To those wondering about Alpha Transparency

[LexiBigCheese]

While the Previous for the first Texenv is the pixel that is currently in the framebuffer,
You instead want to notice this:

citro3d_sys::C3D_AlphaBlend(
    ctru_sys::GPU_BLEND_ADD,
    ctru_sys::GPU_BLEND_ADD,
    ctru_sys::GPU_SRC_ALPHA,
    ctru_sys::GPU_ONE_MINUS_SRC_ALPHA,
    ctru_sys::GPU_SRC_ALPHA,
    ctru_sys::GPU_ONE_MINUS_SRC_ALPHA,
);

which is ran when citro3d is initialised.
src is the output of your Texenvs, dst is the pixel currently in the framebuffer
think of this as:

output.rgb = colorEq(src.rgb * srcClr,dst.rgb * dstClr);
output.a = alphaEq(src.a * srcAlpha,dst.a * dstAlpha);

this means if you're not seeing alpha blending, the issue is probably elsewhere. For example, a misconfigured attr::Info, or perhaps use of buffer::Info::add (on any buffer info) multiple times in the same frame (in which case, use immediate mode rendering, described in #57)
It could also be the result of not dirtying your Texenvs if they are changed more than once in a frame, see #56