let sh;

let dataShader;

let buf01, buf02;

​

​

function preload(){

    sh = loadShader('shader.vert', 'shader.frag');

    dataShader = loadShader('shader.vert','data.frag');

}

​

function setup(){

    pixelDensity(1);

    createCanvas(windowWidth, windowHeight, WEBGL);

    shaderGraphics = createGraphics(windowWidth, windowHeight, WEBGL);

    shaderGraphics.shader(sh);

​

    buf01 = createGraphics(windowWidth, windowHeight, WEBGL);

    buf02 = createGraphics(windowWidth, windowHeight, WEBGL);

    buf01.shader(dataShader);

    buf02.shader(dataShader);

    buf01.clear();

    buf02.background(1);

}

​

function draw(){

    buf01.shader(dataShader);

    dataShader.setUniform("backbuffer",buf02);

    dataShader.setUniform("resolution",[windowWidth,windowHeight]);

    buf01.clear();

    buf01.quad(-1,-1,1,-1,1,1,-1,1);

    [buf01, buf02] = [buf02, buf01];

​

    resetShader();

​

    shaderGraphics.shader(sh);

    sh.setUniform("resolution", [windowWidth,windowHeight]);

    sh.setUniform("data", buf01);

    shaderGraphics.quad(-1,-1,1,-1,1,1,-1,1);

​

    image(shaderGraphics,width*-0.5, height*-0.5);

​

}