RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-26 11:07:35 +00:00
Code Issues Activity Actions

Mandelbrot: Only recalculate missing areas after panning

Browse source 
We can reuse the areas that we have from before and just recalculate
the areas that are fresh. This makes panning super smooth. :^)
This commit is contained in:
sin-ack 2021-08-08 15:04:43 +00:00 • committed by Gunnar Beutner
parent d28802ad22
commit 1be59d663a
1 changed files with 57 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

60
Userland/Demos/Mandelbrot/Mandelbrot.cpp
View file

@ -61,7 +61,23 @@ public:
m_x_end - delta.x() * relative_width_pixel,
m_y_start - delta.y() * relative_height_pixel,
m_y_end - delta.y() * relative_height_pixel);
calculate();
Gfx::IntRect horizontal_missing, vertical_missing;
if (delta.y() >= 0) {
horizontal_missing = { 0, 0, m_bitmap->width(), delta.y() };
} else {
horizontal_missing = { 0, m_bitmap->height() + delta.y(), m_bitmap->width(), -delta.y() };
}
if (delta.x() >= 0) {
vertical_missing = { 0, 0, delta.x(), m_bitmap->height() };
} else {
vertical_missing = { m_bitmap->width() + delta.x(), 0, -delta.x(), m_bitmap->height() };
}
move_contents_by(delta);
calculate_rect(horizontal_missing);
calculate_rect(vertical_missing);
}
double mandelbrot(double px, double py, i32 max_iterations)
@ -116,8 +132,18 @@ public:
{
VERIFY(m_bitmap);
for (int py = 0; py < m_bitmap->height(); py++)
for (int px = 0; px < m_bitmap->width(); px++)
calculate_rect(m_bitmap->rect(), max_iterations);
}
void calculate_rect(Gfx::IntRect const& rect, int max_iterations = 100)
{
VERIFY(m_bitmap);
if (rect.is_empty())
return;
for (int py = rect.top(); py <= rect.bottom(); py++)
for (int px = rect.left(); px <= rect.right(); px++)
calculate_pixel(px, py, max_iterations);
}
@ -148,6 +174,34 @@ private:
m_y_start = y_mid - aspect_corrected_y_length / 2;
m_y_end = y_mid + aspect_corrected_y_length / 2;
}
void move_contents_by(Gfx::IntPoint const& delta)
{
// If we're moving down we paint upwards, else we paint downwards, to
// avoid overwriting.
if (delta.y() >= 0) {
for (int row = m_bitmap->physical_height() - 1; row >= delta.y(); row--)
move_row(row - delta.y(), row, delta.x());
} else {
for (int row = 0; row < m_bitmap->physical_height() + delta.y(); row++)
move_row(row - delta.y(), row, delta.x());
}
}
void move_row(int from, int to, int x_delta)
{
// If we're moving right we paint RTL, else we paint LTR, to avoid
// overwriting.
if (x_delta >= 0) {
for (int column = m_bitmap->physical_width() - 1; column >= x_delta; column--) {
m_bitmap->set_pixel(column, to, m_bitmap->get_pixel(column - x_delta, from));
}
} else {
for (int column = 0; column < m_bitmap->physical_width() + x_delta; column++) {
m_bitmap->set_pixel(column, to, m_bitmap->get_pixel(column - x_delta, from));
}
}
}
};
class Mandelbrot : public GUI::Frame {