vidGrabber with shader

@Koji_Kanao wrote:

I’m trying to manipulate frames from webcam but seems my input has issues.
I could pass texture from oF to shader, but the input is flipped and a little bit glitchy

Screen Shot 2019-07-20 at 5.47.49 PM.png1024×768 683 KB

Any suggestions are really appreciated.

Also would like to get advice about u_resolution.
I’m writing this, but feel this isn’t a good way.

    float fw =ofMap(w, 0, w, .0, 1.0);
    float fh =ofMap(h, 0, h, .0, 1.0);
    shader.setUniform2f("u_resolution", fw, fh);

My code is the following

ofApp.cpp

//--------------------------------------------------------------
void ofApp::setup(){
    w = ofGetWidth();
    h = ofGetHeight();
    vidGrabber.setDeviceID(0);
    vidGrabber.initGrabber(w, h);
}

//--------------------------------------------------------------
void ofApp::update(){
    vidGrabber.update();
}

//--------------------------------------------------------------
void ofApp::draw(){
    shader.load("", "test.frag");
    shader.begin();
    shader.setUniform1f("u_time", ofGetElapsedTimef());
    float fw =ofMap(w, 0, w, .0, 1.0);
    float fh =ofMap(h, 0, h, .0, 1.0);
    shader.setUniform2f("u_resolution", fw, fh);
    shader.setUniformTexture("tex0",vidGrabber.getTexture(),0);
    ofDrawRectangle(0,0, ofGetWidth(), ofGetHeight());
    shader.end();
}

fragment shader

uniform vec2 u_resolution;
uniform sampler2DRect tex0;

void main(){
    vec2 uv=gl_FragCoord.xy/u_resolution.xy;
    gl_FragColor=texture2DRect(tex0, uv);
}

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