Depth is only relevant for translucent objects. Anyway, it doesn't work for opaque either, because they are sorted by state to minimize state changes. So: No, you can't assume that.

No, you can't fix that. Transparent objects have to be sorted to be rendered correctly and you can't do that once they have been merged into one object. You have to leave them as individual objects.

No, sorry. I didn't have the time. I'll try during the weekend...

Then your shader isn't active...

Actually, the blending mode has no impact if you are using a shader, because the shader does the blending. That happens here, in the fragment shader:

texture2D(textureUnit0, texCoord1)+texture2D(textureUnit1, texCoord)


Replacing the + by * gives you modulate blending. You are free to play around with some combination of vertex colors and both textures' colors to get something pleasing.

For specular, you would have to modify the lighting calculation in the shader. A simple hack might be to use the square root of the lighting's intensity instead of the intensity itself. If that's not good enough, you have to switch to per pixel lighting somehow.

Not really. I would say that you'll need an engine tailored to handle this kind of data structures...

That doesn't really help. I need the complete render sequence for all buffers and the final render to the screen.