원본은 https://www.shadertoy.com/view/4lXXWn 이다.

하지만 OF용으로 몇몇것들이 맞지 않아 수정을 해야 했다.

결과물 상세 이미지

쉐이더 1번에 최대한 효과적인 블러를 만들어야 겠다는 목표로.. 

#define STRINGIFY(A) #A

ofImage image1;
ofImage boy;
ofShader shader1;

//--------------------------------------------------------------
void ofApp::setup(){

//원본 : https://www.shadertoy.com/view/4lXXWn
    string shaderProgram = STRINGIFY(

        uniform sampler2DRect iChannel0;
        uniform vec3      iResolution;

        uniform float repeats; 
        uniform float amount; // 범위 0.0 ~ 0.1 

        vec4 texture(vec2 uv) {
            return texture2DRect(iChannel0,vec2(uv.x * iResolution.x ,uv.y * iResolution.y));//.rgb;
        }

            
        //랜덤 이용
        float rand(vec2 co){
            return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
        }

        void mainImage( out vec4 fragColor, vec2 fragCoord )
        {
           
            vec2 uv = (fragCoord.xy / iResolution.xy);

            vec4 blurred_image = vec4(0.);
            for (float i = 0.0; i < repeats; i++) {
                vec2 q = vec2(cos(degrees((i/repeats)*360.)),sin(degrees((i/repeats)*360.))) * (rand(vec2(i*uv.x ,i*uv.y ))+amount);
                vec2 uv2 = uv+(q*amount);
                blurred_image += texture(uv2)/2.;
                q = vec2(cos(degrees((i/repeats)*360.)),sin(degrees((i/repeats)*360.))) *  (rand(vec2(i*uv.x ,i*uv.y ))+amount);
                uv2 = uv+(q*amount);
                blurred_image += texture(uv2)/2.;
            }
            blurred_image /= repeats;
            fragColor = blurred_image;
        }


        void main(void)
        {
            vec2 pos = gl_TexCoord[0].st;
            vec4 color = vec4(0.0 , 0.0 , 0.0 , 0.0);
            mainImage(color , pos);
            gl_FragColor = color;
        }

    );

    shader1.setupShaderFromSource(GL_FRAGMENT_SHADER , shaderProgram);
    shader1.linkProgram();

    boy.load("images/boy.png");
    image1.load("images/scenery.png");
}

//--------------------------------------------------------------

float elapsed_time = 0.0;
void ofApp::draw(){

    elapsed_time += ofGetLastFrameTime();

    int repeats = ofMap(ofGetMouseX() ,0 , ofGetWidth() , 1 , 240);
    float amount = ofMap(ofGetMouseY() , 0 , ofGetHeight() , 0.0 , 0.1);

    boy.draw(0 , 0 , ofGetWidth() , ofGetHeight());

    shader1.begin();
    shader1.setUniform3f("iResolution" , image1.getWidth() , image1.getHeight() , 0.0f);
    shader1.setUniform1f("repeats" , repeats);
    shader1.setUniform1f("amount" , ofMap(ofGetMouseY() , 0 , ofGetHeight() , 0.0 , 0.1));
    image1.draw(0,0);
    shader1.end();

    ofDrawBitmapStringHighlight(ofToString(ofGetFrameRate()) , 30,30);
    ofDrawBitmapStringHighlight("repeats : " + ofToString(repeats) , 30 , 60);
    ofDrawBitmapStringHighlight("amount : " + ofToString(amount) , 30 , 75);

    boy.draw(30 , 90 , 50 , 50);

}

//--------------------------------------------------------------
void ofApp::update(){

}



//--------------------------------------------------------------
void ofApp::keyPressed(int key){

    if(key == '1')
    {
        image1 = ofImage("images/scenery.png");

    }
    else if(key == '2')
    {
        image1 = ofImage("images/CircleAndRect1.png");
    }

}