Question

I wasn’t sure what to call this. I’m building a tile based game where the user can click on a tile.
it is a 2d c++ vector of tiles. right now I have an algorithm that positions them like this:

[][][][][][][][][][][]
[][][][][][][][][][][]
[][][][][][][][][][][]
[][][][][][][][][][][]
[][][][][][][][][][][]
[][][][][][][][][][][]

they are positioned based on their size and my tile class holds each of their x and y coordinates, and I have 2 variables for the height and width.

Basically I’d like to find an algorithm that can return the tile my mouse is on based on the mouse’s position.

For example: if my mouse (relative to the game window)’s position is 37,0 and each of my tiles is 10 * 10 in size and they are each tilewidth apart then by having my mouse over 37,0 it should return (4,1) meaning the 4th element on the x and the first element on the y. I thought about doing bounding box checks against each rectangle but I think that will use up too much cpu if i check 60 times / second.

Thanks

Answer 1

If you’re not using an event based environment, you do need to code your own object intersection, mouse detection, etc.

Here’s the formula in pseudo code for what you want to get:

tile_width = 10;
tile_height = 10;

x_tile = Math.ceil(mousex/tile_width);
y_tile = Math.ceil(mousey/tile_height);