Untitled

#ifdef GL_ES
precision mediump float;
#endif

uniform sampler2D u_texture;
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float u_diag;


varying vec4 v_color;
varying vec2 v_texCoord0;


void main() {

    float glFCx = float(gl_FragCoord.x);
    float glFCy = float(gl_FragCoord.y);

    float sigma = 50000;
    vec2 dist2 = vec2(pow(abs(glFCx-u_mouse.x),2), pow(abs(glFCy-u_mouse.y),2));
    float distScalar2 = dist2.x+dist2.y;
    float normDistScalar = sqrt(distScalar2)/u_diag;
    float lightness = exp(-distScalar2/sigma);


    vec4 baseColor = texture2D(u_texture, v_texCoord0);

    float leftness = glFCx / u_resolution.x;
    float downness = glFCy / u_resolution.y;
    gl_FragColor = vec4(min(leftness+(1.0-baseColor.w), 1), min(downness+(1.0-baseColor.w), 1), min(1.0+(1.0-baseColor.w), 1), 1.0)*lightness;

}