index.html

<link rel="stylesheet" href="styles.scss">
<script id="2d-fragment-shader" type="x-shader/x-fragment">

#ifdef GL_ES
precision mediump float;
#endif

#define PI 3.14159265359

uniform sampler2D u_image;
varying vec2 v_texCoord;

uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_mass;
uniform float u_time;
uniform float u_clickedTime;

vec2 rotate(vec2 mt, vec2 st, float angle){
	float cos = cos((angle + u_clickedTime) * PI); // try replacing * 1.0 with * PI
	float sin = sin(angle * 0.0); // try removing the * 0.0
	
	float nx = (cos * (st.x - mt.x)) + (sin * (st.y - mt.y)) + mt.x;
	float ny = (cos * (st.y - mt.y)) - (sin * (st.x - mt.x)) + mt.y;
	return vec2(nx, ny);
}

void main() {
     vec2 st = vec2(gl_FragCoord.x, u_resolution.y - gl_FragCoord.y)/u_resolution;
	vec2 mt = vec2(u_mouse.x, u_resolution.y - u_mouse.y)/u_resolution;

	float dx = st.x - mt.x;
	float dy = st.y - mt.y;

	float dist = sqrt(dx * dx + dy * dy);
	float pull = u_mass / (dist * dist);
	
     vec3 color = vec3(0.0);
	
	vec2 r = rotate(mt,st,pull);
	vec4 imgcolor = texture2D(u_image, r);
	color = vec3(
		(imgcolor.x - (pull * 0.25)),
		(imgcolor.y - (pull * 0.25)), 
		(imgcolor.z - (pull * 0.25))
	);
	

     gl_FragColor = vec4(color,1.);
}
</script>
<script id="2d-vertex-shader" type="x-shader/x-vertex">
	attribute vec2 a_position;
	attribute vec2 a_texCoord;
	
	varying vec2 v_texCoord;
	void main() {
		gl_Position = vec4(a_position, 0, 1);
		v_texCoord = a_texCoord;
	}
	</script>
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<script src="index.js"></script>