3DFileViewer: Support textured models

Models that contain UV co-ordinates are now supported,
and will display with a texture wrapped around it, provided
a `bmp` with the same name as the object is in the same
directory as the 3D Model.

Userland/Applications/3DFileViewer/Common.h

@@ -16,9 +16,18 @@ struct Vertex {
     GLfloat z;
 };
 
+struct TexCoord {
+    GLfloat u;
+    GLfloat v;
+};
+
 // A triangle defines a single "face" of a mesh
 struct Triangle {
     GLuint a;
     GLuint b;
     GLuint c;
+
+    GLuint tex_coord_index0;
+    GLuint tex_coord_index1;
+    GLuint tex_coord_index2;
 };

Userland/Applications/3DFileViewer/Mesh.cpp

@@ -22,8 +22,9 @@ const Color colors[] {
     Color::White
 };
 
-Mesh::Mesh(Vector<Vertex> vertices, Vector<Triangle> triangles)
+Mesh::Mesh(Vector<Vertex> vertices, Vector<TexCoord> tex_coords, Vector<Triangle> triangles)
     : m_vertex_list(move(vertices))
+    , m_tex_coords(move(tex_coords))
     , m_triangle_list(move(triangles))
 {
 }
@@ -74,18 +75,27 @@ void Mesh::draw()
             m_vertex_list.at(m_triangle_list[i].a).y,
             m_vertex_list.at(m_triangle_list[i].a).z);
 
+        if (is_textured())
+            glTexCoord2f(m_tex_coords.at(m_triangle_list[i].tex_coord_index0).u, 1.0f - m_tex_coords.at(m_triangle_list[i].tex_coord_index0).v);
+
         // Vertex 2
         glVertex3f(
             m_vertex_list.at(m_triangle_list[i].b).x,
             m_vertex_list.at(m_triangle_list[i].b).y,
             m_vertex_list.at(m_triangle_list[i].b).z);
 
+        if (is_textured())
+            glTexCoord2f(m_tex_coords.at(m_triangle_list[i].tex_coord_index1).u, 1.0f - m_tex_coords.at(m_triangle_list[i].tex_coord_index1).v);
+
         // Vertex 3
         glVertex3f(
             m_vertex_list.at(m_triangle_list[i].c).x,
             m_vertex_list.at(m_triangle_list[i].c).y,
             m_vertex_list.at(m_triangle_list[i].c).z);
 
+        if (is_textured())
+            glTexCoord2f(m_tex_coords.at(m_triangle_list[i].tex_coord_index2).u, 1.0f - m_tex_coords.at(m_triangle_list[i].tex_coord_index2).v);
+
         glEnd();
     }
 }

Userland/Applications/3DFileViewer/Mesh.h

@@ -16,7 +16,7 @@ class Mesh : public RefCounted<Mesh> {
 public:
     Mesh() = delete;
 
-    Mesh(Vector<Vertex> vertices, Vector<Triangle> triangles);
+    Mesh(Vector<Vertex> vertices, Vector<TexCoord> tex_coords, Vector<Triangle> triangles);
 
     size_t vertex_count() const { return m_vertex_list.size(); }
 
@@ -24,7 +24,10 @@ public:
 
     void draw();
 
+    bool is_textured() const { return m_tex_coords.size() > 0; }
+
 private:
     Vector<Vertex> m_vertex_list;
+    Vector<TexCoord> m_tex_coords;
     Vector<Triangle> m_triangle_list;
 };

Userland/Applications/3DFileViewer/WavefrontOBJLoader.cpp

@@ -12,6 +12,7 @@
 RefPtr<Mesh> WavefrontOBJLoader::load(Core::File& file)
 {
     Vector<Vertex> vertices;
+    Vector<TexCoord> tex_coords;
     Vector<Triangle> triangles;
 
     dbgln("Wavefront: Loading {}...", file.name());
@@ -20,8 +21,26 @@ RefPtr<Mesh> WavefrontOBJLoader::load(Core::File& file)
     for (auto line = file.line_begin(); !line.at_end(); ++line) {
         auto object_line = *line;
 
+        // Ignore file comments
+        if (object_line.starts_with("#"))
+            continue;
+
+        if (object_line.starts_with("vt")) {
+            auto tex_coord_line = object_line.split_view(' ');
+            if (tex_coord_line.size() != 3) {
+                dbgln("Wavefront: Malformed TexCoord line. Aborting.");
+                dbgln("{}", object_line);
+                return nullptr;
+            }
+
+            tex_coords.append({ static_cast<GLfloat>(atof(String(tex_coord_line.at(1)).characters())),
+                static_cast<GLfloat>(atof(String(tex_coord_line.at(2)).characters())) });
+
+            continue;
+        }
+
         // FIXME: Parse texture coordinates and vertex normals
-        if (object_line.starts_with("vt") || object_line.starts_with("vn")) {
+        if (object_line.starts_with("vn")) {
             continue;
         }
 
@@ -33,10 +52,9 @@ RefPtr<Mesh> WavefrontOBJLoader::load(Core::File& file)
                 return nullptr;
             }
 
-            vertices.append(
-                { static_cast<GLfloat>(atof(String(vertex_line.at(1)).characters())),
-                    static_cast<GLfloat>(atof(String(vertex_line.at(2)).characters())),
-                    static_cast<GLfloat>(atof(String(vertex_line.at(3)).characters())) });
+            vertices.append({ static_cast<GLfloat>(atof(String(vertex_line.at(1)).characters())),
+                static_cast<GLfloat>(atof(String(vertex_line.at(2)).characters())),
+                static_cast<GLfloat>(atof(String(vertex_line.at(3)).characters())) });
         }
         // This line describes a face (a collection of 3 vertices, aka a triangle)
         else if (object_line.starts_with("f")) {
@@ -46,19 +64,30 @@ RefPtr<Mesh> WavefrontOBJLoader::load(Core::File& file)
                 return nullptr;
             }
 
+            GLuint vert_index[3];
+            GLuint tex_coord_index[3];
             if (object_line.contains("/")) {
                 for (int i = 1; i <= 3; ++i) {
-                    face_line.at(i) = face_line.at(i).split_view("/").at(0);
+                    vert_index[i - 1] = face_line.at(i).split_view("/").at(0).to_uint().value_or(1);
+                    tex_coord_index[i - 1] = face_line.at(i).split_view("/").at(1).to_uint().value_or(1);
                 }
+            } else {
+                vert_index[0] = (face_line.at(1).to_uint().value_or(1));
+                vert_index[1] = (face_line.at(2).to_uint().value_or(1));
+                vert_index[2] = (face_line.at(3).to_uint().value_or(1));
+                tex_coord_index[0] = 0;
+                tex_coord_index[1] = 0;
+                tex_coord_index[2] = 0;
             }
 
             // Create a new triangle
             triangles.append(
-                {
-                    face_line.at(1).to_uint().value() - 1,
-                    face_line.at(2).to_uint().value() - 1,
-                    face_line.at(3).to_uint().value() - 1,
-                });
+                { vert_index[0] - 1,
+                    vert_index[1] - 1,
+                    vert_index[2] - 1,
+                    tex_coord_index[0] - 1,
+                    tex_coord_index[1] - 1,
+                    tex_coord_index[2] - 1 });
         }
     }
 
@@ -68,5 +97,5 @@ RefPtr<Mesh> WavefrontOBJLoader::load(Core::File& file)
     }
 
     dbgln("Wavefront: Done.");
-    return adopt_ref(*new Mesh(vertices, triangles));
+    return adopt_ref(*new Mesh(vertices, tex_coords, triangles));
 }

Userland/Applications/3DFileViewer/main.cpp

@@ -137,8 +137,26 @@ bool GLContextWidget::load(const String& filename)
         return false;
     }
 
+    // Determine whether or not a texture for this model resides within the same directory
+    StringBuilder builder;
+    builder.append(filename.split('.').at(0));
+    builder.append(".bmp");
+
+    // Attempt to open the texture file from disk
+    auto texture_image = Gfx::Bitmap::load_from_file(builder.string_view());
+
+    GLuint tex;
+    glGenTextures(1, &tex);
+    if (texture_image) {
+        // Upload texture data to the GL
+        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, texture_image->width(), texture_image->height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, texture_image->scanline(0));
+    } else {
+        dbgln("3DFileViewer: Couldn't load texture for {}", filename);
+    }
+
     m_mesh = new_mesh;
     dbgln("3DFileViewer: mesh has {} triangles.", m_mesh->triangle_count());
+
     return true;
 }