Hi

I'm trying to program a tile-based game in OpenGL. The map consists of quads
which are textured according to their type (water, land, ...).

How do I determine which quad I hit when I pressed the mouse? I tried the
code from NeHe (gluUnproject, article 13 I think), but I can't figure out
how to transform the returned OpenGL coordinates to map coordinates.

The Quads are 1 unit long and wide. I use the z-coordinate for zoom and I
translate the map instead of moving the camera.

Thank you for your help.

Tobias Langner wrote:

> Hi
> 
> I'm trying to program a tile-based game in OpenGL. The map consists of
> quads which are textured according to their type (water, land, ...).
> 
> How do I determine which quad I hit when I pressed the mouse? I tried the
> code from NeHe (gluUnproject, article 13 I think), but I can't figure out
> how to transform the returned OpenGL coordinates to map coordinates.
> 
> The Quads are 1 unit long and wide. I use the z-coordinate for zoom and I
> translate the map instead of moving the camera.

Do you use isometric view?
How many quads are displayed?
Give example values.

>> I'm trying to program a tile-based game in OpenGL. The map consists of
>> quads which are textured according to their type (water, land, ...).
>> 
>> How do I determine which quad I hit when I pressed the mouse? I tried the
>> code from NeHe (gluUnproject, article 13 I think), but I can't figure out
>> how to transform the returned OpenGL coordinates to map coordinates.
>> 
>> The Quads are 1 unit long and wide. I use the z-coordinate for zoom and I
>> translate the map instead of moving the camera.
> 
> Do you use isometric view?
> How many quads are displayed?
> Give example values.

I am at an exprimental stage at the moment. I plan for each map-tile 1 quad
and for each unit/structure 1 quad. I'd like to have at least 100x100 maps
- Units/structures are magnitudes less.

I don't use an isometric view - it's top view.

Zooming is done by changing the camera-angle.

The number of quads displayed depends obviously on the zoom-level - I don't
know if it is useful to show the whole map.