[shame on me]Box dimensions update

[fredlllll]

yeah shame on me for this thread:
i have an entites.prefarbs.box and i change width, height and length, but it doesnt change anything in the simulation. it just remains its normal size (1,1,1) but when i read the values, they are that what i put in. and i searched for a method to date this up, but didnt found anything.
am i blind or dumb or both? ._.

[Norbo]

Is the graphic just not being updated?

The physics engine has no concept of graphics, so a change to the simulation does not automatically tell the graphics system to update.

[fredlllll]

no. the simulation object doesnt seem to update. i do the drawing myself. and the graphic is updated(i use the box.width... for drawing). but when i throw something at it, it still collides with the 1x1x1 box (i do not remove it from the space an readd it. i just change the dimensions)

[Norbo]

Setting the width, height, or length of a Box changes the BoxShape's dimensions. The BoxShape dimensions are used directly in collision detection. So, there are likely some shenanigans afoot. Could you post a simplified demo showing the issue?

[fredlllll]

well here is some code of the class

i use the getters and setters to set the stuff.

and in the drawcall i use them to scale my 1x1x1 box, so it fits the box in the simulation.
so the graphics changes when i do something, but the simulation of the box doesnt.

Code: Select all

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

namespace ZipperEngine
{
    public class StaticCollideBox : Entity, StaticCollide
    {
        public BEPUphysics.Entities.Prefabs.Box box;
        public StaticCollideBox(float width, float height, float length)
            : base(Global.editor, Global.editor)//will not be selected
        {
            box = new BEPUphysics.Entities.Prefabs.Box(Vector3.Zero, width, height, length);
        }

        //here i set the dimensions
        public float DimX { get { return box.Width; } set { box.Width = value; } }
        public float DimY { get { return box.Height; } set { box.Height = value; } }
        public float DimZ { get { return box.Length; } set { box.Length = value; } }

        public override Microsoft.Xna.Framework.Vector3 Position
        {
            get
            {
                return box.Position;
            }
            set
            {
                box.Position = value;
//snip
            }
        }

        public override Microsoft.Xna.Framework.Quaternion Orientation
        {
            get
            {
                return box.Orientation;
            }
            set
            {
                box.Orientation = value;
//snip
            }
        }

        public override void Draw(Microsoft.Xna.Framework.GameTime gameTime, int method)
        {
            if (Global.showCollisionShapes)
            {
                //draw collison shape
                //little bit transparent
                //or own entity for selection?
                if (DynamicCollideBox.be == null)
                {
                    DynamicCollideBox.be = new BasicEffect(worldSpace.Device);
                }
                //and here i use the dimensions for the drawing scale matrix. and the graphics shows correct
                DynamicCollideBox.be.World = Matrix.CreateTranslation(box.Position) * Matrix.CreateFromQuaternion(Orientation) * Matrix.CreateScale(new Vector3(box.Width, box.Height, box.Length));
                DynamicCollideBox.be.View = worldSpace.currentCamera.ViewMatrix;
                DynamicCollideBox.be.Projection = worldSpace.currentCamera.ProjectionMatrix;

                switch (method)
                {
                    //snip
                }
                RasterizerState rs = new RasterizerState();
                rs.FillMode = FillMode.Solid;
                worldSpace.Device.RasterizerState = rs;
            }
        }

        public override void Update(Microsoft.Xna.Framework.GameTime gameTime)
        {
            //snip
        }

        public override void AddToSpace(Worldspace space)
        {
            space.PhysicSpace.Add(box);
        }

        public override void RemoveFromSpace(Worldspace space)
        {
            space.PhysicSpace.Remove(box);
        }
    }
}

the methods add and remove from space are called by my own worldspace class when i add this entity(my own entity class). here it just adds and removes the box.

[Norbo]

Could you create a runnable demo in the BEPUphysicsDemos that reproduces the issue so that I can look at it directly?

[fredlllll]

well i tried to... and i failed. in the demo it just works as intended(although the graphics dont change to the new dimension)[when i change all 3 parameters at once, but when i only change height, the sphere falls right through it]
but what i noticed is, when i change the dimensions in my game, at first nothing happens, then i change the position of the box, and suddenly it accepts the changes of the dimensions o.O

i dont know whats happening =/

but i disccovered some other anomaly in the demo. when changing only the height, the sphere just falls through the box...

Code: Select all

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using BEPUphysics.Entities.Prefabs;
using Microsoft.Xna.Framework;

namespace BEPUphysicsDemos.Demos
{
    public class BoxUpdateBugDemo : StandardDemo
    {
        public override string Name
        {
            get { return "BoxUpdateBug"; }
        }

        System.Timers.Timer t = new System.Timers.Timer(4000);

        Box box;

        Sphere sphere;
        public BoxUpdateBugDemo(DemosGame game)
            : base(game)
        {
            box = new Box(Vector3.Zero, 1, 1, 1);//box which should be modified
            box.Material.Bounciness = 1;
            Space.Add(box);

            sphere = new Sphere(new Vector3(0, 10, 0), 1,1);//then i drop a sphere on it
            sphere.Material.Bounciness = 1;
            Space.Add(sphere);

            t.Elapsed += new System.Timers.ElapsedEventHandler(t_Elapsed);
            t.Start();
        }

        void t_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            sphere.Position = new Vector3(0, 10, 0);//redrop yay
            sphere.LinearVelocity = Vector3.Zero;
            sphere.AngularVelocity = Vector3.Zero;
            if (box.Height == 1)//change the height of the box
            {
                //box.Width = 5;
                box.Height = 5;
                //box.Width = 5;
            }
            else
            {
                //box.Width = 1;
                box.Height = 1;
                //box.Length = 1;
            }
        }
    }
}

[Norbo]

Call box.ActivityInformation.Activate() when changing a sleeping object's shape. Changing the dimensions of the object is not a typical physical operation, so it doesn't automatically wake the object up to update.

While this behavior was intended, I went ahead and automated it a little more in the development version. Changing the shape will now automatically wake up the entity.

[fredlllll]

yay it works!!
this also fixes the fall through bug in the demo.
for now ill stick to the official 1.2 as the changing of dimensions is just relevant for my editor(so i dont care if later releases do the activate twice)

will you change this for the other primitives like radius of a sphere?

[Norbo]

It works for all shapes that can notify the Entity of a change, including spheres.