Nothing showing up in NSOpenGLView [newb]

Nibbie

Posts: 4
Joined: 2011.11

Post: #1

Nov 29, 2011 — 12:23 AM

Hey all,
I'm trying to teach myself OpenGL and Cocoa/Objective-C. I'm a C++/Java developer by trade (so you have some basis of my technical knowledge).

I've been stuck trying to figure out why I can't seem to get, what should be, a simple task working. I'm trying to display a triangle in a window using OpenGL 3.2.

Here is the pertinent method in my AppDelegate.m:

Code:

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification

{

    // Insert code here to initialize your application

    OGLViewController *oglvc = [[OGLViewController alloc] initWithNibName:nil bundle:nil];    

    [oglvc setupViewWithRect:[self.window.contentView bounds]];

    [self.window.contentView addSubview:oglvc.view];

    [oglvc draw];

}

My custom NSViewController, OGLViewController, implementation is as follows (WARNING: wall o' code):

Code:

//

//  OGLViewController.m

//  TriangleMan

//

//  Created by binaryinsomnia on 11/28/11.

//  Copyright (c) 2011 binaryinsomnia. All rights reserved.

//

#import "OGLViewController.h"

#import "GLProgram.h"

#import "error.h"

#import <OpenGL/gl3.h>

@interface OGLViewController()

{

    GLuint positionAttribute;

    GLuint colorAttribute;

}

@property (retain) GLProgram *oglhelper;

@end

@implementation OGLViewController

@synthesize oglhelper = _oglhelper;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

    if (self) {

        // Initialization code here.

    }

    return self;

}

-(void)dealloc

{

    [super dealloc];

    [_oglhelper release];

}

-(void)setupViewWithRect:(NSRect)aRect

{

    NSOpenGLPixelFormatAttribute pixAttribs[] =

    {

        NSOpenGLPFAOpenGLProfile, NSOpenGLProfileVersion3_2Core,

        NSOpenGLPFAColorSize    , 24                           ,

        NSOpenGLPFAAlphaSize    , 8                            ,

        NSOpenGLPFADoubleBuffer ,

        NSOpenGLPFAAccelerated  ,

        NSOpenGLPFANoRecovery   ,

        0

    };

    NSOpenGLPixelFormat *pixFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:pixAttribs];

    self.view = [[NSOpenGLView alloc] initWithFrame:aRect pixelFormat:pixFormat];

    [[(NSOpenGLView*)(self.view) openGLContext] makeCurrentContext];

}

-(void)prepareOpenGL

{    

    self.oglhelper = [[GLProgram alloc] initWithVertexShaderFilename:@"Simple" 

                                              fragmentShaderFilename:@"Simple"];

    [self.oglhelper addAttribute:@"position"];

    [self.oglhelper addAttribute:@"color"];

    if (![self.oglhelper link])

    {

        NSLog(@"Link failed");

        NSString *progLog = [self.oglhelper programLog];

        NSLog(@"Program Log: %@", progLog); 

        NSString *fragLog = [self.oglhelper fragmentShaderLog];

        NSLog(@"Frag Log: %@", fragLog);

        NSString *vertLog = [self.oglhelper vertexShaderLog];

        NSLog(@"Vert Log: %@", vertLog);

        self.oglhelper = nil;

    }

    positionAttribute = [self.oglhelper attributeIndex:@"position"];

    colorAttribute    = [self.oglhelper attributeIndex:@"color"];    

}

-(void)addVertexData

{

    GLfloat positionArray[] = 

    {

    //   x    y    z    w

        0.0, 0.0, 0.0, 1.0,

        2.0, 0.0, 0.0, 1.0,

        0.0, 1.0, 0.0, 1.0

    };

    GLfloat colorArray[] = 

    {

    //   r    g    b    a

        1.0, 0.0, 0.0, 1.0,

        0.0, 1.0, 0.0, 1.0,

        0.0, 0.0, 1.0, 1.0

    };

    // first, set up the position vertex into the GPU    

    GLuint posVAOId, posVBOId;

    glGenVertexArrays(1, &posVAOId); // get valid VAO

    GetError();

    glBindVertexArray(posVAOId); // bind it to the vertex array

    GetError();

    glGenBuffers(1, &posVBOId); // get a valid VBO

    GetError();

    glBindBuffer(GL_ARRAY_BUFFER, posVBOId);  // make it a VBO

    GetError();

    // copy data to VRAM

    glBufferData(GL_ARRAY_BUFFER, 12 * sizeof(GLfloat), positionArray, GL_STATIC_DRAW);

    GetError();

    glVertexAttribPointer(positionAttribute, 3, GL_FLOAT, GL_FALSE, 0, 0);

    GetError();

    glEnableVertexAttribArray(positionAttribute);

    GetError();

    // duplication of code... yeah, yeah.

    // next, set up the color info into the GPU    

    GLuint colVAOId, colVBOId;

    glGenVertexArrays(1, &colVAOId); // get valid VAO

    GetError();

    glBindVertexArray(colVAOId); // bind it to the vertex array

    GetError();

    glGenBuffers(1, &colVBOId); // get a valid VBO

    GetError();

    glBindBuffer(GL_ARRAY_BUFFER, colVBOId);  // make it a VBO

    GetError();

    // copy data to VRAM

    glBufferData(GL_ARRAY_BUFFER, 12 * sizeof(GLfloat), colorArray, GL_STATIC_DRAW);

    GetError();

    glVertexAttribPointer(colorAttribute, 3, GL_FLOAT, GL_FALSE, 0, 0);

    GetError();

    glEnableVertexAttribArray(colorAttribute);

    GetError();

    glBindVertexArray(0);

}

-(void)draw

{

    glClearColor(0.0, 0.0, 1.0, 1.0);

    glClear(GL_COLOR_BUFFER_BIT);

    GetError();

    [self prepareOpenGL];

    [self addVertexData];

    [self.oglhelper use];

    glDrawArrays(GL_TRIANGLE_FAN, 0, 3);

    [[(NSOpenGLView *)(self.view) openGLContext] flushBuffer];

}

@end

I'm using Jeff LaMarche's GLProgram class (https://github.com/jlamarche/iOS-OpenGLE...e/Classes) to help simplify setting up the shaders/compiling/linking.

So, everything compiles and runs without crashing. But, all I see is a window with nothing drawn or colored. I was hoping to at least have the window colored blue, as I'm not entirely sure that my vertex array was correctly setup.

Do you guys see what can be causing this issue?

Thanks,
binaryinsomnia

OneSadCookie

Luminary

Posts: 5,125
Joined: 2002.04

Post: #2

Nov 29, 2011 — 01:57 AM

There's so much code here to sift through, and so much done oddly (creating the whole GL view in code?) that it's hard to guess where the problem lies. Perhaps you could post the whole project?

You should also be aware that not all GPUs supported by Lion support OpenGL 3.2. What are you running this on?

binaryinsomnia

Nibbie

Posts: 4
Joined: 2011.11

Post: #3

Nov 29, 2011 — 08:00 AM

Hey OneSadCookie,
Thanks for the reply!

I'm trying to setup the GL View programmatically instead of going through InterfaceBuilder. My GL View is taking up the whole window frame, so didn't think I need to work with IB. Of course, perhaps my assumption is incorrect.

I was looking at this, https://github.com/beelsebob/Cocoa-GL-Tutorial, to help me get started.

Here's my project: http://www.2shared.com/file/XEUDnkaJ/bin...omnia.html

I'm using the 2011 Mac Mini with the AMD discrete GPU.

Thanks,
binaryinsomnia

OneSadCookie

Luminary

Posts: 5,125
Joined: 2002.04

Post: #4

Nov 29, 2011 — 10:54 AM

Fixed it for you:
http://cl.ly/0O0k2J3d1J361k322O27

1) you can't draw until the view is visible, which doesn't happen until after applicationDidFinishLaunching
2) you were unbinding the VAO but never rebinding the VAO you put data in.

Your code is set up extremely oddly

binaryinsomnia

Nibbie

Posts: 4
Joined: 2011.11

Post: #5

Nov 29, 2011 — 06:41 PM

Sweet! Thank you!

I just checked the changes you'd made. Hmmm... I see you used a block to send the draw message to my view controller. While I've not yet learned about blocks, it seems to me that that is kind of a hack to cover for my extremely odd code.

Speaking of extremely odd code, what makes it odd? How would you go about writing this simple app in the "right way?" I need all the pointers I can get from experienced Cocoa/OpenGL devs as I can get!

In regards to your numerated list...
1) Ah, ok. I need to read up on the lifecycle of a Cocoa app.
2) I have a vague idea what you're talking about there. I'll look over the code to see if I can spot where I'm unbinding and not rebinding the VAO.

Thanks for your time, OneSadCookie!

binaryinsomnia

OneSadCookie

Luminary

Posts: 5,125
Joined: 2002.04

Post: #6

Nov 29, 2011 — 06:54 PM

Code:

diff -cr binaryinsomnia-cookies/ binaryinsomnia/ | open -f

Yes, both changes were hacks. I imagined you'd take the concept and make it work in a nicer way

You can see what I consider the "normal" way of doing things in https://github.com/OneSadCookie/ either ZeroHour or ObjCGameBase (each slightly different with slightly different flaws).

binaryinsomnia

Nibbie

Posts: 4
Joined: 2011.11

Post: #7

Nov 29, 2011 — 07:04 PM

Heh! I fully intend to write this in a more proper form.

Alright, I'll study those examples.

Thanks!

Possibly Related Threads...

Thread:		Author	Replies:	Views:	Last Post
	showing off new space game	gooncorp	1	1,872	Nov 8, 2012 02:35 PM Last Post: PythonBlue
	Cocoa controls on top of NSOpenGLView	wadesworld	5	5,063	Apr 6, 2009 01:38 AM Last Post: arekkusu
	Antialiasing and NSOpenGLView attributes	Jar445	2	5,606	Jan 20, 2009 10:42 AM Last Post: maximile
	Double-Buffering with NSOpenGLView	DesertPenguin	3	4,791	Aug 1, 2006 07:17 AM Last Post: DesertPenguin
	Seams showing on my cubemaps	TomorrowPlusX	4	3,346	Dec 14, 2005 12:56 PM Last Post: TomorrowPlusX