nsys-gl-utils 0.11.2

//! A trait for resource types with arbitrary `draw` functionality and a
//! default implementation that supports switching to a "quad viewport" mode.

use std::iter::FromIterator;
use std::ops::Deref;

use glium;
use image;
use lazy_static::lazy_static;
use strum::{EnumCount, EnumIter, FromRepr};
use vec_map::VecMap;
use winit;

use math_utils as math;

use crate::{color, render, shader, texture, vertex, Render};

pub mod draw2d;
pub mod draw3d;
#[cfg(feature="demo")]
pub mod demo;

pub use self::draw2d::Draw2d;
pub use self::draw3d::Draw3d;

////////////////////////////////////////////////////////////////////////////////
//  constants                                                                 //
////////////////////////////////////////////////////////////////////////////////

pub const MAIN_VIEWPORT        : usize = 0;
#[allow(dead_code)]
pub const LOWER_RIGHT_VIEWPORT : usize = MAIN_VIEWPORT;
pub const UPPER_LEFT_VIEWPORT  : usize = 1;
pub const UPPER_RIGHT_VIEWPORT : usize = 2;
pub const LOWER_LEFT_VIEWPORT  : usize = 3;
pub const OVERLAY_VIEWPORT     : usize = 4;

////////////////////////////////////////////////////////////////////////////////
//  statics                                                                   //
////////////////////////////////////////////////////////////////////////////////

lazy_static!{
  static ref DEFAULT_TEXTURES_16X16_BYTES : VecMap <&'static [u8]> =
    VecMap::from_iter ([
      ( DefaultTexture16Id::Crosshair         as usize,
        texture::CROSSHAIR_PNG_FILE_BYTES.as_slice()
      ), (
        DefaultTexture16Id::CrosshairInverse  as usize,
        texture::CROSSHAIR_INVERSE_PNG_FILE_BYTES.as_slice()
      )
    ]);

  static ref DEFAULT_TEXTURES_POINTER_BYTES_OFFSETS :
    VecMap <(&'static [u8], [i16; 2])> = VecMap::from_iter ([
      ( DefaultTexturePointerId::Hand as usize,
        ( texture::POINTER_HAND_PNG_FILE_BYTES_OFFSET.0.as_slice(),
          texture::POINTER_HAND_PNG_FILE_BYTES_OFFSET.1
        )
      )
    ]);
}

////////////////////////////////////////////////////////////////////////////////
//  typedefs                                                                  //
////////////////////////////////////////////////////////////////////////////////

pub type PointerTextureIndexRepr = u16;

////////////////////////////////////////////////////////////////////////////////
//  traits                                                                    //
////////////////////////////////////////////////////////////////////////////////

/// Represents a generic Glium resource type for a renderer to use as a source
/// of *drawing* (vertex rendering).
///
/// The resource should have all the shader programs, vertex buffers, textures,
/// etc. necessary to make a `draw` call on a given `glium::Frame`.
///
/// The default frame functions will call the `draw_2d` and `draw_3d` methods,
/// which do nothing by default.
pub trait Resource {
  fn new (glium_display : &glium::Display <glutin::surface::WindowSurface>)
    -> Self;
  fn init (_render : &mut Render <Self>) where Self : Sized
    { /* default: do nothing */ }
  /// Default replace self with `Self::new`. Can be overridden.
  fn reset (render : &mut Render <Self>)  where Self : Sized {
    render.resource = Self::new (&render.glium_display)
  }
  fn draw_2d (_render : &Render <Self>, _glium_frame : &mut glium::Frame) where
    Self : Sized { /* default: do nothing */ }
  fn draw_3d (_render : &Render <Self>, _glium_frame : &mut glium::Frame) where
    Self : Sized { /* default: do nothing */ }
}

////////////////////////////////////////////////////////////////////////////////
//  structs                                                                   //
////////////////////////////////////////////////////////////////////////////////

/// A default implementation of `Resource` containing the builtin shader
/// programs and some pre-defined vertex sources.
pub struct Default {
  pub draw2d             : Draw2d,
  pub draw3d             : Draw3d,
  /// Textures of heterogeneous dimensions
  pub textures_anysize   : VecMap <glium::texture::Texture2d>,
  /// Custom pointer textures with offsets for non-centered cursors
  pub textures_pointer   :
    VecMap <(glium::texture::Texture2d, math::Vector2 <i16>)>,
  /// 128x128 pixel tileset texture with 8x8 tile dimensions
  pub tileset_128x128_texture : glium::texture::Texture2d,
  /// 256x256 pixel tileset texture with 16x16 tile dimensions
  pub tileset_256x256_texture : glium::texture::Texture2d,
  // TODO: more tilesets?
  shader_programs        : VecMap <glium::Program>,
  /// Default 16x16 textures indexed by DefaultTexture16Id
  default_textures_16x16 : glium::texture::Texture2dArray,
  /// Texture array of 16x16 pixel general purpose textures
  textures_16x16         : glium::texture::Texture2dArray,
  /// Texture array of 64x64 pixel general purpose textures
  textures_64x64         : glium::texture::Texture2dArray
}

////////////////////////////////////////////////////////////////////////////////
//  enums                                                                     //
////////////////////////////////////////////////////////////////////////////////

#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, EnumCount, EnumIter,
  FromRepr)]
#[repr(u16)]
pub enum DefaultTexturePointerId {
  Hand
}

#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, EnumCount, EnumIter,
  FromRepr)]
#[repr(u16)]
pub enum DefaultTexture16Id {
  // for use with `BLEND_FUNC_NORMAL`
  Crosshair,
  // for use with `BLEND_FUNC_INVERT_COLOR`
  CrosshairInverse
}

#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd, EnumCount, EnumIter,
  FromRepr)]
#[repr(u16)]
pub enum DefaultTilesetId {
  // for use with `BLEND_FUNC_NORMAL`
  EasciiAcorn128,
  EasciiAcorn256,
  // for use with `BLEND_FUNC_INVERT_COLOR`
  EasciiAcornInverse128,
  EasciiAcornInverse256
}

////////////////////////////////////////////////////////////////////////////////
//  impls                                                                     //
////////////////////////////////////////////////////////////////////////////////

impl Default {
  /// Default debug grid vertices (3): [X plane (red), Y plane (green), Z plane
  /// (blue)]
  pub fn debug_grid_vertices() -> [vertex::Vert3dOrientationScaleColor; 3] {
    use std::f32::consts::FRAC_PI_2;
    const HALF_GRID_DIMS : f32 = 0.5 * draw3d::MESH_GRID_DIMS as f32;
    [
      // X plane
      vertex::Vert3dOrientationScaleColor {
        position:    [HALF_GRID_DIMS, 0.0, HALF_GRID_DIMS],
        orientation: (*math::Rotation3::from_angle_y (math::Rad (FRAC_PI_2)))
          .into_col_arrays(),
        scale:       [1.0, 1.0, 1.0],
        color:       color::rgba_u8_to_rgba_f32 ([255, 0, 0, 255])
      },
      // Y plane
      vertex::Vert3dOrientationScaleColor {
        position:    [0.0, HALF_GRID_DIMS, HALF_GRID_DIMS],
        orientation: (*math::Rotation3::from_angle_x (math::Rad (FRAC_PI_2)))
          .into_col_arrays(),
        scale:       [1.0, 1.0, 1.0],
        color:       color::rgba_u8_to_rgba_f32 ([0, 255, 0, 255])
      },
      // Z plane
      vertex::Vert3dOrientationScaleColor {
        position:    [0.0, 0.0, 0.0],
        orientation: math::Matrix3::identity().into_col_arrays(),
        scale:       [1.0, 1.0, 1.0],
        color:       color::rgba_u8_to_rgba_f32 ([0, 0, 255, 255])
      }
    ]
  }
  /// Returns tile pixel [width, height] of the tileset.
  #[inline]
  pub fn tile_dimensions (&self, tileset_id : DefaultTilesetId) -> [u32; 2] {
    let (width, height) = match tileset_id {
      DefaultTilesetId::EasciiAcorn128 =>
        self.tileset_128x128_texture.dimensions(),
      DefaultTilesetId::EasciiAcorn256 =>
        self.tileset_256x256_texture.dimensions(),
      _ => unimplemented!()
    };
    debug_assert_eq!(width  % 16, 0);
    debug_assert_eq!(height % 16, 0);
    [width / 16, height / 16]
  }
  #[inline]
  pub fn shader_programs (&self) -> &VecMap <glium::Program> {
    &self.shader_programs
  }
  #[inline]
  pub fn set_pointer_position (&mut self,
    display  : &glium::Display <glutin::surface::WindowSurface>,
    position : math::Point2 <f32>
  ) {
    let offset = self.draw2d.draw_pointer.clone().map_or (
      math::Vector2::zero(),
      |texture_index| self.textures_pointer.get (texture_index as usize)
        .unwrap().1.numcast().unwrap()
    );
    self.draw2d.set_pointer_vertex (display, position + offset);
  }
  #[inline]
  pub fn set_textures_16x16 (&mut self,
    textures_16x16 : glium::texture::Texture2dArray
  ) {
    assert_eq!(textures_16x16.width(),  16);
    assert_eq!(textures_16x16.height(), 16);
    self.textures_16x16 = textures_16x16;
  }
  #[inline]
  pub fn set_textures_64x64 (&mut self,
    textures_64x64 : glium::texture::Texture2dArray
  ) {
    assert_eq!(textures_64x64.width(),  64);
    assert_eq!(textures_64x64.height(), 64);
    self.textures_64x64 = textures_64x64;
  }
}

impl render::Resource for Default {
  fn new (glium_display : &glium::Display <glutin::surface::WindowSurface>)
    -> Self
  {
    // shaders
    let shader_programs  = shader::build_programs (glium_display).unwrap();
    // shared resources
    let default_textures_16x16 =
      texture::texture2darray_with_mipmaps_from_bytes (
        glium_display,
        &DEFAULT_TEXTURES_16X16_BYTES.values().map (Deref::deref)
          .collect::<Vec <&[u8]>>(),
        image::ImageFormat::Png,
        glium::texture::MipmapsOption::NoMipmap
      ).unwrap();
    let textures_16x16   =
      glium::texture::Texture2dArray::empty (glium_display, 16, 16, 0).unwrap();
    let textures_64x64   =
      glium::texture::Texture2dArray::empty (glium_display, 64, 64, 0).unwrap();
    let textures_anysize = VecMap::new();
    let textures_pointer = DEFAULT_TEXTURES_POINTER_BYTES_OFFSETS.iter()
      .map (|(i, (bytes, offset))|{
        let texture = texture::texture2d_with_mipmaps_from_bytes (
          glium_display, bytes, image::ImageFormat::Png,
          glium::texture::MipmapsOption::NoMipmap
        ).unwrap();
        (i, (texture, math::Vector2::from (*offset)))
      }).collect();
    let tileset_128x128_texture = texture::texture2d_with_mipmaps_from_bytes (
      glium_display,
      // for use with normal blending
      texture::TILESET_EASCII_ACORN_8X8_PNG_FILE_BYTES,
      image::ImageFormat::Png,
      glium::texture::MipmapsOption::NoMipmap
    ).unwrap();
    let tileset_256x256_texture = texture::texture2d_with_mipmaps_from_bytes (
      glium_display,
      // for use with normal blending
      texture::TILESET_EASCII_ACORN_16X16_PNG_FILE_BYTES,
      image::ImageFormat::Png,
      glium::texture::MipmapsOption::NoMipmap
    ).unwrap();
    // TODO
    /*
    let tileset_128x128_inverse_texture =
      texture::texture2d_with_mipmaps_from_bytes (
        glium_display,
        // for use with inverse blending
        texture::TILESET_EASCII_ACORN_8X8_INVERSE_PNG_FILE_BYTES,
        image::PNG,
        glium::texture::MipmapsOption::NoMipmap
      ).unwrap();
    */

    let draw2d = Draw2d::new (glium_display);
    let draw3d = Draw3d::new (glium_display);

    Default {
      shader_programs,
      default_textures_16x16,
      textures_16x16,
      textures_64x64,
      textures_anysize,
      textures_pointer,
      tileset_128x128_texture,
      tileset_256x256_texture,
      draw2d,
      draw3d
    }
  }

  #[inline]
  fn init (render : &mut Render <Self>) {
    render.update_viewport_line_loops();
  }

  #[inline]
  fn draw_2d (render : &Render <Self>, glium_frame : &mut glium::Frame) {
    Draw2d::draw (render, glium_frame);
  }

  #[inline]
  fn draw_3d (render : &Render <Self>, glium_frame : &mut glium::Frame) {
    Draw3d::draw (render, glium_frame);
  } // end fn draw_3d

  #[inline]
  fn reset (render : &mut Render <Self>) {
    render.resource.draw2d = Draw2d::new (&render.glium_display);
    render.resource.draw3d = Draw3d::new (&render.glium_display);
  }
} // end impl Resource for DefaultResource

impl Render <Default> {

  #[inline]
  pub fn camera3d_position_set (&mut self, position : math::Point3 <f32>) {
    for (_, viewport) in self.viewports.iter_mut() {
      if viewport.camera3d().is_some() {
        viewport.camera3d_set_position (position);
      }
    }
  }

  #[inline]
  pub fn camera3d_orientation_set (&mut self,
    orientation : math::Rotation3 <f32>
  ) {
    for (_, viewport) in self.viewports.iter_mut() {
      if viewport.camera3d().is_some() {
        viewport.camera3d_set_orientation (orientation);
      }
    }
  }

  #[inline]
  pub fn camera3d_look_at (&mut self, target : math::Point3 <f32>) {
    for (_, viewport) in self.viewports.iter_mut() {
      if viewport.camera3d().is_some() {
        viewport.camera3d_look_at (target);
      }
    }
  }

  pub fn camera3d_move_local_xy (&mut self, dx : f32, dy : f32, dz : f32) {
    self.viewports[MAIN_VIEWPORT].camera3d_move_local_xy (dx, dy, dz);
    let position = self.viewports[MAIN_VIEWPORT].camera3d().unwrap().position();
    for (_, viewport) in self.viewports.iter_mut().skip (1) {
      if viewport.camera3d().is_some() {
        viewport.camera3d_set_position (position);
      }
    }
  }

  #[inline]
  pub fn camera3d_rotate (&mut self,
    dyaw : math::Rad <f32>, dpitch : math::Rad <f32>, droll : math::Rad <f32>
  ) {
    self.viewports[MAIN_VIEWPORT].camera3d_rotate (dyaw, dpitch, droll);
  }

  /// Scales 3D zoom of viewports 1-3.
  ///
  /// Does nothing in single viewport mode.
  ///
  /// # Panics
  ///
  /// Panics if scale is negative.
  pub fn camera3d_orthographic_zoom_scale (&mut self, scale : f32) {
    assert!(0.0 < scale);
    for (_, viewport) in self.viewports.iter_mut().skip(1) {
      if viewport.camera3d().is_some() {
        debug_assert!(viewport.camera3d().unwrap().projection()
          .is_orthographic());
        viewport.camera3d_scale_fovy_or_zoom (scale);
      }
    }
  }

  /// Scales 3D zoom of viewport 0 (the main viewport) only.
  ///
  /// # Panics
  ///
  /// Panics if scale is negative.
  pub fn camera3d_perspective_fovy_scale (&mut self, scale : f32) {
    assert!(0.0 < scale);
    debug_assert!(self.viewports[MAIN_VIEWPORT].camera3d().unwrap().projection()
      .is_perspective());
    self.viewports[MAIN_VIEWPORT].camera3d_scale_fovy_or_zoom (scale);
  }

  pub fn camera2d_zoom_set (&mut self, zoom : f32) {
    assert!(0.0 < zoom);
    for (_, viewport) in self.viewports.iter_mut() {
      if viewport.camera2d().is_some() {
        viewport.camera2d_set_zoom (zoom);
      }
    }
    self.update_viewport_line_loops();
  }

  /// Modifies the 2D zoom by the given amount for all viewports.
  pub fn camera2d_zoom_shift (&mut self, shift : f32) {
    let mut dirty = false;
    for (_, viewport) in self.viewports.iter_mut() {
      if viewport.camera2d().is_some() {
        let zoom = viewport.camera2d().unwrap().zoom() + shift;
        if 0.0 < zoom {
          viewport.camera2d_set_zoom (zoom);
          dirty = true;
        }
      }
    }
    if dirty {
      self.update_viewport_line_loops();
    }
  }

  pub fn camera2d_move_local (&mut self, dx : f32, dy : f32) {
    self.viewports[MAIN_VIEWPORT].camera2d_move_local (dx, dy);
    let position = self.viewports[MAIN_VIEWPORT].camera2d().unwrap().position();
    for (_, viewport) in self.viewports.iter_mut().skip (1) {
      if viewport.camera2d().is_some() {
        viewport.camera2d_set_position (position);
      }
    }
  }

  /// Moves origin for all viewports to lower left
  pub fn camera2d_move_origin_to_bottom_left (&mut self) {
    for (_, viewport) in self.viewports.iter_mut() {
      if viewport.camera2d().is_some() {
        viewport.camera2d_move_origin_to_bottom_left()
      }
    }
    self.update_viewport_line_loops();
  }

  /// Resize the viewport(s) based on the LogicalSize that was returned by a
  /// WindowEvent::Resized event
  // TODO: come up with a better scheme for quad viewports, overlay viewports
  pub fn window_resized (&mut self,
    physical_size : winit::dpi::PhysicalSize <u32>
  ) {
    let (width, height) = physical_size.into();
    if self.viewports.len() < 4 {
      self.viewports[MAIN_VIEWPORT].set_rect (
        glium::Rect { left: 0, bottom: 0, width, height }
      );
      self.viewports.get_mut (OVERLAY_VIEWPORT).map (|viewport|
        viewport.set_rect (glium::Rect { left: 0, bottom: 0, width, height }));
    } else {
      // quad viewports
      let left_width    = left_width   (width);
      let right_width   = right_width  (width);
      let upper_height  = upper_height (height);
      let lower_height  = lower_height (height);
      self.viewports[LOWER_RIGHT_VIEWPORT].set_rect (
        glium::Rect {
          width:  right_width,
          height: lower_height,
          left:   left_width,
          bottom: 0
        }
      );
      self.viewports[UPPER_LEFT_VIEWPORT].set_rect (
        glium::Rect {
          width:  left_width,
          height: upper_height,
          left:   0,
          bottom: lower_height
        }
      );
      self.viewports[UPPER_RIGHT_VIEWPORT].set_rect (
        glium::Rect {
          width:  right_width,
          height: upper_height,
          left:   left_width,
          bottom: lower_height
        }
      );
      self.viewports[LOWER_LEFT_VIEWPORT].set_rect (
        glium::Rect {
          width:  left_width,
          height: lower_height,
          left:   0,
          bottom: 0
        }
      );
      self.viewports.get_mut (OVERLAY_VIEWPORT).map (|viewport|
        viewport.set_rect (glium::Rect { left: 0, bottom: 0, width, height }));
    }
    self.update_viewport_line_loops();
  }

  /// Updates vertex and index buffers for viewport line loops.
  ///
  /// Should be called whenever viewport sizes or 2D camera zoom or position
  /// changes.
  fn update_viewport_line_loops (&mut self) {
    const VERTS_PER_VIEWPORT : usize = 4;
    let num_vertices = VERTS_PER_VIEWPORT * self.viewports.len();
    let vertices = {
      let mut vertices = Vec::<vertex::Vert2d>::with_capacity (num_vertices);
      for (_, viewport) in self.viewports.iter() {
        if let Some (camera2d) = viewport.camera2d() {
          // pixels are centered on 0.5 unit centers
          let pixel_radius = 0.5 / camera2d.zoom();
          let position     = camera2d.position();
          let ortho        = camera2d.ortho();
          let left         = position.0.x + ortho.left;
          let bottom       = position.0.y + ortho.bottom;
          let top          = position.0.y + ortho.top;
          let right        = position.0.x + ortho.right;
          vertices.append (&mut vec![
            vertex::Vert2d {
              position: [left  + pixel_radius, bottom + pixel_radius] },
            vertex::Vert2d {
              position: [left  + pixel_radius, top    - pixel_radius] },
            vertex::Vert2d {
              position: [right - pixel_radius, top    - pixel_radius] },
            vertex::Vert2d {
              position: [right - pixel_radius, bottom + pixel_radius] }
          ]);
        }
      }
      vertices
    };
    self.resource.draw2d
      .line_loop_vertices_set (&self.glium_display, &vertices[..]);
  }
}

impl std::default::Default for DefaultTilesetId {
  fn default() -> Self {
    DefaultTilesetId::EasciiAcorn128
  }
}

////////////////////////////////////////////////////////////////////////////////
//  private functions                                                         //
////////////////////////////////////////////////////////////////////////////////

// some functions to compute viewport widths for odd window dimensions:
// right viewports will be 1 pixel wider on odd width windows and bottom
// viewports will be 1 pixel taller on odd height windows

#[inline]
fn left_width (window_width : u32) -> u32 {
  window_width / 2
}
#[inline]
fn right_width (window_width : u32) -> u32 {
  window_width / 2 + window_width % 2
}
#[inline]
fn upper_height (window_height : u32) -> u32 {
  window_height / 2
}
#[inline]
fn lower_height (window_height : u32) -> u32 {
  window_height / 2 + window_height % 2
}