lol/doc/tutorial/12_voronoi_setup.lolfx

[vert.glsl]

#version 130

in vec2 in_position;

uniform vec2 u_screen_res;

out vec2 pass_position;

void main()
{
    pass_position = ((vec2(1.0) + in_position) * 0.5 * u_screen_res);
    gl_Position = vec4(in_position, 0.0, 1.0);
}

[frag.glsl]

#version 130

#if defined GL_ES
precision highp float;
#endif

in vec2 pass_position;

uniform sampler2D u_texture;
uniform vec3 u_source_point;
uniform vec2 u_screen_res;

void main(void)
{
    if (floor(u_source_point.xy) == floor(pass_position))
        gl_FragColor = vec4(u_source_point.xy / u_screen_res, u_source_point.z, 1.0);
    else
    {
        vec4 src_color = texture2D(u_texture, pass_position / u_screen_res);
        gl_FragColor = src_color;//vec4(0.0, 0.0, 0.0, 1.0);
    }
        //vec4(pass_position / u_screen_res, 0.0, 1.0);
}