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WindowServer: Coordinate double-buffering with the BochsVGA card.

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Use the BochsVGA card's virtual-height + virtual-y features to implement
a "hardware double buffering" type scheme.

This is a performance degradation since we now draw a bunch more than before.
But there's also no tearing or cursor flickering. I'm gonna commit this and
try to improve upon it. :^)
This commit is contained in:
Andreas Kling 2019-02-07 08:53:57 +01:00
parent 1f159eaab0
commit 443d1c2237
6 changed files with 52 additions and 15 deletions
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49
WindowServer/WSWindowManager.cpp
View file

@ -9,6 +9,7 @@
#include <SharedGraphics/Painter.h>
#include <SharedGraphics/CharacterBitmap.h>
#include <AK/StdLibExtras.h>
#include <Kernel/BochsVGADevice.h>
//#define DEBUG_COUNTERS
//#define DEBUG_WID_IN_TITLE_BAR
@ -115,6 +116,17 @@ static const char* cursor_bitmap_outer_ascii = {
" ## "
};
void WSWindowManager::flip_buffers()
{
swap(m_front_bitmap, m_back_bitmap);
swap(m_front_painter, m_back_painter);
if (m_buffers_are_flipped)
BochsVGADevice::the().set_y_offset(0);
else
BochsVGADevice::the().set_y_offset(m_screen_rect.height());
m_buffers_are_flipped = !m_buffers_are_flipped;
}
WSWindowManager::WSWindowManager()
: m_screen(WSScreen::the())
, m_screen_rect(m_screen.rect())
@ -125,8 +137,7 @@ WSWindowManager::WSWindowManager()
#endif
auto size = m_screen_rect.size();
m_front_bitmap = GraphicsBitmap::create_wrapper(size, m_screen.scanline(0));
auto* region = current->allocate_region(LinearAddress(), size.width() * size.height() * sizeof(RGBA32), "BackBitmap", true, true, true);
m_back_bitmap = GraphicsBitmap::create_wrapper(m_screen_rect.size(), (RGBA32*)region->laddr().get());
m_back_bitmap = GraphicsBitmap::create_wrapper(size, m_screen.scanline(size.height()));
m_front_painter = make<Painter>(*m_front_bitmap);
m_back_painter = make<Painter>(*m_back_bitmap);
@ -389,6 +400,9 @@ void WSWindowManager::compose()
{
LOCKER(m_lock);
auto dirty_rects = move(m_dirty_rects);
auto cursor_location = m_screen.cursor_location();
dirty_rects.append(m_last_cursor_rect);
dirty_rects.append({ cursor_location.x(), cursor_location.y(), (int)m_cursor_bitmap_inner->width(), (int)m_cursor_bitmap_inner->height() });
#ifdef DEBUG_COUNTERS
dbgprintf("[WM] compose #%u (%u rects)\n", ++m_compose_count, dirty_rects.size());
dbgprintf("kmalloc stats: alloc:%u free:%u eternal:%u\n", sum_alloc, sum_free, kmalloc_sum_eternal);
@ -440,9 +454,24 @@ void WSWindowManager::compose()
}
m_back_painter->clear_clip_rect();
}
draw_cursor();
if (m_flash_flush) {
for (auto& rect : dirty_rects)
m_front_painter->fill_rect(rect, Color::Yellow);
}
flip_buffers();
for (auto& r : dirty_rects)
flush(r);
draw_cursor();
}
void WSWindowManager::invalidate_cursor()
{
LOCKER(m_lock);
auto cursor_location = m_screen.cursor_location();
Rect cursor_rect { cursor_location.x(), cursor_location.y(), (int)m_cursor_bitmap_inner->width(), (int)m_cursor_bitmap_inner->height() };
invalidate(cursor_rect);
}
void WSWindowManager::draw_cursor()
@ -451,13 +480,12 @@ void WSWindowManager::draw_cursor()
LOCKER(m_lock);
auto cursor_location = m_screen.cursor_location();
Rect cursor_rect { cursor_location.x(), cursor_location.y(), (int)m_cursor_bitmap_inner->width(), (int)m_cursor_bitmap_inner->height() };
flush(m_last_cursor_rect.united(cursor_rect));
Color inner_color = Color::White;
Color outer_color = Color::Black;
if (m_screen.left_mouse_button_pressed())
swap(inner_color, outer_color);
m_front_painter->draw_bitmap(cursor_location, *m_cursor_bitmap_inner, inner_color);
m_front_painter->draw_bitmap(cursor_location, *m_cursor_bitmap_outer, outer_color);
m_back_painter->draw_bitmap(cursor_location, *m_cursor_bitmap_inner, inner_color);
m_back_painter->draw_bitmap(cursor_location, *m_cursor_bitmap_outer, outer_color);
m_last_cursor_rect = cursor_rect;
}
@ -565,15 +593,12 @@ void WSWindowManager::flush(const Rect& a_rect)
#endif
RGBA32* front_ptr = m_front_bitmap->scanline(rect.y()) + rect.x();
const RGBA32* back_ptr = m_back_bitmap->scanline(rect.y()) + rect.x();
RGBA32* back_ptr = m_back_bitmap->scanline(rect.y()) + rect.x();
size_t pitch = m_back_bitmap->pitch();
if (m_flash_flush)
m_front_painter->fill_rect(rect, Color::Yellow);
for (int y = 0; y < rect.height(); ++y) {
fast_dword_copy(front_ptr, back_ptr, rect.width());
fast_dword_copy(back_ptr, front_ptr, rect.width());
front_ptr = (RGBA32*)((byte*)front_ptr + pitch);
back_ptr = (const RGBA32*)((const byte*)back_ptr + pitch);
back_ptr = (RGBA32*)((byte*)back_ptr + pitch);
}
}