Tile engines: how to figure out what tiles are visble

Hello all,

very short description:

• iso-tile array(100x100)
• loop through array and render textures according to the array-values. (very simple!)

but i think in a broader perspective. an array with a size of 1000x1000 or larger.

so here is my question:

• how can i figure out what tiles are in my visible area to speed up rendering process.
  i have no idea. maybe i think too complicated.

• if you have any suggestions or if there is some documentation available, please let me know.

• does anyone know how to improve tile-engines? (data is not stored in arrays?)

Thanks in advance,
Christoph

Need to do create some planes to represent your view frustrum. all the tiles are then tested to see if thy fall within those planes. If it does draw them, if not dont.
http://www.opengl.org/developers/faqs/technical/viewcull.c

handy FAQ comes to the rescue…