94 lines
2.9 KiB
Rust
94 lines
2.9 KiB
Rust
use crate::{
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colors::{Color16Bit, DEFAULT_PALETTE},
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vga::{PlaneMask, Vga, VideoMode, VGA},
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};
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use core::convert::TryInto;
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use spinning_top::SpinlockGuard;
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const WIDTH: usize = 640;
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const HEIGHT: usize = 480;
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const ALL_PLANES_SCREEN_SIZE: usize = (WIDTH * HEIGHT) / 4;
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/// A basic interface for interacting with vga graphics mode 640x480x16
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///
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/// # Examples
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///
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/// Basic usage:
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///
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/// ```no_run
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/// use vga::writers::Graphics640x480x16;
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///
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/// let graphics_mode = Graphics640x480x16::new();
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///
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/// graphics_mode.set_mode();
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/// graphics_mode.clear_screen();
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/// ```
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#[derive(Default)]
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pub struct Graphics640x480x16;
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impl Graphics640x480x16 {
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/// Creates a new `Graphics640x480x16`.
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pub fn new() -> Graphics640x480x16 {
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Graphics640x480x16 {}
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}
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/// Clears the screen by setting all pixels to `Color16Bit::Black`.
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pub fn clear_screen(&self) {
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let (mut vga, frame_buffer) = self.get_frame_buffer();
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vga.set_plane_mask(PlaneMask::ALL_PLANES);
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vga.set_graphics_enable_set_reset(PlaneMask::NONE);
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for offset in 0..ALL_PLANES_SCREEN_SIZE {
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unsafe {
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frame_buffer
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.add(offset)
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.write_volatile(Color16Bit::Black as u8);
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}
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}
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}
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/// Sets the given pixel at `(x, y)` to the given `color`.
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pub fn set_pixel(&self, x: usize, y: usize, color: Color16Bit) {
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let (mut vga, frame_buffer) = self.get_frame_buffer();
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let offset = x / 8 + (WIDTH / 8) * y;
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// Store the current value for masking.
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let x = x & 7;
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let mask = 0x80 >> (x & 7);
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let mut plane_mask = 0x01;
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for plane in 0u8..4u8 {
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vga.set_read_plane(plane.try_into().unwrap());
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vga.set_plane_mask(plane.try_into().unwrap());
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let current_value = unsafe { frame_buffer.add(offset).read_volatile() };
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let new_value = if plane_mask & color as u8 != 0 {
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current_value | mask
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} else {
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current_value & !mask
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};
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unsafe {
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frame_buffer.add(offset).write_volatile(new_value);
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}
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plane_mask <<= 1;
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}
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}
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/// Sets the graphics device to `VideoMode::Mode640x480x16`.
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pub fn set_mode(&self) {
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let mut vga = VGA.lock();
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vga.set_video_mode(VideoMode::Mode640x480x16);
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// Some bios mess up the palette when switching modes,
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// so explicitly set it.
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vga.load_palette(&DEFAULT_PALETTE);
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}
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/// Returns the start of the `FrameBuffer` as `*mut u8` as
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/// well as a lock to the vga driver. This ensures the vga
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/// driver stays locked while the frame buffer is in use.
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fn get_frame_buffer(&self) -> (SpinlockGuard<Vga>, *mut u8) {
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let mut vga = VGA.lock();
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let frame_buffer = vga.get_frame_buffer();
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(vga, u32::from(frame_buffer) as *mut u8)
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}
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}
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