gooey/interface/view/

coordinates.rs

//! Tile and pixel positions and dimensions.
//!
//! # Coordinate systems
//!
//! The interface works with two types of coordinates: tile and pixel.
//!
//! Tile coordinates are given in (row,column) pairs, while pixel coordinates
//! are defined as (x,y) pairs, where $x$ is understood to be the horizontal
//! component and $y$ the vertical component.
//!
//! Both coordinate systems are left-handed, however they are oriented
//! differently:
//!
//! - The tile coordinate origin is taken to be the upper-left, with
//!   rows increasing towards the bottom and columns increasing towards the
//!   right.
//! - The pixel coordinate origin is taken to be the bottom-left, with $x$
//!   increasing towards the right and $y$ increasing towards the top.
//!
//! The main layout component is the view *`Canvas`* component which contains a
//! coordinates field.
//!
//! ## Presentation backends
//!
//! Different presentation backends may have their own coordinate systems.
//!
//! **Curses**
//!
//! TODO
//!
//! **OpenGL**
//!
//! The OpenGL rendering backend supports both pixel-based and tile-based
//! rendering.
//!
//! By default the 2D camera is centered with (0,0) in the center of the screen.
//! In the presentation implementation, the camera is moved so that (0,0) is at
//! the bottom-left of the screen.
//!
//! TODO: more

use std;
use std::sync::LazyLock;
use derive_more::{From, TryInto};

// TODO: use tagged coordinates?

use crate::math::Vector2;
use crate::geometry::integer::Aabb2;

pub use self::position::Position;
pub use self::dimensions::Dimensions;

pub (crate) static TILE_WH : LazyLock <[u32; 2]> = LazyLock::new (||{
  let width  = std::env::var ("GOOEY_TILE_WIDTH").unwrap().parse().unwrap();
  let height = std::env::var ("GOOEY_TILE_HEIGHT").unwrap().parse().unwrap();
  [width, height]
});
pub (crate) static SCREEN_WH : LazyLock <std::sync::RwLock <[u32; 2]>> = LazyLock::new (
  || std::sync::RwLock::new ([0, 0]));

#[derive(Clone, Copy, Debug, Eq, PartialEq, From, TryInto)]
pub enum Coordinates {
  Tile  (position::Tile,  dimensions::Tile),
  Pixel (position::Pixel, dimensions::Pixel)
}

#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum Kind {
  Tile, Pixel
}

/// Convert a screen pixel (x, y) coordinate to a tile (row, column) coordinate
pub fn pixel_to_tile (x : i32, y : i32) -> [i32; 2] {
  let [tile_w,   tile_h]    = *TILE_WH;
  let [_screen_w, screen_h] = *SCREEN_WH.read().unwrap();
  let column = x / tile_w as i32;
  let row    = (screen_h as i32 - y) / tile_h as i32;
  [row, column]
}

/// Convert a screen pixel (x, y) AABB to tile (row, column) coordinate AABB
pub fn pixel_to_tile_aabb (aabb : Aabb2 <i32>) -> Aabb2 <i32> {
  let [min_x, min_y] = aabb.min().0.into_array();
  let [max_x, max_y] = aabb.max().0.into_array();
  let min = pixel_to_tile (min_x, max_y).into();
  let max = pixel_to_tile (max_x, min_y).into();
  Aabb2::with_minmax (min, max)
}

/// Convert a (row, column) coordinate to a screen pixel (x, y) coordinate
pub fn tile_to_pixel (row : i32, column : i32) -> [i32; 2] {
  let [tile_w,   tile_h]    = *TILE_WH;
  let [_screen_w, screen_h] = *SCREEN_WH.read().unwrap();
  let x = column * tile_w as i32;
  let y = screen_h as i32 - row * tile_h as i32;
  [x, y]
}

/// Convert a (row, column) AABB to a screen pixel (x, y) coordinate AABB
pub fn tile_to_pixel_aabb (aabb : Aabb2 <i32>) -> Aabb2 <i32> {
  let aabb = Aabb2::with_minmax (
    *aabb.min(),
    aabb.max() + Vector2::new (1, 1)
  );
  let [min_row, min_col] = aabb.min().0.into_array();
  let [max_row, max_col] = aabb.max().0.into_array();
  let min = tile_to_pixel (max_row, min_col).into();
  let max = tile_to_pixel (min_row, max_col).into();
  Aabb2::with_minmax (min, max)
}

impl Coordinates {
  #[inline]
  pub fn default_tile() -> Self {
    (position::Tile::default(), dimensions::Tile::default()).into()
  }
  #[inline]
  pub fn default_pixel() -> Self {
    (position::Pixel::default(), dimensions::Pixel::default()).into()
  }
  pub fn tile_from_aabb (aabb : Aabb2 <i32>) -> Self {
    let position   = (*aabb.min()).into();
    let dimensions = ((*aabb.max() - aabb.min()) + Vector2::new (1, 1))
      .numcast().unwrap().into();
    Coordinates::Tile (position, dimensions)
  }
  pub fn pixel_from_aabb (aabb : Aabb2 <i32>) -> Self {
    let position   = (*aabb.min()).into();
    let dimensions = ((*aabb.max() - aabb.min()) + Vector2::new (1, 1))
      .numcast().unwrap().into();
    Coordinates::Pixel (position, dimensions)
  }
  #[inline]
  pub const fn kind (&self) -> Kind {
    match self {
      Coordinates::Tile  (_, _) => Kind::Tile,
      Coordinates::Pixel (_, _) => Kind::Pixel
    }
  }
  #[inline]
  pub fn dimensions (&self) -> Dimensions {
    match self {
      Coordinates::Tile  (_, dimensions) => (*dimensions).into(),
      Coordinates::Pixel (_, dimensions) => (*dimensions).into()
    }
  }
  #[inline]
  pub fn position (&self) -> Position {
    match self {
      Coordinates::Tile  (position, _) => (*position).into(),
      Coordinates::Pixel (position, _) => (*position).into()
    }
  }
  #[inline]
  pub const fn dimensions_horizontal (&self) -> u32 {
    match self {
      Coordinates::Tile  (_, dimensions) => dimensions.columns(),
      Coordinates::Pixel (_, dimensions) => dimensions.width()
    }
  }
  #[inline]
  pub const fn dimensions_vertical (&self) -> u32 {
    match self {
      Coordinates::Tile  (_, dimensions) => dimensions.rows(),
      Coordinates::Pixel (_, dimensions) => dimensions.height()
    }
  }
  #[inline]
  pub fn position_horizontal (&self) -> i32 {
    match self {
      Coordinates::Tile  (position, _) => position.column(),
      Coordinates::Pixel (position, _) => position.0.x
    }
  }
  #[inline]
  pub fn position_vertical (&self) -> i32 {
    match self {
      Coordinates::Tile  (position, _) => position.row(),
      Coordinates::Pixel (position, _) => position.0.y
    }
  }
  #[inline]
  pub fn modify_dimensions_horizontal (&mut self, d : i32) {
    match self {
      Coordinates::Tile  (_, dimensions) =>
        *dimensions.columns_mut() =
          std::cmp::max (0, dimensions.columns() as i32 + d) as u32,
      Coordinates::Pixel (_, dimensions) =>
        dimensions.x = std::cmp::max (0, dimensions.x as i32 + d) as u32
    }
  }
  #[inline]
  pub fn modify_dimensions_vertical (&mut self, d : i32) {
    match self {
      Coordinates::Tile  (_, dimensions) =>
        *dimensions.rows_mut() =
          std::cmp::max (0, dimensions.rows() as i32 + d) as u32,
      Coordinates::Pixel (_, dimensions) =>
        dimensions.y = std::cmp::max (0, dimensions.y as i32 + d) as u32
    }
  }
  #[inline]
  pub fn modify_position_horizontal (&mut self, d : i32) {
    match self {
      Coordinates::Tile  (position, _) => *position.column_mut() = position.column() + d,
      Coordinates::Pixel (position, _) => position.0.x += d
    }
  }
  #[inline]
  pub fn modify_position_vertical (&mut self, d : i32) {
    match self {
      Coordinates::Tile  (position, _) => *position.row_mut() = position.row() + d,
      Coordinates::Pixel (position, _) => position.0.y += d
    }
  }
  #[inline]
  /// &#9888; Position types must match
  pub fn set_position (&mut self, position : Position) {
    match (self, position) {
      (Coordinates::Tile  (position, _), Position::Tile  (p)) => *position = p,
      (Coordinates::Pixel (position, _), Position::Pixel (p)) => *position = p,
      _ => unreachable!()
    }
  }
  #[inline]
  /// &#9888; Dimensions types must match
  pub fn set_dimensions (&mut self, dimensions : Dimensions) {
    match (self, dimensions) {
      (Coordinates::Tile  (_, dimensions), Dimensions::Tile  (d)) =>
        *dimensions = d,
      (Coordinates::Pixel (_, dimensions), Dimensions::Pixel (d)) =>
        *dimensions = d,
      _ => unreachable!()
    }
  }
}

impl From <Coordinates> for Aabb2 <i32> {
  fn from (coordinates : Coordinates) -> Aabb2 <i32> {
    log::trace!("aabb2 from coordinates: {coordinates:?}");
    // NOTE: we subtract (1, 1) below because integer aabbs are inclusive of
    // their max endpoints; however if the dimensions are zero then we can't
    // subtract so it will result in the same Aabb as when the dimensions are 1
    let (min, max) = match coordinates {
      Coordinates::Tile  (position, dimensions) => {
        let mut max = *position + dimensions.numcast().unwrap();
        if dimensions.x > 0 {
          max.0.x -= 1;
        }
        if dimensions.y > 0 {
          max.0.y -= 1;
        }
        (*position, max)
      }
      Coordinates::Pixel (position, dimensions) => {
        let mut max = *position + dimensions.numcast().unwrap();
        if dimensions.x > 0 {
          max.0.x -= 1;
        }
        if dimensions.y > 0 {
          max.0.y -= 1;
        }
        (*position, max)
      }
    };
    log::trace!("aabb2 with min, max: {:?}", (min, max));
    Aabb2::with_minmax (min, max)
  }
}

impl TryFrom <(Position, Dimensions)> for Coordinates {
  type Error = (Position, Dimensions);
  fn try_from ((position, dimensions) : (Position, Dimensions))
    -> Result <Coordinates, (Position, Dimensions)>
  {
    let coordinates = match (position, dimensions) {
      (Position::Tile  (position), Dimensions::Tile  (dimensions)) =>
        Coordinates::Tile  (position, dimensions),
      (Position::Pixel (position), Dimensions::Pixel (dimensions)) =>
        Coordinates::Pixel (position, dimensions),
      _ => return Err ((position, dimensions))
    };
    Ok (coordinates)
  }
}

pub mod position {
  use derive_more::{From, TryInto};
  use crate::math::Point2;

  #[derive(Clone, Copy, Debug, Eq, PartialEq, From, TryInto)]
  pub enum Position {
    Tile  (Tile),
    Pixel (Pixel)
  }

  #[derive(Clone, Copy, Debug, Eq, PartialEq)]
  pub struct Tile {
    pub position_rc : Point2 <i32>
  }

  #[derive(Clone, Copy, Debug, Eq, PartialEq)]
  pub struct Pixel {
    pub position_xy : Point2 <i32>
  }

  // TODO: 3d coordinates?

  impl Tile {
    #[inline]
    pub const fn origin() -> Self {
      Tile {
        position_rc: Point2::new (0, 0)
      }
    }
    #[inline]
    pub fn new_rc (row : i32, column : i32) -> Self {
      Point2::new (row, column).into()
    }
    #[inline]
    pub const fn row (&self) -> i32 {
      self.position_rc.0.x
    }
    #[inline]
    pub const fn column (&self) -> i32 {
      self.position_rc.0.y
    }
    #[inline]
    pub const fn row_mut (&mut self) -> &mut i32 {
      &mut self.position_rc.0.x
    }
    #[inline]
    pub const fn column_mut (&mut self) -> &mut i32 {
      &mut self.position_rc.0.y
    }
  }

  impl Default for Tile {
    fn default() -> Self {
      Tile { position_rc: [0,0].into() }
    }
  }

  impl From <Point2 <i32>> for Tile {
    fn from (position_rc : Point2 <i32>) -> Self {
      Tile { position_rc }
    }
  }

  impl std::ops::Deref for Tile {
    type Target = Point2 <i32>;
    fn deref (&self) -> &Point2 <i32> {
      &self.position_rc
    }
  }

  impl std::ops::DerefMut for Tile {
    fn deref_mut (&mut self) -> &mut Point2 <i32> {
      &mut self.position_rc
    }
  }

  impl Pixel {
    #[inline]
    pub const fn origin() -> Self {
      Pixel {
        position_xy: Point2::new (0, 0)
      }
    }
    #[inline]
    pub fn new_xy (x : i32, y : i32) -> Self {
      Point2::new (x, y).into()
    }
  }

  impl Default for Pixel {
    fn default() -> Self {
      Pixel { position_xy: [0,0].into() }
    }
  }

  impl From <Point2 <i32>> for Pixel {
    fn from (position_xy : Point2 <i32>) -> Self {
      Pixel { position_xy }
    }
  }

  impl std::ops::Deref for Pixel {
    type Target = Point2 <i32>;
    fn deref (&self) -> &Point2 <i32> {
      &self.position_xy
    }
  }

  impl std::ops::DerefMut for Pixel {
    fn deref_mut (&mut self) -> &mut Point2 <i32> {
      &mut self.position_xy
    }
  }
}

pub mod dimensions {
  use derive_more::{From, TryInto};
  use crate::math::Vector2;

  #[derive(Clone, Copy, Debug, Eq, PartialEq, From, TryInto)]
  pub enum Dimensions {
    Tile  (Tile),
    Pixel (Pixel)
  }

  #[derive(Clone, Copy, Debug, Eq, PartialEq)]
  pub struct Tile {
    pub dimensions_rc : Vector2 <u32>
  }

  #[derive(Clone, Copy, Debug, Eq, PartialEq)]
  pub struct Pixel {
    pub dimensions_xy : Vector2 <u32>
  }

  // TODO: 3d dimensions?

  impl Dimensions {
    pub const fn horizontal (&self) -> u32 {
      match self {
        Dimensions::Tile  (tile)  => tile.columns(),
        Dimensions::Pixel (pixel) => pixel.width()
      }
    }

    pub const fn vertical (&self) -> u32 {
      match self {
        Dimensions::Tile  (tile)  => tile.rows(),
        Dimensions::Pixel (pixel) => pixel.height()
      }
    }

    pub fn vec (&self) -> Vector2 <u32> {
      match self {
        Dimensions::Tile  (tile)  => **tile,
        Dimensions::Pixel (pixel) => **pixel
      }
    }
  }

  impl Tile {
    #[inline]
    pub fn new_rc (rows : u32, columns : u32) -> Self {
      Vector2::new (rows, columns).into()
    }
    #[inline]
    pub const fn columns (&self) -> u32 {
      self.dimensions_rc.y
    }
    #[inline]
    pub const fn rows (&self) -> u32 {
      self.dimensions_rc.x
    }
    #[inline]
    pub const fn rows_mut (&mut self) -> &mut u32 {
      &mut self.dimensions_rc.x
    }
    #[inline]
    pub const fn columns_mut (&mut self) -> &mut u32 {
      &mut self.dimensions_rc.y
    }
    #[inline]
    pub fn to_pixel (self) -> Pixel {
      Vector2::new (self.columns(), self.rows()).into()
    }
  }

  impl Pixel {
    #[inline]
    pub fn new_wh (width : u32, height : u32) -> Self {
      Vector2::new (width, height).into()
    }
    #[inline]
    pub const fn width (&self) -> u32 {
      self.dimensions_xy.x
    }
    #[inline]
    pub const fn height (&self) -> u32 {
      self.dimensions_xy.y
    }
    #[inline]
    pub fn to_tile (self) -> Tile {
      Vector2::new (self.height(), self.width()).into()
    }
  }

  impl Default for Tile {
    fn default() -> Self {
      Tile { dimensions_rc: [0,0].into() }
    }
  }

  impl From <Vector2 <u32>> for Tile {
    fn from (dimensions_rc : Vector2 <u32>) -> Self {
      Tile { dimensions_rc }
    }
  }

  impl std::ops::Deref for Tile {
    type Target = Vector2 <u32>;
    fn deref (&self) -> &Self::Target {
      &self.dimensions_rc
    }
  }

  impl std::ops::DerefMut for Tile {
    fn deref_mut (&mut self) -> &mut Self::Target {
      &mut self.dimensions_rc
    }
  }

  impl Default for Pixel {
    fn default() -> Self {
      Pixel { dimensions_xy: [0,0].into() }
    }
  }

  impl From <Vector2 <u32>> for Pixel {
    fn from (dimensions_xy : Vector2 <u32>) -> Self {
      Pixel { dimensions_xy }
    }
  }

  impl std::ops::Deref for Pixel {
    type Target = Vector2 <u32>;
    fn deref (&self) -> &Self::Target {
      &self.dimensions_xy
    }
  }

  impl std::ops::DerefMut for Pixel {
    fn deref_mut (&mut self) -> &mut Self::Target {
      &mut self.dimensions_xy
    }
  }
}

impl std::ops::Add <dimensions::Tile> for position::Tile {
  type Output = Self;
  fn add (self, rhs : dimensions::Tile) -> Self {
    (self.position_rc + rhs.dimensions_rc.numcast().unwrap()).into()
  }
}

impl std::ops::Add <dimensions::Pixel> for position::Pixel {
  type Output = Self;
  fn add (self, rhs : dimensions::Pixel) -> Self {
    (self.position_xy + rhs.dimensions_xy.numcast().unwrap()).into()
  }
}

impl std::ops::Sub <dimensions::Tile> for position::Tile {
  type Output = Self;
  fn sub (self, rhs : dimensions::Tile) -> Self {
    (self.position_rc - rhs.dimensions_rc.numcast().unwrap()).into()
  }
}

impl std::ops::Sub <dimensions::Pixel> for position::Pixel {
  type Output = Self;
  fn sub (self, rhs : dimensions::Pixel) -> Self {
    (self.position_xy - rhs.dimensions_xy.numcast().unwrap()).into()
  }
}

#[cfg(test)]
mod tests {
  use crate::geometry::integer::Aabb2;
  use super::*;
  /// ```text
  /// [0,0]
  /// (tile)    [8,100]
  ///       +---+---------------+
  ///       |   |               |
  /// [0,92]+---+               |
  ///       |    [1,1](tile)    |
  ///       |                   | 100
  ///       |                   |
  ///       |                   |
  ///       |                   |
  ///       |                   |
  ///       +-------------------+
  ///   [0,0]       100
  /// (pixel)
  /// ```
  ///
  /// Sets the screen to dimensions [100,100] and tile dimensions [8,8].
  ///
  /// Given tile coordinates with position [0,0] and dimensions [1,1], computes an AABB
  /// in pixel coordinates which is min = [0,92] and max = [8,100].
  #[test]
  fn tile_to_pixel_aabb() {
    use super::tile_to_pixel_aabb;
    unsafe {
      std::env::set_var ("GOOEY_TILE_WIDTH",  "8");
      std::env::set_var ("GOOEY_TILE_HEIGHT", "8");
    }
    *SCREEN_WH.write().unwrap() = [100, 100];
    let coordinates = Coordinates::Tile (
      position::Tile::new_rc (0, 0),
      dimensions::Tile::new_rc (1, 1));
    let aabb = Aabb2::from (coordinates);
    assert!(aabb.contains (&[0, 0].into()));
    assert!(!aabb.contains (&[1, 1].into()));
    let aabb_pixel = tile_to_pixel_aabb (aabb);
    assert_eq!(*aabb_pixel.min(), [0, 92].into());
    assert_eq!(*aabb_pixel.max(), [8, 100].into());
  }
}