Kernel: Fonts can now be parsed from the filesystem and set to terminal

We currently dont have a fallback font if we cannot get to filesystem
initialization, but that will come later. I can't test on real hardware
for this reason.

kernel/kernel/Shell.cpp

@@ -324,6 +324,21 @@ argument_done:
 
 			TTY_PRINTLN("{}", BAN::StringView((const char*)data.data(), data.size()));
 		}
+		else if (arguments.front() == "loadfont")
+		{
+			if (!VirtualFileSystem::is_initialized())
+				return TTY_PRINTLN("VFS not initialized :(");
+
+			if (arguments.size() != 2)
+				return TTY_PRINTLN("usage: 'loadfont font_path'");
+
+			auto font_or_error = Font::load(arguments[1]);
+			if (font_or_error.is_error())
+				return TTY_PRINTLN("{}", font_or_error.error());
+			auto font = font_or_error.release_value();
+
+			m_tty->set_font(font);
+		}
 		else
 		{
 			TTY_PRINTLN("unrecognized command '{}'", arguments.front());

kernel/kernel/TTY.cpp

@@ -52,6 +52,14 @@ void TTY::set_cursor_position(uint32_t x, uint32_t y)
 	last_y = m_row = y;
 }
 
+void TTY::set_font(const Kernel::Font& font)
+{
+	m_terminal_driver->set_font(font);
+	for (uint32_t y = 0; y < m_height; y++)
+		for (uint32_t x = 0; x < m_width; x++)
+			render_from_buffer(x, y);
+}
+
 static uint16_t handle_unicode(uint8_t ch)
 {
 	static uint8_t	unicode_left = 0;

kernel/kernel/VesaTerminalDriver.cpp

@@ -4,9 +4,7 @@
 #include <kernel/multiboot.h>
 #include <kernel/VesaTerminalDriver.h>
 
-extern const struct bitmap_font font;
-
-VesaTerminalDriver* VesaTerminalDriver::create()
+VesaTerminalDriver* VesaTerminalDriver::create(const Kernel::Font& font)
 {
 	if (!(g_multiboot_info->flags & MULTIBOOT_FLAGS_FRAMEBUFFER))
 	{
@@ -73,29 +71,19 @@ void VesaTerminalDriver::set_pixel(uint32_t offset, Color color)
 
 void VesaTerminalDriver::putchar_at(uint16_t ch, uint32_t x, uint32_t y, Color fg, Color bg)
 {
-	uint32_t glyph_index = 0;
-	for (uint32_t i = 0; i < m_font.Chars; i++)
-	{
-		if (m_font.Index[i] == ch)
-		{
-			glyph_index = i;
-			break;
-		}
-	}
+	const uint8_t* glyph = font().has_glyph(ch) ? font().glyph(ch) : font().glyph('?');
 
-	const uint8_t* glyph = m_font.Bitmap + glyph_index * m_font.Height;
-
-	x *= m_font.Width;
-	y *= m_font.Height;
+	x *= font().width();
+	y *= font().height();
 
 	uint32_t row_offset = y * m_pitch + x * m_bpp / 8;
-	for (uint32_t dy = 0; dy < m_font.Height && y + dy < m_height; dy++)
+	for (uint32_t dy = 0; dy < font().height() && y + dy < m_height; dy++)
 	{
 		uint32_t pixel_offset = row_offset;
-		for (uint32_t dx = 0; dx < m_font.Width && x + dx < m_width; dx++)
+		for (uint32_t dx = 0; dx < font().width() && x + dx < m_width; dx++)
 		{
-			uint8_t bitmask = 1 << (font.Width - dx - 1);
-			set_pixel(pixel_offset, glyph[dy] & bitmask ? fg : bg);
+			uint8_t bitmask = 1 << (font().width() - dx - 1);
+			set_pixel(pixel_offset, glyph[dy * font().pitch()] & bitmask ? fg : bg);
 			pixel_offset += m_bpp / 8;
 		}
 		row_offset += m_pitch;
@@ -128,38 +116,19 @@ void VesaTerminalDriver::clear(Color color)
 
 void VesaTerminalDriver::set_cursor_position(uint32_t x, uint32_t y)
 {
-	ASSERT(m_font.Height == 16 && m_font.Width == 8);
-	constexpr uint8_t cursor[] = {
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		________,
-		XXXXXXXX,
-		XXXXXXXX,
-		________,
-	};
+	uint32_t cursor_h = font().height() / 8;
+	uint32_t cursor_top = font().height() * 13 / 16;
 
-	x *= m_font.Width;
-	y *= m_font.Height;
+	x *= font().width();
+	y *= font().height();
 
-	uint32_t row_offset = y * m_pitch + x * m_bpp / 8;
-	for (uint32_t dy = 0; dy < m_font.Height && y + dy < m_height; dy++)
+	uint32_t row_offset = (y + cursor_top) * m_pitch + x * m_bpp / 8;
+	for (uint32_t dy = 0; dy < cursor_h; dy++)
 	{
 		uint32_t pixel_offset = row_offset;
-		for (uint32_t dx = 0; dx < m_font.Width && x + dx < m_width; dx++)
+		for (uint32_t dx = 0; dx < font().width(); dx++)
 		{
-			uint8_t bitmask = 1 << (font.Width - dx - 1);
-			if (cursor[dy] & bitmask)
-				set_pixel(pixel_offset, s_cursor_color);
+			set_pixel(pixel_offset, s_cursor_color);
 			pixel_offset += m_bpp / 8;
 		}
 		row_offset += m_pitch;

kernel/kernel/kernel.cpp

@@ -76,29 +76,40 @@ extern "C" void kernel_main()
 	dprintln("kmalloc initialized");
 
 	IDT::initialize();
-	dprintln("IDT initialized");
+	dprintln("IDT initialized");	
 
 	MMU::intialize();
 	dprintln("MMU initialized");
 
-	TerminalDriver* terminal_driver = VesaTerminalDriver::create();
-	ASSERT(terminal_driver);
-	dprintln("VESA initialized");
-	TTY* tty1 = new TTY(terminal_driver);
+	//TerminalDriver* terminal_driver = VesaTerminalDriver::create();
+	//ASSERT(terminal_driver);
+	//dprintln("VESA initialized");
+	//TTY* tty1 = new TTY(terminal_driver);
 	
 	InterruptController::initialize(cmdline.force_pic);
 	dprintln("Interrupt controller initialized");
 
 	PIT::initialize();
 	dprintln("PIT initialized");
+
 	if (!Input::initialize())
 		return;
 	dprintln("8042 initialized");
 
 	Scheduler::initialize();
 	Scheduler& scheduler = Scheduler::get();
-	MUST(scheduler.add_thread(BAN::Function<void()>([] { DiskIO::initialize(); })));
-	MUST(scheduler.add_thread(BAN::Function<void()>([tty1] { Shell(tty1).run(); })));
+	MUST(scheduler.add_thread(BAN::Function<void()>(
+		[]
+		{
+			DiskIO::initialize();
+			dprintln("Disk IO initialized");
+
+			auto font = MUST(Font::load("/usr/share/fonts/zap-ext-vga16.psf"));
+			dprintln("Font loaded");
+
+			Shell(new TTY(VesaTerminalDriver::create(font))).run();
+		}
+	)));
 	scheduler.start();
 	ASSERT(false);
 }