macOS NSOpenGLView isn't redrawing...

[Stachelsk]

I'm stumped. I'm by no means familiar with objective-c++ or Apple's libraries, so please bear with me. My renderer code is only getting called once (when the application starts). It only gets called again if I minimize and restore the window. No idea how to make it refresh.

Code in question:

#import "GLView.h"

@implementation GLView

- (id)initWithFrameNSRect)frameRect
{
NSOpenGLPixelFormatAttribute attr[] =
{
NSOpenGLPFAAccelerated,
NSOpenGLPFAColorSize, (NSOpenGLPixelFormatAttribute) 32,
(NSOpenGLPixelFormatAttribute) 0
};
NSOpenGLPixelFormat *nsglFormat = [[[NSOpenGLPixelFormat alloc] initWithAttributes:attr] autorelease];

if (self = [super initWithFrame:frameRect pixelFormat:nsglFormat])
renderer = new Renderer();
return self;
}

- (void)dealloc
{
delete renderer;
[super dealloc];
}

- (void)prepareOpenGL
{
glDisable(GL_DEPTH_TEST);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 400, 300, 0, 0, 1);
glMatrixMode(GL_MODELVIEW);
}

- (void)drawRectNSRect)rect
{
renderer->DrawGL();
// DOESN'T WORK --- [super setNeedsDisplay:YES];
// DOESN'T WORK --- [self setNeedsDisplay:YES];
}

@end

 

[kainjow]

[self setNeedsDisplay:YES];

is the way to do it. But don't call that inside your drawRect: method. When/where are you actually wanting to redraw?

Edit: you need this at the end of your drawRect:

[[self openGLContext] flushBuffer];

 

[Stachelsk]

Thanks for the help, kainjow. Unfortunately, it did not work.

It's still only calling DrawGL() once.

 

[kainjow]

Well what does your code look like now?

 

[Stachelsk]

#import "GLView.h"

@implementation GLView

- (id)initWithFrame:(NSRect)frameRect {
    NSOpenGLPixelFormatAttribute attr[] = {
        NSOpenGLPFADoubleBuffer,
		NSOpenGLPFAAccelerated,
		NSOpenGLPFAColorSize, (NSOpenGLPixelFormatAttribute) 32,
		(NSOpenGLPixelFormatAttribute) 0
	};
	NSOpenGLPixelFormat *nsglFormat = [[[NSOpenGLPixelFormat alloc] initWithAttributes:attr] autorelease];
	
    if ((self = [super initWithFrame:frameRect pixelFormat:nsglFormat]))
		; //...
	return self;
}

- (void)dealloc {
	[super dealloc];
}

- (void)prepareOpenGL {
	glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0, 400, 300, 0, 0, 1);
    glMatrixMode(GL_MODELVIEW);
}

- (void)drawRect:(NSRect)rect {
	render();
    [[self openGLContext] flushBuffer];
    [self setNeedsDisplay:YES];
}

@end

I want the code to redraw as soon as its done rendering a frame... so I put the [self setNeedsDisplay:YES]; after flushing the buffer. Can it just absolutely not be there? Where can I put it so that the screen is constantly redrawing as soon as the render method is done?

 

[lloyddean]

'setNeedsDisplay' does nothing when placed within your draw loop. Instead you'll need to drive your rendering loop from an NSTimer or DisplayLink callback handler.

Check out this document.

 

[Stachelsk]

'setNeedsDisplay' does nothing when placed within your draw loop. Instead you'll need to drive your rendering loop from an NSTimer or DisplayLink callback handler.

Check out this document.

Works perfectly, thanks.
Happy holidays!