import { Filter } from "../filter";
import { Screen } from "../webgl2/screen";
import { Shader } from "../shader";

export class linearBlur extends Filter {
    constructor(screen: Screen, dx = 1, dy = 0) {
        let {width, height} = screen;

        super(screen, linearBlur.getShader(width, height, dx, dy), 512, 512);

    }

    static getShader(width, height, dx, dy) {
        let define = [
            `#define OFFSET (vec2(${dx / width}, ${dy / height}))`,
        ].join('\n');
        return new Shader(blurvs, define + blurfs);
    }


}

let blurvs = `
attribute vec3 POSITION;
attribute vec2 TEXCOORD_0;

varying vec2 uv;
varying vec4 pos;

void main() {
  uv = TEXCOORD_0;
  vec4 position = vec4(POSITION, 1);
  pos = position;
  gl_Position = position;
}
`;

let blurfs = `
#define PI 3.1415926535898
precision highp float;
uniform sampler2D base;

varying vec2 uv;
varying vec4 pos;



vec4 linearBlur() {
    vec4 color = vec4(0);
    color += texture2D(base, uv + OFFSET * 0.0 ) / 7.0;
    color += texture2D(base, uv + OFFSET * -1.0 ) / 7.0;
    color += texture2D(base, uv + OFFSET * -2.0 ) / 7.0;
    color += texture2D(base, uv + OFFSET * -3.0 ) / 7.0;
    color += texture2D(base, uv + OFFSET * 1.0 ) / 7.0;
    color += texture2D(base, uv + OFFSET * 2.0 ) / 7.0;
    color += texture2D(base, uv + OFFSET * 3.0 ) / 7.0;
    return color;
}

void main() {
    vec2 offset = uv * 2.0 - 1.0;
    float mask = dot(offset, offset);
    vec4 color = texture2D(base, uv);
    gl_FragColor = linearBlur();
    // gl_FragColor = vec4(0);
    // gl_FragColor = vec4(0);
    // gl_FragColor = vec4(0);
    // gl_FragColor = vec4(0);
    // gl_FragColor = mix(color, vec4(0,0,0,1), mask * 0.45);
}
`;