2i operator*() {
return pos;
}

_FORCE_INLINE_ bool operator!=(const BresenhamIterator &p_it) const {
return (is_end && p_it.is_end) ? false : (is_end != p_it.is_end || pos != p_it.pos);
}

public:
BresenhamIterator(const Vector2i &p_from, const Vector2i &p_to) {
is_end = false;

pos = p_from;
to = p_to;

Vector2i offset = p_to - p_from;
delta = offset.abs() * 2;
step = offset.sign();
if (delta.x > delta.y) {
err = delta.x / 2;
} else {
err = delta.y / 2;
}
}

BresenhamIterator() {
is_end = true;
}
};

static Iterable<BresenhamIterator> bresenham_iter(Vector2i p_from, Vector2i p_to) {
return Iterable<BresenhamIterator>(BresenhamIterator(p_from, p_to), BresenhamIterator());
}

static Vector<Point2i> bresenham_line(const Point2i &p_from, const Point2i &p_to) {
Vector<Point2i> points;
for (Vector2i point : bresenham_iter(p_from, p_to)) {
points.push_back(point);
}
return points;
}

Expand Down
4 changes: 2 additions & 2 deletions editor/import/editor_atlas_packer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -79,8 +79,8 @@ void EditorAtlasPacker::chart_pack(Vector<Chart> &charts, int &r_width, int &r_h

for (int k = 0; k < 3; k++) {
int l = k == 0 ? 2 : k - 1;
Vector<Point2i> points = Geometry2D::bresenham_line(v[k], v[l]);
for (Point2i point : points) {
Iterable<Geometry2D::BresenhamIterator> bresenham = Geometry2D::bresenham_iter(v[k], v[l]);
for (const Point2i &point : bresenham) {
src_bitmap->set_bitv(point, true);
}
}
Expand Down
18 changes: 9 additions & 9 deletions editor/scene/2d/tiles/tile_data_editors.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1114,9 +1114,9 @@ void TileDataDefaultEditor::forward_painting_atlas_gui_input(TileAtlasView *p_ti
Ref<InputEventMouseMotion> mm = p_event;
if (mm.is_valid()) {
if (drag_type == DRAG_TYPE_PAINT) {
Vector<Vector2i> line = Geometry2D::bresenham_line(p_tile_atlas_view->get_atlas_tile_coords_at_pos(drag_last_pos, true), p_tile_atlas_view->get_atlas_tile_coords_at_pos(mm->get_position(), true));
for (int i = 0; i < line.size(); i++) {
Vector2i coords = p_tile_set_atlas_source->get_tile_at_coords(line[i]);
Iterable<Geometry2D::BresenhamIterator> bresenham = Geometry2D::bresenham_iter(p_tile_atlas_view->get_atlas_tile_coords_at_pos(drag_last_pos, true), p_tile_atlas_view->get_atlas_tile_coords_at_pos(mm->get_position(), true));
for (const Vector2i &c : bresenham) {
Vector2i coords = p_tile_set_atlas_source->get_tile_at_coords(c);
if (coords != TileSetSource::INVALID_ATLAS_COORDS) {
TileMapCell cell;
cell.source_id = 0;
Expand Down Expand Up @@ -2202,9 +2202,9 @@ void TileDataTerrainsEditor::forward_painting_atlas_gui_input(TileAtlasView *p_t
Ref<InputEventMouseMotion> mm = p_event;
if (mm.is_valid()) {
if (drag_type == DRAG_TYPE_PAINT_TERRAIN_SET) {
Vector<Vector2i> line = Geometry2D::bresenham_line(p_tile_atlas_view->get_atlas_tile_coords_at_pos(drag_last_pos, true), p_tile_atlas_view->get_atlas_tile_coords_at_pos(mm->get_position(), true));
for (int i = 0; i < line.size(); i++) {
Vector2i coords = p_tile_set_atlas_source->get_tile_at_coords(line[i]);
Iterable<Geometry2D::BresenhamIterator> bresenham = Geometry2D::bresenham_iter(p_tile_atlas_view->get_atlas_tile_coords_at_pos(drag_last_pos, true), p_tile_atlas_view->get_atlas_tile_coords_at_pos(mm->get_position(), true));
for (const Vector2i &c : bresenham) {
Vector2i coords = p_tile_set_atlas_source->get_tile_at_coords(c);
if (coords != TileSetSource::INVALID_ATLAS_COORDS) {
int terrain_set = drag_painted_value;
TileMapCell cell;
Expand Down Expand Up @@ -2236,9 +2236,9 @@ void TileDataTerrainsEditor::forward_painting_atlas_gui_input(TileAtlasView *p_t
} else if (drag_type == DRAG_TYPE_PAINT_TERRAIN_BITS) {
int terrain_set = Dictionary(drag_painted_value)["terrain_set"];
int terrain = Dictionary(drag_painted_value)["terrain"];
Vector<Vector2i> line = Geometry2D::bresenham_line(p_tile_atlas_view->get_atlas_tile_coords_at_pos(drag_last_pos, true), p_tile_atlas_view->get_atlas_tile_coords_at_pos(mm->get_position(), true));
for (int i = 0; i < line.size(); i++) {
Vector2i coords = p_tile_set_atlas_source->get_tile_at_coords(line[i]);
Iterable<Geometry2D::BresenhamIterator> bresenham = Geometry2D::bresenham_iter(p_tile_atlas_view->get_atlas_tile_coords_at_pos(drag_last_pos, true), p_tile_atlas_view->get_atlas_tile_coords_at_pos(mm->get_position(), true));
for (const Vector2i &c : bresenham) {
Vector2i coords = p_tile_set_atlas_source->get_tile_at_coords(c);
if (coords != TileSetSource::INVALID_ATLAS_COORDS) {
TileMapCell cell;
cell.source_id = 0;
Expand Down
18 changes: 8 additions & 10 deletions editor/scene/2d/tiles/tile_set_atlas_source_editor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1118,12 +1118,11 @@ void TileSetAtlasSourceEditor::_tile_atlas_control_gui_input(const Ref<InputEven
// Create tiles.
last_base_tiles_coords = last_base_tiles_coords.maxi(0).min(grid_size - Vector2i(1, 1));
new_base_tiles_coords = new_base_tiles_coords.maxi(0).min(grid_size - Vector2i(1, 1));

Vector<Point2i> line = Geometry2D::bresenham_line(last_base_tiles_coords, new_base_tiles_coords);
for (int i = 0; i < line.size(); i++) {
if (tile_set_atlas_source->get_tile_at_coords(line[i]) == TileSetSource::INVALID_ATLAS_COORDS) {
tile_set_atlas_source->create_tile(line[i]);
drag_modified_tiles.insert(line[i]);
Iterable<Geometry2D::BresenhamIterator> bresenham = Geometry2D::bresenham_iter(last_base_tiles_coords, new_base_tiles_coords);
for (const Vector2i &c : bresenham) {
if (tile_set_atlas_source->get_tile_at_coords(c) == TileSetSource::INVALID_ATLAS_COORDS) {
tile_set_atlas_source->create_tile(c);
drag_modified_tiles.insert(c);
}
}

Expand All @@ -1133,10 +1132,9 @@ void TileSetAtlasSourceEditor::_tile_atlas_control_gui_input(const Ref<InputEven
// Remove tiles.
last_base_tiles_coords = last_base_tiles_coords.maxi(0).min(grid_size - Vector2i(1, 1));
new_base_tiles_coords = new_base_tiles_coords.maxi(0).min(grid_size - Vector2i(1, 1));

Vector<Point2i> line = Geometry2D::bresenham_line(last_base_tiles_coords, new_base_tiles_coords);
for (int i = 0; i < line.size(); i++) {
Vector2i base_tile_coords = tile_set_atlas_source->get_tile_at_coords(line[i]);
Iterable<Geometry2D::BresenhamIterator> bresenham = Geometry2D::bresenham_iter(last_base_tiles_coords, new_base_tiles_coords);
for (const Vector2i &c : bresenham) {
Vector2i base_tile_coords = tile_set_atlas_source->get_tile_at_coords(c);
if (base_tile_coords != TileSetSource::INVALID_ATLAS_COORDS) {
drag_modified_tiles.insert(base_tile_coords);
}
Expand Down
4 changes: 2 additions & 2 deletions editor/scene/curve_editor_plugin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1087,8 +1087,8 @@ Ref<Texture2D> CurvePreviewGenerator::generate(const Ref<Resource> &p_from, cons
v = (curve->sample_baked(t) - curve->get_min_value()) / curve->get_value_range();
y = CLAMP(im.get_height() - v * im.get_height(), 0, im.get_height() - 1);

Vector<Point2i> points = Geometry2D::bresenham_line(Point2i(x - 1, prev_y), Point2i(x, y));
for (Point2i point : points) {
Iterable<Geometry2D::BresenhamIterator> bresenham = Geometry2D::bresenham_iter(Point2i(x - 1, prev_y), Point2i(x, y));
for (const Point2i &point : bresenham) {
im.set_pixelv(point, line_color);
}
prev_y = y;
Expand Down