What is wrong here?

Unity Engine
, ,
1

Hi, I’ve been looking on entity queries however for some reason I can’t change the velocity of the player. First I created an entity query, something like this;

            _entityQuery = new EntityQueryBuilder(Allocator.Temp)
                .WithAll<PlayerInput, PlayerMovement>()
                .WithAllRW<PhysicsVelocity>()
                .Build(this);

And then, inside the update method I did something like this;

            var inputs = _entityQuery.ToComponentDataArray<PlayerInput>(Allocator.Temp);
            var movements = _entityQuery.ToComponentDataArray<PlayerMovement>(Allocator.Temp);
            var velocities = _entityQuery.ToComponentDataArray<PhysicsVelocity>(Allocator.Temp);
          
            for (var i = 0; i < inputs.Length; i++)
            {
                var input = inputs[i];
                var movement = movements[i];
                var velocity = velocities[i];
              
                velocity.Linear = new float3
                {
                    x = input.MovementInput.x * movement.Speed,
                    y = input.MovementInput.y * movement.Speed,
                    z = 0
                };
              
                velocities[i] = velocity;

The problem is that the velocity is not being applied. I’ve added the system to the FixedStepSimulationSystemGroup and marked it to update before the PhysicsSystemGroup.

After failing I decided to try it in another way, and this is how I got it done;

            Entities.ForEach((
                ref PhysicsVelocity velocity,
                in PlayerInput input,
                in PlayerMovement movement) =>
            {
                velocity.Linear = new float3
                {
                    x = input.MovementInput.x * movement.Speed,
                    y = input.MovementInput.y * movement.Speed,
                    z = 0
                };
            }).Schedule();

However, I am still curious about the first one. What was the reason that I wasn’t able to write to the PhysicsVelocity?

2

The first version you provided uses new buffers that are merely copies of the original chunk data. Writes to those arrays are only writes to a copy of the data, not the original. The second way is pretty much the default way you should have gotten it done.

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