Neat, you do the math yourself and then render the tris/quads in canvas? I did something like that recently (in C/SDL, later RayLib). I found it amusing that to get performant 2D rendering you have to use a 3D API, so my "software rendered" 3D engine which just uses the gfx api for 2D draw calls ends up using 3D for the 2D under the hood...

There's at least one (great) game written like that though, Need for Madness with a custom 3D engine and just using java's 2D gfx api for rendering.