Diff through a colour-vision lens, on the GPU

Both drawings go to WebGL2 as textures. One fragment shader applies a colour-vision-deficiency matrix (Machado et al. 2009, linear RGB) and pixelmatch's YIQ colour delta per pixel. A change that vanishes through a lens is carried by colour alone. The same arithmetic runs on the CPU with pixelmatch to check the GPU count.

Every case through every lens