Irrlicht Engine

Posted: **Sat Jan 22, 2005 1:39 pm**

Hi,
i want to test, if a vector has a collision with my level.
How can I test this case?
Bye,
Christ/off

Posted: **Sat Jan 22, 2005 1:40 pm**

Hopefully somone can help!

Posted: **Sat Jan 22, 2005 10:44 pm**

irr::scene::ISceneCollisionManager::getCollisionPoint
look it up in the manual

BTW Irrlicht's collision code is slow. It isn't that slow, it can be used for a few tests per frame, but beware of it when you're into anything more than, say, 10 tests a frame.
colDet is much better when it comes to collisions. And then a physics engine might also do the job.

Posted: **Sun Jan 23, 2005 4:21 pm**

colDet is much better when it comes to collisions

what is colDet, Morrog? is it easy to implement in irrlicht?

Posted: **Sun Jan 23, 2005 9:51 pm**

colDet is what you think it is, a collision library.

It's pretty simple to use with Irrlicht. You just do this:

Code: Select all

CollisionModel *model = newCollisionModel();
model->addTriangle(....);
model->addTriangle(....);
model->addTriangle(....);
...
model->finalize();

and then you can do mesh-mesh collision, sphere-mesh collisions, ray-mesh collisions, and so forth.

Just google for colDet, it'll come up.

EDIT: Oh, and here's how I build the mesh in my current engine:

Code: Select all

void CLevelManager::createCollisionModel(IMesh *mesh)
{
	if(m_collision_model)
	{
		delete m_collision_model;
		m_collision_model = NULL;
	}

	m_collision_model = newCollisionModel3D(true);

	for(int i = 0; i < mesh->getMeshBufferCount(); ++i)
	{
		IMeshBuffer *mesh_buffer = mesh->getMeshBuffer(i);

		if(mesh_buffer->getVertexType() == EVT_STANDARD)
		{
			S3DVertex *vertices = (S3DVertex *)mesh_buffer->getVertices();
			u16 *indices = mesh_buffer->getIndices();

			for(int i = 0; i < mesh_buffer->getIndexCount(); i += 3)
			{
				m_collision_model->addTriangle(
					vertices[i].Pos.X, vertices[i].Pos.Y, vertices[i].Pos.Z,
					vertices[i + 1].Pos.X, vertices[i + 1].Pos.Y, vertices[i + 1].Pos.Z,
					vertices[i + 2].Pos.X, vertices[i + 2].Pos.Y, vertices[i + 2].Pos.Z
					);
			}
		}
		else
		{
			S3DVertex2TCoords *vertices = (S3DVertex2TCoords *)mesh_buffer->getVertices();
			u16 *indices = mesh_buffer->getIndices();

			for(int i = 0; i < mesh_buffer->getIndexCount(); i += 3)
			{
				m_collision_model->addTriangle(
					vertices[i].Pos.X, vertices[i].Pos.Y, vertices[i].Pos.Z,
					vertices[i + 1].Pos.X, vertices[i + 1].Pos.Y, vertices[i + 1].Pos.Z,
					vertices[i + 2].Pos.X, vertices[i + 2].Pos.Y, vertices[i + 2].Pos.Z
					);
			}
		}
	}

	m_collision_model->finalize();
}

Posted: **Tue Jan 25, 2005 7:49 am**

thanks Morrog.

for you it's simple, but not for me.

could you make an example putting the code into the collision tutorial 7?
so that dummies like me can make a working example from which they can go on.

Posted: **Tue Jan 25, 2005 1:48 pm**

It would be possible to modify the OctTreeTriangleSelector so that it gave accurate detection using the octree to avoid testign uneccesary areas. Currently the OctTreeTriangleSelector function for getting triangles from a ray returns all triangles that intersect with the ray's aabb -- not very useful.

Posted: **Wed Jan 26, 2005 8:59 am**

Good idea.

Posted: **Wed Jan 26, 2005 10:00 pm**

so that explains why the octtreeselector eats my cpu ...
hmmm
lol

Irrlicht Engine

Collision detection between vector and Mesh

Collision detection between vector and Mesh