I have a map (a collection of gltf meshes that all belong to the same parent root node) that gets loaded and a mesh for the players character. I am able to move the player mesh around as expected, and it seems to be working nicely with the ammo js physics engine / plugin.
The meshes of the map however, are an entirely different matter.
I’ve noted that each of the following map mesh position values are different:
- mesh.position
- mesh.physicsImposter.getObjectCenter()
- mesh.physicsImposter.physicsBody position using this code:
export const getPositionFromPhysicsBody = (physicsBody: PhysicsBody, Ammo) => {
tmpTrans = new Ammo.btTransform()
const motionState = physicsBody.getMotionState()
motionState.getWorldTransform(tmpTrans)
return tmpTrans.getOrigin()
}
Further still, using mesh.physicsImposter.setDeltaPosition(new Vector3(0, 10, 0)), or any xyz valued vector, has no affect on any of the aforementioned positional values.
The map meshes all have their physics imposter mass set to zero, and are static bodies. I don’t use any physics root on any of the map meshes, and I set them up like so:
export const convertToImposter = (
{
meshes,
scene,
mass,
isGround = false
},
imposterType = 'BoxImpostor',
) => {
const rigidBodies: Array<PhysicsBody> = []
const staticBodies: Array<PhysicsBody> = []
let rootNodeMass
if (isGround) {
rootNodeMass = 0
} else if (mass !== undefined) {
rootNodeMass = mass
} else {
rootNodeMass = 3.0
}
const childMass = isGround ? 0 : 0.1
let mesh:Mesh
for (let i = 0; i < meshes.length; i++) {
mesh = meshes[i] || new Mesh('appease-typescript')
if (mesh.id === '__root__') {
continue
}
//@ts-ignore
const parent = mesh.parent
//@ts-ignore
mesh.parent = null
mesh.physicsImpostor = new PhysicsImpostor(
mesh,
PhysicsImpostor[imposterType],
{ mass: childMass },
scene
)
const {x, y, z } = mesh.physicsImpostor.getObjectCenter()
mesh.physicsImpostor.setDeltaPosition(new Vector3(x, y, z))
if (isGround === false) {
rigidBodies.push(mesh.physicsImpostor)
} else {
staticBodies.push(mesh.physicsImpostor)
mesh.position.x = x
mesh.position.y = y
mesh.position.z = z
}
mesh.parent = parent
}
return { rigidBodies, staticBodies }
}
The last puzzling thing I noticed, is that if I scale the map meshes by some scalar value, say 10, then the physics bodies have their position coordinates multiplied by -10???
I’m pretty confused, and would appreciate any help at this point.
Ammo…
