I found two nice textures from this website--the first and third pics in the top row are the ones I'm using.
The first picture is the land, the second is the "cloud layer." The cloud image has no alpha channel--and is just black and white.
My naive approach to multitexturing them on top of each other in one pass was this:
Code: Select all
material earth
{
technique
{
pass
{
texture_unit
{
scroll_anim 0.0001 0
texture earth.jpg
}
texture_unit
{
scroll_anim 0.01 0
colour_op add
texture earthclouds.jpg
}
}
}
}
Now I understand why this is happening, but I'm not sure how I can fix it. Do I need to:
a) write a shader to to lookup the prev texture's diffuse value?
b) Photoshop the cloud layer so that it has an alpha layer?
c) open the texture as a luminence texture (does Ogre do these? I remember them in GL as a nice way to do flares and other effects)
d) or hopefully: use a different definition in my material script (!)
Here's a shot of the problem:

Thanks![/code]