@Pappenheimer: The Plants from Loopix are great, i have them already. Thanks.
I think you miss-understood what I meant. I didn't mean Loopix's plants, but the ffp (Fixed Function, "Material") he provided to avoid the sorting problem, because his trees have the sorting issue.
@Landixus and fogman: The overlay is not possible with the texture from the flowers, because the background from this textures have many different colors. I think i have to colored the textures new....
The background color of a flower doesn't need to be black, from you screenshot I see that each model has a single background color - that's sufficient to use the overlay feature for them - no need to re-paint anything.
From the manual:
For opaque textures (below 32 bit and no DDS), pixels become invisible when [...] or have the same color as the left upper pixel when d3d_autotransparency is set.
"pixels become invisible when they have the same color as the left upper pixel" - that's the thing, you need.
