From: Joel VanderWerf <vjoel@...>
Date: 2005-06-03T07:33:32+09:00
Subject: Re: [ANN] librend 0.0.1

Ilmari Heikkinen wrote:
> 
> On 2.6.2005, at 21:03, Joel VanderWerf wrote:
...
>> Do you think this will ever be a replacement for the Tk 2D canvas? I'm 
>> thinking of things like layers, groups, event bindings, etc.  
>> Actually, I guess event bindings wouldn't make sense outside of a GUI 
>> context. Maybe librend could be integrated into Fox?
>>
> 
> I'm not familiar with the Tk canvas, but after reading through the man 
> page it seems that most of the drawing functionality can be implemented 
> with the vector engine. Layers and groups are quite doable already in 
> some form, though not quite at Photoshop level, heh.
> Do you have some specific thing in mind regarding the layers, what 
> should they do?

For example: a "car" is composed of several 2D shapes plus some text 
that floats alongside it. The shapes are all at the same level (above 
the roadway, let say), but the text is at a higher level. So if two cars 
pass near each other, the text is not obscured. I've sometimes emulated 
that in OpenGL by using very small z-axis values, but it seems like a 
hack to use 3D drawing at all in this case.

> Event bindings are there, but use SDL events at the moment. I'll 
> abstract them to a generic event model today, then the window system 
> backend shouldn't matter. There are no mouse cursor hit detection 
> helpers yet, so one now either needs to keep tab of where everything is 
> and react based on that (royal pain, especially with rotating things) or 
> write a general picking system for the renderer. I'll try to get a 
> picking system going soon.
> 
> Fox integration should be doable by writing a backend for the renderer. 
> It needs to initialize GL, tell the renderer the window dimensions and 
> pass input events to it.

Great! Keep us posted.