banan-os/kernel/kernel/VesaTerminalDriver.cpp

#include <BAN/Errors.h>
#include <kernel/Debug.h>
#include <kernel/MMU.h>
#include <kernel/multiboot.h>
#include <kernel/VesaTerminalDriver.h>

extern const struct bitmap_font font;

VesaTerminalDriver* VesaTerminalDriver::create()
{
	if (!(g_multiboot_info->flags & MULTIBOOT_FLAGS_FRAMEBUFFER))
	{
		dprintln("Bootloader did not provide framebuffer");
		return nullptr;
	}

	auto& framebuffer = g_multiboot_info->framebuffer;

	if (framebuffer.type == MULTIBOOT_FRAMEBUFFER_TYPE_GRAPHICS)
	{
		if (framebuffer.bpp != 24 && framebuffer.bpp != 32)
		{
			dprintln("Unsupported bpp {}", framebuffer.bpp);
			return nullptr;
		}
		dprintln("Graphics Mode {}x{} ({} bpp)", framebuffer.width, framebuffer.height, framebuffer.bpp);
	}
	else if (framebuffer.type == MULTIBOOT_FRAMEBUFFER_TYPE_TEXT)
	{
		dprintln("Text Mode is currently not supported");
		return nullptr;
	}
	else
	{
		dprintln("Unknown framebuffer type {}", framebuffer.type);
		return nullptr;
	}

	MMU::get().allocate_range(framebuffer.addr, framebuffer.pitch * framebuffer.height);

	auto* driver = new VesaTerminalDriver(
		framebuffer.width,
		framebuffer.height,
		framebuffer.pitch,
		framebuffer.bpp,
		framebuffer.addr,
		font
	);
	driver->set_cursor_position(0, 0);
	driver->clear(TerminalColor::BLACK);
	return driver;
}


VesaTerminalDriver::~VesaTerminalDriver()
{
	MMU::get().unallocate_range(m_address, m_pitch * m_height);
}

void VesaTerminalDriver::set_pixel(uint32_t offset, Color color)
{	
	uint32_t* pixel = (uint32_t*)(m_address + offset);
	switch (m_bpp)
	{
		case 24:
			*pixel = (*pixel & 0xFF000000) | (color.rgb & 0x00FFFFFF);
			break;
		case 32:
			*pixel = color.rgb;
			break;
	}
}

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 = m_font.Bitmap + glyph_index * m_font.Height;

	x *= m_font.Width;
	y *= m_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 pixel_offset = row_offset;
		for (uint32_t dx = 0; dx < m_font.Width && x + dx < m_width; dx++)
		{
			uint8_t bitmask = 1 << (font.Width - dx - 1);
			set_pixel(pixel_offset, glyph[dy] & bitmask ? fg : bg);
			pixel_offset += m_bpp / 8;
		}
		row_offset += m_pitch;
	}
}

void VesaTerminalDriver::clear(Color color)
{
	if (m_bpp == 32)
	{
		uint32_t cells_per_row = m_pitch / 4;
		for (uint32_t y = 0; y < m_height; y++)
			for (uint32_t x = 0; x < m_width; x++)
				((uint32_t*)m_address)[y * cells_per_row + x] = color.rgb;
		return;
	}

	uint32_t row_offset = 0;
	for (uint32_t y = 0; y < m_height; y++)
	{
		uint32_t pixel_offset = row_offset;
		for (uint32_t x = 0; x < m_width; x++)
		{
			set_pixel(pixel_offset, color);
			pixel_offset += m_bpp / 8;
		}
		row_offset += m_pitch;
	}
}

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,
		________,
	};

	x *= m_font.Width;
	y *= m_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 pixel_offset = row_offset;
		for (uint32_t dx = 0; dx < m_font.Width && x + dx < m_width; dx++)
		{
			uint8_t bitmask = 1 << (font.Width - dx - 1);
			if (cursor[dy] & bitmask)
				set_pixel(pixel_offset, s_cursor_color);
			pixel_offset += m_bpp / 8;
		}
		row_offset += m_pitch;
	}
}