mirror of
https://github.com/sotrh/learn-wgpu.git
synced 2024-11-16 06:12:55 +00:00
256 lines
9.3 KiB
Rust
256 lines
9.3 KiB
Rust
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use std::io::{BufReader, Cursor};
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use cfg_if::cfg_if;
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use wgpu::util::DeviceExt;
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use crate::{math::BoundingBox, model, texture};
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#[cfg(target_arch = "wasm32")]
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fn format_url(file_name: &str) -> reqwest::Url {
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let window = web_sys::window().unwrap();
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let location = window.location();
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let base = reqwest::Url::parse(&format!(
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"{}/{}/",
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location.origin().unwrap(),
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option_env!("RES_PATH").unwrap_or("res"),
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))
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.unwrap();
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base.join(file_name).unwrap()
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}
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pub async fn load_string(file_name: &str) -> anyhow::Result<String> {
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cfg_if! {
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if #[cfg(target_arch = "wasm32")] {
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let url = format_url(file_name);
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let txt = reqwest::get(url)
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.await?
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.text()
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.await?;
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} else {
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let path = std::path::Path::new(env!("OUT_DIR"))
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.join("res")
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.join(file_name);
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let txt = std::fs::read_to_string(path)?;
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}
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}
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Ok(txt)
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}
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pub async fn load_binary(file_name: &str) -> anyhow::Result<Vec<u8>> {
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cfg_if! {
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if #[cfg(target_arch = "wasm32")] {
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let url = format_url(file_name);
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let data = reqwest::get(url)
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.await?
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.bytes()
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.await?
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.to_vec();
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} else {
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let path = std::path::Path::new(env!("OUT_DIR"))
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.join("res")
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.join(file_name);
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let data = std::fs::read(path)?;
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}
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}
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Ok(data)
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}
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pub async fn load_texture(
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file_name: &str,
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is_normal_map: bool,
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device: &wgpu::Device,
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queue: &wgpu::Queue,
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) -> anyhow::Result<texture::Texture> {
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let data = load_binary(file_name).await?;
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texture::Texture::from_bytes(device, queue, &data, file_name, is_normal_map)
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}
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pub async fn load_model(
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file_name: &str,
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device: &wgpu::Device,
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queue: &wgpu::Queue,
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layout: &wgpu::BindGroupLayout,
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) -> anyhow::Result<model::Model> {
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let obj_text = load_string(file_name).await?;
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let obj_cursor = Cursor::new(obj_text);
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let mut obj_reader = BufReader::new(obj_cursor);
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let (models, obj_materials) = tobj::load_obj_buf_async(
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&mut obj_reader,
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&tobj::LoadOptions {
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triangulate: true,
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single_index: true,
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..Default::default()
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},
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|p| async move {
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let mat_text = load_string(&p).await.unwrap();
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tobj::load_mtl_buf(&mut BufReader::new(Cursor::new(mat_text)))
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},
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)
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.await?;
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let mut materials = Vec::new();
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for m in obj_materials? {
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let diffuse_texture = load_texture(&m.diffuse_texture, false, device, queue).await?;
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let normal_texture = load_texture(&m.normal_texture, true, device, queue).await?;
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materials.push(model::Material::new(
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device,
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&m.name,
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diffuse_texture,
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normal_texture,
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layout,
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));
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}
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// NEW!
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let mut model_bounding_box = BoundingBox {
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min: cgmath::Vector3::new(std::f32::INFINITY, std::f32::INFINITY, std::f32::INFINITY),
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max: cgmath::Vector3::new(
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std::f32::NEG_INFINITY,
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std::f32::NEG_INFINITY,
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std::f32::NEG_INFINITY,
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),
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};
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let meshes = models
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.into_iter()
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.map(|m| {
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// NEW!
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let mut bounding_box = BoundingBox {
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min: cgmath::Vector3::new(
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std::f32::INFINITY,
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std::f32::INFINITY,
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std::f32::INFINITY,
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),
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max: cgmath::Vector3::new(
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std::f32::NEG_INFINITY,
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std::f32::NEG_INFINITY,
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std::f32::NEG_INFINITY,
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),
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};
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let mut vertices = (0..m.mesh.positions.len() / 3)
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.map(|i| {
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// NEW!
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let p = cgmath::vec3(
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m.mesh.positions[i * 3],
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m.mesh.positions[i * 3 + 1],
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m.mesh.positions[i * 3 + 2],
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);
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model::ModelVertex {
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position: p.into(), // UPDATED!
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tex_coords: [m.mesh.texcoords[i * 2], m.mesh.texcoords[i * 2 + 1]],
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normal: [
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m.mesh.normals[i * 3],
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m.mesh.normals[i * 3 + 1],
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m.mesh.normals[i * 3 + 2],
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],
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// We'll calculate these later
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tangent: [0.0; 3],
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bitangent: [0.0; 3],
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}
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})
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.collect::<Vec<_>>();
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model_bounding_box.combine(&bounding_box);
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let indices = &m.mesh.indices;
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let mut triangles_included = vec![0; vertices.len()];
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// Calculate tangents and bitangets. We're going to
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// use the triangles, so we need to loop through the
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// indices in chunks of 3
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for c in indices.chunks(3) {
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let v0 = vertices[c[0] as usize];
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let v1 = vertices[c[1] as usize];
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let v2 = vertices[c[2] as usize];
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let pos0: cgmath::Vector3<_> = v0.position.into();
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let pos1: cgmath::Vector3<_> = v1.position.into();
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let pos2: cgmath::Vector3<_> = v2.position.into();
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let uv0: cgmath::Vector2<_> = v0.tex_coords.into();
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let uv1: cgmath::Vector2<_> = v1.tex_coords.into();
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let uv2: cgmath::Vector2<_> = v2.tex_coords.into();
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// Calculate the edges of the triangle
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let delta_pos1 = pos1 - pos0;
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let delta_pos2 = pos2 - pos0;
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// This will give us a direction to calculate the
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// tangent and bitangent
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let delta_uv1 = uv1 - uv0;
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let delta_uv2 = uv2 - uv0;
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// Solving the following system of equations will
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// give us the tangent and bitangent.
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// delta_pos1 = delta_uv1.x * T + delta_u.y * B
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// delta_pos2 = delta_uv2.x * T + delta_uv2.y * B
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// Luckily, the place I found this equation provided
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// the solution!
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let r = 1.0 / (delta_uv1.x * delta_uv2.y - delta_uv1.y * delta_uv2.x);
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let tangent = (delta_pos1 * delta_uv2.y - delta_pos2 * delta_uv1.y) * r;
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// We flip the bitangent to enable right-handed normal
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// maps with wgpu texture coordinate system
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let bitangent = (delta_pos2 * delta_uv1.x - delta_pos1 * delta_uv2.x) * -r;
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// We'll use the same tangent/bitangent for each vertex in the triangle
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vertices[c[0] as usize].tangent =
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(tangent + cgmath::Vector3::from(vertices[c[0] as usize].tangent)).into();
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vertices[c[1] as usize].tangent =
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(tangent + cgmath::Vector3::from(vertices[c[1] as usize].tangent)).into();
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vertices[c[2] as usize].tangent =
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(tangent + cgmath::Vector3::from(vertices[c[2] as usize].tangent)).into();
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vertices[c[0] as usize].bitangent =
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(bitangent + cgmath::Vector3::from(vertices[c[0] as usize].bitangent)).into();
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vertices[c[1] as usize].bitangent =
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(bitangent + cgmath::Vector3::from(vertices[c[1] as usize].bitangent)).into();
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vertices[c[2] as usize].bitangent =
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(bitangent + cgmath::Vector3::from(vertices[c[2] as usize].bitangent)).into();
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// Used to average the tangents/bitangents
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triangles_included[c[0] as usize] += 1;
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triangles_included[c[1] as usize] += 1;
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triangles_included[c[2] as usize] += 1;
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}
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// Average the tangents/bitangents
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for (i, n) in triangles_included.into_iter().enumerate() {
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let denom = 1.0 / n as f32;
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let mut v = &mut vertices[i];
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v.tangent = (cgmath::Vector3::from(v.tangent) * denom).into();
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v.bitangent = (cgmath::Vector3::from(v.bitangent) * denom).into();
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}
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let vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
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label: Some(&format!("{:?} Vertex Buffer", file_name)),
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contents: bytemuck::cast_slice(&vertices),
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usage: wgpu::BufferUsages::VERTEX,
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});
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let index_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
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label: Some(&format!("{:?} Index Buffer", file_name)),
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contents: bytemuck::cast_slice(&m.mesh.indices),
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usage: wgpu::BufferUsages::INDEX,
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});
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model::Mesh {
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name: file_name.to_string(),
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vertex_buffer,
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index_buffer,
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num_elements: m.mesh.indices.len() as u32,
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material: m.mesh.material_id.unwrap_or(0),
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// NEW!
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bounding_box,
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}
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})
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.collect::<Vec<_>>();
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Ok(model::Model {
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meshes,
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materials,
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// NEW!
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bounding_box: model_bounding_box,
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})
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}
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