ofSetBackgroundAuto problem(maybe bug?)

beginners
#1

Hello.

I have a problem with ofSetBackgroundAuto().

I attached simple code to simulate the problem.

If I set ofSetBackgroundAuto() false, OF doesn’t draw from the top.

It looks like it skips 3 or 4 frames.

But it draws OK with true.

testApp.h

  
  
#include "ofMain.h"  
using namespace std;  
  
class CA  
{  
private:  
    int cellSize;  
  
public:  
    int* mCells;  
    int mGeneration;  
    int mInterval;  
    int aa;  
      
    CA()  
    {  
        mInterval = 10;  
        cellSize = ofGetWidth()/mInterval;  
        mCells = new int[cellSize];  
        mGeneration = 0;  
        for(int i=0; i<cellSize; i++)  
        {  
            mCells[i] = i%2;  
        }  
          
    }  
      
    void Generate()  
    {  
        aa++;  
        for(int i=0; i<cellSize; i++)  
        {  
            mCells[i] = (i+aa)%2;  
        }  
        mGeneration++;  
    }  
      
    void Display()  
    {  
        for(int i=0; i<cellSize; i++)  
        {  
            if(mCells[i]==0)   
            {  
                ofSetColor(255);  
            }  
            else  
            {  
                ofSetColor(0);  
            }  
            ofRect(i*mInterval, mGeneration*mInterval, mInterval, mInterval);  
        }  
    }  
      
};  
  
class testApp : public ofBaseApp{  
public:  
    void setup();  
    void update();  
    void draw();  
      
    double w,h;  
      
    CA ca;  
};

testApp.cpp

  
  
#include "testApp.h"  
  
//--------------------------------------------------------------  
void testApp::setup(){  
    ofSetFrameRate(1);  
    //try ofSetBackgroundAuto true and false  
    ofSetBackgroundAuto(false);  
    w = ofGetWidth();  
    h = ofGetHeight();  
    ofBackground(255);  
}  
  
//--------------------------------------------------------------  
void testApp::update(){  
}  
  
//--------------------------------------------------------------  
void testApp::draw(){  
    if(ca.mGeneration < h/ca.mInterval)  
    {  
        ca.Display();  
        ca.Generate();  
    }  
      
}
#2

I can confirm this problem using the more simplified code shown below.
The first three rectangles are not drawn, when ofSetBackgroundAuto() is set to false(works OK, when set to true).

Why is this?

  
#include "testApp.h"  
  
void testApp::setup(){  
	ofSetBackgroundAuto(false);  
	ofSetFrameRate(1);  
	ofSetRectMode(OF_RECTMODE_CENTER);  
	ofBackground(255);  
	ofSetColor(0);  
}  
  
void testApp::update(){  
}  
  
void testApp::draw(){  
	printf("bang!\n");  
	ofRect(ofRandom(ofGetWidth()), ofRandom(ofGetHeight()), 50, 50);  
}