fixed panic on loading obj without normals

code/beginner/tutorial9-models/src/resources.rs

@@ -118,20 +118,34 @@ pub async fn load_model(
         .into_iter()
         .map(|m| {
             let vertices = (0..m.mesh.positions.len() / 3)
-                .map(|i| model::ModelVertex {
-                    position: [
-                        m.mesh.positions[i * 3],
-                        m.mesh.positions[i * 3 + 1],
-                        m.mesh.positions[i * 3 + 2],
-                    ],
-                    tex_coords: [m.mesh.texcoords[i * 2], 1.0 - m.mesh.texcoords[i * 2 + 1]],
-                    normal: [
-                        m.mesh.normals[i * 3],
-                        m.mesh.normals[i * 3 + 1],
-                        m.mesh.normals[i * 3 + 2],
-                    ],
-                })
-                .collect::<Vec<_>>();
+            .map(|i| {
+                if m.mesh.normals.is_empty(){
+                    model::ModelVertex {
+                        position: [
+                            m.mesh.positions[i * 3],
+                            m.mesh.positions[i * 3 + 1],
+                            m.mesh.positions[i * 3 + 2],
+                        ],
+                        tex_coords: [m.mesh.texcoords[i * 2], 1.0 - m.mesh.texcoords[i * 2 + 1]],
+                        normal: [0.0, 0.0, 0.0],
+                    }
+                }else{
+                    model::ModelVertex {
+                        position: [
+                            m.mesh.positions[i * 3],
+                            m.mesh.positions[i * 3 + 1],
+                            m.mesh.positions[i * 3 + 2],
+                        ],
+                        tex_coords: [m.mesh.texcoords[i * 2], 1.0 - m.mesh.texcoords[i * 2 + 1]],
+                        normal: [
+                            m.mesh.normals[i * 3],
+                            m.mesh.normals[i * 3 + 1],
+                            m.mesh.normals[i * 3 + 2],
+                        ],
+                    }
+                }
+            })
+            .collect::<Vec<_>>();
 
             let vertex_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
                 label: Some(&format!("{:?} Vertex Buffer", file_name)),

docs/beginner/tutorial9-models/README.md

@@ -341,19 +341,33 @@ pub async fn load_model(
     let meshes = models
         .into_iter()
         .map(|m| {
-            let vertices = (0..m.mesh.positions.len() / 3)
-                .map(|i| model::ModelVertex {
-                    position: [
-                        m.mesh.positions[i * 3],
-                        m.mesh.positions[i * 3 + 1],
-                        m.mesh.positions[i * 3 + 2],
-                    ],
-                    tex_coords: [m.mesh.texcoords[i * 2], 1.0 - m.mesh.texcoords[i * 2 + 1]],
-                    normal: [
-                        m.mesh.normals[i * 3],
-                        m.mesh.normals[i * 3 + 1],
-                        m.mesh.normals[i * 3 + 2],
-                    ],
+                let vertices = (0..m.mesh.positions.len() / 3)
+                .map(|i| {
+                    if m.mesh.normals.is_empty(){
+                        model::ModelVertex {
+                            position: [
+                                m.mesh.positions[i * 3],
+                                m.mesh.positions[i * 3 + 1],
+                                m.mesh.positions[i * 3 + 2],
+                            ],
+                            tex_coords: [m.mesh.texcoords[i * 2], 1.0 - m.mesh.texcoords[i * 2 + 1]],
+                            normal: [0.0, 0.0, 0.0],
+                        }
+                    }else{
+                        model::ModelVertex {
+                            position: [
+                                m.mesh.positions[i * 3],
+                                m.mesh.positions[i * 3 + 1],
+                                m.mesh.positions[i * 3 + 2],
+                            ],
+                            tex_coords: [m.mesh.texcoords[i * 2], 1.0 - m.mesh.texcoords[i * 2 + 1]],
+                            normal: [
+                                m.mesh.normals[i * 3],
+                                m.mesh.normals[i * 3 + 1],
+                                m.mesh.normals[i * 3 + 2],
+                            ],
+                        }
+                    }
                 })
                 .collect::<Vec<_>>();