windshield_wiper_rect.frag

#ifdef GL_ES
precision mediump float;
#endif

uniform vec2 u_resolution;

float rectshape(vec2 position, vec2 scale){
	scale = vec2(0.5) - scale * 0.5;

	vec2 shaper = vec2(step(scale.x, position.x), step(scale.y, position.y));

	shaper *= vec2(step(scale.x, 1.0 - position.x), step(scale.y, 1.0 - position.y));

	return shaper.x * shaper.y;
}

uniform float u_time;
uniform vec2 u_mouse;

void main(){
	vec2 position = gl_FragCoord.xy / u_resolution;

	vec3 color = vec3(0.0);
	vec3 c = vec3(1.0,0.3,0.3);

    vec2 mp = vec2(u_mouse.x/gl_FragCoord.x,u_mouse.y/gl_FragCoord.y);
	float rectangle = rectshape(mp, vec2(0.2,0.2));

	color = vec3(rectangle);

	vec3 rect_color = mix(color,c,color*0.5);
	gl_FragColor = vec4(rect_color, 1.0);

}