Collision physics for half-blocks or slabs

[ghost]

Wanted to create a half block ,that’s easy but the problem is how can I stand on it , how can I implement collision detection on a half block so I can stand on it thanks Andy

[fenomas]

The short answer is this isn't in the engine yet.

Terrain physics is done in this library. It would be possible (but nontrivial) to add support for blocks with a collision volume smaller than the full voxel, but I haven't tried doing it.

[Patbox]

I think I will try to experiment with it. My idea is to modify engine to output object with block's collision shape and using it for rest of checks. As I never did something similar before, do you have any suggestions/other ideas how it could work?

[ghost]

I think if you check when player inslab like in water and offset him

[ghost]

In physics.js
var createPhysics = require('voxel-physics-engine')
// var createPhysics = require('../../../../npm-modules/voxel-physics-engine')

export default function (noa, opts) {
return makePhysics(noa, opts)
}

/**

• @Class Physics
• @TypicalName noa.physics
• @classdesc Wrapper module for the physics engine. For docs see
• andyhall/voxel-physics-engine
  */

var defaults = {
gravity: [0, -10, 0],
airDrag: 0.1,
}

function makePhysics(noa, opts) {
opts = Object.assign({}, defaults, opts)
var world = noa.world
// physics engine runs in offset coords, so voxel getters need to match
var offset = noa.worldOriginOffset
var blockGetter = (x, y, z) => {
return world.getBlockSolidity(x + offset[0], y + offset[1], z + offset[2])
}
var isFluidGetter = (x, y, z) => {
return world.getBlockFluidity(x + offset[0], y + offset[1], z + offset[2])
}

var physics = createPhysics(opts, blockGetter, isFluidGetter)

return physics

}
...... You could a a new type like getblockfluidity , I tried that but on the physics library I was looking for 1.0 height to converted to 0.5 ,I couldn't figure it out

[fenomas]

@Patbox: I think the best approach would be to start with the dependency voxel-aabb-sweep. That library takes an AABB and a direction, and then "pushes" the AABB along that direction until it hits a solid voxel. Noa internally uses that dependency for both physics and for raycasting, so if voxel-aabb-sweep could handle partially-solid voxels then it should be relatively easy for noa.

Currently the voxel-aabb-sweep learns about collision geometry by way of a getVoxel function, which looks like (x,y,z) => boolean where the boolean means the voxel is solid or empty. If I was attacking this, I would try to make that function return, say, 0 for empty, 1 for full, and 2 for partial, and then when a partial voxel is encountered there would need to be a second function for the library to query that voxel's collision geometry.

But note that the math inside the "sweep" library is pretty complicated, and somewhat hard to test. Also I expect that it would be a lot easier if non-full voxels are required to have simple AABB collision geometries - i.e. things like half-slabs or fenceposts, but not slopes or arbitrary polygons.

[Heath123]

If you don't need to sweep and just need to test overlaps then it's a lot easier, but that would probably be buggy

[ghost]

How would I overlap , explain me wath you know I almost cracked the code