So simple: draw line above mesh (But...)

I can’t believe I’m asking such a simple question on the forum but I’m forced by lack of insight…:persevere:

I build a mesh in setup() because I want to manipulate it in the update/draw loop with some user-directed tools (e.g. mouse). I start with the simplest possible baby-step in the development process: create the mesh and draw a single line in the middle.

The mesh looks great: centered in the larger window and with the requested color. BUT a simple ofDrawLine() request produces no line. Here’s the draw() code – assume setup() make the mesh as requested:

void ofApp::draw() {

ofBackgroundGradient(ofColor(128), ofColor(64), OF_GRADIENT_CIRCULAR);


ofSetColor(255, 255, 255);
ofDrawLine(0, 0, 0, 100, 100, 0);


In ofTranslate(), midPt is the common ofGetWidth()/2, ofGetHeight()/2 translation to center the mesh.
Thanks for input.

silly question, but how big is the mesh? Could it be that the mesh is covering up the line? Have you tried drawing the mesh as wireframe? Can you see the line if you comment out mesh.draw() ?

If it is covered, maybe glDisable(GL_DEPTH_TEST) after drawing the mesh helps make sure the line is on top?

ah I misunderstood “above” to be vertically above, as opposed to “on top of”… yes check depth sorting, also look at ofDisableDepthTest()