3D Physics with ZgeBullet

[Ats]

Now I manage to compile the file using:

gcc -shared -c -I ~/bullet3-3.09/src/ -o ZgeBullet.so ZgeBullet.cpp

But it also compiles with -fPIC instead of -shared, the size of the final library is different though. I don't really know which one to chose, even after reading the explanation: https://stackoverflow.com/questions/486 ... -vs-shared

Anyway, I compiled one of Rado1 example by setting ./ZgeBullet.so to the ZExternalLibrary Modulename, but when I launch the elf, it only displays "./ZgeBullet.so" in the terminal. So I don't think this is working.


Edit:

To produce only the compiled code (without any linking), use the -C option.

Ok, -c option wasn't what I needed to do, as the resulted so file is in fact, the o file...
Option -save-temps just confirmed that.


Edit 2:
I can get an so file by doing that:
gcc -Wall -fPIC -I ~/bullet3-3.09/src -c *.cpp
gcc -shared -Wl,-soname,ZgeBullet.so -o ZgeBullet.so *.o

(still trying to figure out what's going on with soname: https://stackoverflow.com/questions/126 ... raries-for)


Edit 3:
gcc -fPIC -I ~/bullet3-3.09/src -c ZgeBullet.cpp
gcc -shared -o ZgeBullet.so ZgeBullet.o

[Ats]

Oh, maybe it isn't a problem with the compiled library, as I just tried to load my SunVox example, which was working before when compiled on i386, but now it only displays "./sunvox_lofi.so"... Did you change something about the way library path is handled during the SDL2 update?

I also tried to build ZDesigner.exe again, but now I'm getting errors:
[dcc32 Error] ZExpressions.pas(2060): E2003 Undeclared identifier: 'WinApi'
[dcc32 Error] ZExpressions.pas(2060): E2066 Missing operator or semicolon
[dcc32 Fatal Error] BitmapProducers.pas(35): F2063 Could not compile used unit 'ZExpressions.pas'

[VilleK]

I made a update so ZDesigner should build again.

If it displays the .so filename on start then that means the module could not be loaded

ZExpressions line 2037:
ZHalt(Self.ModuleName);

This has not changed with the SDL-update (ZGE still use the dlopen function).

Are you sure the sunvox.so file is a 64-bit build? I think you can check with "objdump" but I don't know the command line syntax.

[Ats]

As ZgeBullet is my last problem before being able to run Omeganaut on linux (maybe), I'm back at experimenting. And after a lot of tries, I finally managed to get something: I had to link the compiled "so" files from bullet3, not the "o" files.

gcc -Wall -fPIC -I ~/bullet3-3.09/src -c ZgeBullet.cpp
gcc -shared -o ZgeBullet.so ~/bullet3-3.09/build_cmake/src/BulletCollision/libBulletCollision.so ~/bullet3-3.09/build_cmake/src/BulletDynamics/libBulletDynamics.so

bullet_demo4.png (257.55 KiB) Viewed 2126 times

The weird thing is that instead of several cubes dropping from the ceiling and going through the two white blocks, there's one cube circling around like a moon on the X/Z plane... I'm not sure if this is coming from ZgeBullet. I'm going to compile all ZGE examples for linux x86_64 and check if everything is correct.


Edit:
Just to be sure, I managed to compile bullet3-2.83.7 using the build sh script that is present in the version 2.89. No errors, but the cube is still satellited.

Edit 2:
Never mind, I didn't add ZgeBullet.o to ZgeBullet.so linking... So there was no way for it to work in ZGE. The cube is at its original position, before being handled by ZgeBullet. And the cube isn't circling around, it's due to the camera movement...
When I add ZgeBullet.o to the linking, the library isn't recognized by ZGE. Same as before.

[zakkwylde]

[quote=Rado1 post_id=7909 time=1449271119 user_id=102]
As part of preparing a "technology" for my new physic-based 3d space flying game I updated also ZgeBulet to version 2.3. The main motivation was to improve and fix rotations and to use Bullet's internal quaternion coputations instead of having this math in ZGE expressions. Thanks to this, ZgeBullet provides quite comfortable means to simply implement movement of an object (airplane or spaceship) in 3D space.

See [url=https://github.com/Rado-1/ZgeBullet/wik ... 2015-12-05]the version history[/url] for details. Download ZgeBullet v2.3 from [url=https://github.com/Rado-1/ZgeBullet/releases/tag/v2.3]here[/url]. All "official" ZgeBullet demos and FL physic-based effects work. It has already been pushed to ZGE git repo, so next beta release of ZGE should have it included as a built-in external library.
[/quote]

Hi Rado,

I am in the midst of building a flight sim as well. Have been trying to make sense of quarternions and how we can code this in ZGE but no, i am still stumped. If ZGEBullet can do it, I am happy to let it. Now for the tutorial - how do we do it? Am new to using libraries, have been making FPSes so far without them, just to clarify my noob status. Would appreciate your help!

[Kjell]

Hi zakkwylde,

Have been trying to make sense of quarternions and how we can code this in ZGE but no, i am still stumped.

Quaternions are pretty unintuitive yes. However, once you get familiar with them they're not that difficult to use & don't require a ton of code either. Below is a very basic example ( use arrow keys + A/D to yaw ).

Code: Select all

<?xml version="1.0" encoding="iso-8859-1" ?>
<ZApplication Name="App" Caption="Quaternion" CameraPosition="0 0 0" FOV="60" RenderOrder="1" FileVersion="2">
  <OnLoaded>
    <ZLibrary Comment="Quaternion">
      <Source>
<![CDATA[//

vec4 quaternionMultiply(vec4 a, vec4 b)
{
  vec4 q;

  q.x = a.x*b.w+a.w*b.x+a.y*b.z-a.z*b.y;
  q.y = a.y*b.w+a.w*b.y+a.z*b.x-a.x*b.z;
  q.z = a.z*b.w+a.w*b.z+a.x*b.y-a.y*b.x;
  q.w = a.w*b.w-a.x*b.x-a.y*b.y-a.z*b.z;

  return q;
}

//

vec4 axisAngleToQuaternion(vec3 axis, float angle)
{
  float h, s, x, y, z, w;

  h = angle*0.5;
  s = sin(h);

  x = axis.x*s;
  y = axis.y*s;
  z = axis.z*s;
  w = cos(h);

  return vector4(x, y, z, w);
}

//

mat4 rotationMatrix(vec4 q)
{
  mat4 m;

  float x2, y2, z2, xx, xy, xz, yy, yz, zz, wx, wy, wz;

  x2 = q.x*2;
  y2 = q.y*2;
  z2 = q.z*2;

  xx = q.x*x2; xy = q.x*y2; xz = q.x*z2;
  yy = q.y*y2; yz = q.y*z2; zz = q.z*z2;
  wx = q.w*x2; wy = q.w*y2; wz = q.w*z2;

  m[0,0] = 1-(yy+zz);
  m[0,1] = xy+wz;
  m[0,2] = xz-wy;
  m[0,3] = 0;

  m[1,0] = xy-wz;
  m[1,1] = 1-(xx+zz);
  m[1,2] = yz+wx;
  m[1,3] = 0;

  m[2,0] = xz+wy;
  m[2,1] = yz-wx;
  m[2,2] = 1-(xx+yy);
  m[2,3] = 0;

  m[3,0] = 0;
  m[3,1] = 0;
  m[3,2] = 0;
  m[3,3] = 1;

  return m;
}]]>
      </Source>
    </ZLibrary>
    <ZExpression>
      <Expression>
<![CDATA[//

CameraQuaternion = vector4(0, 0, 0, 1);]]>
      </Expression>
    </ZExpression>
  </OnLoaded>
  <OnUpdate>
    <Repeat Name="AxisRepeat" Count="3" WhileExp="//">
      <OnIteration>
        <ZExpression>
          <Expression>
<![CDATA[//

int i = AxisRepeat.Iteration;

//

Axis[i] = 0;

//

AxisPositive.CharCode = AxisMap[i,0];
AxisNegative.CharCode = AxisMap[i,1];]]>
          </Expression>
        </ZExpression>
        <KeyPress Name="AxisPositive" CharCode="68">
          <OnPressed>
            <ZExpression>
              <Expression>
<![CDATA[//

Axis[AxisRepeat.Iteration]++;]]>
              </Expression>
            </ZExpression>
          </OnPressed>
        </KeyPress>
        <KeyPress Name="AxisNegative" CharCode="65">
          <OnPressed>
            <ZExpression>
              <Expression>
<![CDATA[//

Axis[AxisRepeat.Iteration]--;]]>
              </Expression>
            </ZExpression>
          </OnPressed>
        </KeyPress>
      </OnIteration>
    </Repeat>
    <ZExpression>
      <Expression>
<![CDATA[//

float dt, rx, ry, rz;

dt = App.DeltaTime;

rx = Axis[2]*2*dt;
ry = Axis[1]*2*dt;
rz = Axis[0]*2*dt;

//

vec4 qx, qy, qz, q;

qx = axisAngleToQuaternion(vector3(0, 1, 0), rx);
qy = axisAngleToQuaternion(vector3(1, 0, 0), ry);
qz = axisAngleToQuaternion(vector3(0, 0, 1), rz);

q = quaternionMultiply(qz, qy);
q = quaternionMultiply(qx, q);

CameraQuaternion = quaternionMultiply(q, CameraQuaternion);]]>
      </Expression>
    </ZExpression>
  </OnUpdate>
  <OnRender>
    <ZExpression>
      <Expression>
<![CDATA[//

mat4 m;

getMatrix(0, m);
setMatrix(0, m * rotationMatrix(CameraQuaternion));]]>
      </Expression>
    </ZExpression>
    <UseMaterial Material="TowerMaterial"/>
    <RenderMesh Mesh="TowerMesh"/>
  </OnRender>
  <Content>
    <Array Name="Axis" SizeDim1="3"/>
    <Array Name="AxisMap" Type="4" Dimensions="1" SizeDim1="3" SizeDim2="2" Persistent="255">
      <Values>
<![CDATA[78DA535755D37071040003820120]]>
      </Values>
    </Array>
    <Variable Name="CameraQuaternion" Type="8"/>
    <Mesh Name="TowerMesh">
      <Producers>
        <MeshImport HasVertexColors="1">
          <MeshData>
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          </MeshData>
        </MeshImport>
      </Producers>
    </Mesh>
    <Material Name="TowerMaterial" Shading="1" DrawBackFace="255"/>
  </Content>
</ZApplication>

K

[zakkwylde]

Kjell, Rado,

Thank you very much for the help.
I will work on it and show you where i am at.

Cheers!


zakkwylde

[Ats]

Hello, I have a little question regarding the zbtRayTest which returns a xptr:

xptr zbtRayTest(float fromX, float fromY, float fromZ, float toX, float toY, float toZ)
Perform ray casting between two points in world and return the first hit collision object, or null if no object appears between the two points.
@param fromX, fromY, fromZ position of the raycasting source point
@param toX, toY, toZ position of the raycasting target point
@return pointer to the first hit collision object, or null if no object was hit

Is there a way to retrieve the coordinates of the collision point from that xptr?

Edit:

All right, I got it. At first, I thought that it could be retrieved as easily as XYZ in a Vector3, but there is a function for that:

void zbtGetRayTestHitPointXYZ(ref float outX, ref float outY, ref float outZ)
Get position of previous ray test hit.
@details To obtain correct value, call zbtRayTest() function before.
@param[out] outX, outY, outZ output vector of hit position in the world space

So my next question is... How does it work? Since that function returns a void...

Edit 2:

Don't mind me, it was pretty easy to use. Unusual, but easy

Code: Select all

xptr point = zbtRayTest(PlayerShip.Position.X, PlayerShip.Position.Y, PlayerShip.Position.Z,
                            PlayerShip.Position.X - 20, PlayerShip.Position.Y, PlayerShip.Position.Z);
vec3 pos;
zbtGetRayTestHitPointXYZ(pos.X, pos.Y, pos.Z);
trace(intToStr(pos.X));

[Ats]

Hello, I'm back at messing with ZGEBullet. I'm trying to get the velocity of an object touched by zbtRayTest, but I can only easily retrieve it's position and rotation. So I'm trying to retrieve the model instead, without success.

Code: Select all

xptr point = zbtRayTest(Player.Position.X, Player.Position.Y, Player.Position.Z,
                            Player.Position.X + 20, Player.Position.Y, Player.Position.Z);

if (point != null)
{
      vec3 pos, rot;
      zbtGetPosRotXYZ(point, pos.X,pos.Y,pos.Z, rot.X,rot.Y,rot.Z);
      trace(intToStr(pos.X));

      model m = zbtGetUserModel(point); <- THIS IS RETURNING NULL!??
      trace(intToStr(m.Position.X)); // <- SO THIS IS CRASHING
}

I don't know what I am missing, since zbtGetUserModel works like this:

model zbtGetUserModel(xptr obj)
@brief Get user-defined ZGE model instance from collision object.
@param obj pointer to collision object
@return object's user-defined ZGE model instance

Edit:
All right, I think I found what I was missing. Writing down the problem always helps to clear the mind...
I had to use this to attach the model to the collision object when creating the model:

Code: Select all

void zbtSetUserModel(xptr obj, model userModel) {}

[zakkwylde]

Kjell,

I have a couple queries with the code provided previously.
1) In the keypress assignments, only 2 keys were shown. But the commands to rotate along the axes are the 4 cursor arrows. Could you point me to where the commands are programmed?

2) What would the code be for moving or increasing velocity in the vector of the camera? Tried using the FPS engine WSAD commands to configure movement but they were not feasible.

3) Speaking of the FPS Engine, which you kindly provided some time back. The projectiles dispensed upon mouseclick worked down if you kept the aimpoint low to the horizon but when you pointed up vertically, they were off the aimpoint and went in some slant direction. Is there any way to harness ZgeBullet commands? if so, how do we start?

Thanks a million guys!
Zakkwylde




[quote=zakkwylde post_id=10218 time=1643086377 user_id=56]
Kjell, Rado,

Thank you very much for the help.
I will work on it and show you where i am at.

Cheers!


zakkwylde
[/quote]

[Kjell]

Hi zakkwylde,

In the keypress assignments, only 2 keys were shown. But the commands to rotate along the axes are the 4 cursor arrows. Could you point me to where the commands are programmed?

The ZExpression in the AxisRepeat component sets the CharCode property of the AxisPositive and AxisNegative components for 3 different axes ( hence the repeat count of 3 ). So even though there are only two KeyPress components, they are used 3 times each .. resulting in a total of 6 keys being used.

What would the code be for moving or increasing velocity in the vector of the camera?

I've attached a example that shows how to move a ship that uses a quaternion for rotation in it's forward direction. The controls are the same as before ( arrow keys to pitch & roll + A/D to yaw ) but i've added shooting using the spacebar and the ability to adjust the camera a little using the mouse. Hopefully this example helps you understand how to do these types of things.

Tried using the FPS engine WSAD commands to configure movement but they were not feasible.

Not exactly sure what FPS example you're referring to.

Speaking of the FPS Engine, which you kindly provided some time back. The projectiles dispensed upon mouseclick worked down if you kept the aimpoint low to the horizon but when you pointed up vertically, they were off the aimpoint and went in some slant direction.

Even though it should be pretty trivial to add vertical aiming ( i assume the FPS example only allowed horizontal aiming ), this won't help you in context of a flight simulator where Euler Angles won't suffice.

Is there any way to harness ZgeBullet commands? if so, how do we start?

No idea, that's a question for Rado1

K