http://glslsandbox.com/e#32378.0

GLSLsandbox

#ifdef GL_ES
precision mediump float;
#endif

#extension GL_OES_standard_derivatives : enable

uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;

vec4 live = vec4(1.,1.,1.,1.);
vec4 dead = vec4(0.,0.,0.,1.);

void main( void ) {

	vec2 position = ( gl_FragCoord.xy / resolution.xy ) + mouse / 4.0;

	gl_FragColor = dead;

}