Add additive blending support

This changes the state API a bit: blending is no longer handled with flags, but
with an additional state_set_blend function, which takes a new enum argument.
The default is STATE_BLEND_DONTCARE, which avoids state changes.

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
Disable draw clamping

We'll want to build this in to states soon.

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
A few minor corrections to the shaders

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
Get rid of normal_transform uniform

We don't need this if we give our normals a 0 w component.

For now anyway. Scaling is still technically wrong for normals, and
inverse-trans might do weird things if we don't kill the translation component.

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>
32-bit floating point textures

These are necessary for HDR rendering and numerous other deferred processes.

Signed-off-by: Casey Dahlin <cdahlin@redhat.com>