Simple soccer goal

[omniyo]

Hi,

I'm developing a simple 3D soccer game with Ogre using OgreBullet wrapper. Now I'm trying to carry out the goals. I don't really know how to get collisions only where the wood is. To be honest, I don't have a good idea of how to implement the goals. Split it into 3 different meshes and hardcode their positions? I think there must be a much better solution.

I write this here because I wrote it in the OgreBullet forums with no answer for long time(http://www.ogre3d.org/addonforums/viewt ... 12&t=29680).
I need some clues please.

Thanks in advance

[Erwin Coumans]

One way is to approximate the goal posts using several cylinders (btCylinderShape) or convex hulls (btConvexHullShape). You could simulate the net using btSoftBody.
Are you using a 3d authoring tool, such as Maya or Blender? If so, you can assign the collision shapes and export a .bullet file, and use the btBulletWorldImporter to load it.

To detect if/where the ball hits the goal posts, you can use a contact added callback, or simply iterate over all contacts after the simulation is done.
For a contact callback example see Bullet/Demos/MultiMaterialDemo.

Code: Select all

static bool CustomMaterialCombinerCallback(btManifoldPoint& cp,	const btCollisionObjectWrapper* colObj0Wrap,int partId0,int index0,const btCollisionObjectWrapper* colObj1Wrap,int partId1,int index1)
{
//handle the collision here
}

int main(...)
{
gContactAddedCallback = CustomMaterialCombinerCallback;

//enable contact callback
staticBody->setCollisionFlags(staticBody->getCollisionFlags()  | btCollisionObject::CF_CUSTOM_MATERIAL_CALLBACK);

}

[omniyo]

Firstly thanks for the answer.

I'll start with the shape before having into account the collisions.
I'm using Blender. I didn't know anything about btBulletWorldImporter but it seems to be amazing.
I haven't found too much doc about it so I need some help:
- I just create the goal (without nets yet) in blender as one piece and following your youtube video I finally assign its collision bound to ConvexHull. But how to obtain the .bullet file from blender? I cannot find it anywhere.

Regards

[omniyo]

I finally managed to export it... Ill post if any new doubt.

[omniyo]

Hi, I finished a simple goal (attached) in blender as a convex hull in order to test the physics export.
When I load it on Bullet Physics Editor I get what you can see in the attached screenshot.
Where is the problem?
Thanks in advance