Hi DarkAngel,
From porting to ES2.0 I noticed that the old way of mip-map generation was to set glTexParameteri before glTexImage2D to say that it needs mips generated, but this has been deprecated in GL 3.x and doesn't exist in ES2.0.
The new way is immediately when you make a call to glTexImage2D you need to do glGenerateMipmap (or in desktop opengl 2.x speak it is probably glGenerateMipmapEXT). Anyway, the good thing is that command is part of the framebuffer object extension so this is indeed possible.
Unfortunately I don't think horde has any elegant API function for this yet, in fact it only got the glGenerateMipmap technique introduced in the later SVN revisions, but I can give you a hint at to what to change.
Under egRendererBase.cpp where it does RendererBase::createRenderBuffer I think this function just needs a bool inserted for genMips, so when this guy is called:
uint32 texObj = createTexture( TextureTypes::Tex2D, rb.width, rb.height, format, false, false, false, false );
it does:
uint32 texObj = createTexture( TextureTypes::Tex2D, rb.width, rb.height, format, false, rb.genMips, false, false );
Then later I guess there just needs to be a hook from the egPipeline parsing which lets you use a tag in the pipeline.xml so that when the renderbuffer is created it generates your mipmaps.
I guess I could integrate this feature, but I think marciano or Volker might have a better idea of integrating it.
Edit: I was reading through it and saw that you probably need an additional call to glGenerateMipmap just before finishRendering() inside of egRenderer.cpp's Renderer::Render, or actually inside of finishRendering which first checks the current bounded framebuffer to see if it has any texObj's and if so, checks to see if they have genMips flagged and if so, bind the texture and call glGenerateMipmap. Maybe it is ideal to have its own function in RendererBase or something...
I'm referencing
http://www.opengl.org/wiki/GL_EXT_framebuffer_object "Quick example, render_to_texture (2D), mipmaps"