Add missing "bridge.glsl" close #3

[davcri]

@patriciogonzalezvivo could we merge this?

I tested with this script on a Macbook Air M1 and it works fine generating all the images and fixing #3

mkdir screenshots

for frag_file in 00-elements/*.frag; do
    base_name=$(basename "$frag_file" .frag)
    output_image="${base_name}.png"
    glslViewer --noncurses --headless "$frag_file" -E screenshot,"screenshots/$output_image"
done