ofVertex without lines or fills

beginners
#1

Hey all

I’m trying to draw a point cloud but I cant find a method to draw points
is there anything efficient out there or do i have to use ofRect with width=0 or 1?

be nice if there was a point drawmode for ofVertex. something like that exists?

thanks
elliot

#2

edit: see Arturo’s post below

Right now this is just done with straight up OpenGL:

  
  
glBegin(GL_POINTS);  
glVertex2f(x, y);  
glVertex2f(x, y);  
...  
glEnd();

There is some talk of extending ofBeginShape to work more like Processing’s beginShape, but right now the more basic things are just handled with OpenGL.

#3

cheers
that’s pretty elegant anyway

you the kyle who did the talk at madlab a couple of weeks back over skype?

#4

That’s me :slight_smile:

#5

indeed you need to use ofBeginShape() and ofEndShape()

in previous versions glBegin/End would work but since 006 that’s internally using a vertex array so the gl functions won’t work.

so:

  
ofBeginShape(GL_POINTS);  
ofVertex(x, y);  
ofVertex(x, y);  
...  
ofEndShape();
#6 
  
  
		ofPushStyle();  
		ofSetColor(0,0,255);  
		  
		glBegin(GL_POINTS);  
		for (int iMarker=0; iMarker < _nMarkers; iMarker++)  
		{  
			xMarker = (*_markers)[iMarker].x * width + x;  
			yMarker = (*_markers)[iMarker].y * height + y;  
			  
			ofVertex(xMarker, yMarker);  
		}  
		glEnd();  
		ofPopStyle();

doesn’t seem to draw anything

but

  
  
		ofPushStyle();  
		ofNoFill();  
		ofSetColor(0,0,255);  
		  
		for (int iMarker=0; iMarker < _nMarkers; iMarker++)  
		{  
			xMarker = (*_markers)[iMarker].x * width + x;  
			yMarker = (*_markers)[iMarker].y * height + y;  
			  
			ofRect(xMarker, yMarker, 1, 1);  
		}  
		ofPopStyle();

and

  
  
		ofPushStyle();  
		ofNoFill();  
		ofSetColor(0,0,255);  
		  
		ofBeginShape();  
		for (int iMarker=0; iMarker < _nMarkers; iMarker++)  
		{  
			xMarker = (*_markers)[iMarker].x * width + x;  
			yMarker = (*_markers)[iMarker].y * height + y;  
			  
			ofVertex(xMarker, yMarker);  
		}  
		ofEndShape(false);  
		  
		ofPopStyle();

do

…

i’ve missed a trick?

#7

Ah, nice. That’s great to hear.

If I understand correctly, it’s not that glBegin/glEnd won’t work, it’s just that you can’t mix it with ofVertex?

So these are both ok:

glBegin(GL_POINTS);
glVertex2f(x, y);
glEnd();

ofBeginShape(GL_POINTS);
ofVertex(x, y);
ofEndShape();

But these aren’t:

glBegin(GL_POINTS);
ofVertex(x, y);
glEnd();

ofBeginShape(GL_POINTS);
glVertex2f(x, y);
ofEndShape();

#8

wow
2 replies whilst i posted that message

anyway…

i’m using 006 but i get a too many argument error with

  
  
		ofBeginShape(GL_POINTS);

is it 0061?

  
  
		glBegin(GL_POINTS);  
		for (int iMarker=0; iMarker < _nMarkers; iMarker++)  
		{  
			xMarker = (*_markers)[iMarker].x * width + x;  
			yMarker = (*_markers)[iMarker].y * height + y;  
			  
			glVertex2f(xMarker, yMarker);  
		}  
		glEnd();

is working great

#9

oh yes, its:

  
ofSetPolyMode(GL_POINTS);  
ofBeginShape();  
ofVertex(x, y);  
ofEndShape();

kyle: yes, both will work, is just glBegin/End dowsn’t exist anymore in opengl es and are deprecated in opengl 3. also vertex arrays are faster.

#10

Hmm, as I don’t normally draw polys, ofSetPolyMode is a bit weird to me. That’s be great if it could get moved into the ofBeginShape call.

#11

oh sorry is not even that, polymode is for the winding, being OF_POLY_WINDING_ODD the default.

you need to use opengl calls to specify GL_POINTS