Paulo, you need something like:
I'd make the bitmap separate from the others (not an alpha channel), so it's easier to change.
Make it black and spray it green (rgb=0,255,0) where you want trees.
Whenever a green pixel is found the coords will be sent to the MakeTreeAt() routine.
For x = 0 to <bitmap width>-1 For y = 0 to <bitmap height>-1 LockBuffer TextureBuffer(bitmap handle) rgb = ReadPixelFast(x,y,TextureBuffer(bitmap handle)) UnlockBuffer TextureBuffer(bitmap handle) nClrR = rgb Shr 16 And %11111111 nClrG = rgb Shr 8 And %11111111 nClrB = rgb And %11111111 If nClrG=255 MakeTreeAt(x,y) Endif Next Next
I'd make the bitmap separate from the others (not an alpha channel), so it's easier to change.
Make it black and spray it green (rgb=0,255,0) where you want trees.
Whenever a green pixel is found the coords will be sent to the MakeTreeAt() routine.