hammeron-art
commented
4 years ago I see this feature as universally necessary for practically all types of 3D games. First, not all 3D games actually use lighting, in which case the normal computation is a waste both in terms of editor processing time and GPU upload time. Even 3D games which do use lighting don't always need normals for every model. Finally, I'd feel remiss if I did not mention that Blender, which heavily inspires Godot, also has this on its export options.
I think the SpatialMaterial requires normal data to work (as well as many other things like tangents, uvs, vertex_colors, etc). It's a common practice because not doing so is more work for almost no advantage in most cases. If you don't write normals to the mesh, the engine will still upload normal data as an array of zero vectors. Godot is even more forgiving than Blender, in Godot a mesh without normals renders fines because the engine takes care of sending the correct data to the shader while in Blender all meshes are required to have predefined normals for correct rendering and it always calculates them on import or edit.
I agree with the proposal to add the option to disable normal generation but if your goal is performance, you need to create a custom material that doesn't use normals or any other vertex data you don't need. I wouldn't recommend it though unless you are dealing with many high-density meshes.
RobertBColton
Calinou
Describe the project you are working on: Subdivision surfaces which require accurate vertex and face adjacency lookup with MeshDataTool or custom half-edge data structure. The forced normal generation for objs without normals produces flat shaded faces leading to inaccurate adjacency lookup in MeshDataTool. Describe the problem or limitation you are having in your project: I would like to disable normal generation for some of my imported models so I could use the builtin obj reader. Describe how this feature / enhancement will help you overcome this problem or limitation: I can dump my custom simple obj reader that uses SurfaceTool in favor of the builtin obj mesh importer. Show a mock up screenshots/video or a flow diagram explaining how your proposal will work:
Describe implementation detail for your proposal (in code), if possible:
Well, I may just jump into my first pull request to Godot and do this myself. I can already see where it needs done in the obj resource importer.
First the setting needs added: https://github.com/godotengine/godot/blob/dec10dd776fca2994277faa3a97b13e70317f784/editor/import/resource_importer_obj.cpp#L492 Then the setting needs to be actually checked: https://github.com/godotengine/godot/blob/dec10dd776fca2994277faa3a97b13e70317f784/editor/import/resource_importer_obj.cpp#L337 If this enhancement will not be used often, can it be worked around with a few lines of script?: This problem can not easily be worked around, no. It would be a total waste to write a script that dumps the normals and reloads the model for no reason. It's also not always sensible to write your own obj reader. Is there a reason why this should be core and not an add-on in the asset library?: I see this feature as universally necessary for practically all types of 3D games. First, not all 3D games actually use lighting, in which case the normal computation is a waste both in terms of editor processing time and GPU upload time. Even 3D games which do use lighting don't always need normals for every model. Finally, I'd feel remiss if I did not mention that Blender, which heavily inspires Godot, also has this on its export options.