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-rw-r--r--src/devices/screen/draw_line.rs223
1 files changed, 223 insertions, 0 deletions
diff --git a/src/devices/screen/draw_line.rs b/src/devices/screen/draw_line.rs
new file mode 100644
index 0000000..94066f4
--- /dev/null
+++ b/src/devices/screen/draw_line.rs
@@ -0,0 +1,223 @@
+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);
+ }
+ }
+ }
+ }
+
+
+
+}
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