5 replies to this topic

[freezzo]

Maybe I'm just ignorant when it comes to image editing software, but do most programs allow you to view just a particular channel of say a RGBA image and edit it.

Basically to do a heightmap on one channel, and other tasks on the other channels, but edit them independent of each other as to not confuse oneself with all the pretty colors?

If its not a standard operation, does anyone know of such an application?

[TheNut]

GIMP, a pretty good and free image editor, can do this for you. I believe Paint.NET supports this as well. Commercial software such as Photoshop and Paint Shop Pro also support this.

[freezzo]

Thanks.

So my idea is to use a 24bit/32bit image and hold data in each channel:

Land
Water
Objects
Texture

Would this be a good technique, or is there a better way to go about it?

[TheNut]

You can group land and water together. Decide on the sea level, say pixel 50. From here, any terrain below a grayscale value of 50 will be under water. If you want higher precision, look into 16bit images instead of 8, which will give you finer control over your landscape.

I'm not sure I follow you on objects & textures. Textures are usually 24/32bpp and contain colour detail. If you use only one channel, all the objects in your world will be painted that colour. Unless your intent is to use that part as a means of lighting your terrain then that's fine, but extra work since you're going to have to extract the texture components before uploading it into your graphics API. You're better off just to separate everything.

As for objects, you should have some kind of database. Store the position, scaling values, materials used, scripts required, etc... in that database. Much easier to maintain.

[freezzo]

What about if say i want sea level to be at 50, but a lake up on a hill at pixel 100?

What i meant by object and texture was storing the greyscale value as an id that links to an object or texture to place there, but i think your idea is better.

[Reedbeta]

If you want to have varying water levels, then having a water texture is a good idea, as it can tell you exactly where to place the boundaries of your water polygons. Storing it in a channel of the heightmap is fine.

Some other things people frequently do with channels: store a full-color diffuse texture in RGB and its gloss map or glow map in the alpha channel; or store a normal map in RGB and its height map (for parallax mapping) in the alpha channel.