uniform sampler2D texSampler;
uniform float animation;

void main() {
    vec4 tex = texture2D(texSampler, gl_TexCoord[0].st);
    float diff = abs(animation - tex.r);

    if (animation>tex.r && tex.r>0.1 && diff<0.1)
        gl_FragColor = vec4(1,1,1,1);
    else discard;
}