+void MeshGL::draw_normals(float scale) const
+{
+ if(!nvao) {
+ glGenVertexArrays(1, &nvao);
+ glBindVertexArray(nvao);
+
+ glGenBuffers(1, &nvbo);
+ glBindBuffer(GL_ARRAY_BUFFER, nvbo);
+
+ glBufferData(GL_ARRAY_BUFFER, normals.size() * sizeof(Vec3) * 2, 0, GL_STATIC_DRAW);
+ Vec3 *data = (Vec3 *)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
+
+ for (size_t i = 0; i < normals.size(); i++)
+ {
+ *data++ = vertices[i];
+ *data++ = vertices[i] + normals[i] * scale;
+ }
+ glUnmapBuffer(GL_ARRAY_BUFFER);
+
+ glVertexAttribPointer(MESH_VERTEX, 3, GL_FLOAT, GL_FALSE, sizeof(Vec3), 0);
+ glEnableVertexAttribArray(MESH_VERTEX);
+ glBindBuffer(GL_ARRAY_BUFFER, 0);
+ } else {
+ glBindVertexArray(nvao);
+ }
+
+ glDrawArrays(GL_LINES, 0, normals.size() * 2);
+ glBindVertexArray(0);
+}
+