This is supposed to

Member

Posts: 131
Joined: 2010.08

Post: #1

Aug 8, 2010 — 07:31 AM

I have a problem with an application but can not find a way to attach the project to this message. Could attachments be added to this forum? It would be nicer than putting the code in the message body.

Code:

#import <Cocoa/Cocoa.h>

@interface OpenGLView : NSOpenGLView

{

    NSTimer * m_timer;

    NSRect m_rectView;

    bool m_keys[256];

    GLfloat ballX;

}

//

//

- (void) keyDown:(NSEvent *)theEvent;

//

//

- (void) keyUp:(NSEvent *)theEvent;

//

//

- (void) keyAction:(const char)inKey isPressed:(const bool)inValue;

//

//

- (BOOL) acceptsFirstResponder;

//

//

- (BOOL) becomeFirstResponder;

//

//

- (BOOL) resignFirstResponder;

//

//

- (id) initWithFrame:(NSRect)frameRect;

//

//

- (void) setupAnimationTimerWithInterval:(const float)inInterval;

//

//

- (void) timerUpdate;

//

//

- (void) resizeGL;

//

//

- (void) prepareOpenGL;

//

//

- (void) drawRect:(NSRect)rect;

//

//

-(void) ball;

//

//

- (void) moveBall;

@end

Code:

#import "OpenGLView.h"

#define BALL_SPEED            1.0f

@implementation OpenGLView

//

//

- (id) initWithFrame:(NSRect)frameRect

{

    NSOpenGLPixelFormatAttribute attributes [] =

    {

        NSOpenGLPFAWindow,

        NSOpenGLPFADoubleBuffer,

        NSOpenGLPFAAccelerated,

        NSOpenGLPFAColorSize, 32,

        NSOpenGLPFADepthSize, 24,

        NSOpenGLPFAStencilSize, 8,

        (NSOpenGLPixelFormatAttribute)nil

    };

    for( unsigned int keyIdx = 0; keyIdx < 256; ++keyIdx )

    {

        m_keys[keyIdx] = false;

    }

    NSOpenGLPixelFormat * pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:attributes];

    self = [super initWithFrame:frameRect pixelFormat:pixelFormat];

    [pixelFormat release];

    return self;

}

//

//

- (void) setupAnimationTimerWithInterval:(const float)inInterval

{

    SEL the_selector = @selector( timerUpdate );

    NSMethodSignature * a_signature = [OpenGLView instanceMethodSignatureForSelector:the_selector];

    NSInvocation * an_invocation = [NSInvocation invocationWithMethodSignature:a_signature] ;

    [an_invocation setSelector:the_selector];

    [an_invocation setTarget:self];

    m_timer = [NSTimer scheduledTimerWithTimeInterval:inInterval

                                           invocation:an_invocation

                                              repeats:YES];

    [m_timer retain];

    [[NSRunLoop currentRunLoop] addTimer:m_timer forMode:NSDefaultRunLoopMode];

    [[NSRunLoop currentRunLoop] addTimer:m_timer forMode:NSEventTrackingRunLoopMode];

    [[NSRunLoop currentRunLoop] addTimer:m_timer forMode:NSModalPanelRunLoopMode];

    ballX = 0.0f;

}

//

//

- (void) timerUpdate

{

    [self moveBall];

    [self setNeedsDisplay:YES];

}

//

//

- (void) resizeGL

{

    NSRect rectView = [self bounds];

    if( m_rectView.size.width != rectView.size.width || m_rectView.size.height != rectView.size.height )

    {

        glViewport( 0, 0, rectView.size.width, rectView.size.height );

        m_rectView = rectView;

    }

}

//

//

- (void) prepareOpenGL

{

    glClearColor(0, 0, 0, 0);

    GLint vblSynch = 1;

    [[self openGLContext] setValues:&vblSynch forParameter:NSOpenGLCPSwapInterval];

    [self setupAnimationTimerWithInterval:(1.0f/60.0f)];

    [super prepareOpenGL];

}

//

//

- (void) drawRect:(NSRect)rect

{

    //

    //

    [self resizeGL];

    glClear(GL_COLOR_BUFFER_BIT);

    [self ball];

    [[self openGLContext] flushBuffer];

}

//

//

- (void) keyDown:(NSEvent *)theEvent

{

    NSString * characters = [theEvent characters];

    if( [characters length] )

    {

        [self keyAction:[characters characterAtIndex:0] isPressed:true ];

    }

}

//

//

- (void) keyUp:(NSEvent *)theEvent

{

    NSString * characters = [theEvent characters];

    if( [characters length] )

    {

        [self keyAction:[characters characterAtIndex:0] isPressed:false ];

    }

}

//

//

- (void) keyAction:(const char)inKey isPressed:(const bool)inValue

{

    m_keys[inKey] = inValue;

}

//

//

- (BOOL) acceptsFirstResponder

{

    return YES;

}

//

//

- (BOOL) becomeFirstResponder

{

    return YES;

}

//

//

- (BOOL) resignFirstResponder

{

    return YES;

}

- (void)moveBall

{ 

    if (m_keys['a'])

    {

        ballX -= BALL_SPEED;

    }

    if (m_keys['d'])

    {

        ballX += BALL_SPEED;

    }

}

- (void) ball {

    glColor3f(0.01f, 0.6f, 5.0f);

    GLint i;

    GLfloat cosine, sine, PI, sizeFraction;

    PI = 3.14159265;

    sizeFraction = 0.3;

    glTranslatef(ballX, 0.0f, 0.0f);

    glBegin(GL_POLYGON);

    for(i=0;i<100;i++){

        cosine=cos(i*2*PI/100.0);

        sine=sin(i*2*PI/100.0);

        glVertex2f(sizeFraction*cosine,sizeFraction*sine);

    }

}

@end

This is supposed to render a circle that moves left or right when a or d is pressed. However, nothing is rendered. The nib is correct, as there is an OpenGLView which has this view, "OpenGLView", as its identity. What should I do to correct this problem? You could also mention other ways to improve this application.

AnotherJake

Moderator

Posts: 3,554
Joined: 2003.06

Post: #2

Aug 8, 2010 — 09:33 AM

I dunno, but you're missing a glEnd() in your ball method. Should be:

Code:

- (void) ball {

    glColor3f(0.01f, 0.6f, 5.0f);

    GLint i;

    GLfloat cosine, sine, PI, sizeFraction;

    PI = 3.14159265;

    sizeFraction = 0.3;

    glTranslatef(ballX, 0.0f, 0.0f);

    glBegin(GL_POLYGON);

    for(i=0;i<100;i++){

        cosine=cos(i*2*PI/100.0);

        sine=sin(i*2*PI/100.0);

        glVertex2f(sizeFraction*cosine,sizeFraction*sine);

    }

    glEnd();

}

Miglu

Member

Posts: 131
Joined: 2010.08

Post: #3

Aug 8, 2010 — 10:18 AM

Thanks. Adding glEnd() caused the background to be rendered and adding {} inside the glBeginglEnd caused the circle to be rendered.
Could you guys also answer my question in http://www.idevgames.com/forums/thread-7930.html