precision highp float;

uniform sampler2D uParticlesA;
uniform sampler2D uParticlesB;
uniform vec4 uTouchPoint;

varying vec2 fUV;

void main() {
    vec4 particleAData = texture2D(uParticlesA, fUV);
    vec2 normalizedPosition = particleAData.xy - uTouchPoint.xy;
    float x = (normalizedPosition.x * normalizedPosition.x) / (uTouchPoint.z * uTouchPoint.z);
    float y = (normalizedPosition.y * normalizedPosition.y) / (uTouchPoint.w * uTouchPoint.w);

    if ((x + y) <= 1.0) {
        particleAData.w = distance(particleAData.xy, uTouchPoint.xy);
        particleAData.z = atan(particleAData.y - uTouchPoint.y, particleAData.x - uTouchPoint.x);
    }

    gl_FragColor = particleAData;
}