vga/src/writers/graphics_640x480x16.rs
2020-03-23 19:38:56 -05:00

116 lines
3.9 KiB
Rust

use crate::{
colors::{Color16Bit, DEFAULT_PALETTE},
drawing::{Bresenham, Point},
registers::{PlaneMask, WriteMode},
vga::{Vga, VideoMode, VGA},
};
use spinning_top::SpinlockGuard;
const WIDTH: usize = 640;
const HEIGHT: usize = 480;
const ALL_PLANES_SCREEN_SIZE: usize = (WIDTH * HEIGHT) / 8;
const WIDTH_IN_BYTES: usize = WIDTH / 8;
/// A basic interface for interacting with vga graphics mode 640x480x16
///
/// # Examples
///
/// Basic usage:
///
/// ```no_run
/// use vga::colors::Color16Bit;
/// use vga::writers::Graphics640x480x16;
///
/// let graphics_mode = Graphics640x480x16::new();
///
/// graphics_mode.set_mode();
/// graphics_mode.clear_screen(Color16Bit::Black);
/// ```
#[derive(Default)]
pub struct Graphics640x480x16;
impl Graphics640x480x16 {
/// Creates a new `Graphics640x480x16`.
pub fn new() -> Graphics640x480x16 {
Graphics640x480x16 {}
}
/// Clears the screen by setting all pixels to the specified `color`.
pub fn clear_screen(&self, color: Color16Bit) {
let (mut vga, frame_buffer) = self.get_frame_buffer();
vga.graphics_controller_registers
.set_write_mode(WriteMode::Mode2);
vga.graphics_controller_registers.set_bit_mask(0xFF);
vga.sequencer_registers
.set_plane_mask(PlaneMask::ALL_PLANES);
for offset in 0..ALL_PLANES_SCREEN_SIZE {
unsafe {
frame_buffer.add(offset).write_volatile(u8::from(color));
}
}
}
/// Draws a line from `start` to `end` with the specified `color`.
pub fn draw_line(&self, start: Point<isize>, end: Point<isize>, color: Color16Bit) {
{
let (mut vga, _frame_buffer) = self.get_frame_buffer();
vga.graphics_controller_registers.write_set_reset(color);
vga.graphics_controller_registers
.write_enable_set_reset(0xF);
vga.graphics_controller_registers
.set_write_mode(WriteMode::Mode0);
}
for (x, y) in Bresenham::new(start, end) {
self._set_pixel(x as usize, y as usize, color);
}
}
/// Sets the given pixel at `(x, y)` to the given `color`.
///
/// **Note:** This method is provided for convenience, but has terrible
/// performance since it needs to ensure the correct `WriteMode` per pixel
/// drawn. If you need to draw more then one pixel, consider using a method
/// such as `draw_line`.
pub fn set_pixel(&self, x: usize, y: usize, color: Color16Bit) {
{
let (mut vga, _frame_buffer) = self.get_frame_buffer();
vga.graphics_controller_registers
.set_write_mode(WriteMode::Mode2);
}
self._set_pixel(x, y, color);
}
/// Sets the graphics device to `VideoMode::Mode640x480x16`.
pub fn set_mode(&self) {
let mut vga = VGA.lock();
vga.set_video_mode(VideoMode::Mode640x480x16);
// Some bios mess up the palette when switching modes,
// so explicitly set it.
vga.color_palette_registers.load_palette(&DEFAULT_PALETTE);
}
/// Returns the start of the `FrameBuffer` as `*mut u8` as
/// well as a lock to the vga driver. This ensures the vga
/// driver stays locked while the frame buffer is in use.
fn get_frame_buffer(&self) -> (SpinlockGuard<Vga>, *mut u8) {
let mut vga = VGA.lock();
let frame_buffer = vga.get_frame_buffer();
(vga, u32::from(frame_buffer) as *mut u8)
}
#[inline]
fn _set_pixel(&self, x: usize, y: usize, color: Color16Bit) {
let (mut vga, frame_buffer) = self.get_frame_buffer();
let offset = x / 8 + y * WIDTH_IN_BYTES;
let pixel_mask = 0x80 >> (x & 0x07);
vga.graphics_controller_registers.set_bit_mask(pixel_mask);
unsafe {
frame_buffer.add(offset).read_volatile();
frame_buffer.add(offset).write_volatile(u8::from(color));
}
}
}