GLES, at least as used in WebGL 2, does not like mixing integers and floats,
for example:
> ERROR: 1:8: '*' : wrong operand types - no operation '*' exists that takes a left-hand operand of type 'mediump 2-component vector of float' and a right operand of type 'const int' (or there is no acceptable conversion)
This patch converts those integer constants into floats.
With this patch the shaders (apart from the master shader) can be used in WebGL contexts too.