First Helper functions for Basis and Transform

[tom-leys]

A quite messy PR which adds some basic Transform and Basis methods. I have been using these so that I can set a simple transform up in my code.

I would appreciate if you could help get these into a state where they are suitable to merge. I really wanted to share them.

I am using code like this to instance a mesh, set up a transform and place it in the world

    pub unsafe fn place_mesh(&mut self, pos: Vector3, scale: f32, rot: f32) -> Spatial {
        let mut instance = self.instance_tile();
        instance.set_name(GodotString::from_str(format!("({}, {})", pos.x as i32, pos.y as i32)));

        let transform =
            Transform3D::create_scale(scale, scale, scale)
                .post_rotate(0.0, 1.0, 0.0, Angle::degrees(rot))
                .post_translate(pos);

//        let transform = Transform

        instance.set_transform(Transform::from_transform(&transform));

        instance
    }

My process was to go to the relevant C++ code in the engine, port the code to Rust and put it in the object.

[karroffel]

PR #207 was merged, if you could rebase this PR it would make reviewing a bit easier :)

[tom-leys]

PR #207 was merged, if you could rebase this PR it would make reviewing a bit easier :)

Hi @karroffel - I've finally done this rebase. Check it out now please :)

[karroffel]

There seems to be issues on CI which make it fail 😅

[tom-leys]

I needed to update my code to support newest Euclid with units.

Here's some more (updated) example code

pub struct InShipSpace;
pub struct WorldSpace;
pub type InShipLoc3 = euclid::Vector3D<f32, InShipSpace>;

    pub unsafe fn place_tile(&mut self, pos: ShipBox) -> Spatial {
        let mut instance : Spatial = self.instance_tile();
        instance.set_name(GodotString::from_str(format!("({}, {})", pos.left, pos.top)));

        let top_left = vec2(f32::from(pos.left), f32::from(pos.top));
        let mut distance : Vector2D::<f32, InShipSpace> = vec2(f32::from(pos.right), f32::from(pos.bottom)) - top_left;
        let centre = top_left + (distance / 2.0);
        let compensation = vec2(1.0, 1.0);

        distance += compensation;
//        distance *= vec2(1/self.mesh_size.0, 1/self.mesh_size.1);
        let (mesh_x, mesh_y) = (f32::from(self.mesh_size.0), f32::from(self.mesh_size.1));

        let avg_size = (distance.x/mesh_x + distance.y/mesh_y) / 2.0;
        let rot = (((centre.x + centre.y * 31.0) / avg_size) % 4.0).trunc();

        let transform =
            Transform3D::<_, InShipSpace, InShipSpace>::create_scale(
                distance.x/mesh_x, avg_size, distance.y/mesh_y)
                .post_rotate(0.0, 1.0, 0.0, Angle::degrees(90.0 * rot))
                .post_translate(vec3(centre.x, 0.0, centre.y));

//        let transform = Transform

        instance.set_transform(Transform::from_transform(&transform));

        instance
    }

    pub unsafe fn place_mesh(&mut self, pos: InShipLoc3, scale: f32, rot: f32) -> Spatial {
        let mut instance = self.instance_tile();
        instance.set_name(GodotString::from_str(format!("({}, {})", pos.x as i32, pos.z as i32)));

        let transform =
            Transform3D::<_, InShipSpace, InShipSpace>::create_scale(scale, scale, scale)
                .post_rotate(0.0, 1.0, 0.0, Angle::degrees(rot))
                .post_translate(pos);

//        let transform = Transform

        instance.set_transform(Transform::from_transform(&transform));

        instance
    }

    pub unsafe fn instance_tile(&mut self) -> Spatial {
        let instance = if self.placed_count < self.parent_children {
            let existing_instance = self.parent.get_child(self.placed_count).unwrap();
            existing_instance.cast::<Spatial>().unwrap()
        } else {
            let mut instance = MeshInstance::new();
            instance.set_mesh(Some(self.template.clone()));
            self.parent.add_child(instance.cast::<Node>(), false);
            instance.cast::<Spatial>().unwrap()
        };
        self.placed_count += 1;

        instance
    }

[tom-leys]

If you check out my blog:

https://medium.com/@recallsingularity/rendering-a-2d-game-in-3d-bd24ddbee6eb

The floor meshes are placed using place_tile and the conveyors by using place_mesh.

[ghost]

@tom-leys It seems like this is duplicated in #254. Could you update this PR with the latest code, so we can review / merge the feature first?

[tom-leys]

#288 (Now duplicates this one)