Are Transparent Tiled Backgrounds Possible?

[jeanpaolo]

Hi everyone I'm new here. The title I guess says it all. I would just like to confirm/deny this. I know Bitmap backgrounds can have transparencies, since it wont make sense to layer them if they weren't. Though I'm not sure about tiled backgrounds. In grit you can set the transparent color even for tiled backgrounds, so does this mean its possible? I can't seem to make it work.

I'm trying to create isometric tiles and dynamically place these on the screen. End result should be something similar to front mission or final fantasy tactics. It wont be practical using sprites as 128 isn't enough for even a 10x10 grid plus animated sprites. And since its dynamic, a pre-generated bitmap background is out of the question too. From the looks of it, if transparencies aren't possible, how are the tiles/maps being loaded by these games? Bitmap background might be the answer but you can see that these "world" background tiles sometimes cover part of the character sprites in these games.

I would be much appreciated if anyone can lead me in the right direction.

Thanks!

[StevenH]

Palette entry 0 on a tile is transparent, so if you want to have large area's that are transparent make sure you have a tile with palette entry 0 in every pixel.

This goes for 16 or 256 colour tiles. (in 16 colour mode palette entry 0 of palette X is transparent).

The way that FFT on the GBA did it was with dual layers or tiles. The base tile map had the main isometric image, and the one above that held any objects that you walked behind.

I've done some iso work before and I was going to use an idea from TANSTAAFL's book - Isometric Games Programming with Direct X 7 - to do a iso tile engine on the DS, since in 256 colour mode the background has to be accessed in 2 pixels at a time, the tranposing of a square image into iso-space would be a simple task. Unfortunatly other things have stepped into my schedule on this project (initially work, then me playing with a console for graphic modes, a nasty little virus wiping my backup drive, then my current game idea...).

[jeanpaolo]

Thanks StevenH. That was what I had in mind but I wasn't sure it was possible. "World" Layer + Sprites Layer + Doodads Layer. However would that entail that the world tiles are pregenerated? Placing tiles in an isometric arrangement requires, from what i can imagine, being able to place a tile halfway between the x and y offsets... Unless one uses 2 layers and places the half-offset tiles in the 2nd layer...
Ah the possibilities! Thanks for confirming the BG tile transparencies.

[StevenH]

In most comercial games you would be looking at pre-rendered game layout, or some very carfully pixeled 16x8 sets of iso edge tiles. I'll see if I can find something to show you what I'm on about as there's been some sites with disection of commercial games that are isometric.