wip: walk along torus ridge

src/arena.rs

@@ -11,10 +11,10 @@ use tile::Tile;
 // 0x40   121  11x11 map matrix
 // 0xB9   7    ???
 pub struct Arena {
-  monster_x: [u8; 16],
+  _monster_x: [u8; 16],
-  monster_y: [u8; 16],
+  _monster_y: [u8; 16],
-  party_x: [u8; 8],
+  _party_x: [u8; 8],
-  party_y: [u8; 8],
+  _party_y: [u8; 8],
   _unknown1: [u8; 16],
   map: Field,
   _unknown2: [u8; 7],

src/bin/tileview.rs

@@ -22,7 +22,7 @@ fn main() {
   let mut ega_vec = Vec::<u8>::new();
 
   file.read_to_end(&mut ega_vec).expect("Read EGA file");
-  let ega_page = ega::decode(&ega_vec, Compression::UNCOMPRESSED, Tiling::TILED(16));
+  let ega_page = ega::decode(&ega_vec, Compression::Uncompressed, Tiling::Tiled(16));
   for (i, tilepixels) in ega_page.iter().enumerate() {
     let out_name = format!("out/{}.png", i);
     let out_file = std::fs::File::create(Path::new(&out_name)).expect("open out file");

src/bin/vrtue.rs

@@ -5,21 +5,33 @@ use vrtue::scene::{Event, Scene};
 extern crate env_logger;
 extern crate gfx_device_gl;
 #[macro_use] extern crate log;
+extern crate piston;
 extern crate piston_window;
 
+use self::piston::input::{Button, Input, Key};
 use self::piston_window::{PistonWindow, Window, WindowSettings};
+use std::env;
+
 
 pub fn main() {
   env_logger::init().expect("env logger");
-  let mut vr = vr::VR::new().expect("VR init");
+  let mut vr = if env::var("NO_VR").is_ok() {
+    None
+  } else {
+    Some(vr::VR::new().expect("VR init"))
+  };
 
   let mut window: PistonWindow =
     WindowSettings::new("Hello, Britannia!", [1024; 2])
         .exit_on_esc(true)
-        .vsync(false)
+        .vsync(vr.is_none())  // Let VR throttle framerate, if available
         .build().expect("Building Window");
 
-  let mut scene = scenes::world::WorldScene::new(&mut window.factory, &mut window.encoder);
+  let mut aux_command = window.factory.create_command_buffer();
+  let mut scene = scenes::world::WorldScene::new(&mut window.device,
+                                                 &mut window.factory,
+                                                 &mut window.encoder,
+                                                 &mut aux_command);
   let view = view::ViewRoot::<gfx_device_gl::Device, view::ColorFormat, view::DepthFormat>
                            ::create_view(&mut window, &mut vr);
 
@@ -32,7 +44,8 @@ pub fn main() {
     // handle window events
     while let Some(ev) = window.poll_event() {
       match ev {
-        piston_window::Input::Text(_) => break 'main,
+        Input::Press(Button::Keyboard(Key::Space)) |
+        Input::Press(Button::Keyboard(Key::Escape)) => break'main,
         _ => debug!("\t{:?}", ev)
       }
 
@@ -40,7 +53,7 @@ pub fn main() {
     }
 
     // handle VR events
-    while let Some(ev) = vr.poll_next_event() {
+    while let Some(ev) = vr.as_mut().and_then(|vr| vr.poll_next_event()) {
       scene.event(Event::Vr(ev));
     }
   }

src/ega.rs

@@ -16,24 +16,80 @@ static EGA_PALETTE: [[u8; 4]; 16] = [[0x00, 0x00, 0x00, 0x00],
                                      [0xFF, 0xFF, 0xFF, 0x00]];
 
 pub enum Compression {
-  UNCOMPRESSED,
+  Uncompressed,
-  RLE,
+  Rle,
-  LZW
+  Lzw
 }
 
 pub enum Tiling {
-  UNTILED,
+  Untiled,
-  TILED(u16)
+  Tiled(u16)
 }
 
 pub struct EgaPage {
   pub data: Vec<u8>,
-  pub tilesize: u16,
+  pub dim: usize,
 }
 
 impl EgaPage {
   pub fn iter<'a>(&'a self) -> impl Iterator<Item=&'a [u8]> {
-    self.data.chunks(self.tilesize as usize)
+    self.data.chunks(4 * self.dim * self.dim)
+  }
+
+  pub fn mipmap(&self, scale_levels: u8) -> Mipmap {
+    let scale = 1 << scale_levels;
+    let scaled: Vec<Vec<u8>> = self.iter().map(|tile| {
+      let mut tilevec = Vec::new();
+      for row in tile.chunks(4 * self.dim) {
+        for _ in 0..scale {
+          for px in row.chunks(4) {
+            for subpx in px.iter().cycle().take(4 * scale) {
+              tilevec.push(*subpx);
+            }
+          }
+        }
+      }
+      tilevec
+    }).collect();
+
+    // dummy buffers just to provide proper sizing on texture for mips
+    let dim = self.dim << scale_levels;
+    let mut dummies = Vec::new();
+
+    let mut level = 1;
+    loop {
+      let mipdim = dim >> level;
+      if mipdim == 0 { break; }
+      dummies.push(vec![0; 4 * mipdim * mipdim]);
+      level += 1;
+    }
+
+    Mipmap {
+      len: self.data.len() / (4 * self.dim * self.dim),
+      dim: dim,
+      backing: scaled,
+      dummies: dummies,
+    }
+  }
+}
+
+pub struct Mipmap {
+  pub len: usize,
+  pub dim: usize,
+  backing: Vec<Vec<u8>>,
+  dummies: Vec<Vec<u8>>,
+}
+
+impl Mipmap {
+  pub fn slices(&self) -> Vec<&[u8]> {
+    let mut slices: Vec<&[u8]> = Vec::with_capacity((1 + self.dummies.len()) * self.len);
+    for tile in self.backing.iter() {
+      slices.push(tile);
+      for dummy in self.dummies.iter() {
+        slices.push(&dummy);
+      }
+    }
+    slices
   }
 }
 
@@ -42,7 +98,7 @@ pub fn decode<'a>(buf: &[u8], compression: Compression, tiling: Tiling)
   let out: Vec<u8>;
 
   out = match compression {
-    Compression::UNCOMPRESSED => buf.iter()
+    Compression::Uncompressed => buf.iter()
                                     .flat_map(|tile_byte| {
                                       EGA_PALETTE[(tile_byte >> 4u8 & 0xF) as usize]
                                         .into_iter()
@@ -53,9 +109,9 @@ pub fn decode<'a>(buf: &[u8], compression: Compression, tiling: Tiling)
                                     .collect(),
     _ => unimplemented!()
   };
-  let tilesize = match tiling {
+  let dim = match tiling {
-    Tiling::TILED(tiledim) => 4 * tiledim * tiledim,
+    Tiling::Tiled(tiledim) => tiledim as usize,
-    Tiling::UNTILED => out.len() as u16
+    Tiling::Untiled => out.len()
   };
-  EgaPage { data: out, tilesize: tilesize}
+  EgaPage { data: out, dim: dim}
 }

src/scene.rs

@@ -10,7 +10,7 @@ pub trait Scene<D: gfx::Device,
                 F: gfx::Factory<D::Resources>> {
   fn event(&mut self, event: Event);
   fn update(&mut self,
-            vr: &mut vr::VR,
+            vr: &mut Option<vr::VR>,  // TODO: abstract this out
             encoder: &mut gfx::Encoder<D::Resources, D::CommandBuffer>);
   fn render(&self,
             factory: &mut F,

src/scenes/shader/tile_frag.glsl

@@ -10,9 +10,9 @@ uniform b_constants {
   uvec4 anim;
   float R1;
   float R2;
+  float R3;
 };
 uniform b_locals {
-  mat4 camera;
   uint millis;
   float treadmill_x;
   float treadmill_y;

src/scenes/shader/torus_vertex.glsl

@@ -15,9 +15,9 @@ uniform b_constants {
   uvec4 anim;
   float R1;
   float R2;
+  float R3;
 };
 uniform b_locals {
-  mat4 camera;
   uint millis;
   float treadmill_x;
   float treadmill_y;
@@ -35,8 +35,8 @@ void main() {
 
   vec2 thetaphi = vec2(TWO_PI_CIRC * (a_pos.x + treadmill_x),
                        TWO_PI_CIRC * (a_pos.y + treadmill_y));
-  float height = R1 * TWO_PI_CIRC;
+  float height = R2 * 4 * TWO_PI_CIRC;
-  vec3 normal = vec3(toroid(thetaphi, 0, height, height));
+  vec3 normal = vec3(toroid(thetaphi, 0, height, height)) *
-  gl_Position = u_matrix * camera *
+                vec3(R2 / R3, 1.0, 1.0);
-      vec4(toroid(thetaphi, R1, R2, R1) + a_pos.z * normal, 1.0);
+  gl_Position = u_matrix * vec4(toroid(thetaphi, R1, R2, R3) + a_pos.z * normal, 1.0);
 }

src/scenes/world.rs

@@ -9,6 +9,7 @@ extern crate gfx;
 extern crate nalgebra as na;
 extern crate num_traits;
 extern crate openvr_sys;
+extern crate piston;
 extern crate piston_window;
 
 use std::collections::BTreeMap;
@@ -19,13 +20,14 @@ use gfx::tex;
 use gfx::traits::FactoryExt;
 use self::na::ToHomogeneous;
 use self::num_traits::identities::One;
+use self::piston::input::{Button, Input, Key};
 
-//const R1: f32 = 4096.0;
-//const R2: f32 = 1024.0;
-//const R1: f32 = 4.0;
-//const R2: f32 = 1.0;
 const R1: f32 = 256.0;
 const R2: f32 = 64.0;
+const R3: f32 = 128.0;
+const PI: f32 = ::std::f32::consts::PI;
+const TWO_PI: f32 = 2.0 * PI;
+const TWO_PI_CIRC: f32 = TWO_PI / 256.0;
 
 gfx_defines! {
   vertex Vertex {
@@ -38,10 +40,10 @@ gfx_defines! {
     anim: [u32; 4] = "anim",
     r1: f32 = "R1",
     r2: f32 = "R2",
+    r3: f32 = "R3",
   }
 
   constant Locals {
-    camera: [[f32; 4]; 4] = "camera",
     millis: u32 = "millis",
     treadmill_x: f32 = "treadmill_x",
     treadmill_y: f32 = "treadmill_y",
@@ -76,8 +78,7 @@ fn get_model(world: &model::World) -> (Vec<Vertex>, Vec<u32>) {
         10 | 11 | 12 => 1.0,
         _ => 0.0,
       };
-      let rf = (((r + 90) % 256) as i16 - 128) as f32;
+      let (rf, cf) = (r as f32, c as f32);
-      let cf = (((c + 144) % 256) as i16 - 128) as f32;
       if alt == 0.0 {
         verticies.extend_from_slice(
           &[Vertex { pos: [ cf + 0., -rf - 1., 0. ], uv: [0., 0.], tileidx: tileidx },
@@ -112,8 +113,8 @@ fn get_model(world: &model::World) -> (Vec<Vertex>, Vec<u32>) {
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 enum TrackMode {
-  TOUCH,
+  Touch,
-  PRESS
+  Press
 }
 
 pub struct WorldScene<D: gfx::Device,
@@ -133,11 +134,15 @@ pub struct WorldScene<D: gfx::Device,
   start_time: SystemTime,
   treadmills: (f32, f32),
   pads: BTreeMap<u32, (TrackMode, Option<openvr_sys::VRControllerState_t>)>,
+
+  pos: (u8, u8),
 }
 
 impl<D: gfx::Device, F: gfx::Factory<D::Resources>> WorldScene<D, F> {
-  pub fn new(factory: &mut F,
+  pub fn new(device: &mut D,
-             encoder: &mut gfx::Encoder<D::Resources, D::CommandBuffer>) -> WorldScene<D, F> {
+             factory: &mut F,
+             encoder: &mut gfx::Encoder<D::Resources, D::CommandBuffer>,
+             aux_command: &mut <D as gfx::Device>::CommandBuffer) -> WorldScene<D, F> {
     let (model, model_idx) = get_model(&get_data_model());
     let (vertex_buffer, slice) =
         factory.create_vertex_buffer_with_slice(&model, &model_idx[..]);
@@ -145,7 +150,8 @@ impl<D: gfx::Device, F: gfx::Factory<D::Resources>> WorldScene<D, F> {
     let constants = factory.create_constant_buffer(1);
     encoder.update_constant_buffer(&constants, &Constants { anim: ANIMDATA,
                                                             r1: R1,
-                                                            r2: R2 });
+                                                            r2: R2,
+                                                            r3: R3});
 
     WorldScene {
       pso: factory.create_pipeline_simple(VERTEX_SHADER_SRC,
@@ -155,8 +161,8 @@ impl<D: gfx::Device, F: gfx::Factory<D::Resources>> WorldScene<D, F> {
       camera: na::Matrix4::one(),
       constants: constants,
       locals: factory.create_constant_buffer(1),
-      atlas: tile::get_tiles::<_, _, view::ColorFormat>(factory),
+      atlas: tile::get_tiles::<_, _, view::ColorFormat>(device, factory, aux_command),
-      sampler: factory.create_sampler(tex::SamplerInfo::new(tex::FilterMethod::Scale,
+      sampler: factory.create_sampler(tex::SamplerInfo::new(tex::FilterMethod::Jrd,
                                                             tex::WrapMode::Tile)),
       f: PhantomData,
 
@@ -165,8 +171,19 @@ impl<D: gfx::Device, F: gfx::Factory<D::Resources>> WorldScene<D, F> {
       start_time: SystemTime::now(),
       treadmills: (0.0, 0.0),
       pads: BTreeMap::new(),
+
+      pos: (90, 144),
     }
   }
+
+  fn toroid((x, y): (u8, u8), r1: f32, r2: f32, r3: f32) -> na::Vector3<f32>
+  {
+    let x: f32 = TWO_PI_CIRC * x as f32;
+    let y: f32 = TWO_PI_CIRC * y as f32;
+    na::Vector3::<f32>::new(r3 * -1.0f32 * x.sin(), // use r3 instead of r2 for "deflated" torus
+                            (r1 + r2 * x.cos()) * y.cos(),
+                            (r1 + r2 * x.cos()) * y.sin())
+  }
 }
 
 const ANIMDATA: [u32; 4] =
@@ -182,24 +199,40 @@ impl<D: gfx::Device,
     use scene::Event::*;
     use vr::Event::*;
     match event {
-      Vr(Touch { dev_idx, controller }) => {
+      Vr(Touch { dev_idx, .. }) => {
-        self.pads.insert(dev_idx, (TrackMode::TOUCH, None));
+        self.pads.insert(dev_idx, (TrackMode::Touch, None));
       },
-      Vr(Press { dev_idx, controller }) => {
+      Vr(Press { dev_idx, .. }) => {
-        self.pads.insert(dev_idx, (TrackMode::PRESS, None));
+        self.pads.insert(dev_idx, (TrackMode::Press, None));
       },
-      Vr(Unpress { dev_idx, controller }) => {
+      Vr(Unpress { dev_idx, .. }) => {
-        self.pads.insert(dev_idx, (TrackMode::TOUCH, None));
+        self.pads.insert(dev_idx, (TrackMode::Touch, None));
       },
-      Vr(Untouch { dev_idx, controller }) => {
+      Vr(Untouch { dev_idx, .. }) => {
         self.pads.remove(&dev_idx);
       },
+      Piston(Input::Press(Button::Keyboard(Key::Left))) => {
+        self.pos = (self.pos.0.wrapping_sub(1), self.pos.1);
+        println!("x: {}, y: {}", self.pos.0, self.pos.1);
+      },
+      Piston(Input::Press(Button::Keyboard(Key::Right))) => {
+        self.pos = (self.pos.0.wrapping_add(1), self.pos.1);
+        println!("x: {}, y: {}", self.pos.0, self.pos.1);
+      },
+      Piston(Input::Press(Button::Keyboard(Key::Up))) => {
+        self.pos = (self.pos.0, self.pos.1.wrapping_sub(1));
+        println!("x: {}, y: {}", self.pos.0, self.pos.1);
+      },
+      Piston(Input::Press(Button::Keyboard(Key::Down))) => {
+        self.pos = (self.pos.0, self.pos.1.wrapping_add(1));
+        println!("x: {}, y: {}", self.pos.0, self.pos.1);
+      },
       _ => ()
     }
   }
 
   fn update(&mut self,
-            vr: &mut vr::VR,
+            vr: &mut Option<vr::VR>,
             encoder: &mut gfx::Encoder<D::Resources, D::CommandBuffer>) {
     const NANOS_PER_MILLI: u32 = 1_000_000;
     const MILLIS_PER_SEC: u64 = 1_000;
@@ -208,10 +241,10 @@ impl<D: gfx::Device,
 
     for (pad, track) in self.pads.iter_mut() {
       let mode = track.0;
-      if let Some(state) = vr.get_controller_state(*pad) {
+      if let Some(state) = vr.as_ref().and_then(|vr| vr.get_controller_state(*pad)) {
         if let Some(old_state) = track.1 {
           match mode {
-            TrackMode::TOUCH => {
+            TrackMode::Touch => {
               const THRESHOLD: f32 = 0.005;
               const SCALE: f32 = 32.0;
               let xdiff = state.rAxis[0].x - old_state.rAxis[0].x;
@@ -219,9 +252,9 @@ impl<D: gfx::Device,
               if xdiff.abs() > THRESHOLD { self.treadmills.0 += SCALE * xdiff; }
               if ydiff.abs() > THRESHOLD { self.treadmills.1 += SCALE * ydiff; }
             },
-            TrackMode::PRESS => {
+            TrackMode::Press => {
               let rot = na::Vector3::new(0.0, 0.0, 0.0);
-              let speed = R2 * 0.01;
+              let speed = R2 * 0.005;
               if state.rAxis[0].x > 0.5 {
                 self.camera = na::Similarity3::new(na::Vector3::new(-speed,  0.0, 0.0),
                                                    rot, 1.0).to_homogeneous() * self.camera;
@@ -246,8 +279,7 @@ impl<D: gfx::Device,
       }
     }
 
-    encoder.update_constant_buffer(&self.locals, &Locals { camera: *(self.camera).as_ref(),
+    encoder.update_constant_buffer(&self.locals, &Locals { millis: millis,
-                                                           millis: millis,
                                                            treadmill_x: self.treadmills.0,
                                                            treadmill_y: self.treadmills.1 });
   }
@@ -272,9 +304,14 @@ impl<D: gfx::Device,
   }
 
   fn origin(&self) -> na::Matrix4<f32> {
-    na::Similarity3::new(na::Vector3::new(0.0, R1 - R2, 0.0),
+    let (x, y) = (self.pos.0, self.pos.1);
-                         na::Vector3::new(0.0, 0.0, 0.0), 1.0).to_homogeneous()
+    let eye = Self::toroid((x, y), R1, R2, R3);
-
+    let looktgt = Self::toroid((x, y.wrapping_add(1)), R1, R2, R3);
+    let normal = Self::toroid((x, y), 0.0, R2, R2) * na::Vector3::new(R2 / R3, 1.0, 1.0);
+    self.camera * na::Isometry3::look_at_rh(eye.as_point(),
+                                            looktgt.as_point(),
+                                            &normal,
+                                           ).to_homogeneous()
   }
 }
 

src/tile.rs

@@ -6,30 +6,45 @@ use ::std;
 use std::io::Read;
 use std::path::Path;
 
+use self::gfx::{CommandBuffer, Typed};
 use self::gfx::tex;
 
+const TILEDIM: u16 = 16;
+
 #[repr(C)]
 #[derive(Clone, Copy)]
 pub struct Tile {
   pub val: u8,
 }
 
-pub fn get_tiles<R, F, T>(factory: &mut F) -> (//gfx::handle::Texture<R, T::Surface>,
+pub fn get_tiles<D, F, T>(device: &mut D,
-                                               gfx::handle::ShaderResourceView<R, T::View>)
+                          factory: &mut F,
-  where R: gfx::Resources,
+                          command: &mut <D as gfx::Device>::CommandBuffer)
-        F: gfx::Factory<R>,
+                          -> gfx::handle::ShaderResourceView<D::Resources, T::View>
+  where D: gfx::Device,
+        F: gfx::Factory<D::Resources>,
         T: gfx::format::TextureFormat {
   let filename = "data/SHAPES.EGA";
   let mut file = std::fs::File::open(Path::new(filename))
     .expect(&format!("failed opening tiles file: {}", filename));
   let mut ega_bytes = Vec::new();
   file.read_to_end(&mut ega_bytes).expect("Read tiles file");
-  let ega_page = ega::decode(&ega_bytes, ega::Compression::UNCOMPRESSED, ega::Tiling::TILED(16));
+  let ega_page = ega::decode(&ega_bytes, ega::Compression::Uncompressed, ega::Tiling::Tiled(TILEDIM));
-  let tiles: Vec<&[u8]> = ega_page.iter().collect();
+  let mipmap = ega_page.mipmap(2);
-  let tex = factory.create_texture_const_u8::<T>(tex::Kind::D2Array(16, 16, 256,
+
+  let tex = factory.create_texture_const_u8::<T>(tex::Kind::D2Array(mipmap.dim as u16,
+                                                                    mipmap.dim as u16,
+                                                                    mipmap.len as u16,
                                                                     tex::AaMode::Single),
-                                                 &tiles)
+                                                 &mipmap.slices())
                    .expect("create tile texture");
+
+  {
+    let mut manager = gfx::handle::Manager::<D::Resources>::new();
+    let view = manager.ref_srv(tex.1.raw());
+    command.generate_mipmap(*view);
+    device.submit(command);
+  }
   tex.1
 }
 

src/town.rs

@@ -6,23 +6,23 @@ use tile::Tile;
 #[allow(dead_code)]
 #[derive(Clone, Copy, Debug)]
 enum Behavior {
-  FIXED = 0x00,
+  Fixed = 0x00,
-  WANDER = 0x01,
+  Wander = 0x01,
-  FOLLOW = 0x80,
+  Follow = 0x80,
-  ATTACK = 0xFF,
+  Attack = 0xFF,
 }
 
 #[derive(Clone, Copy)]
 pub struct Town {
   map: Chunk,
-  npc_tile1: [Tile; 32],
+  _npc_tile1: [Tile; 32],
-  npc_x1: [u8; 32],
+  _npc_x1: [u8; 32],
-  npc_y1: [u8; 32],
+  _npc_y1: [u8; 32],
-  npc_tile2: [Tile; 32],
+  _npc_tile2: [Tile; 32],
-  npc_x2: [u8; 32],
+  _npc_x2: [u8; 32],
-  npc_y2: [u8; 32],
+  _npc_y2: [u8; 32],
-  npc_behavior: [Behavior; 32],
+  _npc_behavior: [Behavior; 32],
-  npc_talk_idx: [u8; 32],
+  _npc_talk_idx: [u8; 32],
 }
 
 impl HasMap for Town {

src/view.rs

@@ -9,7 +9,7 @@ extern crate piston_window;
 use gfx;
 use gfx::Device;
 use gfx::traits::FactoryExt;
-use self::na::Inverse;
+use self::na::{Inverse, ToHomogeneous};
 use self::piston_window::{PistonWindow, Window};
 
 pub type ColorFormat = gfx::format::Srgba8;
@@ -29,62 +29,82 @@ pub struct ViewRoot<Dev, T, D>
         T: gfx::format::RenderFormat + gfx::format::TextureFormat,
         D: gfx::format::DepthFormat + gfx::format::TextureFormat {
 
-  left: vr::EyeBuffer<T, D>,
+  left: Option<vr::EyeBuffer<T, D>>,
-  right: vr::EyeBuffer<T, D>,
+  right: Option<vr::EyeBuffer<T, D>>,
   trans: gfx::handle::Buffer<Dev::Resources, Trans>,
 }
 
 impl ViewRoot<gfx_device_gl::Device, ColorFormat, DepthFormat> {
-  pub fn create_view(window: &mut PistonWindow, vr: &VR)
+  pub fn create_view(window: &mut PistonWindow, vr: &Option<VR>)
                      -> ViewRoot<gfx_device_gl::Device, ColorFormat, DepthFormat> {
+    if let &Some(ref vr) = vr {
+      let render_size = vr.recommended_render_target_size();
 
-    let render_size = vr.recommended_render_target_size();
+      let render_size = vr::Size { width: render_size.width * 220 / 100,
+                                   height: render_size.height * 220 / 100 };
 
-    let render_size = vr::Size { width: render_size.width * 220 / 100,
+      let left = vr::create_eyebuffer(&mut window.factory, render_size)
-                                 height: render_size.height * 220 / 100 };
+          .expect("create left renderbuffer");
+      let right = vr::create_eyebuffer(&mut window.factory, render_size)
+          .expect("create right renderbuffer");
+      let trans = window.factory.create_constant_buffer(1);
 
-    let left = vr::create_eyebuffer(&mut window.factory, render_size)
+      window.window.swap_buffers(); // To contain setup calls to Frame 0 in apitrace
-        .expect("create left renderbuffer");
-    let right = vr::create_eyebuffer(&mut window.factory, render_size)
-        .expect("create right renderbuffer");
-    let trans = window.factory.create_constant_buffer(1);
 
-    window.window.swap_buffers(); // To contain setup calls to Frame 0 in apitrace
+      ViewRoot::<gfx_device_gl::Device, ColorFormat, DepthFormat> {
-
+        left: Some(left),
-    ViewRoot::<gfx_device_gl::Device, ColorFormat, DepthFormat> {
+        right: Some(right),
-      left: left,
+        trans: trans,
-      right: right,
+      }
-      trans: trans.clone(),
+    } else {
+      let trans = window.factory.create_constant_buffer(1);
+      ViewRoot::<gfx_device_gl::Device, ColorFormat, DepthFormat> {
+        left: None,
+        right: None,
+        trans: trans,
+      }
     }
   }
 
   pub fn draw(&self,
               window: &mut PistonWindow,
-              vr: &mut vr::VR,
+              vr: &mut Option<vr::VR>,
               scene: &::scene::Scene<gfx_device_gl::Device, gfx_device_gl::Factory>) {
-    // Get the current sensor state
+    if let &mut Some(ref mut vr) = vr {
-    let poses = vr.poses();
+      // Get the current sensor state
+      let poses = vr.poses();
 
-    let mut hmd_mat = poses.poses[0].to_device.as_matrix4();
+      let mut hmd_mat = poses.poses[0].to_device.as_matrix4();
-    hmd_mat.inverse_mut();
+      hmd_mat.inverse_mut();
 
-    for &(eye, buffers) in [(vr::Eye::Left, &self.left),
+      for &(eye, buffers) in [(vr::Eye::Left, &self.left),
-                            (vr::Eye::Right, &self.right)].into_iter() {
+                              (vr::Eye::Right, &self.right)].into_iter() {
-      window.encoder.clear(&buffers.target, [0.005, 0.005, 0.01, 1.0]);
+        let target = &buffers.as_ref().expect("vr color buffer").target;
+        let depth = &buffers.as_ref().expect("vr depth buffer").depth;
+        window.encoder.clear(target, [0.005, 0.005, 0.01, 1.0]);
+        window.encoder.clear_depth(depth, 1.0);
 
-      window.encoder.clear_depth(&buffers.depth, 1.0);
+        let proj_mat = vr.projection_matrix(eye, NEAR, FAR);
+        let eye_mat = vr.head_to_eye_transform(eye);
+        let scene_mat = scene.origin();
+        let trans = Trans { matrix: *(proj_mat * eye_mat * hmd_mat * scene_mat).as_ref() };
+        window.encoder.update_constant_buffer(&self.trans, &trans);
 
-      let proj_mat = vr.projection_matrix(eye, NEAR, FAR);
+        scene.render(&mut window.factory,
-      let eye_mat = vr.head_to_eye_transform(eye);
+                     &mut window.encoder,
+                     &self.trans,
+                     &target,
+                     &depth);
+      }
+    } else {
+      // If running without VR, just draw from some default projection near the scene origin
+      let head_mat = na::Similarity3::new(na::Vector3::new(0.0, -1.5, 0.0),
+                                          na::Vector3::new(0.0, 0.0, 0.0),
+                                          1.0).to_homogeneous();
+      let proj_mat = na::PerspectiveMatrix3::new(1.0, 90.0, NEAR, FAR).to_matrix();
       let scene_mat = scene.origin();
-      let trans = Trans { matrix: *(proj_mat * eye_mat * hmd_mat * scene_mat).as_ref() };
+      let trans = Trans { matrix: *(proj_mat * head_mat * scene_mat).as_ref() };
       window.encoder.update_constant_buffer(&self.trans, &trans);
-
-      scene.render(&mut window.factory,
-                   &mut window.encoder,
-                   &self.trans,
-                   &buffers.target,
-                   &buffers.depth);
     }
     // draw monitor window
     window.encoder.clear(&window.output_color, [0.005, 0.005, 0.01, 1.0]);
@@ -96,8 +116,12 @@ impl ViewRoot<gfx_device_gl::Device, ColorFormat, DepthFormat> {
                  &window.output_stencil);
 
     window.encoder.flush(&mut window.device);
-    vr.submit(vr::Eye::Left, &self.left.tex);
+    if let (&mut Some(ref mut vr),
-    vr.submit(vr::Eye::Right, &self.right.tex);
+            &Some(ref left),
+            &Some(ref right)) = (vr, &self.left, &self.right) {
+      vr.submit(vr::Eye::Left, &left.tex);
+      vr.submit(vr::Eye::Right, &right.tex);
+    }
     window.window.swap_buffers();
     window.device.cleanup();
   }