I am aiming to set up a virtual grid of sections over my world so that i can cut down on the number of objects checked during collision detection. Therefore i only have to check the objects in the same section as the player''s object. However i am struggling with the code to set this up. I tried making a cSection class and a cGrid class. Each section keeps a list of all objects inside it and the grid keeps track of the positions of all the sections So there is a list of sections in the grid and a list of objects in each section. First of all does that sound like a goo way of implementing it? Second how do i get the objects to tell the sections which section it should be in? Thirdly the reason for doing it this way is so that i don''t have to loop through every object to check which section it is in and that i only have to look at the section data - i don''t think i am managing this though Please could someone provide me with a code sample on how to do this. I am struggling. Also is using a vector a good way of doing a linked list for this kind of thing? (e.g. tracking the objects in a section is done through a vectorObjList

umm....so say if they move right check the section they are in and the one that is right of them. How would i set up the code to handle knowing which grid section is to the right?

If i give each section a id number that acts as reference then if i know that you''re in section 2 then section 3 is to the right. And i could check that if the width of the grid is 5 and 5 high for example, i could do a divide by 5 on each section and if it doesn''t equal 1 it is not the last section. Therefore i could do this:

if(MoveRight)
{
//check if we are in last section
//if we are not then update position
if(CurrentSecionID/GridWidth != 1)
{
UpdatePos(Sect[CurrentSectionID+1],Obj);
}
}

and then updatepos would do this:

void UpdatePos(cSection &theSection, cObject Obj)
{
if((Obj->x > theSection->left) &&
(Obj->x < theSection->right) )
//then check y values

//if it satisfies all the if statements then the object
//has moved to a new section so update section info

theSection->ObjList.push_back(Obj);

//and remove from old section
}

Is that what you mean? I think that would work, hopefully you can follow my code/pseudo code. So to summarise i check section i am in, check next section, if i have moved and it isnt the last section check that after moving if i am now in the next section, if so update object list for that section, if i am not dont update.