Object ID and Mask!

[Isoprog]

Hi,
I am having a little problem with object id and mask. I just wanted to know how do I use id with mask for a scene node?
I am using like this:

Code: Select all

Mask::Node | objectID

While it works, there is a problem with this. Say if mask Node is -> 1 << 2, you can imagine what will happen. First 8 node will have same id, 0-4.
I need this for picking and getting a node.

Thanks in advance.
Regards.

[hybrid]

Yeah, you have to create the ids accordingly. Say, take the lower 16bits for numbering the nodes (from 1..65535) and the upper 16 bits for defining properties and classes. All nodes belonging to NPC types have 1<<24 set, etc. Then you can mask based on the type with upper bit masks, and still have a unique numbering in the lower bits.

[Isoprog]

I am a little confused about numbering the node with lower bitmask. Could you kindly explain a little please.
Thanks for the reply.

Regards

[hybrid]

Just number the nodes with numbers below a certain threshold, in my example 65535, i.e. representable within 16bit. Then, inorder to group or characterize your nodes, you set cetain bits in the upper 2 bytes of the ID via bitwise OR

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// initial numbering
node->setID(192);
// several types of nodes in your app
enum E_MY_NODE_TYPES
{
    E_BUILDING=1<<17,
    E_NPC=1<<18,
    E_VEGETATION=1<<19
};
// make node vegetation
node->setID(node->getID()|E_VEGETATION);
// or to be sure to have just one class, also when changing types later on
node->setID((node->getID()&0xffff)|E_BUILDING);
 

You can also mix several types and characterizations, e.g. add an 'unimportant' flag for things which you can avoid to render if on low-end platforms. Such values can then also be added to the ID via some more OR operators.
For bitmasks you can then choose, e.g. E_VEGETATION, as bitmask to search for all nodes belonging to that class.

[Isoprog]

Ok, got it. Thanks for the reply.

Regards.