sh1106-pico-rs/src/graphics.rs

use crate::sprite::{Sprite, SpriteAtlas};

pub struct GraphicsBuf {
    buffer: [u8; 8192],
    sprites: [Sprite; 30],
    sprite_atlas: SpriteAtlas,
}

impl GraphicsBuf {
    pub fn new() -> Self {
        let sprite_atlas = SpriteAtlas::new(include_bytes!("../sprites/sprites_atlas.bin"));

        let mut sprites = [Sprite::new(); 30];

        sprites[0].sprite_index = 94;
        sprites[0].x = 90;
        sprites[0].y = 30;
        sprites[0].visible = true;

        GraphicsBuf {
            buffer: [0u8; 8192],
            sprites,
            sprite_atlas,
        }
    }

    pub fn clear(&mut self) {
        self.buffer.iter_mut().for_each(|b| *b = 0);
    }

    pub fn redraw(&mut self) {
        let mut gfx_buf = &mut self.buffer;

        self.sprites.iter_mut().for_each(|s| {
            if s.visible {
                self.sprite_atlas.draw_sprite(
                    s.sprite_index,
                    s.x as u8,
                    s.y as u8,
                    s.flip,
                    &mut gfx_buf,
                );
            }
        });

        self.sprite_atlas
            .draw_string(10, 10, "Hello World!", &mut gfx_buf);

        self.sprite_atlas.draw_textfield(
            10,
            20,
            110,
            10,
            "I think this font has a *lot* of 'character'! ;)",
            &mut gfx_buf,
        );

        draw_bresenham_line(0, 0, 127, 0, &mut gfx_buf);
        draw_bresenham_line(0, 63, 128, 63, &mut gfx_buf);
        draw_bresenham_line(0, 0, 0, 63, &mut gfx_buf);
        draw_bresenham_line(127, 0, 127, 63, &mut gfx_buf);
    }

    pub fn get_px_buffer(&self) -> &[u8; 8192] {
        &self.buffer
    }
}

fn draw_bresenham_line(x0: u8, y0: u8, x1: u8, y1: u8, gfx_buf: &mut [u8; 8192]) {
    let x0 = (x0 as i32).clamp(0, 127);
    let x1 = (x1 as i32).clamp(0, 127);
    let y0 = (y0 as i32).clamp(0, 63);
    let y1 = (y1 as i32).clamp(0, 63);

    let mut dx = x1 - x0;
    let mut dy = y1 - y0;

    let mut x = x0;
    let mut y = y0;

    let mut err = 0;

    let mut step_x = 1;
    let mut step_y = 1;

    if dx < 0 {
        dx = -dx;
        step_x = -1;
    }

    if dy < 0 {
        dy = -dy;
        step_y = -1;
    }

    if dx > dy {
        for _ in 0..dx {
            gfx_buf[(y * 128 + x) as usize] = 1;

            x += step_x;
            err += 2 * dy;

            if err > dx {
                y += step_y;
                err -= 2 * dx;
            }
        }
    } else {
        for _ in 0..dy {
            gfx_buf[(y * 128 + x) as usize] = 1;

            y += step_y;
            err += 2 * dx;

            if err > dy {
                x += step_x;
                err -= 2 * dy;
            }
        }
    }
}