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LibGfx: Track edge extent in EdgeFlagPathRasterizer

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This allows avoiding accumulating values we know will be zero, this is
not a huge speedup but does shave off a few %.
This commit is contained in:
MacDue 2023-08-06 14:15:04 +01:00 • committed by Andreas Kling
parent ec24d7555a
commit 2a914a7a59
Notes: sideshowbarker 2024-07-17 06:09:44 +09:00
2 changed files with 44 additions and 24 deletions
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50
Userland/Libraries/LibGfx/EdgeFlagPathRasterizer.cpp
View file

@ -141,7 +141,11 @@ void EdgeFlagPathRasterizer<SamplesPerPixel>::fill_internal(Painter& painter, Pa
// FIXME: We could probably clip some of the egde plotting if we know it won't be shown.
// Though care would have to be taken to ensure the active edges are correct at the first drawn scaline.
auto for_each_sample = [&](Detail::Edge& edge, int start_subpixel_y, int end_subpixel_y, auto callback) {
auto empty_edge_extent = [&] {
return EdgeExtent { m_size.width() - 1, 0 };
};
auto for_each_sample = [&](Detail::Edge& edge, int start_subpixel_y, int end_subpixel_y, EdgeExtent& edge_extent, auto callback) {
for (int y = start_subpixel_y; y < end_subpixel_y; y++) {
int xi = static_cast<int>(edge.x + SubpixelSample::nrooks_subpixel_offsets[y]);
if (xi < 0 || xi >= (int)m_scanline.size()) {
@ -154,20 +158,23 @@ void EdgeFlagPathRasterizer<SamplesPerPixel>::fill_internal(Painter& painter, Pa
SampleType sample = 1 << y;
callback(xi, y, sample);
edge.x += edge.dxdy;
edge_extent.min_x = min(edge_extent.min_x, xi);
edge_extent.max_x = max(edge_extent.max_x, xi);
}
};
Detail::Edge* active_edges = nullptr;
if (winding_rule == Painter::WindingRule::EvenOdd) {
auto plot_edge = [&](Detail::Edge& edge, int start_subpixel_y, int end_subpixel_y) {
for_each_sample(edge, start_subpixel_y, end_subpixel_y, [&](int xi, int, SampleType sample) {
auto plot_edge = [&](Detail::Edge& edge, int start_subpixel_y, int end_subpixel_y, EdgeExtent& edge_extent) {
for_each_sample(edge, start_subpixel_y, end_subpixel_y, edge_extent, [&](int xi, int, SampleType sample) {
m_scanline[xi] ^= sample;
});
};
for (int scanline = min_scanline; scanline <= max_scanline; scanline++) {
active_edges = plot_edges_for_scanline(scanline, plot_edge, active_edges);
accumulate_even_odd_scanline(painter, scanline, color_or_function);
auto edge_extent = empty_edge_extent();
active_edges = plot_edges_for_scanline(scanline, plot_edge, edge_extent, active_edges);
accumulate_even_odd_scanline(painter, scanline, edge_extent, color_or_function);
}
} else {
VERIFY(winding_rule == Painter::WindingRule::Nonzero);
@ -176,15 +183,16 @@ void EdgeFlagPathRasterizer<SamplesPerPixel>::fill_internal(Painter& painter, Pa
if (m_windings.is_empty())
m_windings.resize(m_size.width());
auto plot_edge = [&](Detail::Edge& edge, int start_subpixel_y, int end_subpixel_y) {
for_each_sample(edge, start_subpixel_y, end_subpixel_y, [&](int xi, int y, SampleType sample) {
auto plot_edge = [&](Detail::Edge& edge, int start_subpixel_y, int end_subpixel_y, EdgeExtent& edge_extent) {
for_each_sample(edge, start_subpixel_y, end_subpixel_y, edge_extent, [&](int xi, int y, SampleType sample) {
m_scanline[xi] |= sample;
m_windings[xi].counts[y] += edge.winding;
});
};
for (int scanline = min_scanline; scanline <= max_scanline; scanline++) {
active_edges = plot_edges_for_scanline(scanline, plot_edge, active_edges);
accumulate_non_zero_scanline(painter, scanline, color_or_function);
auto edge_extent = empty_edge_extent();
active_edges = plot_edges_for_scanline(scanline, plot_edge, edge_extent, active_edges);
accumulate_non_zero_scanline(painter, scanline, edge_extent, color_or_function);
}
}
}
@ -205,7 +213,7 @@ Color EdgeFlagPathRasterizer<SamplesPerPixel>::scanline_color(int scanline, int
}
template<unsigned SamplesPerPixel>
Detail::Edge* EdgeFlagPathRasterizer<SamplesPerPixel>::plot_edges_for_scanline(int scanline, auto plot_edge, Detail::Edge* active_edges)
Detail::Edge* EdgeFlagPathRasterizer<SamplesPerPixel>::plot_edges_for_scanline(int scanline, auto plot_edge, EdgeExtent& edge_extent, Detail::Edge* active_edges)
{
auto y_subpixel = [](int y) {
return y & (SamplesPerPixel - 1);
@ -220,7 +228,7 @@ Detail::Edge* EdgeFlagPathRasterizer<SamplesPerPixel>::plot_edges_for_scanline(i
int end_scanline = current_edge->max_y / SamplesPerPixel;
if (scanline == end_scanline) {
// This edge ends this scanline.
plot_edge(*current_edge, 0, y_subpixel(current_edge->max_y));
plot_edge(*current_edge, 0, y_subpixel(current_edge->max_y), edge_extent);
// Remove this edge from the AET
current_edge = current_edge->next_edge;
if (prev_edge)
@ -229,7 +237,7 @@ Detail::Edge* EdgeFlagPathRasterizer<SamplesPerPixel>::plot_edges_for_scanline(i
active_edges = current_edge;
} else {
// This egde sticks around for a few more scanlines.
plot_edge(*current_edge, 0, SamplesPerPixel);
plot_edge(*current_edge, 0, SamplesPerPixel, edge_extent);
prev_edge = current_edge;
current_edge = current_edge->next_edge;
}
@ -242,10 +250,10 @@ Detail::Edge* EdgeFlagPathRasterizer<SamplesPerPixel>::plot_edges_for_scanline(i
int end_scanline = current_edge->max_y / SamplesPerPixel;
if (scanline == end_scanline) {
// This edge will end this scanlines (no need to add to AET).
plot_edge(*current_edge, y_subpixel(current_edge->min_y), y_subpixel(current_edge->max_y));
plot_edge(*current_edge, y_subpixel(current_edge->min_y), y_subpixel(current_edge->max_y), edge_extent);
} else {
// This edge will live on for a few more scanlines.
plot_edge(*current_edge, y_subpixel(current_edge->min_y), SamplesPerPixel);
plot_edge(*current_edge, y_subpixel(current_edge->min_y), SamplesPerPixel, edge_extent);
// Add this edge to the AET
if (prev_edge)
prev_edge->next_edge = current_edge;
@ -278,18 +286,18 @@ void EdgeFlagPathRasterizer<SamplesPerPixel>::write_pixel(Painter& painter, int
}
template<unsigned SamplesPerPixel>
void EdgeFlagPathRasterizer<SamplesPerPixel>::accumulate_even_odd_scanline(Painter& painter, int scanline, auto& color_or_function)
void EdgeFlagPathRasterizer<SamplesPerPixel>::accumulate_even_odd_scanline(Painter& painter, int scanline, EdgeExtent edge_extent, auto& color_or_function)
{
auto dest_y = m_blit_origin.y() + scanline;
if (!m_clip.contains_vertically(dest_y)) {
// FIXME: This memset only really needs to be done on transition from clipped to not clipped,
// or not at all if we properly clipped egde plotting.
memset(m_scanline.data(), 0, sizeof(SampleType) * m_scanline.size());
edge_extent.memset_extent(m_scanline.data(), 0);
return;
}
SampleType sample = 0;
for (int x = 0; x < m_size.width(); x += 1) {
for (int x = edge_extent.min_x; x <= edge_extent.max_x; x += 1) {
sample ^= m_scanline[x];
write_pixel(painter, scanline, x, sample, color_or_function);
m_scanline[x] = 0;
@ -297,19 +305,19 @@ void EdgeFlagPathRasterizer<SamplesPerPixel>::accumulate_even_odd_scanline(Paint
}
template<unsigned SamplesPerPixel>
void EdgeFlagPathRasterizer<SamplesPerPixel>::accumulate_non_zero_scanline(Painter& painter, int scanline, auto& color_or_function)
void EdgeFlagPathRasterizer<SamplesPerPixel>::accumulate_non_zero_scanline(Painter& painter, int scanline, EdgeExtent edge_extent, auto& color_or_function)
{
// NOTE: Same FIXMEs apply from accumulate_even_odd_scanline()
auto dest_y = m_blit_origin.y() + scanline;
if (!m_clip.contains_vertically(dest_y)) {
memset(m_scanline.data(), 0, sizeof(SampleType) * m_scanline.size());
memset(m_windings.data(), 0, sizeof(WindingCounts) * m_windings.size());
edge_extent.memset_extent(m_scanline.data(), 0);
edge_extent.memset_extent(m_windings.data(), 0);
return;
}
SampleType sample = 0;
WindingCounts sum_winding = {};
for (int x = 0; x < m_size.width(); x += 1) {
for (int x = edge_extent.min_x; x <= edge_extent.max_x; x += 1) {
if (auto edges = m_scanline[x]) {
// We only need to process the windings when we hit some edges.
for (auto y_sub = 0u; y_sub < SamplesPerPixel; y_sub++) {

18
Userland/Libraries/LibGfx/EdgeFlagPathRasterizer.h
View file

@ -160,10 +160,22 @@ private:
return (coverage << alpha_shift) - 1;
}
struct EdgeExtent {
int min_x;
int max_x;
template<typename T>
void memset_extent(T* data, int value)
{
if (min_x <= max_x)
memset(data + min_x, value, (max_x - min_x + 1) * sizeof(T));
}
};
void fill_internal(Painter&, Path const&, auto color_or_function, Painter::WindingRule, FloatPoint offset);
Detail::Edge* plot_edges_for_scanline(int scanline, auto plot_edge, Detail::Edge* active_edges = nullptr);
void accumulate_even_odd_scanline(Painter&, int scanline, auto& color_or_function);
void accumulate_non_zero_scanline(Painter&, int scanline, auto& color_or_function);
Detail::Edge* plot_edges_for_scanline(int scanline, auto plot_edge, EdgeExtent&, Detail::Edge* active_edges = nullptr);
void accumulate_even_odd_scanline(Painter&, int scanline, EdgeExtent, auto& color_or_function);
void accumulate_non_zero_scanline(Painter&, int scanline, EdgeExtent, auto& color_or_function);
Color scanline_color(int scanline, int offset, u8 alpha, auto& color_or_function);
void write_pixel(Painter&, int scanline, int offset, SampleType sample, auto& color_or_function);