QPainter and Shader

[shetan]

Hello

I'm using OpenGL in a QGraphicScene with drawBackground(

I create a simple shader that just change the pixel's color of a Qpainter rect
The shader works only the second time I use it

void drawBackground( QPainter *pPainter, const QRectF &pRect )
{
	glClearColor( mBackGroundColor.redF(), mBackGroundColor.greenF(), mBackGroundColor.blueF(), 1.0f );
 
    	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    	glClearDepth(1.0f);
 
    	glMatrixMode( GL_PROJECTION );
    	glPushMatrix();
	glLoadIdentity();
 
	lViewAngle =  lViewAngle * 360.0 / M_PI;
	gluPerspective( lViewAngle, width() / height(), 0.1, 200 );
 
	glMatrixMode( GL_MODELVIEW );
 
	//OPENGL STUFF		
 
        glPopMatrix();
        glMatrixMode( GL_PROJECTION );  
    	pPainter->endNativePainting();	
 
	//shader doesn't work
	shader.bind();
	pPainter->fillRect(0, 0, 128, 128, Qt::black);
    	shader.release();
 
	//shader work
   	shader.bind();
     	pPainter->fillRect(100, 100, 128, 128, Qt::black);
    	shader.release();
}

void drawBackground( QPainter *pPainter, const QRectF &pRect )
{
	glClearColor( mBackGroundColor.redF(), mBackGroundColor.greenF(), mBackGroundColor.blueF(), 1.0f );

    	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    	glClearDepth(1.0f);

    	glMatrixMode( GL_PROJECTION );
    	glPushMatrix();
	glLoadIdentity();
       
	lViewAngle =  lViewAngle * 360.0 / M_PI;
	gluPerspective( lViewAngle, width() / height(), 0.1, 200 );

	glMatrixMode( GL_MODELVIEW );
	
	//OPENGL STUFF		
    
        glPopMatrix();
        glMatrixMode( GL_PROJECTION );  
    	pPainter->endNativePainting();	
	
	//shader doesn't work
	shader.bind();
	pPainter->fillRect(0, 0, 128, 128, Qt::black);
    	shader.release();
	
	//shader work
   	shader.bind();
     	pPainter->fillRect(100, 100, 128, 128, Qt::black);
    	shader.release();
}

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Thanks for your help

[high_flyer]

what happens if you switch the order - first use the 100,100 one, then the 0,0?