Drag and drop

[Temechon]

Hello guys, 

 

I'm currently workng on several small thing with our favorite 3D engine, and one of these things is the mesh drag 'n drop.

I know this feature is in the babylon roundmap, but I will need it very soon for a bigger project.

 

Today, I have a drag and drop that is currently working in 2 dimensions (on X and Y axis). I use the scene.pick method to get the picked mesh.

Here is the code : 

var pickedMesh;

// Add event listener

window.addEventListener("click", function(evt){

	var pick = scene.pick(evt.clientX, evt.clientY);

	if (pick.pickedMesh) {

		pickedMesh = pick.pickedMesh;

	}

});


window.addEventListener("mousemove", function(evt) {

	if (pickedMesh){

		var pick = scene.pick(evt.clientX, evt.clientY);

		pickedMesh.position.x = pick.pickedPoint.x;

		pickedMesh.position.y = pick.pickedPoint.y;

	}

});

However, it is not working as intended : if the mouse is out of the selected mesh, then pick.pickedPoint is null, and the box position is not updated.

 

What I would like is a way to convert the mouse coordinates to scene coordinates. I tried to look at the class BABYLON.Ray, but I need a world matrix. In the method scene.pick, the mesh world matrix is used, but obviously i cannot use it (as my scene can be empty).

Is there a way to create a "scene.getWorldMatrix" in BABYLON ? What is the best way to do it ?

 

Thank you for your help !

 

[GameMonetize]

Just use BABYLON.Matrix.Identity()

[Temechon]

Hi Delta,

 

Thanks for your answer.

I tried to use the method scene.createPickingRay(x, y), with x and y my mouse coordinates. In this method, the identity matrix is used when world is not defined, so I guess I was using it without declaring it explicitly.

 

However, it does not work : the origin of the ray is always something like (0,9,0). (My camera is in (0,10,0) and look at (0,0,0) ).

[GameMonetize]

It should be ok with (0, 9,0) because the camera has a minZ offset value

[Temechon]

Thank you Delta, 

 

I used another solution : I created a pseudo infinite ground. This way, scene.pick.pickedPoint is never null. I know this does not answer the question correctly, but it do the trick.

[GameMonetize]

If this works this is good:)