This simplifies the spheremap shader to avoid the eye / reflections calculations, which it turns out can be avoided because we are using a simplified concept of environment map where the "eye" is always looking straight down.
It also reduces shader duplication by using mix and moving a parameter into a uniform (u_zoom_scale). Because Tangram now shares source-identical program objects, this will avoid an additional program compile.
This simplifies the spheremap shader to avoid the eye / reflections calculations, which it turns out can be avoided because we are using a simplified concept of environment map where the "eye" is always looking straight down.
It also reduces shader duplication by using
mix
and moving a parameter into a uniform (u_zoom_scale
). Because Tangram now shares source-identical program objects, this will avoid an additional program compile.