precision mediump float; uniform sampler2D sampler; uniform float time; varying vec2 texcoords; void main() { float t = (sin(time)+1.0)/2.0; vec4 textureColor = texture2D(sampler, vec2(texcoords.x+time,texcoords.y)); gl_FragColor = vec4( abs(t - textureColor.rgb), textureColor.a); }