https://www.shadertoy.com/view/Xsl3DH

Shockwaves.shader

shader_type canvas_item;
uniform float _PI = 3.1415926535897932384626433832795;
uniform float xx = 4.0;
uniform float yy = 2.0;

vec2 getPixelShift(vec2 center,vec2 pixelpos,float startradius,float size,float shockfactor, vec2 iResolution) {
	float m_distance = distance(center,pixelpos);
	if( m_distance > startradius && m_distance < startradius+size ) {
		float sin_dist = sin((m_distance -startradius)/size* _PI )*shockfactor;
		return ( pixelpos - normalize(pixelpos-center)*sin_dist )/ iResolution.xy;
	} else
	
	return pixelpos / iResolution.xy;
}
	
void fragment() {
	vec2 iResolution = (1.0 / SCREEN_PIXEL_SIZE);
	vec2 shockcenter1 = vec2(iResolution.x / xx, iResolution.y / xx * yy);
	float startradius = mod(TIME , 1.0) * 600.0;
	float size = mod(TIME , 1.0) * 200.0;
	float shockfactor = 50.0 - mod(TIME , 1.0) * 50.0;
	
	vec2 total_shift = getPixelShift(shockcenter1, FRAGCOORD.xy,startradius,size,20.0,iResolution);
	
	// getPixelShift(shockcenter2,FRAGCOORD.xy,startradius,size,20.0,iResolution);
	
	COLOR = texture(SCREEN_TEXTURE,total_shift);
}