Point covers entire screen when hidden

[lilleyse]

Sandcastle - looks good until you uncheck Other/Unclassified. This is a linux only bug. The way we hide points in PointCloud.js is to multiply gl_Position by 0.0 and hope the point is outside the clip space cube, but I could see how gl_Position.x / gl_Position.w (i.e. 0 / 0) might be undefined behavior. A better fix is to explicitly change the xyz coordinates to be greater than the w value so it clearly gets clipped. It would be nice to do this without the if statement though.

        if (hasShowStyle) {
            vs += '    if (show == 0.0) \n' +
                  '    { \n' +
                  '        gl_Position.xyz = vec3(gl_Position.w * 2.0); \n' +
                  '    } \n';
        }

Whatever we go with here we should test with every other system that hides points, like #7557 (comment). Look for any code that hides points by doing *= show and switch to the new approach.