#ifdef GL_ES
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
#endif
uniform sampler2D tex;
varying vec4 col;
varying vec2 tex_c;
void main()
{
   vec3 inv = vec3(1.0, 1.0, 1.0) - texture2D(tex,tex_c.xy).rgb;
   gl_FragColor = vec4(inv.r, inv.g, inv.b, 1.0);
}