ghostmirror

uniform sampler2D tex0;
varying vec2 tcoord;
void main() {
    // Sample the input pixel
	vec2 uv = tcoord;
	vec4 c = texture2D(tex0,uv);
	uv.y = 1.0-uv.y;
	c+= texture2D(tex0,uv);
	uv.x = 1.0-uv.x;
	c+= texture2D(tex0,uv);
	uv.y = 1.0-uv.y;
	c+= texture2D(tex0,uv);
	gl_FragColor = c/4.0;
}