wip(rendering): obj model loading

src/model.rs

@@ -1,4 +1,8 @@
+use crate::Vertex;
 use crate::texture::Texture;
+use cgmath::{Vector2, Vector3, Zero};
+use tobj::Model;
+
 pub struct Material {
     pub name: String,
     pub diffuse_texture: Texture,
@@ -12,3 +16,42 @@ pub struct Mesh {
     pub num_elements: u32,
     pub material: usize,
 }
+
+pub fn parse_obj(obj: &Vec<Model>) -> (Vec<Vertex>, Vec<u32>) {
+    let mut combined_vertices = Vec::new();
+    let mut combined_indices = Vec::new();
+    let mut vertex_offset = 0;
+
+    for object in obj {
+        let mesh: &_ = &object.mesh;
+        let vertices: Vec<Vertex> = (0..mesh.positions.len() / 3)
+            .map(|i| Vertex {
+                position: Vector3::from([
+                    mesh.positions[i * 3],
+                    mesh.positions[i * 3 + 1],
+                    mesh.positions[i * 3 + 2],
+                ]),
+                color: cgmath::Vector3::from([1.0, 1.0, 1.0]),
+                normal: if !mesh.normals.is_empty() {
+                    Vector3::from([
+                        mesh.normals[i * 3],
+                        mesh.normals[i * 3 + 1],
+                        mesh.normals[i * 3 + 2],
+                    ])
+                } else {
+                    Vector3::zero()
+                },
+                tex_coords: if !mesh.texcoords.is_empty() {
+                    Vector2::from([mesh.texcoords[i * 2], mesh.texcoords[i * 2 + 1]])
+                } else {
+                    Vector2::zero()
+                },
+            })
+            .collect();
+        combined_vertices.extend(vertices);
+        combined_indices.extend(mesh.indices.iter().map(|&index| index + vertex_offset));
+        vertex_offset += (mesh.positions.len() as u32) / 3;
+    }
+
+    (combined_vertices, combined_indices)
+}