RockOS/kernel/drivers/vga/vga.c

#include <stddef.h>
#include <stdint.h>

#include <lib/stream.h>

#include <drivers/vga/vga.h>
#include <drivers/serial/serial.h>

#include <common.h>
#include <memory/mm.h>

static uint32_t framebuffer_address;
static uint32_t framebuffer_width;
static uint32_t framebuffer_height;
static uint32_t framebuffer_total_pixels;
static uint32_t framebuffer_pitch;
static uint32_t framebuffer_bpp;

static uint8_t red_mask_sz;
static uint8_t red_field_pos;
static uint8_t green_mask_sz;
static uint8_t green_field_pos;
static uint8_t blue_mask_sz;
static uint8_t blue_field_pos;

static uint32_t create_pixel(uint8_t r, uint8_t g, uint8_t b) {
    return (r >> (8 - red_mask_sz)) << red_field_pos
         | (g >> (8 - green_mask_sz)) << green_field_pos
         | (b >> (8 - blue_mask_sz)) << blue_field_pos;
}

vga_color_t VGA_COLOR_BLACK = {0, 0, 0, 255};
vga_color_t VGA_COLOR_RED	= {0, 0, 255, 255};
vga_color_t VGA_COLOR_GREEN	= {0, 255, 0, 255};
vga_color_t VGA_COLOR_BLUE	= {255, 0, 0, 255};

void vga_init(
	uint32_t fb_paddr,
	uint32_t fb_width,
	uint32_t fb_height,
	uint32_t fb_pitch,
	uint8_t fb_bpp,
	uint8_t _red_mask_sz,
	uint8_t _red_field_pos,
	uint8_t _green_mask_sz,
	uint8_t _green_field_pos,
	uint8_t _blue_mask_sz,
	uint8_t _blue_field_pos
) {
	framebuffer_address = VGA_FRAMEBUFFER;
	
	red_mask_sz = _red_mask_sz;
	red_field_pos = _red_field_pos;
	green_mask_sz = _green_mask_sz;
	green_field_pos = _green_field_pos;
	blue_mask_sz = _blue_mask_sz;
	blue_field_pos = _blue_field_pos;

	print_serial("initializing vga.\r\n");
	print_serial_hex(fb_paddr);
	print_serial("\r\n");
	print_serial_hex(framebuffer_address);
	print_serial("\r\n");
	print_serial("BPP: ");
	print_serial_hex(fb_bpp);
	print_serial("\r\n");

	uint32_t fb_size_bytes = fb_height * fb_pitch;
	uint32_t num_pages = (fb_size_bytes + 4095) / 4096; 
	for (uint32_t i = 0; i < num_pages; i++) {
		uint32_t phys_addr = fb_paddr + (i * 4096);
		uint32_t virt_addr = VGA_FRAMEBUFFER + (i * 4096);
		map_page(virt_addr, phys_addr, PAGE_PRESENT | PAGE_WRITABLE);
	}

	framebuffer_width = fb_width;
	framebuffer_height = fb_height;
	framebuffer_total_pixels = framebuffer_width * framebuffer_height;

	framebuffer_pitch = fb_pitch;
	framebuffer_bpp = fb_bpp;

	vga_clear_scrn(0x00000000);
}

uint32_t vga_get_framebuffer() {
	return framebuffer_address;
}

uint32_t vga_get_width() {
	return framebuffer_width;
}

uint32_t vga_get_height() {
	return framebuffer_height;
}

uint32_t vga_get_pitch() {
	return framebuffer_pitch;
}

uint8_t vga_get_bpp() {
	return framebuffer_bpp;
}

void vga_clear_scrn(uint32_t color) {
	if (framebuffer_address == 0) return;

    uint8_t* fb_bytes = (uint8_t*)framebuffer_address;
    uint8_t bytes_per_pixel = framebuffer_bpp / 8;

    for (uint32_t y = 0; y < framebuffer_height; y++) {
        uint8_t* row = fb_bytes + (y * framebuffer_pitch);

        for (uint32_t x = 0; x < framebuffer_width; x++) {
            uint8_t* pixel = row + (x * bytes_per_pixel);

			switch(framebuffer_bpp) {
				case 32: {
					*(uint32_t*)pixel = color;
					break;
				}
			}
        }
    }
}

uint32_t vga_write(vfs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buf) {
	return size;
}

void test_draw_vertical_line(uint32_t x, uint32_t y_start, uint32_t y_end, uint32_t color) {
    if (framebuffer_address == 0) return;

    uint8_t* fb_bytes = (uint8_t*)framebuffer_address;

    for (uint32_t y = y_start; y < y_end; y++) {
        if (y >= framebuffer_height) break; 

        uint8_t* row = fb_bytes + (y * framebuffer_pitch);

        uint32_t* pixel_row = (uint32_t*)row;

        if (x < framebuffer_width) {
            pixel_row[x] = color;
        }
    }
}