use super::*;
impl ScreenDevice {
pub fn draw_line(&mut self, colour: u8, layer: ScreenLayer) {
let [p0, p1] = [self.cursor, self.vector];
match (p0.x == p1.x, p0.y == p1.y) {
(false, false) => self.draw_diagonal_line(colour, layer),
(false, true) => self.draw_horizontal_line(colour, layer),
( true, false) => self.draw_vertical_line(colour, layer),
( true, true) => self.draw_pixel(colour, layer, p0),
};
}
pub fn draw_line_1bit(&mut self, params: u8, layer: ScreenLayer) {
let [p0, p1] = [self.cursor, self.vector];
match (p0.x == p1.x, p0.y == p1.y) {
(false, false) => self.draw_diagonal_line_1bit(params, layer),
(false, true) => self.draw_horizontal_line_1bit(params, layer),
( true, false) => self.draw_vertical_line_1bit(params, layer),
( true, true) => self.draw_pixel_1bit(params, layer, p0),
};
}
pub fn draw_pixel_1bit(&mut self, params: u8, layer: ScreenLayer, point: ScreenPosition) {
let dim = self.dimensions;
let sprite = self.sprite_buffer.get_1bit_sprite(params);
let colour = sprite[point.y as usize % 8][point.x as usize % 8];
if !dim.contains_point(point) || colour == 0xff { return }
let index = point.x as usize + ((dim.width as usize) * (point.y as usize));
match layer {
ScreenLayer::Background => self.background[index] = colour,
ScreenLayer::Foreground => self.foreground[index] = colour,
};
}
fn draw_horizontal_line(&mut self, colour: u8, layer: ScreenLayer) {
if let Some([x0, y, x1, _]) = self.find_vector_bounding_box() {
let screen_width = self.dimensions.width as usize;
let i = screen_width * y;
let buffer = match layer {
ScreenLayer::Background => &mut self.background,
ScreenLayer::Foreground => &mut self.foreground,
};
buffer[i+x0..=i+x1].fill(colour);
}
}
fn draw_horizontal_line_1bit(&mut self, params: u8, layer: ScreenLayer) {
if let Some([x0, y, x1, _]) = self.find_vector_bounding_box() {
let screen_width = self.dimensions.width as usize;
let i = screen_width * y;
let buffer = match layer {
ScreenLayer::Background => &mut self.background,
ScreenLayer::Foreground => &mut self.foreground,
};
let sprite = self.sprite_buffer.get_1bit_sprite(params);
let row = sprite[y % 8];
for x in x0..=x1 {
let colour = row[x % 8];
if colour != 0xff { buffer[i+x] = colour };
}
}
}
fn draw_vertical_line(&mut self, colour: u8, layer: ScreenLayer) {
if let Some([x, y0, _, y1]) = self.find_vector_bounding_box() {
let screen_width = self.dimensions.width as usize;
let mut i = (screen_width * y0) + x;
let buffer = match layer {
ScreenLayer::Background => &mut self.background,
ScreenLayer::Foreground => &mut self.foreground,
};
for _ in y0..=y1 {
buffer[i] = colour;
i += screen_width;
}
}
}
fn draw_vertical_line_1bit(&mut self, params: u8, layer: ScreenLayer) {
if let Some([x, y0, _, y1]) = self.find_vector_bounding_box() {
let screen_width = self.dimensions.width as usize;
let mut i = (screen_width * y0) + x;
let buffer = match layer {
ScreenLayer::Background => &mut self.background,
ScreenLayer::Foreground => &mut self.foreground,
};
let sprite = self.sprite_buffer.get_1bit_sprite(params);
let mut column = [0u8; 8];
for y in 0..8 { column[y] = sprite[y][x % 8] }
for y in y0..=y1 {
let colour = column[y % 8];
if colour != 0xff { buffer[i] = colour };
i += screen_width;
}
}
}
fn draw_diagonal_line(&mut self, colour: u8, layer: ScreenLayer) {
fn abs_diff(v0: u16, v1: u16) -> u16 {
let v = v1.wrapping_sub(v0);
if v > 0x8000 { !v + 1 } else { v }
}
let [p0, p1] = [self.cursor, self.vector];
// If the slope of the line is greater than 1.
if abs_diff(p0.y, p1.y) > abs_diff(p0.x, p1.x) {
// Swap points 0 and 1 such that y0 is always smaller than y1.
let (x0, y0, x1, y1) = match p0.y > p1.y {
true => (p1.x, p1.y, p0.x, p0.y),
false => (p0.x, p0.y, p1.x, p1.y),
};
let dy = y1 - y0;
let (dx, xi) = match x0 > x1 {
true => (x0 - x1, 0xffff),
false => (x1 - x0, 0x0001),
};
let dxdy2 = (dx.wrapping_sub(dy)).wrapping_mul(2);
let dx2 = dx * 2;
let mut d = dx2.wrapping_sub(dy);
let mut x = x0;
for y in y0..=y1 {
self.draw_pixel(colour, layer, ScreenPosition::new(x, y));
if d < 0x8000 {
x = x.wrapping_add(xi); d = d.wrapping_add(dxdy2);
} else {
d = d.wrapping_add(dx2);
}
}
// If the slope of the line is less than or equal to 1.
} else {
// Swap points 0 and 1 so that x0 is always smaller than x1.
let (x0, y0, x1, y1) = match p0.x > p1.x {
true => (p1.x, p1.y, p0.x, p0.y),
false => (p0.x, p0.y, p1.x, p1.y),
};
let dx = x1 - x0;
let (dy, yi) = match y0 > y1 {
true => (y0 - y1, 0xffff),
false => (y1 - y0, 0x0001),
};
let dydx2 = (dy.wrapping_sub(dx)).wrapping_mul(2);
let dy2 = dy * 2;
let mut d = dy2.wrapping_sub(dx);
let mut y = y0;
for x in x0..=x1 {
self.draw_pixel(colour, layer, ScreenPosition::new(x, y));
if d < 0x8000 {
y = y.wrapping_add(yi);
d = d.wrapping_add(dydx2);
} else {
d = d.wrapping_add(dy2);
}
}
}
}
fn draw_diagonal_line_1bit(&mut self, params: u8, layer: ScreenLayer) {
fn abs_diff(v0: u16, v1: u16) -> u16 {
let v = v1.wrapping_sub(v0);
if v > 0x8000 { !v + 1 } else { v }
}
let [p0, p1] = [self.cursor, self.vector];
// If the slope of the line is greater than 1.
if abs_diff(p0.y, p1.y) > abs_diff(p0.x, p1.x) {
// Swap points 0 and 1 such that y0 is always smaller than y1.
let (x0, y0, x1, y1) = match p0.y > p1.y {
true => (p1.x, p1.y, p0.x, p0.y),
false => (p0.x, p0.y, p1.x, p1.y),
};
let dy = y1 - y0;
let (dx, xi) = match x0 > x1 {
true => (x0 - x1, 0xffff),
false => (x1 - x0, 0x0001),
};
let dxdy2 = (dx.wrapping_sub(dy)).wrapping_mul(2);
let dx2 = dx * 2;
let mut d = dx2.wrapping_sub(dy);
let mut x = x0;
for y in y0..=y1 {
self.draw_pixel_1bit(params, layer, ScreenPosition::new(x, y));
if d < 0x8000 {
x = x.wrapping_add(xi); d = d.wrapping_add(dxdy2);
} else {
d = d.wrapping_add(dx2);
}
}
// If the slope of the line is less than or equal to 1.
} else {
// Swap points 0 and 1 so that x0 is always smaller than x1.
let (x0, y0, x1, y1) = match p0.x > p1.x {
true => (p1.x, p1.y, p0.x, p0.y),
false => (p0.x, p0.y, p1.x, p1.y),
};
let dx = x1 - x0;
let (dy, yi) = match y0 > y1 {
true => (y0 - y1, 0xffff),
false => (y1 - y0, 0x0001),
};
let dydx2 = (dy.wrapping_sub(dx)).wrapping_mul(2);
let dy2 = dy * 2;
let mut d = dy2.wrapping_sub(dx);
let mut y = y0;
for x in x0..=x1 {
self.draw_pixel_1bit(params, layer, ScreenPosition::new(x, y));
if d < 0x8000 {
y = y.wrapping_add(yi);
d = d.wrapping_add(dydx2);
} else {
d = d.wrapping_add(dy2);
}
}
}
}
}
