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extern crate glium;
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extern crate image;
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use glium::{VertexBuffer, IndexBuffer};
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use glium::texture::Texture2d;
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use std::vec;
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#[derive(Debug, Copy, Clone)]
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pub struct V3D {
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pub pos: [f32; 3],
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pub nrm: [f32; 3],
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pub tex: [f32; 2],
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}
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implement_vertex!(V3D, pos, nrm, tex);
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#[derive(Debug, Clone)]
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pub struct Model {
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pub points: Vec<V3D>,
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pub tris: Vec<u16>,
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pub texture: Option<Vec<u8>>,
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}
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impl Model {
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pub fn load_from_file(path: &str) -> Result<Model, String> {
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use std::fs::File;
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use std::io::Read;
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let mut f = match File::open(path) {
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Ok(f) => f,
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Err(_) => return Err("Unable to open file".to_string()),
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};
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let mut buf = Vec::new();
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let _ = f.read_to_end(&mut buf);
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(Reader { bytes: buf.into_iter() }).read_model()
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}
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pub fn get_vbuf(&self, display: &glium::Display) -> VertexBuffer<V3D> {
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VertexBuffer::new(display, self.points.as_slice()).unwrap()
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}
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pub fn get_ibuf(&self, display: &glium::Display) -> IndexBuffer<u16> {
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IndexBuffer::new(
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display,
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glium::index::PrimitiveType::TrianglesList,
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&self.tris).unwrap()
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}
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pub fn get_tex(&self, display: &glium::Display) -> Option<Texture2d> {
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use std::io::Cursor;
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use glium::texture::RawImage2d;
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if let Some(ref tex) = self.texture {
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let img = image::load(Cursor::new(tex.clone()),
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image::PNG).unwrap().to_rgba();
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let dims = img.dimensions();
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let img = RawImage2d::from_raw_rgba_reversed(img.into_raw(),
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dims);
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Some(Texture2d::new(display, img).unwrap())
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} else {
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None
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}
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}
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}
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/// A `Reader` is just a tiny wrapper over a mutable byte iterator, so we
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/// can parse things more easily.
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struct Reader {
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pub bytes: vec::IntoIter<u8>,
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}
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#[test]
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fn reader_tests() {
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assert!(Reader::from_slice(&[0x00]).read_twip() == Ok(-32.0));
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assert!(Reader::from_slice(&[0x00]).read_prefix_int() == Ok(0x00));
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assert!(Reader::from_slice(&[0x7f]).read_prefix_int() == Ok(0x7f));
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assert!(Reader::from_slice(&[0x80,0xff]).read_prefix_int() == Ok(0xff));
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}
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impl Reader {
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fn from_slice(lst: &[u8]) -> Self {
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Reader { bytes: lst.to_vec().into_iter() }
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}
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/// This gets the next byte, or fails if it's out of input.
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fn next(&mut self) -> Result<u8, String> {
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Ok(try!(self.bytes.next().ok_or("out of input")))
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}
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/// This reads a one-byte or two-byte float in the rough range of
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/// (192 .. -128). We're going to treat all models as if they're
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/// supposed to be centered in a 64x64x64 square, so this gives
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/// us 128 units on either side of the central square, as well.
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fn read_twip(&mut self) -> Result<f32, String> {
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let b1 = try!(self.next());
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if (b1 & 0x80) != 0 {
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let b2 = try!(self.next());
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let val = ((b1 as u16 & 0x7f) << 8) | b2 as u16;
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Ok((val as f32 / 102.0) - 128.0)
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} else {
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Ok((b1 as f32) - 32.0)
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}
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}
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/// This reads a single byte and treats it as a ratio.
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fn read_ratio(&mut self) -> Result<f32, String> {
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let b = try!(self.next());
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Ok(b as f32 / 255.0)
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}
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/// This reads a 64-bit int with a packed PrefixInteger representation.
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/// The shorter the int, the shorter the representation.
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fn read_prefix_int(&mut self) -> Result<u64, String> {
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fn match_bits(n: u8, mask: u8) -> bool {
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n & mask == mask
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}
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let b = try!(self.next());
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if match_bits(b, 0xff) { self.continue_prefix_int(8, 0) }
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else if match_bits(b, 0xfe) { self.continue_prefix_int(7, 0) }
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else if match_bits(b, 0xfc) { self.continue_prefix_int(6, b & 0x01) }
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else if match_bits(b, 0xf8) { self.continue_prefix_int(5, b & 0x03) }
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else if match_bits(b, 0xf0) { self.continue_prefix_int(4, b & 0x07) }
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else if match_bits(b, 0xe0) { self.continue_prefix_int(3, b & 0x0f) }
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else if match_bits(b, 0xc0) { self.continue_prefix_int(2, b & 0x1f) }
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else if match_bits(b, 0x80) { self.continue_prefix_int(1, b & 0x3f) }
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else { self.continue_prefix_int(0, b) }
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}
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/// This is a helper function for parsing prefix ints, too.
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fn continue_prefix_int(&mut self, mut left: u8, upper: u8) -> Result<u64, String> {
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let mut ret = upper as u64;
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while left > 0 {
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left -= 1;
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ret = (ret << 8) | try!(self.next()) as u64;
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}
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Ok(ret)
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}
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/// This reads a single V3D: three twips for the x/y/z, three twips
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/// for the normal, and two ratios for the uv coords.
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fn read_v3d(&mut self) -> Result<V3D, String> {
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Ok(V3D { pos: [ try!(self.read_twip()) * 0.1,
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try!(self.read_twip()) * 0.1,
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try!(self.read_twip()) * 0.1],
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nrm: [ try!(self.read_twip()),
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try!(self.read_twip()),
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try!(self.read_twip()) ],
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tex: [ try!(self.read_ratio()),
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try!(self.read_ratio()) ],
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})
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}
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/// This reads a PrefixInteger to find out how many other things to read,
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/// and then reads that number of things.
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fn read_several<F, R>(&mut self, reader: F) -> Result<Vec<R>, String>
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where F: Fn(&mut Reader) -> Result<R, String>
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{
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let ct = try!(self.read_prefix_int());
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let mut ret = Vec::with_capacity(ct as usize);
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for _ in 0..ct {
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ret.push(try!(reader(self)))
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}
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Ok(ret)
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}
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/// This reads a model: right now, a list of tris, followed by a list of
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/// v3ds. This could be very small: a V3D could be as small as eight bytes,
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/// an index as small as one, and each size tag can be one byte. A simple
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/// model that contains only a triangle is going to be
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/// (1 + 3*8) + (1 + 3) == 28 bytes
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/// in contrast to the older UTM models, where an equivalent would be 50
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/// bytes per V3D and a two-byte overhead per list, as well as miscellaneous
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/// structure data, so
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/// (2 + 3*50) + (2 + 3 * 3) + 13 == 176 bytes
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/// That's a pretty good savings!
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fn read_model(&mut self) -> Result<Model, String> {
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Ok(Model {
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tris: try!(self.read_several(|r| r.read_prefix_int().map(|x| x as u16))),
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points: try!(self.read_several(|r| r.read_v3d())),
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texture: None,
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})
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}
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}
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