`visit()` and `draw()` are improved.
they both receive:
- `Renderer`
- `kmMat4` for transformation
- `bool` whether or not the transform changed from the previous frame
Although `draw` and `visit` are not using the 3 new parameters,
they will start using it in the coming days (or weeks, or months).
Those parameters are needed for:
- `Renderer` shouldn't be a singleton. There should be one renderer per Director. There could be more than one renderer
- we should get rid of `kmGLXXX` functions since nodoby knows what is happening. the `kmMat4` is for that.
- whenever possible, we should try to optimize the multiplications. the `dirty` flag is for that.
We need those changes, so, it is better to change the API now, and not right after v3.0-final is released.
Instead of using a 64-bit int key with viewport, opaque and depth,
it only uses a 32-bit float with only the depth.
Saves time in:
- No need to convert the 32-bit float into 24-bit int
- keys are shorter
Huabing.Xu